What did you're engine builder have to say about the shape of the dome in terms of squish around then edge of the pistons? it looks like the pistons ared designed for a crossflow 4 valve combustion chamber, does that work ok with the kidney shaped 2 valve combustion chamber?

well my engine builder didnt mention the shape of the dome but it is only very slight. He spent a lot of time shaping the chambers and would have taken the dome into considertion. The engine builder is a 4 banger specialist but he hadnt done an A series motor in a decade, however the last one he built was the same specifications and pistons as mine and made a dyno proven 117 hp at the wheels albeit a decade ago.

Impressive. Domed pistons.... wish I could hear that engine roar.

No valve reliefs
Hows piston to valve clearance ?
And what exactly are the pistons out of

What sort of fuel are you using with the 12 to 1 CR?

I know it easily over looked but was the head gasket on front to back they look similar but will leak like a bastard
ONLY a suggestion dont bite my head off!!

cheers
I did this once Ha Ha !!! thats what made think of this

yer i will ask the engine builder what the pistons came out of exactly all i can recall is that they are from some daihatsu. Yes there are no valve reliefs in the pistons and clearance seems to be fine with this cam even though it has 470 thou lift on it, the block has been flycut though as it is running massive valaves. It seems to run fine on premium unleaded believe it or not and it will have too as it is just a street car. In regard to the water leak i believe the head gasket was put on correctly and we think there is a pin prick hole somewhere in the head, probably due to the novelty sized port job!

Yes, a lot of new cars are over 11:1 compression, and they use standard "pump" premium gasoline. No racing gasoline needed.

Quote:

Do you have a custom head gasket to suit? the extra room cut for the valves could be preventing the gasket from sealing properly, because the metal ring around the edge of the bore may be exposed due to the fly cut.

Im sure the head gasket would have been modified to suit the flycuts but i will double check. You would assume that the head gasket would have been modified anyway as the block has also been bored 1.5mm.

finally got the motor fixed, it was a slight leak in the head. She got dynod today to set the webers up and it made 81kw at the wheels, with the dizzy still needing to be regraphed. went for a drive and i couldnt believe how quick it was! it pulls like a v8 and i have to remind myself its all from an a15.

Quote: Your cam has 470 thou lift? Are you sure?

It might be 470 valve lift.That would be fine.