Mephis

Well i bought my car at 100,000miles and it runs great Sence ive had the Ecu replaced.I want to know if i have anything to worry about any time soon , im planing on doing a full restoration , i will buy a new engine havd have it installed , get a 5spd and have all the wiring replaced! i have a 90 Mazda RX7 GXL FCS5 N/A , all stock but the stero!

ZachSpazz

Check your compression. That's the only reasonably accurate way of gauging your engine's health.

Mephis

ok thanks whats the compression like 4.5:1?

ZachSpazz

If you're using Mazda's compression tool, then expect around mid-7's on all rotor faces. If you're using a standard Pepboy's PSI gauge, then around 110-120's(?)

Stock compression on your car is 9.7:1

I've NEVER heard of a car with 4.5:1 compression, unless it was puked.

hypntyz7

You all are confusing compression *RATIO* and compression PRESSURE. The 2 are related but one is a characteristic that will not change(ratio) and one is an indicator of wear(pressure). HIs car has a 9.7:1 compression ratio, adn this will never change unless he swaps rotors. A car with new apex seals and new housings will give you 125psi of compression pressure, and average for a 100k mile motor is 100psi. 90psi and below means it could blow at any time. THe mazda tester gives numbers like 6.0. 7.2, etc. This is a measurement of compression pressure, except in bar and not psi. 1bar-14.7psi IIRC. So the strong compression figure of 120psi for a new engine(most american made comp. testers measure in psi) equates to about 8.0 bar, which just so happens to be mazda's spec pressure for a new engine.