LMM: Pistons?
- Thread starter Andrewslmm7
- Start date
The cast pistons have a steel insert for the ring land. The forged pistons can not have the steel insert, so the rings are softer (and don't last as long in a DD theoretically). If the rings were harder, they would bash out the aluminum ring land over time in a DD.
It depends on your goals. If you want a high mileage engine at lower power levels use a cast piston. If you are going to turn up the wick, use a forged piston.
The last time I talked to Guy, he recommended a forged piston, because at the higher power levels we seem to get back inside the engines more than most people want to admit.
I have no direct knowledge, but the Fingers piston seems to be a nice compromise between strength and longevity, but I have only "read" that, and I am saying NOTHING bad about the Fingers piston, I just don't know.... :hug:
I am personally struggling between the Fingers piston and a forged set...
It depends on your goals. If you want a high mileage engine at lower power levels use a cast piston. If you are going to turn up the wick, use a forged piston.
The last time I talked to Guy, he recommended a forged piston, because at the higher power levels we seem to get back inside the engines more than most people want to admit.
I have no direct knowledge, but the Fingers piston seems to be a nice compromise between strength and longevity, but I have only "read" that, and I am saying NOTHING bad about the Fingers piston, I just don't know.... :hug:
I am personally struggling between the Fingers piston and a forged set...
Finger bowls are available in Forged too.
It should be noted that the Mahle cast are not the same as the OEM cast. I couldn't tell you the specific alloys and such, but they machine totally differently and are not the same material.
IMO, if you are serious, go forged.
It should be noted that the Mahle cast are not the same as the OEM cast. I couldn't tell you the specific alloys and such, but they machine totally differently and are not the same material.
IMO, if you are serious, go forged.
If you are buying new I wouuld go with Finger's pistons. I reused the ones in the truck, it was something like $220ish to have them cut and coated for all 8.
I'm afraid of forged, I put 20K miles on the truck a year and do starts at -20*F temps
I'm afraid of forged, I put 20K miles on the truck a year and do starts at -20*F temps
Forged pistons, in general, grow more when they get hot than cast. Different Alloys. So Forged pistons require more piston-cylinder clearance than Cast. They slap around a bit more when cold, and tend to blow by a bit more when cold.
The Fire ring on the Cast Pistons is of the Keystone configuration. This design seals better than just a straight ring grove and maintains a good seal through the life of the engine. More durable. However, it places a huge load on the ring lands. So the cast pistons have a steel insert to handle the load. The aluminum lands on the Forged pistons can not handle this load and use a conventional straight land instead. They still hold out well, just not as long as the keystone design.
The problem is my truck is an lmm can't reuse my stock pistons so either way I'm buying new..... Truck is going to be driven not just a trailer queen just want a strong setup for the best price and fingers iv seen videos of marks truck with your pistons sounds nasty! I'd love a set I'm just trying to be price conscious:thumb:
The price for his cast pistons won't be much more than buying new LB7 pistons and having them cut and coated. Saving $3-500 on a 15k build doesn't make much sense when you could risk having an issue down the road.
I meant LLY and LBZs are different from each other. LB7 and LLY are stronger. LBZ and LMM have been known to crack.