Date: Thu, 13 Sep 2007 11:40:08 -0700
Reply-To: "Mike \"Rocket J Squirrel\" Elliott" <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Mike \"Rocket J Squirrel\" Elliott" <camping.elliott@GMAIL.COM>
Subject: Re: How do you check compression?
In-Reply-To: <46E97ED4.204@earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Standardized measurements? What a concept!
Yesterday I did a slap-dash quickie to see if one of the cylinders was
significantly different from the others. Made rough note of numbers.
Posted information and that triggered a series of questions which is
making me go back and look again. There is a Bentley's way of doing it
(thanks Mark) but there might also be a rule of thumb way of doing it
and since everyone is looking over my shoulder to judge what I am
seeing, if they use some rule of thumb method which is different from
the manual, I wanted to know about it.
Measurements per Bentley's after lunch, Pacific time.
--
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 9/13/2007 11:17 AM Mark Drillock wrote:
> 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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>
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