VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Aluminum pistons? 29 rebuild

I sent my engine out for rebuild. I am curious if the mechanic installs aluminum pistons will this be a problem? does the balance change? Are cast iron pistons available?
Thanks, Pete

Cast iron pistons are available from a few people that have horded them for years. They are older stock from 50+ years ago. Once the machine shop knows what bore will clean up the block then piston oversize determined.

I have used cast iron pistons in all my recent rebuilds. Used aluminum many years ago and went back to cast iron for several reasons.

I also recommend cast iron pistons as well. They work just fine, especially if you have the engine balanced. If Chevrolet wanted to use aluminum pistons in their 1929 engines they would have done so.

I put aluminum pistons in our '31 in 1960. Almost 50,000 miles and still running fine with no problems. Haven't removed a rod shim to date. These are .020 oversize. What ever floats your boat.

I need to cast my vote for aluminum. Owners tend to drive their cars faster these days - out of necessity. Simple physics indicate that lighter weight pistons will function better at higher speeds and significantly improved the life of the rod bearings if they are babbitted.

If you are going to drive a lot on dirt or middy roads at low speeds, then, by all means, stay with cast iron. (Or if you are restoring a truck).

But most people will be happier in the long run with light-weight aluminum.

--Bill
I've been aluminum since 1972.

I have never had a problem using aluminum pistons.

Alex Taub is reported to have said cast iron pistons were less expensive.

The cast iron pistons were more durable than aluminum pistons made in the '20's and '30's
The lighter aluminum pistons are much lighter and easier on the rod bearings if you drive at higher speeds.
I have used aluminum in my cars and my 1950 has the original iron and engine has never been apart.

I have a 31 which had aluminum pistons when I tore it down for rebuild. They measured out fine so I simply put them back in. I have driven the car about 3,000 miles, runs perfectly and smoothly.

I'm curious , when did they switch to Aluminum? Your 1950 has cast iron?

First year for aluminum was 1928....correct....for one year only.

first year for 6 cylinder engines was the 1953 with Power Glide.
From 1954 and up all were aluminum.
Previous engines were limited to 4000 RPM and produce most power at 3200 Rpm. The newer more powerful and higher reving engines required lighter pistons as they could atain up to 5000 Rpm and produed the maximum horse power in the 3500 to 4000 RPM range.
The 1929-1933 engines prdouced their power under 3000 RPM.
The 1929-1936 engines used the same pistons with some improvements made through the years. The pistons weighed 1.83 pounds.Pistons Were lighter for 1937 and up, 1.42 pounds.
The aluminum pistons are 30 to 40 % lighter.