Sprint Pistons

[Dolly-Nut]

The preferred choice for performance engines seems to be Mahles but what is the other alternative called fitted by the factory? I believe there were at least 2 different types. Can they be mixed in an engine? The Mahles and whatever the other ones are I just fitted looked almost identical with only a mild casting difference internally.
I now have a couple good spares of each type (Mahle, and JE) in +20 and am wondering whether I can mix them. The JEs are quite different but the Mahles had almost no difference. Obviously they would need to weigh the same and produce the same C.R.

[mikew]

I wouldn't mix, forged and cast pistons need different bore clearance, indeed any piston made from a different alloy will need different clearance as its expansion rates will be different due to the alloy type

[Dolly-Nut]

None are forged, all cast. I'm aware JE and Mahles can't be mixed because they're so different I'm just curious as to whether I can mix the standard fitment types i.e. Mahle and whatever the other type is called because they're basically identical.

[Mad Mart]

Hepolite were the factory fitted pistons.

[xvivalve]

Even if you were to 'balance' them to the same weight, the weight distribution between two types would be different and affect the dynamics of the engine in use.

[Dolly-Nut]

Hepolite

That's the word I was after!!

Were Mahles not standard fitment then?

[Dolly-Nut]

Even if you were to 'balance' them to the same weight, the weight distribution between two types would be different and affect the dynamics of the engine in use.

I agree, although in a Sprint engine for the road below 6k rpm I can't see it being much of a problem. North of 6k it would be far from ideal.

[xvivalve]

Can't you? At only a high idle of 900 rpm those pistons will be stroking 15 times per second, any imbalance will have a negative effect....

[trackerjack]

I read somewhere (so not quoting) that a 2 litre square engine at 5k a piston weighs ten tons to stop and throw it back down or up the bore!

I understand that some factory engines did have Mahles fitted but were never common.

[tony g]

Ive got 2 engines apart at the mo and both have Mahle std size. These are cast and not forged (steel expansion strips inside)

Tony

[soe8m]

You cannot use two different types of pistons in an engine. All the sprints that i ever did see had Mahle pistons.

Jeroen

[Dolly-Nut]

I have also seen a lot of Mahles. I seem to have acquired quite a few in STD bore size, so if they weren't fitted to that many standard engines where are they all coming from?

Why are Mahles the preferred option? They look so similar to the Hepolites you can barely tell.

[soe8m]

Quality.