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Old 03-08-2012, 01:30 AM   #1
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Default Compression/ Leakdown results...what now?

Today I started up my car and let it warm up until the water temp gauge was like 1/3 of the way up. I shut it off and removed all 4 spark plugs. Cylinder number one came out looking like this:
Compression/ Leakdown results...what now?-plug2.jpg
I'm not sure what happened.
Anyway, after all 4 plugs were out I had my wife sit in the car and crank it after I screwed the compression tester in. Results are:
Cyl 1: 175psi
Cyl 2: 110psi
Cyl 3: 150psi
Cyl 4: 175psi

I also noticed that it looked like there was a puddle of oil just laying on top of cylinder 3's piston, and all my plugs were soaked in oil. In fact, they were all F'd up. I've never seen em this bad and needless to say, they're not going back in the car. They are NGK-ZFR6-11 gapped at .030".
Compression/ Leakdown results...what now?-plugs2.jpg

Then it was leakdown time. I made my own version of a leakdown tester by welding a pipe nipple to old spark plug threads, and the rest was pretty much copied from this video:

Here is a picture of my homemade leakdown tester:
Compression/ Leakdown results...what now?-leakdown.jpg
I turned each cylinder over to TDC and put the car in 2nd with the ebrake pulled before I blew 100psi into any cylinder.
Here are my leak down results, take note I never pulled my IC plumbing at the throttle body, but I did pull my oil cap and dipstick:
Cyl 1: 30% leakage..Blew air out the oil cap and dipstick tube, possibly also intake and exhaust?
Cyl 2: 80% leakage..no air out crankcase, either exhaust or intake.
Cyl 3: 40% leakage..no air out crankcase, either exhaust or intake.
Cyl 4: 10% leakage..no air out crankcase, either exhaust or intake.

So even though cylinder 2 is lowest compression, think it's all in my valves? It did have the least amount of compression, but it also had the highest leak, and with no air going in the crankcase at all. Does this prove my theory of "I need do to a head swap" true? This motor has almost 160,000 miles on it, and it's been boosted for the past 40,000.

Here's the video of "how to do a leakdown test" that goes alone with the "how to build a homemade leakdown tester" video.
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Old 03-08-2012, 01:41 AM   #2
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You'll need more than a head swap IMO.

Sounds like a full on refresh is in order. I'd take this opportunity to build the motor and run MOAR BOOST as always
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Old 03-08-2012, 07:42 AM   #3
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Quote:
Originally Posted by 18psi View Post
You'll need more than a head swap IMO.

Sounds like a full on refresh is in order. I'd take this opportunity to build the motor and run MOAR BOOST as always
I had 60-80% leak in my bent intake valves. After the new head, leak numbers are ~5% cold.
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Old 03-08-2012, 08:32 AM   #4
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Quote:
Originally Posted by hustler View Post
I had 60-80% leak in my bent intake valves. After the new head, leak numbers are ~5% cold.
The logical thing for me to do would be a full rebuild, but I'm cheap and lazy. Would you say the results look like it's head swap time, and I should be ok?
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Old 03-08-2012, 09:51 AM   #5
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Looks like most of your issues is with the head (with the exception of cylinder #1). As for the oil in the spark plug recesses, that's just the valve cover gasket leaking.

If it were me, I'd slap on the new head and drive it. Start collecting parts for a complete rebuild on the side.

Thanks for the links. Think I'll do this over the weekend.
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Old 03-08-2012, 10:24 AM   #6
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If it were me, I'd slap on the new head and drive it. Start collecting parts for a complete rebuild on the side.
I like the way you think.
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Old 03-08-2012, 11:54 AM   #7
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You should have just said you're looking for confirmation instead of suggestions lol

Good luck
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Old 03-08-2012, 12:09 PM   #8
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The car does run and drive right?

Just start saving parts and cash for the build. Why waste time half-assin it when you know your gonna rebuild in the near future anyway. Just keep an eye on the oil level.
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