Compression test Low Numbers :(

[GSX93DSM]

Did a compression test when the car was cold needles to say, I don't think the car warmed up would make a difference.

Cylinder 1: 120
Cylinder 2: 100
Cylinder 3: 100
Cylinder 4: 120

I don't think a port and polish head on the bottom end helped any.

 

[JacksonAuto]

Try a squirt of oil in the cylinders through the spark plug hole then redo the test. Rings need a thin film of oil to form a hydraulic seal. They leak when dry.

If that doesn't help then it's time for a leakdown test. That will tell you where the compression is leaking from.

 

[jakelandry]

If it makes you feel any better I ran my old motor to death with compression of something like 125 110 80 130. It ran consistent 11's and I daily drove it like that for a year without a single issue. Recently re-ringed it and rebuilt the head and it runs the same times in the 1/4 and feels nearly the same for dd applications. So its not really the end of the world.

 

[GSX93DSM]

It would have to be rings wouldnt it, to have that low of compression. The head couldnt cause that would it? The guy said it was leaking oil from one exhust port?

 

[92AWDHX40]

The head? The problem could be the head gasket, simple as that.

 

[GSX93DSM]

They put a cometic gasket on it. Like I said supposedly the head was ported and polished. Who knows Also theres oil coming out of exhaust ports...

 

[JacksonAuto]

It would have to be rings wouldnt it, to have that low of compression. The head couldnt cause that would it? The guy said it was leaking oil from one exhust port?

Not necessarily. The rings are one possible culprit but so are the valves. They could be bent or there could be rust or carbon on the seat not allowing them to close properly. This is why a leakdown test is imperative. It will tell you where the compression is escaping. If you're not experiencing an over-pressurizing of the cooling system or a loss of coolant, then I don't suspect the head gasket. To determine this you'll need a coolant system pressure testing too which goes on the radiator cap. If there's a leak in the system (head gasket) it will show up here.

 

[GSX93DSM]

Thanks, the car wont even run do to the fact the fpr is set at 50 psi and it smokes bad.....

 

[JacksonAuto]

They put a cometic gasket on it. Like I said supposedly the head was ported and polished. Who knows Also theres oil coming out of exhaust ports...

They? So you didn't do this work yourself? How did they clean the deck surface? If the shop used abrasive pads then the dust/grime/grit could have made its way into the cylinders and destroyed the rings. Oil in the exhaust could be rings, valve guides or seals. A leakdown test will narrow it down.

 

[GSX93DSM]

I bought the car as is..I took the valve cover off and its really clean. New valve seals,springs and retainers.

 

[JacksonAuto]

I bought the car as is..I took the valve cover off and its really clean. New valve seals,springs and retainers.

That means nothing. Are you reading what's being posted in this thread?

 

[GSX93DSM]

I'am kind of hard to do a leak down test with no air compressor,so I will have to do a wet test.

 

[JacksonAuto]

A wet compression test will not tell you what you need to know.

 

[GSX93DSM]

I'm just gonna pull the head,because I don't trust anybody.Clarification I don't trust what people say what they have done to a motor.

 

[JacksonAuto]

I understand your frustration. The problem is that once you take it apart it will be more difficult to diagnose the bottom end. You'll be pretty much committed to stripping the shortblock as well.

 

[boost97gst]

If it makes you feel any better I ran my old motor to death with compression of something like 125 110 80 130. It ran consistent 11's and I daily drove it like that for a year without a single issue. Recently re-ringed it and rebuilt the head and it runs the same times in the 1/4 and feels nearly the same for dd applications. So its not really the end of the world.

I ran mine for most likely a few thousand miles not knowing that cyl 2 wasnt fully seated. 185 90 185 185. Car pulled like a raped ape. Just imagine what all 4 cylinders would feel like! . OP get to an air compressor and do a leak down. Thats how i found my problem. My dad has a big compressor. Im sure you can find someone to let you use theirs too run a test or worse case take it to a mom n pop shop and give em 20 bucks to use their compressor.

 

[GSX93DSM]

I got a tester, so I'm gonna to do it on Saturday and I will give you results then...

 

[GSX93DSM]

Did a leak down test and heard nothing out of exhaust or manifold, but soon as I took the oil cap and dipstick out you could hear air. Looks like its new rings for me...

 

[red1993gsallmt]

Air always goes past turbo seal, make sure your doing leakdown test at TDC to prevent air going past valves. Is it bubbling in the oil?

 

[JacksonAuto]

You're always going to have a small amount of air going past the rings because of the gaps, cold temps, etc. What was the percentage of loss on each cylinder?

 

[jed344]

We need the numbers on the leak down test.

 

[Abe'sGST]

When you're doing a leak down test make sure both intake and exhaust valves are completely closed on that cylinder. Like stated above you will hear air going past the rings.

 

[GSX93DSM]

It was at top dead center, checked twice to make sure. It dropped 30 psi on the guage. You might have a little air going past the rings, but it sounded pretty significant... Couldnt hear air through intake ports or through exhaust. Soon as I pulled the oil cap and diptick out the air flowed. here is a pic of the block.

 

[GSX93DSM]

I ended up putting water in each intake and exhaust ports. Well,I have 13 out of 16 valves leaking cylinders 2 and 3 leak pretty good. The rest are really wet around the valve...I guess its either carbon ,bent or not seated properly.