GT6 mk 2 &3 engines

[Pete GT6]

I was wondering if anyone can tell me if are there any other differences between the GT6 mk2 and mk3 engines other than the; rocker cover, crank case ventilator, smiths emissions valve, oil filler cap, vacuum piping and Carb change stated in the John Thomason book - guide to originality?

Are the rest of the engine internals, pistons, conrods, bearings, block and head the same and intercompatable? 

Guess what i am asking is could you make a mk3 engine into a mk2 and visa versa with just a rocker cover/ head change?

Also are exhaust manifolds different?

Thanks Pete

[Pete Lewis]

everything on the mk2 engine across the gt6 vitesse range is   basically interchangeable...but ...........

there are subtle changes but that doesnt affect whether it fits or not   , 

manifold porting is identical on all mk2 engine designs

 you MUST with later blocks with recessed bores   different head gaskets and  deep heads  with domed pistons are required as matched  designs

cam timing may vary a little as state of tune changes but all will fit 

just from memory,

just  off the dump all the gear at Duxford   for sunday 

Pete

[Gully]

It depends really how early a Mk3 engine it is. Prior to KE10001 the engines were pretty much identical - just tweaks to the carbs and air box. Thereafter there were changes brought about by the standardising of heads with the 2000 saloon - domed pistons were introduced, along with a milder cam and longer push rods. Compression ratio dropped from 9.25:1 to 9.0:1. As Peter has noted above, the change in heads corresponds with a different gasket to work with the recessed bores.

My early Mk3 (engine KE154) retains the same oil filler cap and crankcase ventilation set up as the Mk2 engine.

Gully