2731 6015 block engine rebuild

[Elise]

Hi,
I'm having my Elan S4 engine rebuilt. Somewhere in its past the block has been replaced and I now have a 2731 6015. My friend who's doing the re-build usually works on porsche race cars so hasn't done much on old lotuses, and we were just hoping someone may be able to give us some advice on a few things?
The block's already been bored out to +20, and we are looking to take it out to +40. has anyone done this on the block I have, and will it take being bored out to +40?

The front cover courrently sits a little higher than the block itself, does anyone know if it should fit flush with the block, or should it infact be a bit higher?

Finally, is there a conversion for the valve guide oil seals or should it be left with no seals?

I hope that all makes sense?? I'd be grateful for any tips/advice...

Cheers
Elise

[elj221c]

Elise,
Have a look here for block info:-
http://www.lotus-cortina.com/library/block/blocks.htm
According to my manual the bottom of the front cover is the important bit. It should be aligned with the bottom of the block with a maximum step of 0.01".
As for valve stem oil seals, some people have used them but there are none as standard.

Roy
'65S2

[Elise]

Thanks Roy,

I'll pass the info on to my friend!

Elise

[bcmc33]

The block's already been bored out to +20, and we are looking to take it out to +40. has anyone done this on the block I have, and will it take being bored out to +40?

Why not +30?

[rgh0]

Taking any Ford 1500 block ( including L blocks) out +40 to 83.5 mm from the Lotus standard 82.5 is starting to push the limits given the tolerances on the castings and the amount of corrossion in the blocks after all these years.

Most will still take it if the boring is done to maximise the available wall thickness through ultrasonically measement and offset boring to centre the new bore in the casting. If you just bore it out on the existing bore centres you may end up with a thin section in the wall that will fail later in service or you may be lucky and its OK.

cheers
Rohan

[Elise]

Hi, thanks for the advice.

We've been suggested +40 because of the wear.

Yes, the inside does look quite corroded, so boring out could be an issue. I think I'm going to have a look round for another block as it looks like the one I have might not take it.

Thanks again,
cheers
Elise