i have a 26 the motor was freshened up with new rings on the cast old cast pistons but i am still getting blow by when driving the block is stock i was thinking of taking the cylinders out ten or 20 and put new pistons in not shur weather to go alum or cast they tell me that the motor needs the wieght of the cast to run right and some say that alum are better less weight on the bearings witch way to go what do you run i want this to be a good driver mike
cast or alum piston
- Thread starter mike37cdn
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Kohnke Rebabbitting
Well-known member
Those that say you need cast for weight to run right, don't take there advice on anything. Herm
John Otis
Senior Member
If you are getting blow by it's probably because the cylinders are a bit oval, the rebuilder failed to break the glaze on the cylinder walls, or that the rings were installed in the wrong order or with the gaps in line.
That being said, I have had lots of T's with iron pistons and several with aluminum. I am sure there is a good argument both ways but Henry sure built a bunch with iron pistons that worked perfectly well. I built a few engines years ago using 312 Thunderbird pistons and they performed great but that isn't to say that a carefully built iron pistoned engine is inferior. I think if I were going for a bore job today I'd probably use oversize aluminum pistons. To freshen up an old engine I'd probably clean things up and re-ring it properly.
That being said, I have had lots of T's with iron pistons and several with aluminum. I am sure there is a good argument both ways but Henry sure built a bunch with iron pistons that worked perfectly well. I built a few engines years ago using 312 Thunderbird pistons and they performed great but that isn't to say that a carefully built iron pistoned engine is inferior. I think if I were going for a bore job today I'd probably use oversize aluminum pistons. To freshen up an old engine I'd probably clean things up and re-ring it properly.
ChiefRider
New member
If you are going to the trouble of a bore job and you plan to really drive the car, use modern aluminum pistons.
Iron pistons generally run quieter, as a plus. The added weight of the iron piston is always a negative, although in practice it really wouldn't matter much.
Iron pistons generally run quieter, as a plus. The added weight of the iron piston is always a negative, although in practice it really wouldn't matter much.
Your choice will be new aluminum pistons, either foreign (China) mfg or Jahns or USA Egge ones.
You can't get 'new' cast iron Model T pistons anyway.
I like the Egge, they make great pistons
Have them on hand prior to the machine shop bore, as they will check the clearance needed for the actual set of pistons to be used.
Lighter piston is better, even in the T days, the fast drivers used lightweight pistons over the heavier cast iron.
You can't get 'new' cast iron Model T pistons anyway.
I like the Egge, they make great pistons
Have them on hand prior to the machine shop bore, as they will check the clearance needed for the actual set of pistons to be used.
Lighter piston is better, even in the T days, the fast drivers used lightweight pistons over the heavier cast iron.
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Kohnke Rebabbitting
Well-known member
Not True, Herm
Doug Money
Senior Member
I run cast because I didn't need to bore. If I were to bore cylinders I would run aluminum. You might also check to see if you are getting valve guide leakage also.