912 Head 907 Block

[peteyg]

We noticed on @Nelly Neil's S2 that a previous owner has put a 912 head on the 907 block.

Is there and what would the benefit, if any, of this be? 

Pete

[andydclements]

It could be one (or more) of many things, or it may not have been an "improvement" as just a straightforward replacement of a damaged part such as when a valve breaks or a head starts leaking past the water jacket. There was an improved coolant flow around one of the cylinders.

[peteyg]

Ah OK. I was assuming that there may be bigger valves or larger 'bang' area for the 2.2 over the 2.0.

Pete

[andydclements]

Mike Taylor's document gives a good indication of the differences in the engine configurations.

http://www.lotusbits.com/improving_your_lotus.pdf page 25