Well, I was scared to death when my engine hit the 100k mile mark. Everyone keeps on telling me that these engines blow or needs a rebuild at around 100k.

Well, I bit the bullet and did a compression test today.

At 76% Humidity and 22C ambient temp, my engine tested the following

120-125-125psi front
125-120-120psi rear

Not too shabby would you say??

I have 230 000 km on the chassis and 160 000 km on the Mazda reman motor.

Oil changes every 4000 km, spark plug change every 15000 km.

BTW, I recently went to a dyno and pulled 142 rwhp an 112lbs/ft of tq.

Mods :

Stock exhaust manifold, gutted cat, stock exhaust.
Generic cone intake, Pineapple racing sleeves
S-AFC
Crane Hi-6R
SR Motorsports FD flywheel
ACT SS clutch
Turbo II transmission
FD Torsen rearend
BBS Vert rims

I think I can use alittle bit more tq.

 

Well whoever told you these engines blow up or need a rebuild after 100k miles is stupid.

 

No, he was talking about FD's probably.

 

Funny you said that.

I just tested a FD's compression too.
Stock engine running stock boost.

90-90-90 psi front
85-85-90 psi rear

Weather was probably same humidity and at around 33C

He has 60k miles on stock engine.

 

^ ouch

 

Sounds about right! Poor FDs.....

 

Anyone know the specs on a new engine??

My engine still going strong?

 

looks like you need a little more tuning too.

 

Strong would be an understatement, great readings man.

 

You have very good compression numbers. Probably as good as a fresh rebuilt.

 

Yeah, I have it down to 13.0 right now on WOT.

 

mine went to 205k until i needed to rebuild

 

stock on an FD is probably about 130PSI.

those are awesome numbers man, congrats, I guess

 

I have 185K miles on mine, stock everything pretty much except for a few little tweaks (no exhaust, cone and whatnot no aftermarket fuel control) and i have 95 psi all faces. On my last dyno run i managed to squeze out 145whp and 124 lb/ft of torque. No loss of coolant into the motor or anything, i expect quite a few more miles out of this motor. BTW never listen to anyone that does not have experience with rotarys, 9 times out of 10 they will be wrong/retarded.

 

any car/engine that is taken care of, not abused and maintained regularly and properly will last a nice time before any major work is to be done. plain simple fact. the reason someone may have told you this is because RX7's have a more likelyhood of abuse than say a honda accord

 

You're talking NA right???
NA's are good to at least 200k miles.
With good maintenance, 300k miles is not uncommon.

If this is a 13BT, then 100k to 150k miles is about average life.
This is especially true for those engines making more power than stock, especially with full exhaust systems.


-Ted

 

i just grenaded my 13bT at 154 but i was running too much boost like a fool!!! i knew better.. ahh well time for rebuild

 

200 - 300k on an N/A?
Is this with all stock parts or could this still be obtained with a RB street dual exhaust? I know it's a dumb question, but I'm curious. I'm looking forward to keeping this in good shape if I can obtain those numbers. Right now, at 89k on my N/A.

 

Doesn't matter.
The upper limit of the engine with stock ECU is about 200 at the wheels.
Even with those elevated power levels, the 13B 6-port should be able to easily hit 200k miles with proper maintenance.


-Ted

 

I concur, having owned 4 NA FCs I have never blown or wore out an engine.

 

i think na is the best suitable fc for the street , thats why i love mine....hoping to get her started this weekend

as far as his tuning it looks to be too lean , if it was more rich i bet he would get more hp but he said its been tuned to 13.0 afr

edit - in my opinion reted is totally right these engine can last if you take care of it properly and dont beat on it , my 2 rx7s i have one suffered a blown coolant seal at 146,000 miles (s4 na), the other suffered blown apex seals at 113,000 (s4 na also) , probably due to lack of maintainence and being beat on alot

maintainence and oil changes are very important on rx7 , if u dont maintain it right and beat on it , it will show in the long run

 

My NA motor lasted until 102k.
I had a 88 SE which at 155k showed coolant seal signs but then miraculously fixed itself!

I sold it and someone else is driving it no problem now.

 

Knowing my engine is good...

Maybe it's time to boost it....

I've tried header, presilencer, exhaust but it was too loud for my liking....

 

I dunno where that logic came from, but it's not recommended.


-Ted

 

Hell, I had ~250K on my engine when I turbocharged it. Ran it for another 10K after that, before I decided to pull it apart for the porting. The engine was original to the car (as was the clutch!).