Date: Thu, 13 Sep 2007 14:29:39 -0700
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: How do you check compression?
In-Reply-To: <46E97ED4.204@earthlink.net>
Content-Type: text/plain; charset="US-ASCII"
I doubt this is in the Bentley, but some books even suggest, beside what you
list below, holding the throttle wide open during the compression testing.
I generally, though, never bother to do this.
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mark Drillock
Sent: Thursday, September 13, 2007 11:18 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: How do you check compression?
Why not read and follow the MANUAL?!!! Then we can compare over time
with meaningful results.
The VW service manual says warm engine, all plugs out, disable coil,
crank until gauge stops increasing, then read gauge.
Bentley 15.20
Mark
David Kao wrote:
> It sounds like chuck, chuck, chuck. The needle of the gauge
> will jump (upward) upon each chuck (stroke). The question
> is should it be measured until the needle stops moving higher
> or should the reading be taken at the 4th stroke.
>
> Dennis suggested to take the reading at the 4th or 5th. But he also
> said to read it until it reaches the highest reading.
>
> I believe a cylinder with excellent compression will give you highest
> reading on the 4th stroke. A cylinder not in optimal compression
> will require 6 - 8 strokes to reach max. reading. So the reading as
> well as number of stroke should both be considered for judging the
> compression of a cylinder.
>
> Vanagon engine seems need more than 4-5 strokes to reach max compression
> reading. Correct me if I am wrong about this.
>
> David
>
>
>
>
> --- Michael Elliott <camping.elliott@GMAIL.COM> wrote:
>
>
>>Engine warmed-up, cold, doesn't matter?
>>
>>Counting number of strokes -- is that the number of wuh-wuh-wuh sounds the
>>starter makes?
>>
>>--
>>Mike "Rocket J Squirrel" Elliott
>>71 Type 2: the Wonderbus
>>84 Westfalia: Mellow Yellow ("The Electrical Banana")
>>74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>>KG6RCR
>>
>>
>>
>>On 9/12/2007 8:29 PM Dennis Haynes wrote:
>>
>>
>>>Some more variables. Crank until gauge stops rising. You can hear the
>>>change. Count the number of strokes. Should be 4-5. The design of the
>>>gauge can affect this. The hose length and placement of the valve will
>>>make a difference. Of course you will also want to do a leak down test.
On
>>>older engines it is common for the front two cylinders (1-3), to show
>>>lower compression then the rear and still check good with the leak down.
>>>This can indicate worn cam lobes.
>>>
>>>Dennis
>>>
>>>-----Original Message-----
>>>From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of
>>>David Kao
>>>Sent: Wednesday, September 12, 2007 10:31 PM
>>>To: vanagon@GERRY.VANAGON.COM
>>>Subject: How do you check compression?
>>>
>>>I was told by a mechanic that when checking compression for a 4 cylinder
>>>engine I should get 4 strokes, no more than that, and get the reading.
>>>But Bentley Manual says to continue to crank until getting the highest
>>>reading. So how do you folks do it? How many strokes on the average do
>>>you crank to get the highest reading?
>>>
>>>David
>>>
>>>
>>>
>>>
>>>
>>>_________________________________________________________________________
_
>>>__________
>>>Luggage? GPS? Comic books?
>>>Check out fitting gifts for grads at Yahoo! Search
>>>http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz
>>>
>>
>
>
>
>
>
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