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I recently checked my 87 3.5EFI that has a 9.35:1 comp ration.
My gauge was reading around 120PS1 per cylinder (+/-5%)
It is not the absolute figure that counts but how even the readings are.
A very low reading on one or more cylinders spells problems
 

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should be between 130-160 psi but all within 10 psi ideally.
no1 cylinder is usually the lowest for some reason
 

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I was always taught to test the compression with all the plugs out so that the engine spins over with the least of resistance/compression, the HT disconnected at the coil and the accelerator full down. A well charged battery will ensure that the last cylinder you test gets a proper 'spin'. I let the engine turn over for around five seconds each time. Also it is worth ensuring that you have a good seal between the gauge and the spark plug seat. I had a shock with a low reading and all it was, was the o-ring on the gauge that was damaged and not sealing well.....BTW Good luck!
 

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Discussion Starter · #6 ·
I have to accept my luck, my gauge is brand new, the G*dd*m** seal is perfect, the other cyls shows between 85 & 100 PSI, the f****ng engine is done. Im going to buy an hidraulic engine lifter and do the overhaul. :mad:

Thanks for the help.
 

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steady on there chap!!!! the normal cause of poor compression on a V8 is head gasket blow by and valves lift the heads off and have a look before riving the engine out also check cam and tappet condition as this also affects compression
 

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Discussion Starter · #8 ·
Thanx 4 the tip. I'll take off the heads and check b4 doing major job. I've just thougt that the engine is over 'cause the car has like 300000km after last overhaul. Numbers are wise. But, with some luck, maybe I don't have 2 spend lots of money in repair. I hope u r right. Wish me luck.

Thanks.
 

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onslow said:
steady on there chap!!!! the normal cause of poor compression on a V8 is head gasket blow by and valves lift the heads off and have a look before riving the engine out also check cam and tappet condition as this also affects compression

check for blow by between the cylinders usually turns the headgasket black or in the worst cases blows it away also common to blow by into the valley normally causing black deposits along the edge of the head gasket.

No 7 and 8 cam lobes wear the most (the 4 lobes at the back) ive seen them wear badly enough that the cam lobe has been round in shape
The V8s tend not to wear the bores much
 

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hey buddy Kaliman
did you try squirting some oil in the cylinder and then check the compression?
if not do it .. if doing this brings up compression u may need new piston rings...... that is all and scince u are at it u gotta change the headgasket....
 
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