[DeTomaso] WARNING: .050 may be the wrong kind of Bomb

[Dan Courtney]

Paul, very high dome pistons.
This is why I had to go with large cc heads, to keep the compression around 
10.5:1.
The valves are brand new Ferera's, not cheap.
But I'm not sure the damage to the plugs was caused by contact. On #6 the 
tip is still intact, yet the electrode is eroded aprox. 1/4" below / inside 
the threaded case. On #5 the tip is 1/2 intact, and the electrode is about 
1/3" down. I don't see how the electrode could have been impacted while 
being "blocked" by the tip. The tips don't look bent, either.
If the bits and pieces are already gone, I'll proceed to check the 
compression and leak-down.
Assuming it checks out I'll add a couple more rings and go with .045, then 
take it to the Dyno Shop to check the advance, etc. I was thinking about 
having it dynod anyway.

Dan
Dan F. Courtney

La Jolla, CA

(858) 551-5455 Phone
(858) 551-5456 Fax
----- Original Message ----- 
From: "P. Rimov" <rimov at charter.net>
To: "Dan Courtney" <dfcex at excaliburre.com>
Sent: Sunday, May 24, 2009 7:45 AM
Subject: Re: [DeTomaso] WARNING: .050 may be the wrong kind of Bomb


> Dan are you running domed pistons or have you had the heads milled to 
> increase the CR? If so you may need to add an extra ring or two on the 
> plugs of the offending cylinders. It is possible the extra gap on the plug 
> was just enough to result in contact with the piston. Plugs are great for 
> heat but not so good when they are dropped or bumped by a piston.  It is 
> possible the spark plug wire was loose or popped off at some time to cause 
> the #? to foul. I would not start worrying about pulling the heads just 
> yet. What ever pieces broke off in the cylinder are long gone through the 
> exhaust. I would be more concerned about any valve damage from the plug 
> remnants before or while they exited the exhaust valve. Valve damage can 
> easily be ruled out through a compression check and lead down check, but 
> again I don't think you have to start worrying just yet. One last thing I 
> would change your oil and make sure to filter it and check for any foreign 
> material.
>
> Cheers my friend
>
> Paul
> ----- Original Message ----- 
>