BigCajun

iTrader: (1)

You know, it does bother me when I try to help someone and it turns out I was wrong.
I do try to help and I have had a lot of experience with bad catalytic converters as I worked as a mechanic for many years in 4 different shops in between jobs as a machinist between 1978 and '97.


I can be mistaken from time to time, and will readily admit if I'm wrong when someone corrects me.
I went back to your post when you said the "mesh' was cracked, which I thought was an odd description.
The strata, or as some call it, brick, or honeycomb, is wrapped with a type of mesh blanket between it and the shell.
I assumed that was what you were talking about.
I looked closer at your image and saw what appears to be a crack in the strata.
Is that what you were talking about?
If so, then yes, your cat was definitely bad.

titaneum_grey

I have a pretty powerful lamp and no light came through but I also noticed that the rear mesh was offset from the front mesh. I don't know if that is why or not. All the mesh that came out was unclogged, light shines through it easily. You can look at the pics I posted of the mesh after I took it out.
I didn't have a problem with your advice, and I still don't. It made sense. I said I'm guessing that it wasn't the problem because light shines through the mesh.
PS, This is my first time working with cats. I'm assuming my old cat was good because it doesn't seem to have been clogged. I'm going on that from what I have gotten from this forum. Can a cat be bad and not clogged, to the point that light still shines through it?
The magna-flow cat has only one area of mesh in the cat (before the O2 sensor, none behind it) un-like the OEM cat that had both.
The car runs better in that there is less breaking up at high rpms, in high gears. But, like when the O2 sensor was out of the OEM cat, when the car stalls after being on the parkway it doesn't want to start again.
I had continued to investigate the matter I would have noticed that before I cut up the old cat and put it back in. My problem was that I bought into the idea that it was figured out and got lazy. I cut corners and that's on me.
What I was at odds with was the response you posted. I said my peace and now I'm past that as well.
So as little confidence that I have for my dealers techs for not finding the problem the last time I sent it in to them, my lack of tools for testing compression and fuel pressure will force me back to them next week to have those specific tests done. Hopefully It will give me some idea of which way I go from here.

Regards.

titaneum_grey

I'm still hoping for an answer to my question; could a cat be bad and not clogged.

Dealer got back to me tonight and said they diagnosed my problem as a intake valve problem and want to take apart the intake to identify which or now many of the three valves is hanging up. Then he said they would do a compression test.
I don't get it!! I sent it in to have the compression and the fuel presser tested and they haven't done either. What point is determining which valve is hanging up if my seals are gone and I don't have compression in the first place? Aren't the intake ports on the other side from the compression point?
Well after a little back and forth with him for a bit he acquiesced and will have the compression tested first. Then, if it's good, they will go into the intake to see about the valves.

BigCajun

iTrader: (1)

You keep saying mesh.
You mean the inside ceramic part, correct?
The crack means it's bad. If it wasn't clogged, it was going to break up eventually, so you didn't destroy a good cat.
There is a mesh that wraps around the ceramic brick or honeycomb.
Did you get that out?

Gravey

iTrader: (3)

No one is changing their tune, the people who think it's your cat still do.

Also, no one told you to smash out the core of your stock cat, they told you to try and shine a light through it. That is all...

200.mph

iTrader: (9)

lol you smashed up a possibly good cat? the better way to check it is with a flexible fiber optic camera. ive seen cats look fine from the front and the back was clogged shut.

Gravey

iTrader: (3)

Oh... and you might not be totally out of the water with that magnaflow cat either...

BigCajun

iTrader: (1)

If you go back and look at the first pic, you can see a big crack in it.

titaneum_grey

I thought the honeycomb was made of some kind of expensive metal but yes, that is what I have been referring to when I wrote 'mesh'.
OK then. A cat can be bad and not clogged.
Thank you Big.


Regards.

BigCajun

iTrader: (1)

The strata has expensive metals in it, platinum being one.
It has a ceramic quality to it, that's why they sometimes melt.
Once they crack, they will eventually break up into smaller pieces and clog the pipe, and muffler.

titaneum_grey

While that sounds reasonable I have to wonder if it is not also feasible that some of the hard landings I use to make when I first got my 8 couldn't have put that crack there as well.
Not that it really matters at this point. I had already replaced the cat before I decided to see what it looked like inside. And the new one was not returnable.
Anyways, that was yesterday and I think I've learned a lot. Now I have a the dealer telling me it is one of my intake valves. I guess that would account for the throaty sound above 6 grand and the breaking up. And of course, I'm still keeping my fingers crossed for a positive compression check. so it looks like there was an overall bigger issue than the cat going on that might help the next guy experiencing these symptoms.

I will post more as I get it.

Thanks Big


Regards.
Angelo

titaneum_grey

Update;
The dealer called and said my compression is low and my seals are most likely bad.
Now I have to wonder about a few things;
1) When I asked them to do the compression test I was told that one was most likely done the last time they had the car, which was three months ago. I asked if they were sure and I was told no, but it would have been procedure.
2) The work they did 3 months ago was when I brought it to them for an oil leak that wound up being the oiler lines. They explained to me that if I left them leaking I might starve my rotors of lubrication and ruin the engine.
So, if I had good compression before they did the work and now 3 month later I lost compression and my engine is ruined, did the work they did have anything to do with it or could it have been the cat, which I'm assuming was bad but not clogged, and the high RMP intake valve not opening? Both of which were probably going on since before they did the work.

Any rotary mechanics out there wanna weigh in on this?

Regards.
Angelo

Loki

iTrader: (1)

A compression test is not procedure for an oil leak. So the answer to your question is in whether they did a test or not. They should have a record if they did one, if for no other reason than their own time billing.

It's a bit hard to piece together the sequence of events from this thread, to be honest. Can you clarify what complaints you had each time you visited them, and what their actions were?

Did they provide actual compression numbers?

The intake valve won't affect compression, a clogged cat definitely would, and quickly.

titaneum_grey

The first time I went in I had a oil leak and the car was breaking up at high rpms, in only high gears. and a new change had appeared that made me bring it in, it was also not accelerating when I hit the gas while in cruise control.

I actually met the tech who did the oiler lines on my car and was working on the new diagnostic, while retrieving something from the car on Friday. I didn't get around to asking him if they did the compression test when they did the oiler lines, However, he did enlighten me as to why he had not done the compression test yet and had not diagnosed the valve problem the last time it was in.
He stated he just checked the cruise control system and did the oiler lines. The service rep told me they fixed the oilers lines and did a thorough diagnostic on the system, finding nothing wrong.
Apparently the service rep didn't put down what I asked him to check on the car and only writes down the symptoms I report, in the space available. Intern, the tech is only allowed to do specific diagnostics according to those symptoms.

So I need give more ambiguous symptoms from now on.

It was the rep who told me they would have done the compression test when replacing the oiler lines, when I asked for the compression test last week. He must have thought he talked me out of it, until a railed him when he called and told me that he was doing the valves.
He didn't give me number on the compression test and just said the compression was low. But he was also still trying to have me do the valves. I guess we have different priorities.

Anyways I need a new motor and am hunting today.
Thanks for the weigh in and the help.

PS, what should the numbers be on a good engine? I' will probably wind up getting used or rebuilt.

Regards.

titaneum_grey

Just saw a motor compression test on a video for JDM motors using "what looked like" a regular compression gage.
03 08 JDM Mazda RX 8 renesis 13B Engine 1 3L Rotary Motor 6 Speed Trans 6 Port | eBay

Can you tell me why is this acceptable or is not?

Loki

iTrader: (1)

It's almost meaningless. I mean you tell me, from that video what the actual compression is. Can you?

This tells you that the compression is not 0 (yay). What it doesn't tell you is what each face's compression is or what the rpm is. 100psi at 200rpm could pass, 100psi at 300rpm is no bueno. So. That's sort of important. Unlike piston engines, rotary compression changes with engine speed up to at least 800rpm. Also I'm not sure if there is oil in the motor they're cranking over. That's also sort of important.

The engine could be fine. Or it could be borderline. Up to you if you want to risk it.

At the price they're asking, you're not far from a Rotary Resurrection rebuild price. But at least with RR you're getting a known good motor.

titaneum_grey

Thank you.
You make a lot of sense.
Now I understand more how my car can run good on the parkway but not be able to say running at idle.
I am thinking of going with the rebuilt but that is also just a core and I have to, then, somehow get them my core. I also need intake valves. And a spare tranny wouldn't be a bad idea either. But that's another issues.
The idea behind getting this engine is almost a straight install. I am no where's near deciding which way to go. I'm also looking into having something built out of mine. I have to give the dealership an answer on Tuesday, so there's not a lot of time to figure this our either.

Thanks again for the sense.
I appreciate the time and help.

Regards.

PSS.
I contacted the engine seller and asked for compression numbers. The response was 140 -150 psi. I wrote them back asking 'at what RPMs' that would be.

Understanding that compression should increase as RPMs do shouldn't I be able to use/get a baseline or starting compression number for, say, idle or 75-100 thousand RPMs for people using an old style compression tester? Is there a reason why that idea won't work?

Gravey

iTrader: (3)

Yes, there is a reason that won't work... in order to get a compression score at idle speeds you would have to have the engine running... In order to test the engine for compression you CANNOT have the engine running... you have to remove a spark plug and screw the tester sensor into the plug socket.

titaneum_grey

hmm.
So then how is a regular compression gage no good for checking a rotary engine?

Loki

iTrader: (1)

Check the video, the needle never reaches 140-150 (actually a brand new Renesis doesn't have that at starter speed, soo... they're living in a fantasy world).

The problem is 140-150 psi is not a result. It's like if you asked me if it's raining, and I said "yes it is, somewhere".

You have 3 faces per rotor and you need to know the compression of each face. Normally all 3 faces have the same compression, so you should get 3 pressure spikes for every rotor revolution. But what if one face has a failed seal? Then you would get 2 spikes and 1 smaller spike (with a difference of say 10 psi), but they go by so fast that the regular meter isn't a good tool for observing that. Or suppose an apex seal has failed and 2 faces are leaking into each other. Then you get 2 smaller spikes and 1 big spike, again with maybe a 10psi difference. You might not even notice.

On a piston engine, none of that is a problem because you're only plugged into 1 combustion chamber at a time, so the needled always comes to the same spot on top. On a rotary, you're plugged into 3 combustion chambers at once.

The proper rotary tools are electronic, they can keep track of which face is which and give an individual result for each face, which is really what you're looking for in assessing health. A few points of compression on a single face make the difference between a happy engine and rebuild time. That tells you where it's raining.

Extrapolating what the compression would be at idle isn't useful, since the spec is given at 250rpm. If a face doesn't meet the spec at 250, it won't meet it at idle.

titaneum_grey

wow, thanks.
Three faces, one for each; intake, compression and exhaust. I hope they all have to have the same compression or this could really get confusing.
The numbers (140-150) I gave you were not from the eBay seller but from SW Engines and Engine and Transmission World. They seem to both be selling the same replacement engine. This engine doesn't come with the tranny but if I read it right it is complete, so it should have the valves I need as well. not something I will leave to chance if I do go that way.
If they get back to me with the rpms I asked about in my last e-mail and they say 250 will that work, or do they need to give a compression number for each face?

Thanks again for everything.
Hope you are having a good 4th.

Regards.
Angelo

Williard

iTrader: (18)

Grey,

It will look like this
THESE NUMBERS ARE PSI
Rotor 1: 105, 105, 107 RPM 250
Rotor 2: 108, 107, 108 RPM 250




Or something along those lines



Travis

This will help

Loki

iTrader: (1)

Actually each face performs intake, compression and exhaust in 1 rotation. So 3 faces are 3 combustion chambers, getting fired one after another. The rotor is a spinning triangle, right. When each side of the triangle is up against the spark plugs, it ignites. 120 degrees later it exhausts. 120 degrees later it intakes. 120 degrees later it's back at the spark plug.

titaneum_grey

so three complete revolutions to get all three sides of the rotor to have combusted against the housing.

Loki

iTrader: (1)

Negative, 1 revolution to combust all 3 faces. There are a bunch of animations of how a rotary works if you google image search, that might clarify.

You sound like you're interested in the tech, so maybe this is interesting :

https://www.google.ca/url?sa=t&sourc...J2tC9ZDPmTqHFw

It's a military research paper on the use of rotaries in drones. Explains more than is healthy