Cast Pistons

[Ianashdown]

I am going through a recently acquired Twin Cam kit of parts. It has 0.030” oversized cast pistons which are in good condition, and I think the bores can be recovered with a light hone.

This engine will be built with very mild tune to power my ‘61 Lotus 7, which will, I hope, give plenty of power for such a lightweight car.

My question is: are these cast pistons worth using at all or are forged pistons an automatic replacement.

Thanks

Ian

[512BB]

Absolutely nothing wrong with cast pistons, I use NOS cast pistons all the time in my rebuilds. Obviously you will need to use a new set of rings. What I have found though, is that the weights of individual pistons can vary a lot between the set and careful shaving needs to be carried out. Also make sure that the slots that the rings fit into is within spec, and not sloppy.

Leslie

[elans3]

+1 for cast pistons, no need at all to go forged unless you're building a proper competition engine.

[StressCraxx]

I replaced my original std bore pistons in 1982 with 0.020" oversize cast pistons. Another 100K miles, we rebuilt with new rings on the 20 over pistoins. Still good.

[Ianashdown]

This is good news! If I can get a good finish in the bores with a light hone I should be able to re-use pistons and rods. The crank needs to be replaced I think, it has some rust that may be a bit too deep and is a 4-bolt. I’d like a 6 bolt and I’d like to keep the standard stroke. What is a good crank to use?

Thanks,

Ian