This test would be done the same way, and give the same results for diesel
engines.  You're applying +/- 85psi shop air to a cyl @ TDC, then
determining the amount and source of the leakdown.....

Mike B.

----- Original Message -----
From: "John Rodgers" <inua@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, January 01, 2007 11:15 AM
Subject: Re: Leak Down Testing

> Here is a web site that gives a complete, technical, professional
> description of doing a differential compression check on an aircraft
> engine. If you ever want to understand the what's, the why's, the
> wherefores of compression testing on any gasoline (don't know how this
> applies to diesels) engine, then this is a very worthwhile read. Flat,
> opposed cylinder aircraft engines are not that much different from
> aircooled or WBX watercooled engines, so the principles apply.
>
> The Differential Compression Test is more accurate that the standard
> automotive test, and it is worth knowing how to do, and to do it.
>
> http://www.amtonline.com/publication/article.jsp?pubId=1&id=2234
>
> Regards,
>
> John Rodgers
> 88 GL Driver
> Chelsea, AL
>
>
>
>
>
>
> Geza Polony wrote:
>> John,
>>
>> What I'm reading from this person's description is basically that you
>> pump
>> air into the spark plug holes and listen where it comes out--exhaust,
>> intake, or coolant. Why do you need even to measure the pressure? Are
>> there
>> some specs to measure against, eg., each cylinder should hold x amount of
>> pressure for x seconds? If so, what are the specs? I've never done one of
>> these tests before.
>>
>> Thanks,
>>
>>
>> Geza
>>
>>
>>
>