>TeriAnn,
>
>Why does it seem like you don't think the early uncamphored head should be
>used with anything other than 83mm pistons?
Sorry if I gave that impression. What I was trying to say is that I
believe that the factory never knowingly sold Triumphs with uncamphored
combustion chambers and 86mm pistons (Well maybe initially when the 86mm
pistons first became an orderable option).
It is my understanding that the factory matched heads to pistons:
uncamphored heads to 83mm pistons and cylinder heads with camphored
combustion chambers to 86mm pistons.
The camphor was added to to keep the compression ratio down to 9:1 when
using the 86mm pistons.
>I had figured the 87mm pistons took the CR up to around 9:1, maybe a bit
>higher, but with the uncamphored head, I wonder just how high it really is.
Maybe someone with a unmilled uncamphored head sitting around could cc a
chamber and run the numbers for 87mm pistons.
With 86mm pistons and the extra volume in the combustion chambers created
by the camphor you are at a nominal 9:1. You added a little bit to the
swept volume and have significantly less compressed volume.
I suspect your compression ratio is a tad higher than 9:1. I hope
someone has the combustion chamber + head gasket volume and can run the
numbers.
TeriAnn Wakeman Marigold Ltd.
Santa Cruz, California Web design, site updating, testing
webmaster@overlander.net search engine optimization, graphics
and more
http://www.overlander.net/Marigold/index.html
|