Date: Mon, 13 Feb 2006 23:21:07 -0600
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: compression testing... on the bench
In-Reply-To: <43F19600.4040007@mchsi.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Al,
One could crank it by hand to compression stroke - TDC - and do a
differential compression test (leakdown test) . Should be easy done if
the engine is on the bench. Of course one would want to lock that
crankshaft so it would not turn during the test.
It has been a long time since I did one, but I seem to recall that on
the aircraft engines we would load the cylinder to 90 psi, then watch
for a pressure drop. I can't recall ever using a pressure greater than
that on an aircraft engine. Severely different pressures between
cylinders called for a cylinder change. or pressure at 65 psi or lower
also called for a cylinder change. The testing device used had two
guages - one was line pressure one could regulate to 90 psi, and the
other was the actual pressure in the cylinder.
Regards,
John Rodgers
88 GL Driver
Al and Sue Brase wrote:
> I've got a 36hp on the stand right now, and since I have the crank and
> nut from my 56 pickup, I figured I'd try a compression test with the
> hand crank. It is hard to get consistent results when cranking by hand.
> So, no, not really possible to check compression with meaningful results.
> Al Brase
>
> Tabe Johnson wrote:
>
>> It's pretty hard to turn an engine over by hand fast
>> enough to get a realistic compression reading. I have
>> done the bench compression. It worked fine. I got a
>> spare starter & bell housing, bolted it up, got out
>> the spare battery, and cranked away happily. I
>> was seriously considering how to mount a carb on the
>> engine to get it running until I realized I'd need the
>> computer for spark control. Then I gave up.
>>
>> tabe johnson/87 westy
>>
>>
>>
>>
>>
>>> Subject: Re: compression testing... on the bench
>>>
>>> Why wouldn't you just turn it by hand?
>>>
>>> Cya,
>>> Robert
>>>
>>> ----- Original Message -----
>>> From: "Matthew" <mpteleski@YAHOO.COM>
>>> To: <vanagon@GERRY.VANAGON.COM>
>>> Sent: Monday, February 13, 2006 3:15 PM
>>> Subject: compression testing... on the bench
>>>
>>>
>>> folks, i have a wasserboxer long block NOT IN A CAR
>>> which i'd like to check its compression. Has anybody
>>> bolted a bellhousing and starter to a longblock on
>>> their workbench and tested the compression? (i know it
>>> is a cold test, but it will give me an idea of the
>>> quality of it, etc)
>>>
>>> thanks
>>> matthew
>>>
>>>
>>
>>
>>
>
>
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