DeTomaso Mailing List: July 97, Message #437
     



From: JDeRyke@aol.com

Subject: Re: Pinging engine

Date: Tue, 22 Jul 1997 15:31:07 -0400 (EDT)



10-1/2:1 C.R is just too much for iron-head engines with a mild cam. To make

it work, you've got to back way off the timing which causes other problems as

you found out. Three suggestions: -1-pull the heads and slip thicker head

gaskets in there to cut the C.R down. A composite gasket (not a shim-gasket)

will usually drop the C.R 1/2 point. Two gaskets can be successfully used on

each side.-2-try a much wilder cam; this actually reduces the compression

pressure which is what's causing the detonation. -3- if you can find it, try

either racing gas (maybe from ELF), or aircraft gas in 115-145 octane which

burns more slowly thus cutting the chance of detonation. Unfortunately, you

have built a mid-'60s-type engine which just won't live long on mid-'90s-type

gasoline. J DeRyke



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