[Healeys] Piston questions

[Andrew Thorp]

Hello Everyone,

I'm part way through reassembling my BN4 engine and have a couple of questions
that somebody may be able to help with.

Firstly, I have aftermarket pistons with a second oil control ring below the
gudgeon and would like to leave it out and change to using a three-piece upper
oil ring instead of the original single piece cast iron oil rings. Has anyone
had good/bad experience running without the lower oil ring?

And secondly, I have read a few comments that 9.5:1 is a good c/r for a road
Healey on premium pump gas. I also read up a lot on 'squish' and quench and
their importance in preventing detonation. After finding my squish clearance
was very big at 0.106" I decked the block 0.067"  to get the generally
recommended ~0.035" clearance. Is anyone successfully running a Healey engine
with higher than 9.5:1 c/r on pump gas? What squish clearance does your engine
have? I am mainly interested in making it more efficient rather than go
faster, it is after all a two-port head engine.

Regards,
Andy.