I am certainly not an expert but I heartily agree with David. Years ago on
my Detroit iron I had a piston sleeve (bottom portion) shatter and the
pieces broke a damper as well as scoring the cylinder wall. Only real fix
since I had the engine out anyway was to rebore ALL cylinders to the same
specs, install the new oversize pistons and rings and I got a new engine
that lasted years. As long as you are pulling, might as well do the complete
rebuild job. Anything else just means that you are postponing the
John Sims, BN6
From: owner-healeys@Autox.Team.Net [mailto:owner-healeys@Autox.Team.Net] On
Behalf Of David Nock
Sent: Tuesday, January 09, 2007 6:55 PM
To: Freese, Ken
Subject: Re: Pistons damaged again
If this problem was addressed in 2004 it would have been easy.
Possible just install a set of rings and that would have been it.
What has happened now is due to the detonation the side of the piston
has eaten away and all the little bits of aluminium has traveled
around the engine via the intake manifold into the other cylinders.
Thus damaging the other pistons. We have one in the shop right now
that the rear exhaust valve seat came out and broke up. The pieces
have embedded them self in 4 other pistons.
There is only one answer to fix this. Pull the engine and rebore.
Any other repair would be just putting a bandaid on the motor.
When you get the pistons out you will find that the entire side of
the piston has melted away.
British Car Specialists
Stockton Ca 95205
On Jan 9, 2007, at 7:17 AM, Freese, Ken wrote:
> 1. Swallowed debris
> 2. Detonation
> 3. Defective pistons
> Incidental facts:
> A - oil never filtered only changed for about the past 40000 miles due
> to faulty spin on filter adapter.
> B - last rebuild in 1982 and 70000 miles ago due to melted pistons
> Compression 1997 Compression 2004 Compression 2007
> 165 130 110
> 155 135 90
> 150 145 70
> 150 90 70
> 155 130 115
> 175 150 145
> Any thoughts on the cause until the pistons are actually out?
> Ken Freese
> 65 BJ8