>
>In a message dated 97-04-03 17:57:18 EST, Joe writes:
>
><<
> Friends of Triumph.
>
> We have one book that says that .125 milling will get you about 10.5:1
> on a TR head and this seems to be borne out by one of the FOT
> calculations.
>
> The book goes on to say that .150 milling can be done without any
> trouble but later on it says that .250 is achievable.
>
> Our preliminary look says that it will take about .185 to get near
> 11.7:1 (without pop-ups.)
>
> THE QUESTION:
>
> If I have to take off .185 of the head, what are the consequences, if
> any?
>
> Clearances? Thin castings to water passages? Thin squish area?
>
Joe-
Ok its time for another OPINION...(and remember, you get what you pay for)
I've run 150 off the head on several different heads with no trouble. One of
those heads, I cut another 010 without a hitch. Spurred on by this success,
I went to 175 off and promptly lost the top of the squish area. Turned that
head fom a useful racing part immediately into a piece of expensive "art".
Ihave heard tales of people cutting the head at an angle so that the squish
area remained as thick as possible. As I have never actually tried this, it
remains "urban legend". Lou Ghillotti, who raced a TR3 back in the dark
ages, told me he had done this, but I can not actually corroborate the
practice. My personal guess is that 250 off the head is not a good idea
(unless you have one of those 6" thick Massey Ferguson tractor heads.
As I see it, the real question here is, why not just go to a pop up piston ?
In the long run I think it will actually be cheaper to maintain and replace
pieces.
Definetly a head case myself...
Nick in Nor Cal
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