quick question for engine techies

[TwoLitrePinto]

if i put 2.8 cologne pistons in a 2.1 pinto and DIDNT deck it, how far down would the piston sit at TDC?

 

im trying to work out the CR on a calculator i found and i need to know the dish size in CC of the piston so basically how much of the bore is left in CC's? how will i work this out?

 

even just roughly would be nice thanks, i know everything else i need.

 

 

EDIT: Sorry i have worked that bit out its 0 lol theyre flat,

 

i need the Piston - Deck clearance in mm with a 2.8 piston. (how much shorter the piston is)

[TwoLitrePinto]

if they sit about 1.8m down from the deck face then im looking at a CR of 8.5:1

 

please tell me the good news lol

[Vista]

I have this quote from an engine builder called Dave Walker

 

To create a 2.1 Pinto - Bore the block to 93.5 (or 94mm), from its standard bore size of 90.8mm, supply KS pistons and rings (2.8 Capri type), fit them to your Pinto rods, deck block by the 1.4mm necessary.

[TwoLitrePinto]

result as i had the head off a pinto today and realised that the standard pistons already sit in the head at least a mil, so that would probably bring the CR to about 8.0:1 which means my skimmed head will be going on to bring it up a tad

 

2.8 pistons are 93mm i think

[TwoLitrePinto]

This is how ive worked it out. I know the CR of a standard 2.0 is 9.2:1

 

Engine bore size: 90.8 mm

Stroke length: 76.95 mm

head gasket bore diameter: 93.5 mm (measured one today)

Compressed gasket thickness: 0.5mm?? (guess)

Combustion Chamber cc's: 50cc

Piston Dome/Dish volume: 0

Piston Deck clearance: 1.13mm (guess)

 

the deck clearance is a guess but give exact CR of 9.2:1

 

now if i change bore to 93mm and add the above 1.4mm mentioned to deck clearance...

 

 

Engine bore size: 93 mm

Stroke length: 76.95 mm

head gasket bore diameter: 93.5 mm (measured one today)

Compressed gasket thickness: 0.5mm?? (guess)

Combustion Chamber cc's: 50cc

Piston Dome/Dish volume: 0

Piston Deck clearance: 2.53mm (guess)

 

that gives a CR of 8.4:1 and if i need to raise it a tad i can just put a mildly skimmed head on with a few less cc's in the combustion chamber.

 

can anyone confirm that the above is correct?