so i have a 95 gsx and i did a compresion test on it the other day an i got 90, 45, 60, and 90 could this be a blown head gaskit or would it be bent valves?I am woundering because before i did the compression test i would be driving and everytime i shifted and the rpm's dropped below 2500 it would shake hard when i give it some gas.
any help would be appriciated

 

Either your rings are shot... or your exhaust valves or shot... or your head gasket is shot.

I would start by pulling off the head and checking to see if the valves are deformed. If not... examine the head gasket for signs of a break or leak or some kind of deformaty.

If nothing is aparent... time for a rebuild

 

it hasnt broken or jumped the timing belt so i dont think it would be the valves but what could make the rings go bad?

 

Sometimes the exhaust valves actually melt and the seals can go bad too. There are a couple things that can cause ring failure. Poor break in, not changing oil frequantly enough, general abuse... stuff like that.

 

is there any way to check the rings without takeing the pistons out ?

 

Compression tests usually. Basically you have to do it as a process of elimination. If the valves are ok... and the head gasket looks fine... then its the rings... if the valves or the head gasket is bad.. you know the rings are more than likely ok.

Do you see any smoke from the exhaust?

 

okay thanks for the advice ill take the head off tommarow . No there is no white smoke

 

Its actually decently easy to figure out exactly where the compression is leaking out. What you need to do is called a leak down test. This requires a leakdown test tool, and a compressor that makes at least 90 psi.

Make sure the car has been sitting for quite a while and isnt hot at all.
First make sure the no.1 cylinder is at TDC
Nexttake off the following things:
-intake hose from the manifold, and block the throttleplate open
-radiator cap, and make sure you are full of fluid
-oil dipstick
-oil filler cap
Now you hook the tool intothe no.1cylinder just like a compression test, turn the pressure up to 90 psi(there is a **** on the tool).
Now, the tool will have another gauge on it that tells you what percentage of the compression is leaking from the cylinder. From the sound of it, you are going to be in the red zone on the meter.
Now you need to use your ears. Listen to the following places, and if you hear leaking air it is leaking from something to do with that which is in parenthesis.
Leaking from:
Intake manifold(bad intake valve)
Tip of exhaust(bad exhaust valve)
Oil filler cap(bad valve)
Dipstick holder(bad ring)
Radiator cap-YOU WILL SEE BUBBLES!(bad head gasket)

If you dont want to spend 60 bucks on a tester, or dont have an air compressor, a mechanic will probably do this test relatively cheap. It only takes about 20-30 minutes for a skilled tech to test all 4 cylinders

 

^^ glad someone finally said it

Or if you want to eliminate the rings from the picture there is an even easier way to do it. Take 30 weight motor oil and dump alittle into the spark plug hole, then repeat the compression test on that cylinder. The reason for the oil is its gonna seal them alittle better so now if you get higher compression, then its your rings

 

Good point Engineer.

DAMN forgot about the leakdown test...