compression test - failed, need advice
 

Luckily I'm under warranty with 7 months to spare so the 8 gets an extra life. My vehicle is a '05 6sp w/ 84k miles, I've done some research but I wanted to ask if anyone has any input or sees something I missed as far as stuff to have done while getting the engine replaced (so I can take advantage of the free labor) :yumyum:

new spark plugs
new intake filter
clean/service injectors
decarb intake valves
replace clutch
replace motor mounts
racing beat oil lines
replace AC/alt belts
racing beat silicon coolant hoses
replace starter

a new water pump, thermostat, oil pan, flywheel are included with engine core and they also cover the oil/coolant. My other fluids and coils/wires are fresh, I'm going to have a fuel pressure test done as well for fuel pump functionality. Thanks in advance for the input I should have everything completed by the end of next week.

You will overpay having those done at the dealer, most are dirt easy at home, and you will beat the parts cost. The clutch replacement is labor saved, though I cringe at paying their 300% markup on the parts.

Good list though.

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I plan to provide most the parts and don't mind paying for labor (to a limit)..

I just want to make sure, as much as possible, to get everything covered while the engine is out and avoid a huge labor charge 6 months from now on something I could have replaced for the cost of parts while the engine swap occurs.

Ah, ok. Yup, you should be good. The clutch is the main big one that is labor saved.

I have no value to add to this thread, but just wanted to thank you for your post. I'm will be putting in a rebuilt engine into my 8 this summer and was trying to gather info on what to upgrade while the engine is out. This is the list I was looking for.

Now I can narrow my search to how to clean/rebuild the injectors and intake manifold( since I have extras, might as well do it ahead of time.)

Thanks

Edit:

Maybe I do have something to add. I also ordered a sohn adaptor for the omp.

Good move on the SOHN

never thought too much about doing the sohn but maybe now that I'm starting with a new core I should try it out? Probably looking at something simple, like this kit
Anything else worthwhile to replace or upgrade while the dealership labor is cheap?

BHR coils. Have the catalytic converter checked out

what kind of inspection should I have them do for the cat? I think I had mentioned them taking a look in the past and the service person commented there is no need unless the CEL had been thrown.

Bad compression means the engine is not burning fuel air mix all the way or correctly letting unburnt fuel pass to the CAT damaging it. To do a shade tree inspection I'd drop it shine a really good flash light through it and see what you can on the other side. Not a lot of light or no light = bad CAT. Can clearly see the mesh or lots of light coming through = good CAT

The cat pipe isn't straight, so there won't be any light coming through anyway :)

Not 100% true this is why I said a really good flash light like a LED rifle light or something with some power if it is in good shap you can see light I have done this to mine.

I guess I'll tell the dealer I'm concerned due to the low compression of damage to the cat and see if they have any slightly more scientific tests they can perform. There's got to be something a shop can do to test functionality?

The worst cat failure can't be detected without a visual inspection.

after pressing the dealer further stating:

"Is there any way the tech can visually inspect it before we test the new engine? I'm worried with the low compression, damage may have occurred to the cat and now it may be partially or fully clogged. I'm just worried a clogged cat could cause damage to the new core and would feel better knowing its functioning properly. I'm obviously willing to cover the extra labor/diagnostic for the inspection"

the dealer replied:

"Unfortunately, the only way to test and monitor the catalytic converter is with the vehicle running at operating temperature and using the before and after oxygen sensor output data to determine converter health and efficiency."

so granted I am not sure that the cat is actually damaged, how long would it take for any damage to occur? Would I know without a CEL? Regardless I'm thinking I'll probably replace it soon, maybe with a midpipe to prevent any chance of future damage from occurring.

Damage to the CAT can be instantaneous and I have seen people post about fried CATs without a CEL. Damage to the engine that's a crap shoot can hapen right away or take time. What kills the engin is two things heat built up by hot gasses not getting out and back pressure from again gasses not getting out. Back pressure can cause apex and other seals to let go. Heat can melt springs and seals so it's really a matter of what kills it first or a combination of the two.

The dealer can't really deviate from the Mazda-approved procedures, so I'm not sure you'll get far with that. If they haven't been through a few rx8 cat failures before, or you particular service manager hasn't, they won't get it.

The oxygen sensors will tell you that the exhaust gasses are being scrubbed of carbohydrates, they won't tell you if the flow rate is too low and back pressure too high, which is the mode of failure we're looking to avoid. Maybe that will get through to them?

Maybe show them this thread?

I would think these are implied, but I'll say them just to be safe.

Throwout bearing, input shaft bearing, transmission front seal, Plug wires and coils.

I would suggest BHR coils but mazda probably won't install them for you.

It's not a bad time to replace trans and diff oil if you can afford it.

Bring this to the dealer:


It should be clean and unbroken mesh, and you shouldn't be able to see the O2 sensor tip.
https://www.rx8club.com/attachments/...2154-large-jpg

So if it's cracked: (Won't be picked up by O2 sensor monitoring/testing) (Not an RX-8 cat)
http://www.2carpros.com/images/artic...t_material.jpg

Clogged: (Won't be picked up by O2 sensor monitoring/testing, extremely dangerous to the engine and can cause car fires)
https://www.rx8club.com/attachments/...r-imag0260-jpg

Chunked: (Should be picked up by O2 monitoring, P0420, but it may take a while, the 2nd element may also be clogged, so may be dangerous)
https://www.rx8club.com/attachments/...113_1333_1-jpg

or missing: (Should be picked up by O2 monitoring, is not dangerous to the engine)
https://www.rx8club.com/attachments/...-p0302-12-jpeg

...it's a problem.

I followed up with the dealer asking them to PLEASE inspect the cat visually before testing the engine. I attached the pictures for reference, we'll see what they say, hopefully the cat is fine regardless in the meantime.

I'm on the opposite side of the warranty issue. I have almost 105k when I took my 06 Automatic to the dealer today for issues of hard cranking when warm. They ran a compression test and gave readings for 1 rotor between 520-540, in the 400s for rotor 2. Recommended replacing the engine, something I was not prepared to hear quoting almost $6k including replacing the leaking water pump...

Is anyone near Winston-Salem, NC that could offer other reputable shops within a couple hours drive?

So the dealer is working on the replacement of the engine core and gave me the water pump and thermostat of the core since I'm going foward with the remedy versions. Do the remanufactured cores keep the original bolt on components? I know they get new seals and gaskets but it appears the water pump/thermostat are not "new" I'm guessing they just check for functionality and keep existing parts from the reman?

Remans don't come with a new thermostat, but they do come with a new water pump. They also come with a new flywheel, though everything else should be transfered over.

so if the water pump the water pump they gave me has rusty blades should I question it or is that normal even for a new pump? The flywheel they returned to me appears to be new as I had them replace with the mazdaspeed version but I guess I could inspect closer.

I would suspect that a rusty water pump came off your old engine, not the new one (though there shouldn't be rust at all, since coolant has rust inhibitors, and I'm fairly sure the water pump is made of aluminum)

If they gave you a new flywheel, than that certainly suggests that it came from the new reman.