Date:         Mon, 23 Mar 1998 06:54:55 -0500
Reply-To:     Scot Douglas <sdoug@CONCENTRIC.NET>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Scot Douglas <sdoug@CONCENTRIC.NET>
Organization: Mitsubishi Motors R&D of America
Subject:      Re: compression
Comments: To: Patrick Dooley <pdooley@GTE.NET>
Comments: cc: Vanagon@VANAGON.COM
Content-Type: text/plain; charset=us-ascii

Patrick Dooley wrote:
>
> >Here's the problem, just checked the compression today:
> >
> >1    100psi
> >2    100psi
> >3    150psi
> >4    155psi
> >
> >My book says that the min is 118psi with a maximim variance of 44 psi
> >between cylinders.  The rings have only about 10,000 miles on them.  Anyone
> >out there have any suggestions.
> >
> Could possibly be a valve sealing problem.  A slightly warped valve will
> kill your compression.  If you pull the heads, be sure to lap the valves and
> check the valve/seat sealing surface.   I don't think a valve could be
> hanging open, due to hyd. lifters, but it wouldn't hurt to back off the
> adjusting nuts on the rockers and check the compression again.

I would suggest doing another thing while doing the second comprssion
test before pulling the heads.  If you squirt oil in the cylinder first,
then test and the compression comes up, it's the rings; if there is
little or no change in the compression, it's the valves.

--
Best Regards,
Scot Douglas
Project Engineer; Chrysler/Mitsubishi Joint Programs
Mitsubishi Motors R&D of America
P: (734) 971-0900 x124
F: (734) 971-0901