Does 120psi compression on t11 mean the seals are good to ?
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Rotary Freak
Joined: Dec 2001
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From: sandiego, ca
Does 120psi compression on t11 mean the seals are good to ?
Just wandering. The apex seals tell you the compression the rotory makes BUt cant you have bad oil and water seals and still have high compression ?
If yes then a engine with good compression can still blow smoke right ?
If yes then a engine with good compression can still blow smoke right ?
Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
yes a compression test only tests the compression seals, the apex corner and side seals. it does not test the water and oil seals. so a compression test is only a part of the picture
mike
mike
Joined: Apr 2002
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From: Rotaryland, New Hampshire
Originally posted by von
sooo can you overheat a 7 and still have full compression ?
sooo can you overheat a 7 and still have full compression ?
-Jacob
Greek Power
Joined: Aug 2001
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From: Greece
A "good compression" engine may very well have horrible oil or water seals 
I mean, you can have all apex seals intact and in pristine shape, only to have leaking oil and/or water seals, making the car undrivable. Ofcourse this also goes the other way around, but you cannot test the oil and water seals that easily....and if you have bad apex seals, you know it
I mean, you can have all apex seals intact and in pristine shape, only to have leaking oil and/or water seals, making the car undrivable. Ofcourse this also goes the other way around, but you cannot test the oil and water seals that easily....and if you have bad apex seals, you know it
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Haven't we ALL heard this
Joined: Mar 2001
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From: Indiana
Because doing it cold is not the time to do it. You should only do a compression check on a fully warmed up engine.
My theroy is that a cold engine should yeild higher numbers. When metal is cold it contracts. As it heats it expands. Different metals expand at different rates of course. The rotor housings should expand differently than the intermediate housings.
Need to do that check warmed up before you can bank on your numbers. Also, engine speed at which the test was done will affect your readings. The height above sea level will also affect your readings.
Download a service manual and find compression checks. They have graphs for compensating for higher than sea level and for engine speed during the test.
James
My theroy is that a cold engine should yeild higher numbers. When metal is cold it contracts. As it heats it expands. Different metals expand at different rates of course. The rotor housings should expand differently than the intermediate housings.
Need to do that check warmed up before you can bank on your numbers. Also, engine speed at which the test was done will affect your readings. The height above sea level will also affect your readings.
Download a service manual and find compression checks. They have graphs for compensating for higher than sea level and for engine speed during the test.
James
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