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I was thinking about, was is good and was is bad?
Also soon I will test the heads (you can see them on one of the pictures)
Let's say the heads has the same leak as the short block, what is OK leak for a old engine, and what would it be, if it was "new"
What would be "acceptable" for a old engine like this engine?
I don't know what is acceptable......I hand-lapped/dressed-up the valve seats and installed new valve stem seals on a set of heads (to be safe) after checking for bent stems/cracked valves...it's an easy repair (compared to re-ringing the pistons....which I would do if needed).
I don't know what is acceptable......I hand-lapped/dressed-up the valve seats and installed new valve stem seals on a set of heads (to be safe) after checking for bent stems/cracked valves...it's an easy repair (compared to re-ringing the pistons....which I would do if needed).
I did the same, first the valves came into my valve grinder ,and then I took my valve seat cuttter tool, to cut the seats a bit. After that I hand lapped with fine paste only, untill I had a "big seal" on the valve.
<13% across the board is very good for a 40 year old engine. It is ok for a fresh broken in engine. Over 20% has issues that should be watched. Much over 20% or a drastic difference between cylinders needs repair
<13% across the board is very good for a 40 year old engine. It is ok for a fresh broken in engine. Over 20% has issues that should be watched. Much over 20% or a drastic difference between cylinders needs repair
Great to hear 63mako :- )
Last numbers from the second head is:
2 = 0%
4 = 0%
6 = 0%
8 = 0%
Since bore number 5 has the biggest leak (13%), and combustion chamber number 5 has a 3% leak in the head, then combustion chamber number 5 will be "re grinded" with fine past again to 0% leak.
I did the same, first the valves came into my valve grinder ,and then I took my valve seat cuttter tool, to cut the seats a bit. After that I hand lapped with fine paste only, untill I had a "big seal" on the valve.
An engine is supposed to be at operating temp for the most accurate stats for this test. I realize this was impossible for your specific situation. I'm just mentioning it as "FYI".
An engine is supposed to be at operating temp for the most accurate stats for this test. I realize this was impossible for your specific situation. I'm just mentioning it as "FYI".
From: Las Vegas - Just stop perpetuating myths please.
I dont see how that test can be valid with only 12psi source pressure. U really need 70psi or more for a reliable reading. The higher the source pressure the greater the leakdown will be. But usually on a new block and rings and vlv job differential will be less than detectible using even 80psi source press.
I dont see how that test can be valid with only 12psi source pressure. U really need 70psi or more for a reliable reading. The higher the source pressure the greater the leakdown will be. But usually on a new block and rings and vlv job differential will be less than detectible using even 80psi source press.
Why only 12psi source press c3_dk?
I did it like on this video. I looked at a few on youtube, and they did it the same way. Is it wrong ??
Where was the piston in the bore during the leak down?
It needs to be TDC. That is where compression takes place and leakage and wear tend to be the greatest.
Where was the piston in the bore during the leak down?
It needs to be TDC. That is where compression takes place and leakage and wear tend to be the greatest.
This is what the gauge is, when I set it to zero? (like on youtube movie)
Is there an other way to do it?
No the pistons was not on TDC. But I can do that, I didn't think about this.
Yes I have min. 0.060" after lapping, I have a very good seal after lapping. I did use ALOT of time hand lapping, with fine past only. (the valve you can see being grinded in my valve grinder is not mine, my valves is in the blue boxes behind the grinder, not grinded at the time the movie was made)
Keep in mind that with the piston at TDC that is is going to want to turn the crank very quickly to BDC. So you need a way to secure the piston at TDC.
From most leakdown test documentation that I can find it is usually much higher pressure than 12psi.
!00 psi is common as with the one gauge method it makes math easy. IE, If the gauge shows 100 psi before connected and 90 psi after connected it's 10% leakage.
Leak down test, short block
It is ok for a fresh broken in engine. Over 20% has issues that should be watched. Much over 20% or a drastic difference between cylinders needs repair
