speedpro domed pistons

I have an old heavy set of those pistons with D3 heads and it runs good with 93 octane. Don't use 87 octane or it will ping!

The old TRW pistons are heavy, heavy, pistons, with pin and rings on the piston mine were over 1,000 grams. You need to keep in mind the size of valve you are running and the size of the valve releif in the piston. I put 2.25 and 1.76 valves in my D3 heads and it is a good thing my cam is only a .530 lift or else it would hit the piston since the valve releifs are not big enough. I have about .080 clearance when I clayed my heads and that is with a 10.322 deck height not 0 decked.

tiger wrote:
The old TRW pistons are heavy, heavy, pistons, with pin and rings on the piston mine were over 1,000 grams.

The L2443 piston typically weighs around 735 grams for the 0.030" overbore version, 760g from the 0.060" version. In fact I took a set of 0.060" overs and milled the dome down to 0.100" tall and now their weight is 736g, just like the 0.030"s in an engine of mine (so now when I bore 0.060" I won't need to rebalance).

Such a piston mass was actually considered to be pretty lightweight in its day. Remember, these are solid-domed pistons, and so the 735g for the 0.030" overbore pistons was not a bad piston weight for its time, especially when compared to the 820g piston weight TRW L2404 of the same era (and that's a dished piston, not domed).

It's really the thick-walled, steel piston pin that adds a lot to the overall weight. Today, most all 460-applicable pistons pins are 2.930" in overall length, but the L2443's pins are 3.300", adding a lot of mass to the assembly. The supplied pin weighs in at about 180g--there's your total piston weight. But since they are used on a 3.85 stroke engine, piston speed is not as critical as is would be in a stroker, so you can get away with the piston weight. Yes, a dome top from a supplier today will weigh a lot less.

Paul