did a compression test on my 302, these ok numbers

[need a fast car]

I shot 125 on each cylinder. the milage is unknown. post up, thanks.

 

[88GT17MA]

I'd say thats alright but a little low. What really matters is that all the cylinders are in the same range so if you have 125 on each cylinder I'd say you should be alright. Maybe someone else can chime in with some more input for you....

 

[SicStang89]

125 sounds alright. The numbers vary depending if the motor is cold or hot too...also like 88gt said its good that your pulling about the same number threw all of the cylinders....

 

[need a fast car]

the engine was cold. so that means it would have done better if warmed up?

 

[giddyup306]

COmpression tests will only tell you the condition of the compression rings and not the oil controll rings.

 

[Funanin]

yea u can have 140 on each cylinder and ur oil rings can be shot to hell and u will blow blue smoke all over town. What u need to do if u are unsure about ur rings is buy a leakdown tester or take it to a shop and have them do it. That is the only real good way to test the rings. It shoots air from a compressor into the cylinders until it starts to leak under a certain pressure.

 

[crazypete]

I had readings of 110-115 ice cold and 170-175 hot. Temperature makes all the difference. Do this with all 8 plugs out and the throttle pulled all the way open and coil disconnected. Connect to one cylinder and repeat. Give like 5-7 turnovers or until it stabalizes. You can see if you leave the tester pressurized for a long time if it bleeds air. This is a good indicator. The best indicator of oil control wear is oil usage. Do it with non-syntethic 10w-30 and see how much is missing by the next oilchange. Less than 1/2 a quart is considered acceptable.

 

[rd]

These are on the low side, but if they are all about the same, they are ok.

A number of things affect compression, hot, cold, if the throttle body is open fully, etc. Also, many performance oriented engines have relatively low cranking compression because they have more cam, and therefor more overlap, which tends to bleed off cylinder pressure when cranked.

If it is otherwise running ok, no problem.

 

[5.0b303]

i just did a test the other day...175 across the board cold. Not only can rings affect the reading but also if the valves are seating correctly. If not, they will bleed off pressure. Throw a squirt of oil in the cylinder u are testing...if it shoots up to like 180, u have some worn rings.

 

[Darkhorse845]

125 sounds o.k.