compression test...

[therex]

ok i so i got curious and wanted to do a compression test so i went to autozone and rented the tester, did the test on the rear and first couple times i got nothing on the guage, but it did the three wooshes perfectly even, and on the front rotor and got it up to 25 but thats it, also did the wooshes perfectly so i think im doing it wrong?

car starts perfectly, does burn some oil, idles great and this sounds kinda gay but it rips! like theres no power loss at all like i have no idea how its like that, any suggestions?

was hoping to drift at the next local event but im kinda skeptical now...

88 t2 motor btw

[Mitchocalypse]

Well if you car is able to make it past 60 mph, that usually a pretty good indication that you have compression ins both rotors.

You need a special compression tester from Mazda as well. This is probably the problem. It would register your compression in each of the 3 chambers of the engine. However, a standard comp tester will usually give you the highest compression of the 3 chambers so that's what's throwing me off.

[Prodigy]

Did you have the TB open...?

When checking comp, you need to have the TB open to get accurate (or as close as can be with conventional tester) reading from the engine...

That's something I never knew till about a year ago....


J.

[rxspeed7]

Apps need to take the Valve core out of the normal tester

[therex]

Originally Posted by Mitchocalypse

Well if you car is able to make it past 60 mph, that usually a pretty good indication that you have compression ins both rotors.

You need a special compression tester from Mazda as well. This is probably the problem. It would register your compression in each of the 3 chambers of the engine. However, a standard comp tester will usually give you the highest compression of the 3 chambers so that's what's throwing me off.

yeah i heard that around but i thought id give this a try, but yeah it runs like a champ, 60 is no problem so yeah i dont get it i guess i have nothing to worry about

Originally Posted by Prodigy

Did you have the TB open...?

When checking comp, you need to have the TB open to get accurate (or as close as can be with conventional tester) reading from the engine...

That's something I never knew till about a year ago....

sadly yes it was open


J.

Originally Posted by rxspeed7

Apps need to take the Valve core out of the normal tester

it was haha

[speedjunkie]

Did you warm up the car first? It's supposed to be done on a warm engine.

For the record though, I've never had any luck with a normal compression tester either lol. Although I don't remember if the engine was warm when I did it either, because the only reason I did it was because the car wouldn't start lol.

[RETed]

Tell the store the gauge is broken.
Even worst case, it'll still do around 50psi - 80psi on a running engine.

Actually, a cold engine will register higher numbers on compression.
Cold engine will normally register 5psi - 10psi higher.

Not propping the TB will show 10psi - 20psi lower numbers.

Did you pull out *both* trailing spark plugs?
(You're supposed to use the top / trailing holes.)
If you're using the leading holes, numbers will be down 5psi - 10psi.
If you don't remove the other side spark plug, compression can be down 10psi - 25psi.


-Ted

-Ted