[DeTomaso] Valve Seat Cutting

[JDeRyke at aol.com]

In a message dated 3/8/08 1:18:46 PM, tonydigi at optonline.net writes:

> Was thinking of ,picking up some Neway valve seat cutters and associated 
> parts.  Thinking of
> driving them in my Bridgeport.  Any experience out there or other tips, like 
> what sizes are best for 2v and 4v heads, or positive experience with 
> suppliers?
> 
Unless you have lots and lots of time, I suggest using Lisle seat cutters 
that pilot off the existing guides and are driven by a 1/2" drill rather that 
trying to set up each seat in a mill. The compound angles for 351-Cs make this 
extremely slow to set up correctly; each actual cut will be quick, but.... Pick 
your valve size, then select a cutter to match the seats you want to use. 
Hardened seats are a real pain to grind after being installed; I used Martin-Wells 
Industries 'well-tite' valve seats for low-lead, LPG, propane and diesel with 
no complaints in any performance engine.   I cut the seat reliefs 0.002" 
undrsized (automatic with piloted Lisle cutters), then heated the head up in 
Judy's oven to 350F before broaching the seats in using the same cutter pilot. If 
you degrease the head first, the kitchen will smell of hot degreaser and if 
not, it will smell like charred oil; I suggest a night out for the wife..... Once 
cooled, grind the new seats concentric with the guide also using piloted 
cutters, port as desired etc. I never had a seat come out in either cast iron or 
aluminum heads this way; cold-broaching them in will certainly lose you a seat 
now 'n then, and magic glues don't work at combustion-chamber temperatures. 
FWIW- J DeRyke



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