[Spridgets] Engine guru's Mk II..

[Andy Webster]

OK...I have never done it before, but I would expect , with all 1098 internals in a 948 block , that you will have pop up pistons! The 1098 crank has the longest stroke.
  I would expect the pistons to pop up by approximately 0.5 x the difference between the 948 stroke length and the 1098 stroke length.
   
   
   
  0.5(83.82mm - 76.2mm) 
   
  = about 3.502mm to be taken of the top of each piston..plus whatever you mill of the block to get it flat.
   
  If I am talking crap then i am sure someone will let us all know.
   
  Andy

Lester <oldsaabguy at comcast.net> wrote:
  Good afternoon all,

some more questions if you don't mind regarding performance changes:

as a reminder..
948 block bored 60 over,
1098 head that has been ported and milled to 22.6 cc combustion chamber,
1098 small journal crank
1098 lightened and statically balanced rods


Will a 1098 piston end up with lower compression due to pin-face 
height differences?

Will a 1098 piston (of appropriate diameter) end up being a "pop-up" 
piston?

Can I measure the lobe height minus the lobe height opposite to 
determine lift on a cam (Are the rockers a 1:1 ratio?)?

When you look at where I am going with this what jumps out at you and 
screams "NOOOOO!!" ?

.. and I can not find this info in Vizard/Haynes/Factory manual. 
Vizard lists all sorts of info on aftermarket stuff but little on 
stock stuff that I can find

Thanks again!

Lester
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