Rebuild warranty issue
04-29-2017, 02:55 PM
#76
What am I doing here?
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I've just got so much Omar fatigue right now. Honestly, the visible shipping damage is minimal. Probably only a few dollars. It's the other **** that he did in his shop that **** me off.
05-01-2017, 10:37 AM
#77
Oil from the spark plug holes? It tipped to the side of the oil filter, so maybe the oil was draining out of the MOP system into the chambers. Or...he put oil in there to temporarily raise compression numbers on a cold test. Or...its leaking right past the oil control rings...which would be just awesome for you.
*sigh*
EDIT:
What's that warranty tag on the rear rotor housing? I've not seen that before.
*sigh*
EDIT:
What's that warranty tag on the rear rotor housing? I've not seen that before.
Last edited by MikeTyson8MyKids; 05-01-2017 at 10:46 AM.
05-03-2017, 11:38 AM
#79
kevin@rotaryresurrection
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I havent kept up with this thread from the beginning, but I saw a reddit post about it and thought I'd post some thoughts. A lot of these thoughts stem from the fact that I myself am also a builder who deals with customers, their budgets and expectations often, and I see some of the issues being brought to light here that I wish more owners/customers were educated about. The customer feels like the builder should have complete responsibility for every aspect of the build, yet there are some aspects that are not under the direct control of the builder. In reality the customer should share some of the responsibility for choosing what type of build and parts go into the engine based on some of the knowledge below, but unfortunately most buyers are not aware of any of these facts. They simply say "I bought a new engine and darnit, that thing should run better than it does. _____ builder sucks!" but in reality there is more to it than that.
First off...any rebuild from any shop in the $3000 or under price range WILL NOT have new rotor housings. That means it WILL have used rotor housings. Now as anyone who has ever tried to rebuild a renesis knows, used rotor housings are condition dependent and are also hard to find in any reusable condition, much less in great condition. All used housings will have some wear; some more than others, some in different areas, with different effects on compression and longevity. Think of used housings like used tires. There are a few defects that make a housing completely unusable, then there are new housings that are perfect, then there is a WIDE area in between of usable housings that are a judgement call as to whether or not they are suitable for a certain build, project, or owner. Finally, reusing rotor housings is ALWAYS a compromise in compression, longevity, and build quality, no matter who the builder is.
So with that said. If you bought a $2100 block then I don't see how you can sit there and say you are expecting compression values anywhere approaching what would be in the dealer book for a new engine. Any educated builder or enthusiast will tell you that's simply not going to happen with a used housing build. And for $2100, how nice do you think the used housings in that build are going to be? Assuming you can get the builder to supply you with an accurate list of what new seals etc. go into the build, anyone can do simple math and add up the prices of all those seals...usually around $800-1000 depending on the builder and what brand of parts they are buying...and also start adding up the used cost/value of components to build that block from such as rotors, housings, irons, etc. and then add at least 400 bucks for the builder's labor. IF you do all of that you can quickly get an idea of the condition of the used components being put into the build. No one is going to work for free and so you have to do the math and see where the money is going and where it's being saved. So in this case we have to figure out that the builder is building with used housings with a very low value, and for that to be the case consistently that means the builder is using worn housings that are near the bottom of their service life. Once you arrive at that conclusion, it would be foolhardy to expect such an engine build to last anywhere near as long as the original nor to perform anywhere near what the original did in terms of passing/failing compression tests.
Now the non-engine-builders among you out there are going to read that and say "oh well if you can't pass the dealer compression test with the used housings being put into that build then they should never be used to begin with. a builder should only build an engine he knows will pass the dealer tests and be like it was when it was new in 2003". Okay, fine, who wants to line up to build all-new-parts blocks for 6 grand or more? Because that is the only way that's going to happen for you. Oh, I bet now some of you are backing off of that statement.
Yes reusing rotor housings is always a compromise but it's necessary for budget reasons. Not many owners are going to spend more than $4k for a rebuild with new rotor housings, which is really what's necessary if you expect to get anywhere near the original engine's lifespan or compression values. The whole car is not worth more than 4 or 5 grand so who wants to put that much into just the engine? Not many owners. So you have to figure out how to cut costs while still getting a decent result. The bottom line is the lower the cost, the more parts with wear on them that you have to reuse, and the weaker the result in terms of compression and longevity.
For the builder, the real skill lies in figuring out how far you can approach the borderline of worn parts reused for budget vs compression quality and longevity going forward for the owner. Every builder will have their own mindset here based on their customer base and their own experiences. For me I tend to err a little bit more on the side of caution and only reuse middle of the road parts that will provide at least 25k miles of normal use going forward. However that still doesnt mean that every used housing engine I build would pass a dealer compression test. In fact I've had to explain this concept a few times to customers of mine who equated a $2500 rebuild with a "new engine" and then were surprised their engine didnt have new compression numbers. I don't care if felix wankel himself stacks your block, if you don't give him all new or perfectly resurfaced components to do it with, you're not going to see strong compression values that pass dealer tests.
In my experience most rebuilds utilizing used rotor housings, used irons, etc. and mostly new oem compression seals/springs, will see 90-105psi of compression with an accurate test after break in, with the variation depending on the specific condition of the rotor housing surfaces used in that particular build. In fact a couple years ago I had a customer bring me an all original, well maintained rx8 with 72k miles for rebuild. The housings looked nice with light wear and were in above average condition. The iron housings had very light wear well within spec. All new oem rotor compression seals and springs were used in the rebuild. I recently did a comp test on that engine after 10k miles of break in and driving. The engine shows about 96psi on the front and 91psi in the rear. It starts cold or hot on the first 2 rotations, idles perfectly, makes good power, and runs like it should with no issues. On a dealer test those compression numbers are failing, a "bad engine" in their view. Does that mean the engine is bad? Heck no. In reality a used rotor housing rebuild isn't ever going to get a whole lot better than that.
IF you want more, you have to use new rotor housings in the rebuild. Right off the bat, a pair of new rotor housings is over $1400 even at most builders' cost. And you still have to pay for all the other seals and parts needed for a build, and the builder's labor. I would expect most new rotor housing rebuilds that utilize reused iron housings with mild/normal wear, to produce in the 105-115psi compression range. This is considered a middle of the road, acceptable but not great passing compression value but still not what the specs say a new hiroshima-assembled rotary from 2003 would have made. Finally, an engine built from new rotor housings, new or resurfaced iron housings with zero wear, and all new rotor compression seals, I would expect to see 115-125psi of compression. I have done a couple such builds and that is what they produced when tested.
Now, let's broach the subject of aftermarket apex seals. The bottom line is that in my experience aftermarket seals have nowhere near the long term longevity or sealing compression of oem apex seals. So you might ask, why do people make them and use them? Well one obvious answer is budget, a lot of these seals are half the cost of oem.
The other answer has a bit more psychology involved. Let's say your rotary engine blows up and you say "oh the apex seals failed. I don't think the apex seals should ever wear out or fail, so there must be something wrong with the stock seal design. there should be a better apex seal! let's make one". So you and your machinist select a random metal to design your seal out of. You size a few to fit the rotors and build a couple of test engines, which you run on the street and/or on the track for a few months or maybe a year or two. You take the test engine(s) apart and if those seals didn't catastrophically fail, you say "well dang man, my seals look like they work good, I'm gonna start selling them to other people. Down with stock apex seals!". That's essentially what happens with all these aftermarket seals. They get minimal testing and R&D before being released to market for you to be the long-term tester. They were produced based on the fallacy that because oem apex seals wear out or fail after 100k miles of use, those oem seals must be of poor design and should be replaced with something better. Yet in reality, the aftermarket seals rarely reach HALF of the lifespan of the oem seals before those engines fail or have to come apart for some reason. This is because they were only designed and tested in the short term. Sometimes they were only designed and tested for the race track under very specific circumstances which don't work out well in the long term on a street engine that needs good hot starting, idle, low rpm throttle response, and cranking compression. Maybe they are built to hold up to 28psi of boost and 10,000rpm of abuse on the track, but in order to do that, their material hardness properties had to be changed and now the rotor housing sealing surface that it rides against will get worn out much sooner than if stock seals were riding against the housing surface. Bear in mind that the seal and the housing surface were both designed to wear together, and when you drastically change the material properties of one, you will also upset that balance and change the longevity of the other. Mazda put decades and millions of dollars of R&D into designing their apex seals for maximum compression and longevity in stock form. Do you really think a random shop with one or a handful of dudes working on the project for a few grand investment are going to be able to improve on that tech? It's possible but unlikely.
This is further compounded by the fact that the average owner sees "racing seals" and decides they are going to be better suited for his naturally aspirated street driven rotary, even though in reality those seals are likely to perform worse in his engine than stock ones would have because he isn't using his engine for the specific "racing" that the aftermarket seal was developed for.
So looking again at the big picture, aftermarket seals were used in this build as a budget lowering tool and so it is not surprising that they a) don't make oem compression and b) don't last as long as oem. Now, again, you might look at this and say "well if the builder knows that ____ aftermarket seal won't last 100k miles like stock, then they shouldn't be building with that seal at all". Okay, well that means they will have to raise the price. And by the time you do everything you should do to produce an engine capable of lasting about as long as the original and making about as good of compression values that would pass a dealer test, guess what? Now your build is priced so high that nobody will buy it. As a builder you have to strike a balance and compromise between quality and budget.
In this case it looks like this builder fell a little short of that line, and maybe should have done better both with the initial build/parts selection and/or the warranty evaluation. But that also doesnt mean that I will side completely with the buyer here either, because as you can see above there are many considerations that the buyer should take into account going into the rebuild and with their expectations vs budget, and that doesn't seem to have happened here either.
YOU CAN NOT EXPECT A 2 OR 3 THOUSAND DOLLAR ROTARY REBUILD TO BE ANYWHERE LIKE NEW.
First off...any rebuild from any shop in the $3000 or under price range WILL NOT have new rotor housings. That means it WILL have used rotor housings. Now as anyone who has ever tried to rebuild a renesis knows, used rotor housings are condition dependent and are also hard to find in any reusable condition, much less in great condition. All used housings will have some wear; some more than others, some in different areas, with different effects on compression and longevity. Think of used housings like used tires. There are a few defects that make a housing completely unusable, then there are new housings that are perfect, then there is a WIDE area in between of usable housings that are a judgement call as to whether or not they are suitable for a certain build, project, or owner. Finally, reusing rotor housings is ALWAYS a compromise in compression, longevity, and build quality, no matter who the builder is.
So with that said. If you bought a $2100 block then I don't see how you can sit there and say you are expecting compression values anywhere approaching what would be in the dealer book for a new engine. Any educated builder or enthusiast will tell you that's simply not going to happen with a used housing build. And for $2100, how nice do you think the used housings in that build are going to be? Assuming you can get the builder to supply you with an accurate list of what new seals etc. go into the build, anyone can do simple math and add up the prices of all those seals...usually around $800-1000 depending on the builder and what brand of parts they are buying...and also start adding up the used cost/value of components to build that block from such as rotors, housings, irons, etc. and then add at least 400 bucks for the builder's labor. IF you do all of that you can quickly get an idea of the condition of the used components being put into the build. No one is going to work for free and so you have to do the math and see where the money is going and where it's being saved. So in this case we have to figure out that the builder is building with used housings with a very low value, and for that to be the case consistently that means the builder is using worn housings that are near the bottom of their service life. Once you arrive at that conclusion, it would be foolhardy to expect such an engine build to last anywhere near as long as the original nor to perform anywhere near what the original did in terms of passing/failing compression tests.
Now the non-engine-builders among you out there are going to read that and say "oh well if you can't pass the dealer compression test with the used housings being put into that build then they should never be used to begin with. a builder should only build an engine he knows will pass the dealer tests and be like it was when it was new in 2003". Okay, fine, who wants to line up to build all-new-parts blocks for 6 grand or more? Because that is the only way that's going to happen for you. Oh, I bet now some of you are backing off of that statement.
Yes reusing rotor housings is always a compromise but it's necessary for budget reasons. Not many owners are going to spend more than $4k for a rebuild with new rotor housings, which is really what's necessary if you expect to get anywhere near the original engine's lifespan or compression values. The whole car is not worth more than 4 or 5 grand so who wants to put that much into just the engine? Not many owners. So you have to figure out how to cut costs while still getting a decent result. The bottom line is the lower the cost, the more parts with wear on them that you have to reuse, and the weaker the result in terms of compression and longevity.
For the builder, the real skill lies in figuring out how far you can approach the borderline of worn parts reused for budget vs compression quality and longevity going forward for the owner. Every builder will have their own mindset here based on their customer base and their own experiences. For me I tend to err a little bit more on the side of caution and only reuse middle of the road parts that will provide at least 25k miles of normal use going forward. However that still doesnt mean that every used housing engine I build would pass a dealer compression test. In fact I've had to explain this concept a few times to customers of mine who equated a $2500 rebuild with a "new engine" and then were surprised their engine didnt have new compression numbers. I don't care if felix wankel himself stacks your block, if you don't give him all new or perfectly resurfaced components to do it with, you're not going to see strong compression values that pass dealer tests.
In my experience most rebuilds utilizing used rotor housings, used irons, etc. and mostly new oem compression seals/springs, will see 90-105psi of compression with an accurate test after break in, with the variation depending on the specific condition of the rotor housing surfaces used in that particular build. In fact a couple years ago I had a customer bring me an all original, well maintained rx8 with 72k miles for rebuild. The housings looked nice with light wear and were in above average condition. The iron housings had very light wear well within spec. All new oem rotor compression seals and springs were used in the rebuild. I recently did a comp test on that engine after 10k miles of break in and driving. The engine shows about 96psi on the front and 91psi in the rear. It starts cold or hot on the first 2 rotations, idles perfectly, makes good power, and runs like it should with no issues. On a dealer test those compression numbers are failing, a "bad engine" in their view. Does that mean the engine is bad? Heck no. In reality a used rotor housing rebuild isn't ever going to get a whole lot better than that.
IF you want more, you have to use new rotor housings in the rebuild. Right off the bat, a pair of new rotor housings is over $1400 even at most builders' cost. And you still have to pay for all the other seals and parts needed for a build, and the builder's labor. I would expect most new rotor housing rebuilds that utilize reused iron housings with mild/normal wear, to produce in the 105-115psi compression range. This is considered a middle of the road, acceptable but not great passing compression value but still not what the specs say a new hiroshima-assembled rotary from 2003 would have made. Finally, an engine built from new rotor housings, new or resurfaced iron housings with zero wear, and all new rotor compression seals, I would expect to see 115-125psi of compression. I have done a couple such builds and that is what they produced when tested.
Now, let's broach the subject of aftermarket apex seals. The bottom line is that in my experience aftermarket seals have nowhere near the long term longevity or sealing compression of oem apex seals. So you might ask, why do people make them and use them? Well one obvious answer is budget, a lot of these seals are half the cost of oem.
The other answer has a bit more psychology involved. Let's say your rotary engine blows up and you say "oh the apex seals failed. I don't think the apex seals should ever wear out or fail, so there must be something wrong with the stock seal design. there should be a better apex seal! let's make one". So you and your machinist select a random metal to design your seal out of. You size a few to fit the rotors and build a couple of test engines, which you run on the street and/or on the track for a few months or maybe a year or two. You take the test engine(s) apart and if those seals didn't catastrophically fail, you say "well dang man, my seals look like they work good, I'm gonna start selling them to other people. Down with stock apex seals!". That's essentially what happens with all these aftermarket seals. They get minimal testing and R&D before being released to market for you to be the long-term tester. They were produced based on the fallacy that because oem apex seals wear out or fail after 100k miles of use, those oem seals must be of poor design and should be replaced with something better. Yet in reality, the aftermarket seals rarely reach HALF of the lifespan of the oem seals before those engines fail or have to come apart for some reason. This is because they were only designed and tested in the short term. Sometimes they were only designed and tested for the race track under very specific circumstances which don't work out well in the long term on a street engine that needs good hot starting, idle, low rpm throttle response, and cranking compression. Maybe they are built to hold up to 28psi of boost and 10,000rpm of abuse on the track, but in order to do that, their material hardness properties had to be changed and now the rotor housing sealing surface that it rides against will get worn out much sooner than if stock seals were riding against the housing surface. Bear in mind that the seal and the housing surface were both designed to wear together, and when you drastically change the material properties of one, you will also upset that balance and change the longevity of the other. Mazda put decades and millions of dollars of R&D into designing their apex seals for maximum compression and longevity in stock form. Do you really think a random shop with one or a handful of dudes working on the project for a few grand investment are going to be able to improve on that tech? It's possible but unlikely.
This is further compounded by the fact that the average owner sees "racing seals" and decides they are going to be better suited for his naturally aspirated street driven rotary, even though in reality those seals are likely to perform worse in his engine than stock ones would have because he isn't using his engine for the specific "racing" that the aftermarket seal was developed for.
So looking again at the big picture, aftermarket seals were used in this build as a budget lowering tool and so it is not surprising that they a) don't make oem compression and b) don't last as long as oem. Now, again, you might look at this and say "well if the builder knows that ____ aftermarket seal won't last 100k miles like stock, then they shouldn't be building with that seal at all". Okay, well that means they will have to raise the price. And by the time you do everything you should do to produce an engine capable of lasting about as long as the original and making about as good of compression values that would pass a dealer test, guess what? Now your build is priced so high that nobody will buy it. As a builder you have to strike a balance and compromise between quality and budget.
In this case it looks like this builder fell a little short of that line, and maybe should have done better both with the initial build/parts selection and/or the warranty evaluation. But that also doesnt mean that I will side completely with the buyer here either, because as you can see above there are many considerations that the buyer should take into account going into the rebuild and with their expectations vs budget, and that doesn't seem to have happened here either.
YOU CAN NOT EXPECT A 2 OR 3 THOUSAND DOLLAR ROTARY REBUILD TO BE ANYWHERE LIKE NEW.
The following 3 users liked this post by RotaryResurrection:
05-03-2017, 12:01 PM
#80
What am I doing here?
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Thanks for your thoughts on this. I appreciate the extra info you've provided. Really, the contents of your post should be sticky'd so that others don't get killed in the expectations management phase.
It sounds like my expectations were out of line with reality but none of this was made clear to me at the time of the original rebuild. I don't know what I would have chosen to do if he had told me that the housings were worn and that I could get by with them but it would be better to replace them. It was a weird time for my budget but I've been leaning more towards paying more to have the job done right the first time in the last few years.
If Omar had taken the time to explain this to me before I shipped the motor back to him, I'd have been unhappy but I'd have gotten over it and neither one of us would have had to go through this experience.
It sounds like my expectations were out of line with reality but none of this was made clear to me at the time of the original rebuild. I don't know what I would have chosen to do if he had told me that the housings were worn and that I could get by with them but it would be better to replace them. It was a weird time for my budget but I've been leaning more towards paying more to have the job done right the first time in the last few years.
If Omar had taken the time to explain this to me before I shipped the motor back to him, I'd have been unhappy but I'd have gotten over it and neither one of us would have had to go through this experience.
Last edited by NotAPreppie; 05-03-2017 at 12:04 PM.
05-08-2017, 04:34 PM
#83
I agree, it would be nice if this were a sticky. As RX8 owners, we will all eventually have to get an engine rebuilt so it would be nice to know this information when seeking out rebuilding costs. Thanks for the info!
05-12-2017, 09:43 AM
#84
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Well Put!
Kevin that was well put! A lot of customers do not know the price of engine parts and think for $2500 it should be like a new engine. A engine is only going to be good as it's weakest link.
05-21-2017, 06:29 PM
#85
What am I doing here?
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Engine is back in the car and runs about the same as before. Occasional warm hard starts. I haven't had a chance to compression test it again.
It smoked like craaaaazy for the first 50 miles but has settled down now.
It smoked like craaaaazy for the first 50 miles but has settled down now.
05-22-2017, 08:23 AM
#86
You gonna eat that?
iTrader: (1)
I havent kept up with this thread from the beginning, but I saw a reddit post about it and thought I'd post some thoughts. A lot of these thoughts stem from the fact that I myself am also a builder who deals with customers, their budgets and expectations often, and I see some of the issues being brought to light here that I wish more owners/customers were educated about. The customer feels like the builder should have complete responsibility for every aspect of the build, yet there are some aspects that are not under the direct control of the builder. In reality the customer should share some of the responsibility for choosing what type of build and parts go into the engine based on some of the knowledge below, but unfortunately most buyers are not aware of any of these facts. They simply say "I bought a new engine and darnit, that thing should run better than it does. _____ builder sucks!" but in reality there is more to it than that.
First off...any rebuild from any shop in the $3000 or under price range WILL NOT have new rotor housings. That means it WILL have used rotor housings. Now as anyone who has ever tried to rebuild a renesis knows, used rotor housings are condition dependent and are also hard to find in any reusable condition, much less in great condition. All used housings will have some wear; some more than others, some in different areas, with different effects on compression and longevity. Think of used housings like used tires. There are a few defects that make a housing completely unusable, then there are new housings that are perfect, then there is a WIDE area in between of usable housings that are a judgement call as to whether or not they are suitable for a certain build, project, or owner. Finally, reusing rotor housings is ALWAYS a compromise in compression, longevity, and build quality, no matter who the builder is.
So with that said. If you bought a $2100 block then I don't see how you can sit there and say you are expecting compression values anywhere approaching what would be in the dealer book for a new engine. Any educated builder or enthusiast will tell you that's simply not going to happen with a used housing build. And for $2100, how nice do you think the used housings in that build are going to be? Assuming you can get the builder to supply you with an accurate list of what new seals etc. go into the build, anyone can do simple math and add up the prices of all those seals...usually around $800-1000 depending on the builder and what brand of parts they are buying...and also start adding up the used cost/value of components to build that block from such as rotors, housings, irons, etc. and then add at least 400 bucks for the builder's labor. IF you do all of that you can quickly get an idea of the condition of the used components being put into the build. No one is going to work for free and so you have to do the math and see where the money is going and where it's being saved. So in this case we have to figure out that the builder is building with used housings with a very low value, and for that to be the case consistently that means the builder is using worn housings that are near the bottom of their service life. Once you arrive at that conclusion, it would be foolhardy to expect such an engine build to last anywhere near as long as the original nor to perform anywhere near what the original did in terms of passing/failing compression tests.
Now the non-engine-builders among you out there are going to read that and say "oh well if you can't pass the dealer compression test with the used housings being put into that build then they should never be used to begin with. a builder should only build an engine he knows will pass the dealer tests and be like it was when it was new in 2003". Okay, fine, who wants to line up to build all-new-parts blocks for 6 grand or more? Because that is the only way that's going to happen for you. Oh, I bet now some of you are backing off of that statement.
Yes reusing rotor housings is always a compromise but it's necessary for budget reasons. Not many owners are going to spend more than $4k for a rebuild with new rotor housings, which is really what's necessary if you expect to get anywhere near the original engine's lifespan or compression values. The whole car is not worth more than 4 or 5 grand so who wants to put that much into just the engine? Not many owners. So you have to figure out how to cut costs while still getting a decent result. The bottom line is the lower the cost, the more parts with wear on them that you have to reuse, and the weaker the result in terms of compression and longevity.
For the builder, the real skill lies in figuring out how far you can approach the borderline of worn parts reused for budget vs compression quality and longevity going forward for the owner. Every builder will have their own mindset here based on their customer base and their own experiences. For me I tend to err a little bit more on the side of caution and only reuse middle of the road parts that will provide at least 25k miles of normal use going forward. However that still doesnt mean that every used housing engine I build would pass a dealer compression test. In fact I've had to explain this concept a few times to customers of mine who equated a $2500 rebuild with a "new engine" and then were surprised their engine didnt have new compression numbers. I don't care if felix wankel himself stacks your block, if you don't give him all new or perfectly resurfaced components to do it with, you're not going to see strong compression values that pass dealer tests.
In my experience most rebuilds utilizing used rotor housings, used irons, etc. and mostly new oem compression seals/springs, will see 90-105psi of compression with an accurate test after break in, with the variation depending on the specific condition of the rotor housing surfaces used in that particular build. In fact a couple years ago I had a customer bring me an all original, well maintained rx8 with 72k miles for rebuild. The housings looked nice with light wear and were in above average condition. The iron housings had very light wear well within spec. All new oem rotor compression seals and springs were used in the rebuild. I recently did a comp test on that engine after 10k miles of break in and driving. The engine shows about 96psi on the front and 91psi in the rear. It starts cold or hot on the first 2 rotations, idles perfectly, makes good power, and runs like it should with no issues. On a dealer test those compression numbers are failing, a "bad engine" in their view. Does that mean the engine is bad? Heck no. In reality a used rotor housing rebuild isn't ever going to get a whole lot better than that.
IF you want more, you have to use new rotor housings in the rebuild. Right off the bat, a pair of new rotor housings is over $1400 even at most builders' cost. And you still have to pay for all the other seals and parts needed for a build, and the builder's labor. I would expect most new rotor housing rebuilds that utilize reused iron housings with mild/normal wear, to produce in the 105-115psi compression range. This is considered a middle of the road, acceptable but not great passing compression value but still not what the specs say a new hiroshima-assembled rotary from 2003 would have made. Finally, an engine built from new rotor housings, new or resurfaced iron housings with zero wear, and all new rotor compression seals, I would expect to see 115-125psi of compression. I have done a couple such builds and that is what they produced when tested.
Now, let's broach the subject of aftermarket apex seals. The bottom line is that in my experience aftermarket seals have nowhere near the long term longevity or sealing compression of oem apex seals. So you might ask, why do people make them and use them? Well one obvious answer is budget, a lot of these seals are half the cost of oem.
The other answer has a bit more psychology involved. Let's say your rotary engine blows up and you say "oh the apex seals failed. I don't think the apex seals should ever wear out or fail, so there must be something wrong with the stock seal design. there should be a better apex seal! let's make one". So you and your machinist select a random metal to design your seal out of. You size a few to fit the rotors and build a couple of test engines, which you run on the street and/or on the track for a few months or maybe a year or two. You take the test engine(s) apart and if those seals didn't catastrophically fail, you say "well dang man, my seals look like they work good, I'm gonna start selling them to other people. Down with stock apex seals!". That's essentially what happens with all these aftermarket seals. They get minimal testing and R&D before being released to market for you to be the long-term tester. They were produced based on the fallacy that because oem apex seals wear out or fail after 100k miles of use, those oem seals must be of poor design and should be replaced with something better. Yet in reality, the aftermarket seals rarely reach HALF of the lifespan of the oem seals before those engines fail or have to come apart for some reason. This is because they were only designed and tested in the short term. Sometimes they were only designed and tested for the race track under very specific circumstances which don't work out well in the long term on a street engine that needs good hot starting, idle, low rpm throttle response, and cranking compression. Maybe they are built to hold up to 28psi of boost and 10,000rpm of abuse on the track, but in order to do that, their material hardness properties had to be changed and now the rotor housing sealing surface that it rides against will get worn out much sooner than if stock seals were riding against the housing surface. Bear in mind that the seal and the housing surface were both designed to wear together, and when you drastically change the material properties of one, you will also upset that balance and change the longevity of the other. Mazda put decades and millions of dollars of R&D into designing their apex seals for maximum compression and longevity in stock form. Do you really think a random shop with one or a handful of dudes working on the project for a few grand investment are going to be able to improve on that tech? It's possible but unlikely.
This is further compounded by the fact that the average owner sees "racing seals" and decides they are going to be better suited for his naturally aspirated street driven rotary, even though in reality those seals are likely to perform worse in his engine than stock ones would have because he isn't using his engine for the specific "racing" that the aftermarket seal was developed for.
So looking again at the big picture, aftermarket seals were used in this build as a budget lowering tool and so it is not surprising that they a) don't make oem compression and b) don't last as long as oem. Now, again, you might look at this and say "well if the builder knows that ____ aftermarket seal won't last 100k miles like stock, then they shouldn't be building with that seal at all". Okay, well that means they will have to raise the price. And by the time you do everything you should do to produce an engine capable of lasting about as long as the original and making about as good of compression values that would pass a dealer test, guess what? Now your build is priced so high that nobody will buy it. As a builder you have to strike a balance and compromise between quality and budget.
In this case it looks like this builder fell a little short of that line, and maybe should have done better both with the initial build/parts selection and/or the warranty evaluation. But that also doesnt mean that I will side completely with the buyer here either, because as you can see above there are many considerations that the buyer should take into account going into the rebuild and with their expectations vs budget, and that doesn't seem to have happened here either.
YOU CAN NOT EXPECT A 2 OR 3 THOUSAND DOLLAR ROTARY REBUILD TO BE ANYWHERE LIKE NEW.
First off...any rebuild from any shop in the $3000 or under price range WILL NOT have new rotor housings. That means it WILL have used rotor housings. Now as anyone who has ever tried to rebuild a renesis knows, used rotor housings are condition dependent and are also hard to find in any reusable condition, much less in great condition. All used housings will have some wear; some more than others, some in different areas, with different effects on compression and longevity. Think of used housings like used tires. There are a few defects that make a housing completely unusable, then there are new housings that are perfect, then there is a WIDE area in between of usable housings that are a judgement call as to whether or not they are suitable for a certain build, project, or owner. Finally, reusing rotor housings is ALWAYS a compromise in compression, longevity, and build quality, no matter who the builder is.
So with that said. If you bought a $2100 block then I don't see how you can sit there and say you are expecting compression values anywhere approaching what would be in the dealer book for a new engine. Any educated builder or enthusiast will tell you that's simply not going to happen with a used housing build. And for $2100, how nice do you think the used housings in that build are going to be? Assuming you can get the builder to supply you with an accurate list of what new seals etc. go into the build, anyone can do simple math and add up the prices of all those seals...usually around $800-1000 depending on the builder and what brand of parts they are buying...and also start adding up the used cost/value of components to build that block from such as rotors, housings, irons, etc. and then add at least 400 bucks for the builder's labor. IF you do all of that you can quickly get an idea of the condition of the used components being put into the build. No one is going to work for free and so you have to do the math and see where the money is going and where it's being saved. So in this case we have to figure out that the builder is building with used housings with a very low value, and for that to be the case consistently that means the builder is using worn housings that are near the bottom of their service life. Once you arrive at that conclusion, it would be foolhardy to expect such an engine build to last anywhere near as long as the original nor to perform anywhere near what the original did in terms of passing/failing compression tests.
Now the non-engine-builders among you out there are going to read that and say "oh well if you can't pass the dealer compression test with the used housings being put into that build then they should never be used to begin with. a builder should only build an engine he knows will pass the dealer tests and be like it was when it was new in 2003". Okay, fine, who wants to line up to build all-new-parts blocks for 6 grand or more? Because that is the only way that's going to happen for you. Oh, I bet now some of you are backing off of that statement.
Yes reusing rotor housings is always a compromise but it's necessary for budget reasons. Not many owners are going to spend more than $4k for a rebuild with new rotor housings, which is really what's necessary if you expect to get anywhere near the original engine's lifespan or compression values. The whole car is not worth more than 4 or 5 grand so who wants to put that much into just the engine? Not many owners. So you have to figure out how to cut costs while still getting a decent result. The bottom line is the lower the cost, the more parts with wear on them that you have to reuse, and the weaker the result in terms of compression and longevity.
For the builder, the real skill lies in figuring out how far you can approach the borderline of worn parts reused for budget vs compression quality and longevity going forward for the owner. Every builder will have their own mindset here based on their customer base and their own experiences. For me I tend to err a little bit more on the side of caution and only reuse middle of the road parts that will provide at least 25k miles of normal use going forward. However that still doesnt mean that every used housing engine I build would pass a dealer compression test. In fact I've had to explain this concept a few times to customers of mine who equated a $2500 rebuild with a "new engine" and then were surprised their engine didnt have new compression numbers. I don't care if felix wankel himself stacks your block, if you don't give him all new or perfectly resurfaced components to do it with, you're not going to see strong compression values that pass dealer tests.
In my experience most rebuilds utilizing used rotor housings, used irons, etc. and mostly new oem compression seals/springs, will see 90-105psi of compression with an accurate test after break in, with the variation depending on the specific condition of the rotor housing surfaces used in that particular build. In fact a couple years ago I had a customer bring me an all original, well maintained rx8 with 72k miles for rebuild. The housings looked nice with light wear and were in above average condition. The iron housings had very light wear well within spec. All new oem rotor compression seals and springs were used in the rebuild. I recently did a comp test on that engine after 10k miles of break in and driving. The engine shows about 96psi on the front and 91psi in the rear. It starts cold or hot on the first 2 rotations, idles perfectly, makes good power, and runs like it should with no issues. On a dealer test those compression numbers are failing, a "bad engine" in their view. Does that mean the engine is bad? Heck no. In reality a used rotor housing rebuild isn't ever going to get a whole lot better than that.
IF you want more, you have to use new rotor housings in the rebuild. Right off the bat, a pair of new rotor housings is over $1400 even at most builders' cost. And you still have to pay for all the other seals and parts needed for a build, and the builder's labor. I would expect most new rotor housing rebuilds that utilize reused iron housings with mild/normal wear, to produce in the 105-115psi compression range. This is considered a middle of the road, acceptable but not great passing compression value but still not what the specs say a new hiroshima-assembled rotary from 2003 would have made. Finally, an engine built from new rotor housings, new or resurfaced iron housings with zero wear, and all new rotor compression seals, I would expect to see 115-125psi of compression. I have done a couple such builds and that is what they produced when tested.
Now, let's broach the subject of aftermarket apex seals. The bottom line is that in my experience aftermarket seals have nowhere near the long term longevity or sealing compression of oem apex seals. So you might ask, why do people make them and use them? Well one obvious answer is budget, a lot of these seals are half the cost of oem.
The other answer has a bit more psychology involved. Let's say your rotary engine blows up and you say "oh the apex seals failed. I don't think the apex seals should ever wear out or fail, so there must be something wrong with the stock seal design. there should be a better apex seal! let's make one". So you and your machinist select a random metal to design your seal out of. You size a few to fit the rotors and build a couple of test engines, which you run on the street and/or on the track for a few months or maybe a year or two. You take the test engine(s) apart and if those seals didn't catastrophically fail, you say "well dang man, my seals look like they work good, I'm gonna start selling them to other people. Down with stock apex seals!". That's essentially what happens with all these aftermarket seals. They get minimal testing and R&D before being released to market for you to be the long-term tester. They were produced based on the fallacy that because oem apex seals wear out or fail after 100k miles of use, those oem seals must be of poor design and should be replaced with something better. Yet in reality, the aftermarket seals rarely reach HALF of the lifespan of the oem seals before those engines fail or have to come apart for some reason. This is because they were only designed and tested in the short term. Sometimes they were only designed and tested for the race track under very specific circumstances which don't work out well in the long term on a street engine that needs good hot starting, idle, low rpm throttle response, and cranking compression. Maybe they are built to hold up to 28psi of boost and 10,000rpm of abuse on the track, but in order to do that, their material hardness properties had to be changed and now the rotor housing sealing surface that it rides against will get worn out much sooner than if stock seals were riding against the housing surface. Bear in mind that the seal and the housing surface were both designed to wear together, and when you drastically change the material properties of one, you will also upset that balance and change the longevity of the other. Mazda put decades and millions of dollars of R&D into designing their apex seals for maximum compression and longevity in stock form. Do you really think a random shop with one or a handful of dudes working on the project for a few grand investment are going to be able to improve on that tech? It's possible but unlikely.
This is further compounded by the fact that the average owner sees "racing seals" and decides they are going to be better suited for his naturally aspirated street driven rotary, even though in reality those seals are likely to perform worse in his engine than stock ones would have because he isn't using his engine for the specific "racing" that the aftermarket seal was developed for.
So looking again at the big picture, aftermarket seals were used in this build as a budget lowering tool and so it is not surprising that they a) don't make oem compression and b) don't last as long as oem. Now, again, you might look at this and say "well if the builder knows that ____ aftermarket seal won't last 100k miles like stock, then they shouldn't be building with that seal at all". Okay, well that means they will have to raise the price. And by the time you do everything you should do to produce an engine capable of lasting about as long as the original and making about as good of compression values that would pass a dealer test, guess what? Now your build is priced so high that nobody will buy it. As a builder you have to strike a balance and compromise between quality and budget.
In this case it looks like this builder fell a little short of that line, and maybe should have done better both with the initial build/parts selection and/or the warranty evaluation. But that also doesnt mean that I will side completely with the buyer here either, because as you can see above there are many considerations that the buyer should take into account going into the rebuild and with their expectations vs budget, and that doesn't seem to have happened here either.
YOU CAN NOT EXPECT A 2 OR 3 THOUSAND DOLLAR ROTARY REBUILD TO BE ANYWHERE LIKE NEW.
I've linked this thread to the rebuilder's thread.
If you have any more input you'd like to share there, please do.
https://www.rx8club.com/rx-8-discuss...ilders-265177/
01-19-2018, 07:18 AM
#87
What am I doing here?
Thread Starter
Join Date: Mar 2006
Location: 2017 Miata RF Launch Edition
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Update:
Car sputtered and coughed at cold start this morning and was rougher than usual for the first minute. Also got a nice big cloud of blue oil smoke. Got another big cloud of blue oil smoke when starting after filling up the tank on my way into work.
Car still runs. Occasional hard warm starts even with a fresh battery and 2kW starter.
Car sputtered and coughed at cold start this morning and was rougher than usual for the first minute. Also got a nice big cloud of blue oil smoke. Got another big cloud of blue oil smoke when starting after filling up the tank on my way into work.
Car still runs. Occasional hard warm starts even with a fresh battery and 2kW starter.
01-19-2018, 09:58 PM
#88
Update:
Car sputtered and coughed at cold start this morning and was rougher than usual for the first minute. Also got a nice big cloud of blue oil smoke. Got another big cloud of blue oil smoke when starting after filling up the tank on my way into work.
Car still runs. Occasional hard warm starts even with a fresh battery and 2kW starter.
Car sputtered and coughed at cold start this morning and was rougher than usual for the first minute. Also got a nice big cloud of blue oil smoke. Got another big cloud of blue oil smoke when starting after filling up the tank on my way into work.
Car still runs. Occasional hard warm starts even with a fresh battery and 2kW starter.