Later Head Gasket Thickness

tubbylad

Hello Collective,
I've received the attached head and base gasket from Stein #78610055A as alternative to #78610054A for the 888.

Does anyone have a measurement for a compressed/used #78610054A - my micrometer measurement of an unused part settles upon 0.43mm

Looking to calculate squish by measurement of components and need the compressed dimension of a used part please.

Compared with original thicker head and thinner base gaskets the new parts (0.97mm thick base + 0.43mm head) end up about 0.4mm thinner than original.

Regards

Martin

brad black

i usually allow 0.5mm for them.

Mr.R

The amount of squish clearance has quite an effect on the performance of your motor.
Personally I wouldn't F'ck around with measuring the gaskets to come up with the clearance needed.
I use soft solder spaced out around the piston crown, the solder should be at least 1mm thick.
I generally plait thinner threads of solder together to get it that thick.
Then fit the heads (without the belts) and turn the motor over to squash the solder down to measure the clearance that you have.
What you're looking for is between 0.8 and 1mm, anything bigger than 1mm and the squish clearance isn't doing it's job, anything less than 0.8mm and you run the risk of the piston hitting the head at High revs. Some race teams ran them as close as 0.75mm but I feel it's a bit risky.
It's because of these parameters that I set my motors squish at "EXACTLY" 0.8MM.
It's OK to pull/torque down your heads with the new gaskets, as long as you don't run the motor up it'll be OK to put them in again.
To get the squish "Spot On" I use base gaskets/shims to get the correct clearance, these shims are available in 0.2, 0.3 and 0.5mm so by juggling them you should be able to get it correct, if you need less then skim the base of the barrels until it is correct.
I've NEVER found the need to use the 1mm thick base shims.

A search on the forum could have found this info', so hopefully it's the last time that I need to repeat it?

Steve R