RockLobster

iTrader: (7)

Ok,

Car is a 91 Turbo (TII) with 97k on the ODO. I've had the car only a couple months.

I bought this car from a guy who know very little history about it as he only owned it for a year and badly needed the money.

I ran a compression test on it with the mazda tester (paper graph).

I warmed up the car completely. Though not by driving it because the interior is completly torn apart. Then I removed the top spark plugs (trailing).

I disconnected the crank angle sensor, problem was it took about a half hour to do this without destroying the contector. Plus the time to pull the plugs and get the tester threaded in. (TII engines are realy packed in there!)
Thus the car had cooled off quite a bit I would assume.

For thoes who have tested compression on alot of rotaries how does an engine that has cooled off some affect the results of a compression test?

The reason I ask is because I got SOLID numbers for a turbo car with 97k miles on it.

All faces were consistant between 7.8 & 8.0 kg/cm2 on the mazda tester.

So either the engine has been rebuilt/replaced with a reman one. OR, somehow the results were affected by either a tester that is not calibrated anymore or the temp of the engine?!?!?!

Thoughts?

YearsOfDecay

Usually.... a cold engine has less compression that a warm engine.

If you warmed the engine up to operating temperature, and it cooled for only a half an hour, I'd say your numbers are good.

At 110 psi on all the faces, at 97K... i'd bet thats a reman in there!!

I've used the Mazda testor, but have no idea how its calibrated, can't help there.

SureShot

Sounds like a good motor.

How's the rest of the car?

RotaryResurrection

iTrader: (8)

A warm engine makes less compression than a cold engine. I have verified this on several engines. This is why we have hot start problems...the rotary loses 5-10psi compression when warmed up. ON some, it won't matter, because compression is still high. But if you have a weak engine already, that 5-10psi drop when warm can be enough to cause startup/flooding problems.

Still sounds like you have a pretty solid engine making 100-115psi all around. Perhaps repeat the test with the car still hot, but you wont see them change too much.

casio

out of curiosity, why'd you disconnect the CAS ?

RockLobster

iTrader: (7)

Car has been painted. Fairly Decent Job, Just a few paint lines around the door outer weather striping. Did not find any evidence of an accident and I looked VERY throughly for bondo, or frame pull crease marks body crease marks from the inside etc. No rust anywhere that I can find. Checked the underside pretty throughly. Only mod was an apex cone intake. New stock mazda mufflers were put on right before I bought the car. Exhaust is getting chucked soon anyway.

Car had numerous little chassis electrical issues, the usual suspects:
- Sunroof drive tape broken (replaced assembly already).
- Window Wiper Relay was toast. (replaced with icemark rebuilt switch cluster)
- Stereo system wiring not great. (replaced speaker wires) replaced head unit as well, while I was in there. Sadly some of the harness side sterio wiring was taped into with scotchlok style electrical taps probably for a sub box or something that was removed. Leaving the scotch locks on to try to avoid problems. (Crosses Fingers)
- Missing some misc interior parts all of which I found from the junk yard.
- Power mirrors are not working right. Right side dosnt work at all. Left side works sporatically. Going to take the switch apart and clean it allong with the mirrors themselves, hopefully that will fix it.
- Cleaned out one of the power window motors as it was quite slow to move the window up and down.
- Hopeing to get it all back togeather soon and start on the suspension and brakes.

Suspension:
- Stock dampers were replaced with tokico blues.
- Bushings and other parts seem to be in good shape rides very smoth, very responsive.

- weather striping around the tail lights is kinda falling off. going to take them out and try to fix that.

- stock underbelly pan was gone. Replaced with a custom aluminum one
- door lock cylinders were totatly screwed. Had them rebuilt/replaced by a local locksmith.

Interior was in good shape. I just wanted to fix it up and make it like new. New seats going in.

Engine has a high idle. Kinda rough but not too bad. But never idles below 1100 RPM. TPS needs adjusting?

Oil cooler lines were leaking. Replaced with Corksport braided stainless lines.

RockLobster

iTrader: (7)

What the manual said to do as part of the test....I have a 91 mazda shop manual for it that came with the car. Probably to stop spark?

kevin,

I had thought that was the case because of the famed warm engin flood problems.

I am going to run it again now that I know how to get the CAS disconnected much more easily.

casio

i had a T2 comp tested once by a mazda employee (off the clock) with a mazda tester and i don't remember him doing that. had to ask!