Date: Sat, 16 Jun 2007 20:14:15 -0700
Reply-To: David Kao <dtkao0205@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Kao <dtkao0205@YAHOO.COM>
Subject: Re: Is this the cause of my engine compression problem?
In-Reply-To: <01f401c7b09e$cd7f45a0$6501a8c0@valuedba5d11bc>
Content-Type: text/plain; charset=iso-8859-1
Bob:
I did the pressure test at TDC. The leak is obvious comparing to the cylinders
that do not leak.
I now wonder why a few times I got 150-160 PSI compression out of cylinder #1.
The compresstion test I did after re-torguing the head nuts cold engine got
all 4 cylinders at 150 PSI or better. This is inconsistent to what I found
today. It's back to exactly right after I completed assembling the engine,
#1 and #3 around 90-100 PSI but #2 and # at 150.
Driving around the block it's not bad. But when it needs some power to climb
a small hill it just lacks the energy reasonably expected. My 84' with a tired
engine does better. This is why I know something is not right with the rebuilt
83' engine.
Now that I kind of know what the problem is I will just take a break then
attack it again when I regain energy to drop it and take it apart again.
If I need invidual cylinder/piston I will buy from you. Thanks for mentioning
it.
David
--- Bob Donalds <donalds1@verizon.net> wrote:
> 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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>
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