On this subject I must throw in my .02. If I were to do this again I
would make my compression increases with the piston NOT milling the head.
Only mill the head if you have to get it true if it is warped. Using the
pistons to increase the compression is the best way to go.
aaron
On Wed, 18 Nov 1998 rgb@exact.com wrote:
>
> Camshafts, I used the Good Parts S2 cam in one car and
> the TR5 early TR6 PI cam in the other, both idle fine, I was
> surprised, this with stock carbs. The former has 10 to 1, the
> later 8.5 to 1. This is one place NOT to get carried away as
> you'll likely want to mill the head again later and you start
> stressing pistons, gas octane, etc. 9.5 to 1 is a good maximum.
> (this gives you a little room for error and remilling).
>
> Don't forget when you bore the engine the compression increases
> due to the chamber ratio change... include this in your calculations!
>
> Talking how much to take off the head is an error...
>
> Use the final thickness of the head as the measure. These heads
> came in differing thickness and may have been milled before.
> (example: anyone want a 14 to 1 head, I have a spare...)
>
> If you use the S2 or PI cam and moderate head milling the
> geometry will match perfectly. These cams have a smaller base curve.
> (see the mix of cams and pushrods part numbers for PI cars)
> (believe PI or S2 cam and 9.5 to 1 head use the same pushrods as
> US cars, better double check this...)
>
> >putting .060" shims under the rocker gear to maintain rocker geometry
>
> Wrong, this is just plain wrong, short pushrods is the only proper way
> correct this, draw a diagram, this is obvious. THINK!
>
> If you really mill the head, the easy way is to measure the geometry after
> its done and order the pushrods cut to length... Brit Frame and
> Engine will do this.
>
>
> --
> Roger G. Bolick, rgb@exact.com 512-794-9567, FAX 512-345-2879
>
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