Um I wonder if a valve job might sure up the compression #'s.
Cylinder #7 down on compression
- Thread starter gtgto
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Inertia
Well-Known Member
Really happy to hear. Now you know the rings aren't washing that piston head.
It's a comparison between cylinders, if all but one hold fluid for a reasonable amount of time while one drains in 10 mins, as I have seen many times, that's significant.
It's a tool, Rusty, - and of course, like many tools, if you don't know about it, it's of no use to you.
It's your untested opinion, vs my tested one, which was passed on to me, and I have passed on to you and others.
Nothin worse than doing a valve grind on a vehicle, have it come back a few months later running shitty, puffing smoke cuz you didn't know a way to test rings, when a leak down test had leaks everywhere.
A splash of solvent in cyls, a few seconds, while scraping gaskets.
The things you learn from mentors and on the job, - - experience .
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Newbomb Turk
Well-Known Member
Your theory would be correct except you can’t assess ring seal without pressure.
The rings do not seal based on radial tension.
All piston rings are gas operated. They require combustion pressure to get down past the top of the piston to the top of the ring. Then that pressure goes across the top of the ring to the space behind the ring and that pressure forces the the ring to the cylinder wall and causes the seal.
Plus we need to remember that engine oil is the gasket that seals the rings.
Testing without pressure doesn’t mean much if anything.
Inertia
Well-Known Member
Yes, we know all that, - we're testing gravity
Don't knock it till you've tried it, several dozen times .
Otherwise, it's just your untested opinion .
Newbomb Turk
Well-Known Member
It’s not my opinion on how rings seal. That’s the facts.
What your test doesn’t show is why nothing got past the rings. That’s a sure sign the results are skewed by something.
Even if the gaps are not lined up (and they do line up while running) the gaps leave a leak space. So the solvent SHOULD get past the rings.
If it doesn’t that tells me carbon or some other **** us stopping the solvent from getting past the rings.
Your test proves nothing. The guy now thinks he knows what he has but he doesn’t.
This test has me left with wondering too.
How can a bucket full of holes hold a fluid? In my 75 years, never heard or saw this test performed. I will not argue, I would just never bother doing it. I stand by my previous post, but money seems to be an obstacle.
I do hope that this all works out for the OP.
How can a bucket full of holes hold a fluid? In my 75 years, never heard or saw this test performed. I will not argue, I would just never bother doing it. I stand by my previous post, but money seems to be an obstacle.
I do hope that this all works out for the OP.
Inertia
Well-Known Member
It's a tool that has worked for us for decades.
Use it, or Don't, I don't care .
Use it, or Don't, I don't care .
Here's a thought, you can have good compression and still have oil getting past the rings. lol The op say's it's not using oil.
I believe the rebuilt cylinder heads and proper gasket seal will even up the compression.
I believe the rebuilt cylinder heads and proper gasket seal will even up the compression.
Newbomb Turk
Well-Known Member
See post 78. Yall go ahead and think it's a test. It's not. The rings must have pressure to push them against the cylinders to give them their seal. That's the whole purpose of a leakdown test. ......with the heads on. You can "pass on" anything. That doesn't mean it's correct.
Yup. That gives the story "after" everything has happened. It's even more accurate than a leakdown test, although the results from each would back each other up.
Yup. He's gonna latch on to bad advice. I see it already. Yall have a good time. I'm out.
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