VOODOO8

Following in the traditions of its predecessors, my RX-8 has suffered premature engine failure due to lost compression. Car is dealer maintatined, oil changes at better than factory recommended intervals, no modifications. Engine started to fade in the 45K-48K miles range. Having been an RX-7 owner, I had my suspicions. Dealer, however, said there was no issue.

Condition remained and now at 58K the compression has dropped to the point (dealer nows confirms) that I am encountering starting problems. I had hoped that the redesign of the Renesis would eliminate this issue, unfortunately my hopes now appear to have been in vain.

Initial discussions with dealer and area Mazda area rep did not fare well regarding warranty coverage, looks like I'll have a battle on my hands.

Anyone else share on similar issues?

Brice-RX8

Do you have a manual or auto? Also, can you post your build date, it is located on the sticker on the inside of your drivers door.

Go48

I hope you have some documentation on your earlier trip to the dealer showing your concerns at that time. Good luck.

Nemesis8

iTrader: (3)

I hate these threads. What are your compression numbers?

swoope

iTrader: (5)

funny how people only find this forum after they blow an engine or have a major problem!!!!!

hmmm i wonder why that is. i know i was here 6 months before i got my car. i just spent a hour on a hybrid site trying to find 0w20 oil.

go figure.

beers

rogue2

This stuff scares the crap out of me. Would some people with over 50k on their 8s please check in to this thread and tell me they are having no problems!

VOODOO8

Answers to questions from Brice:
1> Manual Transmission
2> Build Date June 2003

Answer to question from Go48:
Rotor#1 - Chamber 1 = 98.6, Chamber 2 = 99.035, Chamber 3 = 94.54
Rotor#2 - Chamber 1 = 102.66, Chamber 2 = 97.295, Chamber 3 = 101.79

General Note:
To anyone reading this thread, strongly suggest you get your motor compression tested, even if you have to pay for it, so you will have a baseline of comparison for the future. I wanted to do this when I first took delivery on my ride back in 09/03 but never got around to it - placed too much faith in the good press on the Renesis design.

Brice-RX8

What could possibly cause this? Carbon buildup? It doesn't sound like he has any other kind of trouble, just doesn't make sense that he would loose compression for no possible reason.

expo1

5/2003 build date 51,500 stills runs great

swoope

iTrader: (5)

my guess is a bad metering oil pump that did not get caught. i know mine didnt get repalced till 30k miles and it does cause me some concen.

my build date was 10/03

beers

VOODOO8

In my RX-7 days, there was a 'mystery' around premature engine failures too. Never heard a good reason, although the closest was minor deviations to primary machining specs during production would cause excessive wear and premature failure. With the movement of the ports in the Renesis design, some tech writers I read prior to buying my RX-8 noted that this change should improve engine life and reduce the occurences of premature wear/failure. I bought in to the logic of those statements.

I understand dealers who change out engines must immediately return the ENTIRE engine INTACT to Mazda to get credit on it (note: this is just 2nd hand info on my part). Hence the dealers are not allowed to do any diagnostic disaasembly and hence no validation of the causes for the 'mystery' failures.

MadDog

are these the 'before' or 'after' readings?

Mazmart

iTrader: (12)

Compression readings are based upon cranking rpms as a factor in the equation. Without these we don't truly know what we are looking at. If you can get these it would be really helpful to everyone.

VOODOO8

After (dealer diagnostics results).

VOODOO8

MAZMART:
I was not in the repair bay when the compression testing was done by the dealer, but I assume these were static numbers taken when cranking the engine over as it was not in running condition when the car was towed in and the dealer did change out the plugs (it was due, had 40K on the plugs and saw 2 samples afterward that the dealer showed me that were worn & needed replacing).

MadDog

He means the cranking RPM. There is a chart in the service manual that shows what the compression should be as a function of cranking RPM. The faster the starter turns the engine, the higher the compression reading should be.

VOODOO8

MadDog:
Sorry, but I don't have that info specifically. Best is that I assume they were cranking it at whatever the standard RPMs are that a starter is capable of generating on a cold engine start in a heated service bay with the car's battery in decent working order, a compression tester hook to one chamber/rotor combination, and the plugs out in all other chambers (complete guess on my part).

zoom44

the numbers arent that bad are they? where's the chart-somebody post here. besides it seems to me we usually see rear rotor compression loss not front-odd i know.

Mazmart

iTrader: (12)

Some dealers are sharp and some are clueless. Hopefully they realise the neeed for rpms in this test. The tech line folks probably asked them for this before authorizing a motor. See if they would be kind enough to provide you with these numbers. By the way, there was someone about a year ago who had 80,000 miles on theirs; travelling salesman or something.
Paul.

VOODOO8

To ZOOM's Note:
If someone can post the info on testing compression relative to cranking RPMs, etc. from the service manual on this thread I will use that info to try and get an explanation from the dealership on how they established the numbers that I provided earlier and put them up here. This would also give me a point of reference to use in deciding just how bad my results are relative to factory specs and how to proceed in seeking relief from Mazda for this problem.

Thanks!

MadDog

Here you go.

Brice-RX8

From what all I have read on this forum the average cranking speed is between 200 and 250rpms, so if you are seeing numbers lower than 100, either your car was cranking very slowly or you really do have bad compression in that rotor housing.

VOODOO8

MadDog - thanks for the chart!

I checked with the tech at my originating dealer that tested out the compression numbers provided earlier in this thread. He was cranking at 250-270 RPMs which should yield numbers in the 130 range based on the chart. Numbers I got on my rotor pairs were obviously below this by a wide margin across all chambers and hence his decree of a DOA status on my motor.

I am now in negotiation with Regional Mazda Rep and my dealer about coverage for the replacement. By my records I am able to document that my first claim regarding power loss occurred between 47K & 52K on the factory motor (which the dealer did not choose to investigate - remedy was to drop some injector cleaner in the tank, their part code on same being BG208 44K). I am being offered a 50/50 deal to replace with a reman motor and a 12/12 warranty on the reman unit. Rather than a long and drawn out fight over whether I should get full warranty coverage on the failure I am leaning toward paying the 50/50 but with inclusion of an extended 36K warranty from either Mazda or a reputable 3rd party with a policy that is not loaded with exceptions and escape clauses. A 12K based waranty does nothing for me given the possibility that the reman unit may prematurely expire under the same scenario as the factory motor did.

Does this arrangement disagree in any major way with what others have worked out with Mazda for engine replacements? Does anyone have experience, good or bad, with a 3rd party firm offering extended warranties on rotary engines?

zoom44

i think the 50/50 with 12k (not 12months) is pretty decent

Go48

Your engine was dying at 44K miles so Mazda is responsible, under their warranty, to replace it. If you're willing to shell out at least $1,500 for your part of the replacement, go for it. Personally, I would hold their feet to the fire until they came through with an engine replacement at their cost. THE ENGINE DIED WHILE IT WAS UNDER A FULL WARRANTY.