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Date:         Sun, 17 Jun 2007 09:34:14 -0400
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
Comments:     RFC822 error: <W> MESSAGE-ID field duplicated. Last occurrence
              was retained.
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: Is this the cause of my engine compression problem?
Comments: To: David Kao <dtkao0205@YAHOO.COM>
In-Reply-To:  <51610.94765.qm@web82710.mail.mud.yahoo.com>
Content-Type: text/plain; charset="iso-8859-1"

Damaged or worn ring lands, (piston groove walls) can cause the leakage and inconsistent compression reading you are getting. Now you also know the value of the leak down test I promote. Saves a lot trouble shooting time.

Dennis

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of David Kao Sent: Saturday, June 16, 2007 11:14 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Is this the cause of my engine compression problem?

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 > > > > > > > > > > > > > > > > > > > > __________________________________________________________________________ __________ > > Finding fabulous fares is fun. > > Let Yahoo! FareChase search your favorite travel sites to find flight and > > hotel bargains. > > http://farechase.yahoo.com/promo-generic-14795097 > >

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