fundamental differences between a 998 Cooper engine/head

[rolesyboy]

Hi Folks. Just bought my latest project (oops!) and it has a regular 998 engine. What are the fundamental differences between a 998 Cooper engine/head than a Wolseley 998? Especially interested to hear of any block differences. Cheers. Mark

[251 ENG]

Head , carbs , manifolds , pistons , cam are all different .

Some early cranks had different oil drillings

Blocks are identical

[rolesyboy]

Brill, thanks. I have a feeling that the pistons were D topped? Is that right and if I don't have them can I buy them (or get them machined if not?) Cheers. Mark

[Lord Croker]

You are correct in saying that the pistons were 'D' topped, the D shape was in the form of a raised area of the piston crown, although you could probably achieve that shape by machining a flat top piston, it would not give the correct compression ratio because the D area is above the height of a normal piston, something I found out to my cost when I once fitted an 850 head to a 998 Cooper, (in an emergency situation), there was contact between the pistons & the peaks of the combustion chambers. The sharp peaks do not exist on a 12G295 head.