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Cold Leak down test

 
Old 02-21-2019, 12:53 PM
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firemn131
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Default Cold Leak down test

So, I did a leak down on this engine.

Engine has been out of a car for at least 18 months. Don't know the maintenance history, but I bought it from 928Int.

Looks like it has had regular maintenance as the cam gears look newish with belt appearance good.

Intake and fuel components are off.
So how totally unreliable are the leak down results with this engine in this state since it hasn't run in about 2 years?

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Old 02-21-2019, 01:35 PM
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Cold or warm..you wanna see consistent values...IMHO.

Sitting, there could be a chance that a low cyl is just rings not sitting right after time..

But more importantly, if something is not even with the others, listen..you hear the leak from the oil fill tube, or in the exhaust header?
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Old 02-21-2019, 02:47 PM
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Post the numbers.
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Old 02-21-2019, 03:29 PM
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Default Numbers

At the machine shop now watching heads get built up. Measuring spring height and tensions. A great education.
Will post numbers when I get home
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Old 02-21-2019, 05:55 PM
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Umm normally you would do a leak down before doing machine work.
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Old 02-21-2019, 07:29 PM
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Merlin you crack me up..

I haven't started on my engine yet. Just removed the intake and exhaust.

I am at the machine shop being a fly on the wall. Learning about the engine build process and basically interviewing to see if I will use this shop.

He has let me observe and be involved for the last two days. An amazing education. cleared up a great deal of my questions.

So engine numbers are as below.

He also told me not to get concerned as the engine has sat and don a cross country trip.



So, I think I can begin the tear down of my engine.

I will post another thread about advice and opinions.
At a minimum the heads will get new seals and guides if needed. machined as necessary. Block may get rings and rod bearings. I haven't convinced myself of that yet, if there aren't obvious issues.
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Old 02-21-2019, 08:00 PM
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Where did you hear leaking coming from?

Thats as important as numbers.
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Old 02-21-2019, 08:27 PM
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Mostly from below I think.

I took the tester back today, but I have one that the % gauge is inaccurate. I will redo the test just to hear the escapes.

I actually think it was a combination of the exhaust and past the pistons. If I recall, very little from the intake side.

And so it begins.
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Old 02-21-2019, 09:04 PM
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Well I guess I misunderstood your first post,
it definitely would have made things more clear if the picture of your leakdown numbers was in post 1 instead of post 6
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Old 02-21-2019, 09:12 PM
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True Dat
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Old 02-21-2019, 10:13 PM
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Did you oil the cylinders prior to the test?
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Old 02-21-2019, 10:20 PM
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I oiled #1 only, just for a reference.
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Old 02-22-2019, 11:33 PM
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Originally Posted by firemn131 View Post
So, I did a leak down on this engine.

Engine has been out of a car for at least 18 months. Don't know the maintenance history, but I bought it from 928Int.

Looks like it has had regular maintenance as the cam gears look newish with belt appearance good.

Intake and fuel components are off.
So how totally unreliable are the leak down results with this engine in this state since it hasn't run in about 2 years?
Completely useless, as a compression test will also be.

Choice 1: Just make sure that there actually is compression in each cylinder, stick it in, and hope for the best.
Choice 2: As long as the intake is off and it's out of the car, pull the heads, replace the head gaskets, have a good machine shop do a valve grind, and surface the heads. (The engine is how many years old?)

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Old 02-23-2019, 10:14 AM
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Default Sounds like a plan

Hey Greg,
I am pulling the heads today and found the machine shop that I trust. That’s the plan. I may end up doing rings, we’ll see when we get it taken apart.
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Old 02-23-2019, 11:16 AM
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Default Removing heads

This is a new level of tear down for me. I’ve put it off for a little bit just to wrap my head around it. Hanging out of the machine shop for the last couple days has really helped me become a little more comfortable.
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