Help! I may need to replace my engine...
11-25-2016, 08:31 PM
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Help! I may need to replace my engine...
About 2 months ago I bought a used RX-8 2004 GT. When I bought the car I was told that it had a newly rebuilt engine, thought I did not get paper work for that or a compression test before I bought it. (Please do not lecture me on the need to do this, I have learned my lesson I assure you). Today I took the car to my local Mazda dealer, and had it compression tested, and the results were less than acceptable. I have 6.5 as the lowest on both rotors, no numbers above 6.9 on either. I have done a whole lot of research on the car and I know that I will likely need to replace the engine soon. My question is does anybody know of a good rotary rebuild place near silicon valley in California, or is there any rebuild kit that people recommend? I don't have a whole lot of money on hand as I am a college student, though I am working and can likely get away with not having my car for a few weeks. Thank you so much everyone, I am looking for someone to help me get through this!
11-25-2016, 11:13 PM
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The reason I got the test done was I was at the dealership anyway, I was getting an oil change from a coupon I found online, and there were two recalls out on the vehicle. I have been aware of issues with the engines, so I wanted to get a baseline test done on the car to see how healthy the engine really is. I have had no issues with the engine in the car, no hot start problems, though I have been getting rather low fuel economy, about 14.9 mpg. So I take it I don't need to be mourning the loss of my beloved first car just yet? Thanks guys.
11-27-2016, 08:32 AM
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An S2 starter and good coils and plugs will stave off eventual death, but with compression failing it's gonna die. I'm positive there has to be a shop somewhere in the Valley that can help you out, or at least local cali guys that know what they are doing.
11-27-2016, 01:06 PM
#7
I wouldn't be so quick to say the engine is about to die just cause of compression.
I recommend getting a new starter from a later gen rx8, like the 2009 Manual transmission one.
I would start the car and let it come up to temp. connect some rubber vacuum lines to the service ports on the side of the lower intake manifold, T them together, these items can be obtained from autozone for cheap, get a bottle of water or a cup, perhaps 64oz or 32oz or so, have someone hold the revs at 3-4K and slowly suck water into the engine from the vacuum line, 1/4" line or so. Go through a good 64oz or so of water through the engine. This will decarb the engine. you may need to do this two times. take your time sipping the water through the engine, you don't want to just ingest all of it in a straight shot, run some through, let it idle and cool down, run some more, etc.
this will allow the seals to unstick themselves over time if the engine is carboned up, which most are.
another source of low compression is from a small coolant leak into the combustion chamber, if you want a quick fix, run some Kseal through the coolant and it will block the leak permenantly. not a bad fix for something you think is already bad.
Root cause of carbon build up is rich air fuel ratio, poor ignition which doesn't burn all the fuel, and can also clog up cat convertors. I suggest ensuring that all of the maintenance is up to date. I also suggest running a JASO FD 2 cycle oil in the gas tank, .5oz per gallon with a working oil metering pump and this will also prevent a lot of carbon build up, it will also help the seals in the engine seal better and reduce wear. I run Motul 710 2 cycle for just an example. I suggest running a lower flash point oil if you run the car on the street, higher ones for racing all out, as you get more soot with oils with super high flash points while cruising all the time.
I recommend getting a new starter from a later gen rx8, like the 2009 Manual transmission one.
I would start the car and let it come up to temp. connect some rubber vacuum lines to the service ports on the side of the lower intake manifold, T them together, these items can be obtained from autozone for cheap, get a bottle of water or a cup, perhaps 64oz or 32oz or so, have someone hold the revs at 3-4K and slowly suck water into the engine from the vacuum line, 1/4" line or so. Go through a good 64oz or so of water through the engine. This will decarb the engine. you may need to do this two times. take your time sipping the water through the engine, you don't want to just ingest all of it in a straight shot, run some through, let it idle and cool down, run some more, etc.
this will allow the seals to unstick themselves over time if the engine is carboned up, which most are.
another source of low compression is from a small coolant leak into the combustion chamber, if you want a quick fix, run some Kseal through the coolant and it will block the leak permenantly. not a bad fix for something you think is already bad.
Root cause of carbon build up is rich air fuel ratio, poor ignition which doesn't burn all the fuel, and can also clog up cat convertors. I suggest ensuring that all of the maintenance is up to date. I also suggest running a JASO FD 2 cycle oil in the gas tank, .5oz per gallon with a working oil metering pump and this will also prevent a lot of carbon build up, it will also help the seals in the engine seal better and reduce wear. I run Motul 710 2 cycle for just an example. I suggest running a lower flash point oil if you run the car on the street, higher ones for racing all out, as you get more soot with oils with super high flash points while cruising all the time.
