Avanti Pistons

[Fourward]

Hi,

   How can you tell if your pistons are original? Also, should the top two rings be identical? My top ring is narrower than the second ring. There is a .007 inch gap between the ring and groove on the first ring. There is a .004 inch gap on the second ring.

[Gunslinger]

First thing...they should be flat top.  If they're dished they're replacements.  

[Fourward]

Thank you. They are flat top.

 

[Leo B]

I recommend to buy a Avanti Workshop Manual. You will find answers from the Manual page 26. You find the manual from Ebay. Also Parts Catalogue is good to have.
From manual:
Two piston rings and one oil ring are used. Both compression rings are chamfered on the inside and must be installed with chamfer up. The top compression ring is cast iron chrome plated and the second ring is cast iron granoseal.
End Cap. Top ring .012" to .020"
Second ring .008" to .016"
Oil ring .015" to .055"
Ring side clearence in the ring groove is very important. Compression rings should have a .0025" to .004"clearence between the ring and the top of the ring groove. Oil ring should have no side clearence.

 

Edited August 31, 2022 by Leo B

[Fourward]

Leo,

   Thank you. I have a Shop Manual, and, never go anywhere without it. As stated above, the top ring is narrower than the second ring. Both grooves are the same dimensions. The top ring has .007 inches of clearance, which is out of spec. They seem to be factory pistons, did someone install incorrect compression rings? Can anyone tell me if their first and second rings are the same size, or is the top one narrower? Thanks.

[Fourward]

Do original, factory Studebaker rings have a dimple that should be on top? Mine do.