Im new to Rx8s/Rotarys so any insight is appreciated. I am looking at buying this car as a project to tinker on, and learn more about rotaries and the plus to this particular one, is it runs. It was supposedly rebuilt 4-5 months ago and has since had about 2k miles put on. It was built by a reputable person/shop that knows what they are doing. Pending everything I've been told has been correct, which I do believe the seller is being honest...

Based on numbers, it is technically failing in compression, but Ive also been told the numbers are acceptable on a rebuild that had the housings reused. Im just trying to decide whether or not I should risk this engine failing as soon as I get the car.. If i was going to do that Id buy one that's closer to me and cheaper, etc..

It has a slight delay on hot starts (1-2 seconds) and he said it's really only after "spirited" driving.

2 weeks ago compression test done by Mazda resulted in: @250 RPM 6.3 6.3 5.9 and 5.9 5.9 6.3

I am hearing conflicting information on the old housings/new housing and compression readings when it comes to rebuilds...

 

To put it short, failing is failing. Compression doesn't go up, it goes down.

The whole point of a rebuild is to fix an issue right? It's possible that it wasn't rebuilt well, or that they reused parts that shouldn't have been to save money.
The shop may be reputable however, they will still only do what the customer is willing to pay for; so if he couldn't afford to replace something that in all reality should have been, they still would have done it. It's also possible that his "spirited driving" is leaving every stop light at 9k on every trip, not warming the car properly, not keeping up with maintenance like he should.

If you are going to buy this car the situation will only get worse until the motor is properly fixed or replaced. Just remember that you are buying someone else's problem or what they have decided on giving up on. You'll want to be prepared for that.

It's awesome that you got the compression test done BEFORE you bought it, so you know what you are in for.

 

Those numbers are failing, but that motor will likely run for a little while longer with proper care and an upgraded starter.

PN, When a new motor is being broken in, compression is actually not "optimal". As the seals break in and create their wear path so to speak, compression improves. After you reach "optimal" is when it starts to drop again. So Technically, it does go up lol. Sorry im really bored..

Overall PN is correct, your purchasing what someone else is giving up on. If you buy it, i would make sure that you have the cash available for a new motor sooner rather than later though, and one from a proper shop. You could always contact Kevin at RR. He's one of the best when it comes to rebuilds.

yup, my rants done for now.

Travis

 

The interesting thing is this engine was (allegedly) built by Kevin at RR. He said he has the signed letter and all pictures of the build. Is it possible it just hasn't been broken in yet and sealed properly? I'd imagine by 2k it was. Also the seller claimed he actually bought the entire car from them. It was not his prior to the rebuild I tried getting in touch with them to confirm if they sold the car, as maybe more history could be provided.. I might have to try to contact them again. This car had already had the engine replaced in 2008 according is carfax.

 

Curious If the compression ever increased? I also looked at a car with a motor from Kevin and tested around 6.5 on all faces of both rotors. 4k on rebuild with new housings.

 

Holy blast from the past thread.

Yes, I bought the car and re-tested compression about 1k miles later and it had improved once all the parts broke in to each other. The previous owner had done the comp test pretty soon after receiving the car I think & his description of "hot start" delay really wasn't accurate either. Can't remember what the numbers were, but if you search for my build thread It's all in there. At 4k miles your engine is already "broken in" though. I drove it for 5 years after buying it (albeit, limited mileage as it was a weekend car, etc) and and sold it 2 years ago. It's still going strong last I talked to the current owner, and sounds like its been driven a lot more in recent years than I ever did. I did a 3rd compression test before selling it and it had begun "going down" but was not symptomatic.

A rebuild will never match compression of an engine with all new parts.. but they still can render some good life and I would 100% buy a rebuild from Kevin in the future if I ever got back into rotarys. Once getting into that car in person, the engine was the one thing I really wasn't worried about (yet). The motor was strong.

 

^^look who’s feeling kind of bullish today



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