Rob Christopher <robc@cisco.com>
>
> My engine block is cleaned and painted and will be back in my basement
> this afternoon. Next step is to get the last manifold stud out of the
> head and get it cleaned next week.
>
> While it's at the machine shop, I'll be getting it shaved to increase
> compression from the stock 7.5:1, assuming the head is still stock.
>
> Questions, now, are:
> 1. How do I determine if it has previously been shaved?
> 2. How much do I have removed from the head to bring the compression up
> to around 9:1 or 9.5:1?
>
> Rob
> Ottawa, ON
> 74.5 TR6 CF28217UO
I assume the head is off and the valves have been re-ground and are
installed along with the spark plugs. With the head upside down and
horizontally levelled on a bench, take a measuring cup graduated in
milliliters. Put some water into the cup, note the volume of water and pour
the water into the combustion chamber to determine the volume of water
needed to fill just the combustion chamber.
This gives you the volume for the combustion chamber.
Then knowing the bore diameter and the stroke, mathematically calculate the
swept volume of one cylinder.
Divide the total of the (volume of the chamber + the swept volume) by the
(cylinder swept volume) and you get the compression ratio. If you want to be
really accurate also include about 80% of the volume represented by the
thickneess of the head gasket.
Then caculate the volume of water to add for the 9.0 or 9.5 ratio, add this
water to the combustion chamber (it will be less full) and the vertical
distance down to the water level represents the amount to be skimmed.
Don Elliott, 1958 TR3A - TS 27489 LO
Montreal, Canada
/// triumphs@autox.team.net mailing list
/// To unsubscribe send a plain text message to majordomo@autox.team.net
/// with nothing in it but
///
/// unsubscribe triumphs
///
/// or try http://www.team.net/cgi-bin/majorcool
|