Hey all, just purchased a 2005 rx8 with 82k miles and a trashed engine. Previous owner disassembled block and found that apex seals let go, doing FOD damage. Car is clean, and for a couple hundred bucks, I can't complain. I'm having a bit of back and forth about what to do for then engine, though. Been doing a lot of research on this site and others, and have talked with the rotarydoctor about options. Obviously, a reman would be ideal, but I need all new components and the price would be $3k just for the short block.
I also have no reference how things go, not a big deal, just annoying to have to get new gaskets and clutch and so forth.
I see eBay has jdm engines, and have talked/read about how it's a risky chance, but everything is there and would save a little money on the short end. My goals for the car is to do some canyon carving and track day or 2 and maybe some autocross, not going to be a DD, so miles won't accumulate quickly.
Who or what do you guys recommend for the engine, and what are some things you would do for reliability while the engine is out? I was thinking Sohn adaptor, maybe doing careless midpipe, but I'm a little leery about that. Plugs wires and coils, of course.
If you guys were to buy a jdm engine, what would you guys ask for? I asked for compression test with video, valve core out, and want close to 100 psi. Maybe one with aftermarket ignition components, since someone obviously maintained it? Appreciate any input.

 

If you think 3k is expensive for a remain I've got some bad news for you....

I would never buy a "jdm" engine

 

^ This. Buying a used Renesis is one of the worst decisions one could make while owning this car.

 

So lets say compression comes back even on all rotors at around 100 psi, how good of shape is that engine in? I mean, what else is there to worry about? I'm not really concerned with super longevity, 25k or so is fine, I'll rebuild later. I just think with all the extra stuff, and a good core, I would come out the same with a rebuild later on. 2k now, 2k later for a used with rebuild, or 3-4k with a reman, and no extra components.

 

Good core is the rub there. When you rebuild these, often big oarts need to be replaced. It's not just seals and gaskets.

 

with 100psi it's boarder line failing and every engine is different as to how they end their life. some will run until the fail to start again and others will pop with a loud bang




why spend the money twice?

 

Compression tests have to be done when the engine is hot. If it's done cold, you will get numbers that are higher than they should be.

Compression tests are very sensitive to RPM. You have to know what RPM the engine is turning at during the test or you literally know nothing.

If you buy a any Renesis (JDM or otherwise) that shows 100 psi cold using that method, you will get a bad engine.

If you can get them to do a hot compression test then it will depend on what RPM the engine is spinning at to say whether 100 psi is passing or failing.

JDM Renesis sellers on eBay very, very, VERY rarely offer any kind of warranty and when they do, it's just that the engine will start. Nothing to do with whether the coolant seals are intact, that it makes anywhere near good compression or leaks oil.

After freight, you're going to pay over $2000 for a JDM engine with no idea about whether it will last more than 10 minutes. Even if it does last longer than that, many Rennies failed at mileages lower than those quoted for these motors. Mine made it about 50k miles. Bare minimum, a rebuild will be $1600 but I can almost guarantee it won't end up with passing compression scores for that cost. So, it will need to be rebuilt again sooner.

Or, you can pay $2925 (+$125 freight) for a Mazda reman that comes with a 12 month warranty. You will have to ship your old engine back (just get all the parts back together, won't matter if the reassembly is perfect) or pay a $1000 core fee.

 

But you only get the 12 month warranty if Mazda installs it.

 

$2925 *sold*

 

Yah, yah, blah, blah...

The point is more that it's a declaration of quality. eBay JDM engine importers won't even give you that much.

The caveat about having Mazda do the install is eliminate yahoos screwing things up in their garage and then making warranty claims.

 

Yeah they are smart to have that stipulation.