Hi
If the head bolts are the normal non torque to yield type then they can be reused.
Compression wise it is the old chestnut of depends on your cam but assuming fairly normal cam timing (standard cam of a little more timing) then I would think 10.25:1 is the upper limit on the rover on unleaded petrol so your 9:75:1 is safe.
How long is it since the shells were last changed? as if it was less than 60k miles ago I can't see why you would want to change them, again I presume this is a pretty standard lump. If I was to freshen anything then it would be cam and tappets, over about 25-30k the cam is loosing lift over a new one.
Best regards
Mike
thankyou mike , i intend to use second hand pistons and rods so for the sake of £18.00 i was going to change the shells for new ones
it is a very std engine , just it's only 8.13:1 at the moment ...
anyone got any 9.75:1 pistons sitting around collecting dust ....???
Your head gaskets depend on your head combustion chamber volume. If you want to use composite gaskets with tin-gasket-heads, then you need to skim 1mm from the heads to allow for the thicker composite gaskets.
I would skim and fit composites with old style head bolts.
if you are upping the CR you should see brtter peek torque and peek power however your LPG set up should strangle all the peek power gain out of it! If you are on lpg you really want to get the CR up much higher but that is another issue!
Mike
If 9.35 CR is with a comp gasket then use a tin one and gain a bit more compression, just have to shim the rocker shaft pedistals a bit . I would rather use a tin gasket as it gives you a slightly better squish.
Mike
. I would rather use a tin gasket as it gives you a slightly better squish.