>Thanks for the help. I'm looking at skimming the head vice fitting
> new pistons because of the cost difference, as well as the fact
> that my current pistons and bores look pretty good.
Understood ...
> Do you know of a site on the web that would list the piston dish
> for both the pre-18v and 18v engines, as well as the combustion
> chamber size for the 18v heads?
Combustion Chamber Capacity:
18G/18GG ---> 43 cc +/- .5cc
18V ---> 39 cc +/- .5cc
Piston Dish:
High Compression ---> 6.25 cc
Low Compression ---> 12.8 cc
Assuming that you have the LC pistons and the pre-18V head ...
to obtain a CR of 10:1 the unswept volume would have to be reduced
by approximately 12.8cc so .115 to .128 would have to be removed
from the head face ... 8^0
I'm unable to determine, from my reference material, the maximum
that can be machined from the head face ... perhaps one of the racers
on the list can enlighten us as to what is possible.
As the thickness of the head is reduced you have to ensure that
the exhaust valves do not foul the top face of the block. At full lift
you need a minimum clearance of .062. For example ... the depth of
the combustion chamber was reduced on the 18V head ... this
necessitated machining of the block face to provide clearance for the
exhaust valves.
IMHO ... I'd be fitting a different set of pistons ... Venolia will forge
a set of pistons to your specifications for less than $300.
>Thanks again, and I'll let you know how it goes.
Please do ... best of luck.
Safety Fast! ... larry.g.unger@lmco.com
'61 MGA 1600 MkII
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