VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Piston replacement

I pulled the head on my 1930 1.5ton truck to replace a blown head gasket and found that this engine has had a hard life. Three of the six pistons are dented from what I assume is metal debris. One of them is cracked on the shoulder above the rings. Please look at the photo on photo bucket. Haven't figured how to attach the photo. http://s1015.photobucket.com/user/tcwells6/media/IMG_1452_zps15e601ae.jpg.html
I plan to replace the piston myself as we don't have anyone on the island I would trust. Any advice or links to previous posts would be appreciated.
The valves were easy to clean up and they look pretty good but not too sure how to clean the recesses of the head or lap the seats. can you point me in the right direction.

Makes me wonder where that part went? Did it exit through the head and out to the muffler or down the cylinder to scratch its way up and down. I would guess that it broke off due to the stress of the ring moving due to rust (or ??) on cylinder wall. In either case a through inspection of the cylinder is advised. If you have questions or problems there are plenty of guys on Chat that have rebuilt similar engines. Some of us have horded parts in anticipation of needing them in the future or bought them so they don't go to make Chinese knives.

"lap the seats" is a temporary repair. Should have the seats regound to the proper angle and width,same for the valves.
To replace piston remove pan unbolt rod cap. From the top it will be necessary to "remove" the ring ridge on top of the cylinder wall and then with the rod "disconnected" the piston will be pushed out - push from the bottom and wil side out on top.
Good time to clean the oil pan and oil pockets above the main bearings. This project has been cover well in the last few months.

Wow...

as for "Good time to clean the oil pan and oil pockets above the main bearings. This project has been cover well in the last few months."

I have done this and HIGHLY RECOMMEND this to be safe and ensure you have good free flow of Oil !!

The cracked part of the piston is still there. My guess is that its been that way for a while.
My big mistake is not doing a compression test before doing the rest of the restoration. I have done the bottom side, the rockers, lifters, starter and electrics.
Looks like I'll be taking the pan off again. My question is should all cylinders be replaced or just the one. I will measure the cylinders before making the decision.

Yes, for sure check the cylinder walls first.
The piston must be an original and in standard size due to the cyl. number being stamped into it.
If every thing else looks good I would replace all the pistons with new cast iron.

I found someone to do the valves. He asked me if I wanted valves seals and I said I didn't think so but I'd ask on this site. Has anyone ever used them on these old motors?

They are not necessary especially for the few miles you will be rooling up in the next 20 years.
I woulld have the head checked for cracks though.

Valve seals and hardened valves are not needed on your engine.

Thanks Guys. I pulled the pistons and they look OK except for the #2. I would like to replace them all with a matched set. The filling station has aluminum but they don't list cast iron. Does anyone know who might have them?
I must acquire a proper gauge before I can measure the cylinders.

Gary Wallace has a set of pistons for '29-'31. I don't know if these are cast iron or not though. Might try giving him a call.

http://www.20schevyparts.com/

Happy Motoring,

Dan

I have several sets of cast iron '29-36 pistons and rings. Send me an email or PM with the size you need.