Lucas9214

15 hours ago, Vladislav said:

Looking your pics I dont see a reason you need new pistons. Cylinders relining is too probably on the way and suitable compression rings chosen by the size. When you recondition the liners you just bore new ones to get required gap to the existing pistons. There may be another way of ordering new custom made pistons already oversized to rebore the block. If you find yourself lucky finding a NOS set of oversized pistons and rings for them that's the most straight and correct way.

Those flathead Mack engines were of multiple models and of different displacements. Yours is probably EN354 of 354 ci. But this point definitely needs determination since you should start from it in your search.

Vlad

Thank you for your response, unfortunately that was one of the better pistons that I took out. the skirt on one broke off and the guts on most of the rest are pretty well deformed. I'm afraid that if the pistons aren't properly balanced it could cause a problem at high rpm. I have thought about resizing the cylinders but think it would be best to have a machine shop do that so I was hoping to get lucky finding the original pistons.

Hello, I am in the process of rebuilding a Mack model EQSW with a flat head 6 cylinder Magnadyne engine. When I bought it they said it was a 52 but I'm not convinced of that, I believe it is a 49. It had a seized engine so I had to beat the pistons out and cannot find replacements for them. This is my first post and I'm far from a professional mechanic but any help would be appreciated.