ddsneversummer

Hey all,

First off, thank you for the wealth of information on this forum. It has helped me sort out a lot of questions I had and fixes I needed.

I have an 04, 6-speed, 115k miles, just changed the coils/wires/plugs/oil and filter.

So I got a compression test done this morning: 6.7/6.6/6.3 @272 (rotor 1) and 7.2/7.3/7.1 @283 (rotor 2).

I know that rotor 1 is getting weak, so that's why I'm here. I haven't noticed a significant loss of power nor weird fluids in odd places. There is sometimes a sputter above 8k RPMs, though I suspect that is my fuel pump getting old. The only CEL I have is from the O2 sensor, and I've had one misfire (blinking CEL). I also drive pretty aggressively and premix with premium fuel.

I'm looking for what I can do from here on out. I want the engine to last until the spring, at which point I was planning on putting in a different engine anyway. How can I make sure this happens? How should I drive for the next ~5,000 miles?

Thank you,

-ddsneversummer

RIWWP

iTrader: (2)

Rotor1 is worst than just "weak". It's pretty bad.

Basically, if you just want the engine to last as long as possible, increase the premix amount (it provides a bit of 'false compression" by improving the sealing a bit), remove the cat if you have one attached still (because it will die fast).

Other than that, drive it as little as possible. Mileage is going to be your enemy here.

ddsneversummer

Ugh. Alright.
About how long does a rebuild take? And would doing it myself offset the cost significantly?

It is my daily driver, so that makes things tough.

Also, thanks for the quick reply!

RIWWP

iTrader: (2)

A rebuild can vary considerably in time. A reputable builder can disassemble it and reassemble it properly within a day, provided they have all replacement parts at their disposal. I'd bet that most of the delays in rebuilding are the shipping transit times (there aren't too many reputable builders in the US) and waiting for parts to arrive after teardown and inspection has determined what needs to be replaced and what doesn't.

Yes, you MIGHT save considerably by rebuilding it yourself, but you probably won't. Most garage rebuilds tend to be done improperly, resulting in an engine that is only good for 8-10,000 miles. Or even zero miles. Plus, at that mileage and compression score, it is unlikely that many, if any, of the major parts of the engine will be able to be reused. The front rotor, housing, and probably the whole eshaft will need to be replaced (along with all the seals throughout the engine), and that is if you have the front, center, and rear irons lapped correctly and the rear rotor seal seats aren't too worn and the rear housing isn't flawed/worn anywhere. A rebuild will likely be more than the cost of just getting a Mazda reman, which can be had for as low as $3,300 + shipping + core (core is an extra ~$1,000 if you don't give them your current engine before getting your replacement, refunded if you then give them your old engine). Not cheap, but chances are a rebuild will run you $3,000-$4,500+

A used engine is an alternative too, though you will pay $2k+ for a known good compression engine, and anything less is going to be a risk of the unknown.

ddsneversummer

Oof dah. Due to my inexperience I'd probably be better off with having someone else do it.

I'll be looking around for some options. My spring project fund just took a little hit, mostly because there is no way I will live without an RX8 again- good gracious this girl is fun.

Thank you for all of your help!

I will post back here when I get things sorted.