The leak down test should be done at TDC for the cylinder to be tested

I use cofap but I do inspect and remove the taper from the cylinders. If the
cylinder is the problem its scuffed due to overheating or the pin clip did
not stay in the groove
I have good used pistons and cylinders if someone feels the need
This is what I use on my own vans. I fluff and buff them in the Boston Bob
style
The cofaps are a good option and the feed back I get is positive when it
come to power

B Bob

----- Original Message -----
From: "David Kao" <dtkao0205@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, June 16, 2007 4:49 PM
Subject: Re: Is this the cause of my engine compression problem?

> This is to keep everyone posted. I found the real problem eventually by
> doing
> a pressure test to the engine.
>
> I borrowed a compressor and coverted my compression tester into an adapter
> for
> pressure testing the engine. Found excessive leak in my #1 cylinder
> through the
> piston rings into the crank case. I could feel a strong flow or air coming
> out
> of the blowby breather hose, which has an opening inside the S shaped
> intake
> rubber bellow. I could feel a strong flow of air flowing from the crank
> case
> through the hose into the bellow. It pushed my finger out when I tried to
> block
> it off.
>
> Ouch..... It's a new liner there!!! How will it leak like that? When I did
> the
> same to cylinder #2 the pressure was only at 20 PSI and it pushed down the
> piston
> and caught me by surprise. It could not push the #1 piston even at 50 PSI.
> I had
> transmission in 1st gear and parking brake on with wooden blocks in front
> of the
> front wheels. So the van did not try to run away but the tail of the van
> sank a
> few inches. There was no obvious air flow through the blowby breather hose
> when
> testing cylinder #2.
>
> Repeated the pressure test 4 -5 times and the results were consistant.
>
> The leak is less severe for cylinder #3. But the air flow is obvious
> there. I
> think these are enough to conclude that I have leaking rings on #1 and #3
> cylinders.
> The leak was so bad it actually caused slight over heating during my
> weekend trip
> of 320 miles.
>
> The liner is new, with 800 break-in miles. I have to conclude that Cofap
> is junk.
> Or at least the set I got is near junk. Further breaking-in probably won't
> make
> any improvement as I have had 800 mile on it.
>
> My patience is running out for now. I won't try to fix it for the next
> week or two.
> I don't think I did anything wrong in istalling the liner. I did not align
> the rings.
> According to Benny this is not likely a problem. I have heard that Cofap
> has a wide
> range of quality distribution between junk and excellent. Can anyone
> confirm this?
>
> David
>
>
>
>
>
>
>
>
>
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