Cast iron or Aluminum - 01/15/06 05:43 PM
When did Chevy change from cast iron pistons to aluminum ? Thanks
Re: Cast iron or Aluminum - 01/15/06 06:11 PM
1928, the last 4 cylinder.Had a very modern looking steel strut aluminum piston.
The first 6 cyl. was the 1953 235 Power Glide engine.Was the up dated engine with full pressure oiling and rod inserts.
The Canadian Pontiacs that used Chevrolet engines back before WWII had aluminum pistons and a 3 9/16" bore....giving 224 C.I.
Strange because Pontiac flat head 6 and 8 cyl. engines had cast iron pistions.
The later 235 aluminum pistons can be used in 1941-53 235 engines that had iron pistons.Will raise the compression ratio by .4 as the come up level with the top of the block.
They can also be used in a bored out 216 but will come up slightly higher than the top of the block surface.
For an engine that is not driven over 50 MPH and used mainly for low speed driving the cast irons are a good choice.
The first 6 cyl. was the 1953 235 Power Glide engine.Was the up dated engine with full pressure oiling and rod inserts.
The Canadian Pontiacs that used Chevrolet engines back before WWII had aluminum pistons and a 3 9/16" bore....giving 224 C.I.
Strange because Pontiac flat head 6 and 8 cyl. engines had cast iron pistions.
The later 235 aluminum pistons can be used in 1941-53 235 engines that had iron pistons.Will raise the compression ratio by .4 as the come up level with the top of the block.
They can also be used in a bored out 216 but will come up slightly higher than the top of the block surface.
For an engine that is not driven over 50 MPH and used mainly for low speed driving the cast irons are a good choice.
Re: Cast iron or Aluminum - 01/15/06 06:12 PM
I believe it was 1953 with the "Blue Flame" 235 cu. in. 6 cyl. that also had full oil pressure lubrication.
Re: Cast iron or Aluminum - 01/15/06 11:00 PM
The 1953 235 full pressure engine was powerglide only, however. Of course that has nothing to do with whether or not it had aluminum pistons.
Re: Cast iron or Aluminum - 01/15/06 11:17 PM
Thats correct-the PG engine only was called the Blue Flame in 1953-and the first Chevrolet engine to be painted blue.
Re: Cast iron or Aluminum - 01/16/06 01:05 AM
I disagree with the 50 mph or less speed for cast iron pistons. Also The 1932 -'53 engines were counterbalanced for cast iron pistons. If you use lighter weight aluminum or alloy pistons then the counterweight will be too heavy for the piston/rod assembly causing an imbalance. Therefore I believe that it is best to use the pistons that were designed for the engine.
Based on my personal experience after rebuilding '31-'32 engines with both aluminum and cast iron pistons I now only use cast iron.
Based on my personal experience after rebuilding '31-'32 engines with both aluminum and cast iron pistons I now only use cast iron.
Re: Cast iron or Aluminum - 01/16/06 01:37 AM
I'm a cast iron man too. I have been driving my 1951 Chevrolet with a 216 engine and cast iron pistons at highway speeds since 1960 and I have never had a problem whatsoever. To this day I still drive the car 55 to 65 MPH with ease and the car loves to cruise right around the 60 MPH mark...and that is with a 4.11 rear end also.
Re: Cast iron or Aluminum - 01/16/06 01:39 AM
I was using 50 MPH as a consertive figure....I know of a lot of 216s with 4.11 rear ends that are constantly driven at 65 MPH with no problem.Wouldn't recommend that speed on a pre 1937 for long distances and with a 4.11 rear end.
The crankshaft of any 6 cylinder engine does not require rebalancing when different weight pistons are installed.Chevrolet did nothing to change the weight of the 235 crankshaft when they went to aluminum pistons.The only thing they said they changed due to the aluminum pistons was to decrease the width of the rod bearings because -in their words "The lighter pistons impose lower reciprocating loads".
This is not true for a V8...if different weight pistons are installed the weight of the crankshaft (counter weights) must be "adjusted" accordingly.265 pistons were only used with the correct 265 crank-283 crank was balanced for use with the slightly heavier 283 pistons.Chevrolet even sold a balancing kit for use when the high domed Fuel Injection pistons were used with the regular 283 crank.
McGurk's balancing comments are "On a 6 cylinder engine,changing piston weight does not affect engine balance, providing all of the pistons are in balance with each other,However, it is not true on a V8 type engine".
Both of my converted cars have extreemly smooth engines, both at idle and at high speed and the engines are more flexible with the less reciprocating weight of the pistons.
The crankshaft of any 6 cylinder engine does not require rebalancing when different weight pistons are installed.Chevrolet did nothing to change the weight of the 235 crankshaft when they went to aluminum pistons.The only thing they said they changed due to the aluminum pistons was to decrease the width of the rod bearings because -in their words "The lighter pistons impose lower reciprocating loads".
This is not true for a V8...if different weight pistons are installed the weight of the crankshaft (counter weights) must be "adjusted" accordingly.265 pistons were only used with the correct 265 crank-283 crank was balanced for use with the slightly heavier 283 pistons.Chevrolet even sold a balancing kit for use when the high domed Fuel Injection pistons were used with the regular 283 crank.
McGurk's balancing comments are "On a 6 cylinder engine,changing piston weight does not affect engine balance, providing all of the pistons are in balance with each other,However, it is not true on a V8 type engine".
Both of my converted cars have extreemly smooth engines, both at idle and at high speed and the engines are more flexible with the less reciprocating weight of the pistons.