Compression test psi ?

[lukey4x4]

Hi lads , so got my mate down today wif his compression tester as i was overheating to check the head and all 4 read the same between 95-98 , its the 1.6 8v spi engine anyone no what they shud be at as my mate said that was ok , so next was check waterpump we took it off and noticed 3 of the blades were snapped so that and not the best shape radiator myt be the problem so will order on monday but next problem is i dont no the year of the engine so gettin parts is lyk pullin tearh with the shops , anyway of telling with the engine numbers ? Thanks

[donkeychomp]

Was that the correct reading? Did mine a while back and all were 175!

[lukey4x4]

Yea mate all 4 were the same just over 95 , whats ya thorts on that reading to low ?

[RickUK]

I would have said that 95 was very low,when checking the compression normally on say a 4 cylinder engine they should all be even across the board about 175 but if one is down to say 100 then that usually indicates that a valve is shot in that one cylinder or possible ring problem,but in your case when all 4 are so low i am thinking that the head gasket could well possibly have gone as they are all low and valves in theory dont go all the same time in theory that is.

As its over heating and the compression is down it is indicating to me to possibly be the head gasket,but i could well be wrong,what ever the problem is i hope you get it resolved pretty quick,you could always get a pressure test done on the radiator and cooling system done.

[lukey4x4]

Thanks rick i wanted to double check cheers for the help i have a spare engine not sure if its worth putting that in i no it ran but not sure how good , myt just be best fixing it so i no its good n gunna last

[twiss]

Have you tried testing with a teaspoon of oil in each cylinder?
If they all even it could be wear on the piston rings from age. When I've tested engines with blown head gaskets they usually read low on the cylinder where it has gone.

[lukey4x4]

We never twiss after the compression test we thort was ok as were all same readings we took the water pump out and that was broke so never took the head off , or do you not have to test with some oil ?

[twiss]

If you put a bit of oil into the cylinders and the test numbers increase, the oil is partially blocking the gaps around the rings. A uniform increase across the cylinders could just mean that they engine is tired and needs new rings putting in.
If the numbers stay the same even with the oil it usually means the rings are OK and it's headgasket/valve related.

[lukey4x4]

Thanks twiss will ask my mate for a lend of the compression tester and try agen , when we did it the engine was cold will this matter when testing , thanks

[twiss]

You should always do a compression test when the engine is at running temperature! Otherwise it will always give low readings!
Also you MUST have a good battery to have the starter turning as fast as it can.

Sort of sounds like your mate doesn't know how to use his comp tester
Do it again warmed up and test all cylinders no oil, then all with oil and post results