Anyone done a compression tests? What should be the readings?
Thanks,
M
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Anyone done a compression tests? What should be the readings?
Thanks,
M
Around 150psi on each cylinder.
Absolutely tons of threads on this subject if you're looking for advice on how best to do it. Just use the search function :agree:
make sure throttle is flat floor too while cranking too otherwise you wont get the correct reading:agree:
How low compression resolts are bad?
110 psi we had and we scrapped pistons, 145 is ideal as i say with throttle to floor while cracking
Thank you for info! Will report how it went :scared:
Anything much below 130 and you need to start looking into whether there is a problem. :agree:
Its mostlly round 110-115... :cry:
The car is driving fine. Not shure what to do now.
Quote:
Originally Posted by FSP
was that with throttle fully pressed??
If all in balance (say 10% of each other) then it could be a low compression engine. If you know it not to be, drop a teaspoon of oil down each cylinder and re- test. If compression goes up then suspect the rings/ bores are at fault.
Enigine is OE, T2 turbo.
I did the test in hurry so will do it again and hope for better resaults. Not shure on tool if its OK. Might be leaking pressure.
It was tested with full throtle thou.
Just to add the instructions from other threads to this thread to freshen them up (thanks to Michael Tierney):
- remove spark plugs
- remove coil lead from distributor cap and place near a good earth/return/chassis/engine
- fit compression tester into first spark plug hole
- crank engine with throttle open until gauge doesn't read any higher
- repeat for the other cylinders
- for each cylinder, take note of how high the needle on gauge jumps with the first pulse
- take note of each final reading
- for a good prognosis do the test cold and at a later stage do it hot
- cold should be more than 9 bar (130psi), and hot should be more than 9.5bar (137psi)
I also noted from other threads that if your timing is unduly retarded, it can lower the readings across all four cylinders. Andrew Cooke said it so it must be right. Since your readings are similar across the cylinders FSP, I'd suggest checking the timing (and rechecking that your engine is definitely OE and not low compression). :agree:
Thats valve timing, right? Wouldnt say the engine was ever tuned, it had broken standard T2 on it when I bought it. Aso the car is looking all OE.
This is the tool, anyone have it? is it OK?
http://www.ebay.co.uk/itm/4010589790...%3AMEBIDX%3AIT
Quote:
Originally Posted by FSP
Not sure. Check here. You might understand it better than me: https://www.rtoc.org/boards/showthrea...rand-new-build
Yes, valve timing.
Did you keep cranking until the needle didn't rise any further?
My gauge was not that exactly, but similar.
I was cranking like 5-10sec and the gauge stoped climbing.
Dont think the engine was ever disassembled. It has like 145000kms on clock. Would this be alot for this engine and how long do piston rings last?
thanks!
M
I guess that depends on the quality of the oil and frequency of change and type of mileage.
Have you checked the tappets so the valve adjustment is correct?
From the thread Trev linked to, check the cam (valve) timing as well. They were initially talking about tappets and clearance being to large or small. Cam timing is a more difficult thing to measure and adjust, and that was a newly built engine so he could have made a cam timing error.
Perhaps try the trick Matt suggested of a bit of oil in the cylinders.
Possibly repeat the compression test but each time leave the gauge in and see how much time it takes for the pressure to leak away. I forget how long that should take on a healthy engine.