Aarontucker22

Hi, I'm new to this but hope someone can help me ASAP as I've been without my 8 for over 2 weeks.

It's been running sweet no problems at all and then started misfiring, took it straight to my mechanic who has since changed all plugs, leads and the coil and it is still misfiring when he gets it to start as it only seems to start first thing in the morning. The code is coming up as misfire cylinder 2. The next step he said is to check the head gasket as the water was low and if not then a replacement engine may be needed!
Not what I need especially over Christmas.

If anyone has had this problem or can help I will be very grateful!

Cheers, Tucker

RIWWP

iTrader: (2)

The RX-8 doesn't have a head gasket. The equivalent is a coolant seal, but no, this most likely isn't your problem.

Lots of causes for misfires though, this is a very good thread that walks you through the possibilities: https://www.rx8club.com/series-i-tec...t-here-222280/

Aarontucker22

Nice one! Thanks a lot

Fendamonky

This is the main reason why many rotary owners refuse to take their cars to any mechanic who doesn't have specific experience with rotary engines... and many owners become their own mechanics over years of ownership...

I don't have an 8 (yet) but I've had my FD (RX-7) since 2006, you'll get a LOT of misdiagnosis from people that don't understand rotaries..

It's a good thing you asked here before shelling out for a new motor (when the problem could have been something as simple as an unplugged vac line).

RIWWP

iTrader: (2)

We believe this is a contributing factor to why many of the early engine replacements happened. Coil failure misdiagnosed as engine failure since the dealer techs didn't know that they could fail, much less fail so early.

RIWWP

iTrader: (2)

I remember several instances where owners were given engine replacements, and going through several remans before it left the dealer, before the dealer figured out that the coils were bad.

Mazda is quite a bit more strict now than they were, and the service manual doesn't always have a compression test as a precursor to "If symptoms still exist, replace the engine". More dealers today know about coil failure, but not even all. Back then dealers didn't acknowledge the possibility on a much grander scale.

Sure, there were plenty of other failure methods, but coil failure was a cause for incorrect replacements in addition to those correct causes.

Fendamonky

Out of curiosity, how much experience do you have working on earlier generation rotaries? Obviously each generation of the motor has its own personality changes (4 port, 6 port, sequential "rats nest", side exhaust, etc., etc.) but at the end of the day the basic principles remain the same, its the ancillaries that change.

I should think that an intelligent person, who understands rotaries, should be flexible enough to figure out those mild generational differences and get them sorted with a little motivation.

Bridgeporting a motor doesn't mean that NONE of the same diagnostic/mechanical/tuning principles apply, neither does Peri Porting. How does a side exhaust port make it dramatically different?

Carbon8

iTrader: (4)

One would think in theory, but in practicality it rarely works out that way.

Fendamonky

True. Common sense is, unfortunately, NOT very common

Fendamonky

I've def gotta agree with you here. The whole attention to detail (or lack thereof) is absolutely critical!! I have, unfortunately, paid top dollar for rebuild(s) by big name shops only to have my engines die in under 5k miles (two engines may have lasted 5,000 miles between them both) because the guy stacking them up overlooked virtually all the little details. When we pulled the second engine apart, in my garage, we discovered that the "clearance" between the side seals and corner seals had what seemed like literally a centimeter of gap between the two seals (as opposed to the .002"-.005" recommended by Mazda, there were at least a few mm's in there!!). The shop owner tried to play that off as normal and acceptable

My faith in a lot of the "shops" in the rotary community has definitely been tested


I asked some of my buddies that have been running 8's for a while, I heard that you DEF know your **** and are one of a small handful of people here that you can trust (without doubt) to be speaking the truth when you're talking on technical data and practical applications

Yeah, I've been looking around a bit more and come to learn a bit more regarding how the side exhaust ports do change the behavior (and failure points) a bit.

I actually lost an engine due (in large part) to the fact that I paid a "professional" to install my dual oil coolers. The guy decided that he knew more than the company that made the kit and tossed a mount in the trash... Fast forward, the thermostat that would have gone on the mount vibrated itself loose from the AN connection, dumping a full pan of oil on the highway.. If I had done that install myself it *probably* wouldn't have happened.... (Guess it's now a good excuse to upgrade to an R-8 e-shaft and stat gears, lol).



In closing... I can come off a bit abrasive at times, please don't take that as my being intentionally offensive though. I respect your experience and the knowledge you've gained over the years

Aarontucker22

Ok the mechanic is adamant that I need a new motor after going through all other possibilities as it still shows up misfire cylinder 2 and will only start when cold. Now I have a number of options, buy a used engine, fit it and then sell while it's running sweet (although I've only had my 8 for 12 months it feels too premature to get rid already) there are also companies that do rebuilds and offer a guarantee which would mean I could drive it for a little longer and would make it more appealing to a buyer when I come to sell it later this year. I could sell it as it is in bits or for repair . Or would it be worth or is it possible to fit a 'normal' engine in it's place I.e. Type r or nissan motor?
I could do with some guidance as I can't really afford big mechanic bills and like I say am new to the rotary engine. I would love to just be able to drive it for a little while longer and sell in my own time :/ sad stressful times

RIWWP

iTrader: (2)

Swapping to an older RX-7 engine is around 3 times the cost of a quality rebuild of that engine.
Swapping to any other engine, no matter the packaging, configuration, availability, etc... is around 5 times the cost of a quality rebuild, and climbs higher fast.

The absolute cheapest option is just buying a used engine.

Beyond that, I can't really give solid cost information for UK rebuilds/engines, I just don't know the market and vendors.

Aarontucker22

Ye it is looking that way, I may also try a letter to mazda because I think something needs to be done or some form of compensation offered in situations. If they can see a problem in the us and extend the warranty etc then there IS obviously a problem. A common issue with another car would cause for a recall. I may not get anywhere but not losing anything by trying and maybe a gesture of goodwill could be made . Thanks anyway