VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 '53 PG 235 oil usage

Assuming all systems being well and the 235 engine with 50k miles with a PG transmission is in a serviceable condition; what would be the normal oil consumption over a 500 miles distance?

Based on the 235 I had years ago, I would say from almost nothing to less than a half a quart. That is with everything up to snuff, including the rings.

Can I assume that running at interstate speeds for the most part with this '54 PG as a rule, consuming approximately 1 qt/ 500 miles is within acceptable limits?

We always figured that 1000 miles per quart was good and down to 500 miles per quart normal for those era engines with that mileage. Most leaked or burned clean as there was hardly ever any blue smoke! Never felt there was a consumption problem until they got to approx. 200 -300 miles per quart. If they got less than that it was a candidate for re-refined oil. Remember that? Often it was in the glass bottles at the best stations so you could see it was not just drained from some other vehicle.

I'm in agreement with Chip on the expected oil consumption. But I’d just like to offer another example. I've had my 1950, truck for about three years. It's about 95% original and has it's original 216 engine with 53k miles on it. It's a good running truck and in those three summers I have put around 10k miles on it and it has never failed me yet. Even though she's not a show truck I take it to a lot of shows because there are fewer and fewer examples of stock AD farm or work trucks every year.
I check the plugs about every 1000 miles and keep it in tune. I did give it a full valve job when I first brought it home and the compression still runs 130 across the board. However, the oil control rings are shot and it uses a quart of Rotella T 15w40 about every 100 to 150 miles. There is no visible smoke on acceleration or deceleration or when driving steady. I drive it in city traffic, and on the highway at 55mph a few times a week and I have never had a black deposit on the AC R45 plugs. When I check them, they always have burned with a nice even tan deposit. I have he usual oil drip from the front and rear seals, so I have a cardboard under the engine but there are no pools or puddles of oil when it sets.
So it is possible to consume large amounts of oil and still have a good running engine. This winter is finally the one that the short block gets bored, fitted up with aluminum pistons and insert rod brgs. Hopefully next summer I can get the oil consumption down to the expected, one quart in one thousand as Chipper mentioned earlier.
Denny Graham
Sandwich, IL

The 1953 Power Glide engines and the 1954 engines (these cars were the first to have aluminum pistons and full pressure lubrication) generally used more oil than the previous models with the cast iron pistons and "dippers". I would assume more oil was thrown onto the cylinder walls. This was back when the cars were new. Consumer Reports even commented on this after experiancing this on their test cars.
When new the "cast iron" cars would generally run a Qt. in 2000 miles and a Qt. in 1000 was good for the aluminum piston cars and some didn't do that good when new. I would assume that the cast iron pistons did eleminate some oil consumption also.
Fast forward to the present time. If the rings have never been replaced on these engines today most use a quart to a tank of gas. Following them on tours I see smoke billowing of the the tail pipes when decending steep hills. I would say the oil rings loose tension after all these years. They still used a cast iron oil ring with a very weak expander behind it where as in the later years a much better oil ring was used. I have seen several of the local cars really puffing smoke at only 35,000 miles and the owners eventually re-rung them.
My 1950 PG with over 50,000 miles has almost no oil consumption and the head has never been off.
I would say a Qt. in 500 miles is exceptionally good for a 1954 that has never been apart. It probably wouldn't have done much better when new.

To the best of my knowledge this 54 PG 235 has yet to be cracked open. She does not puff blue smoke under any circumstance.

Given what I read in the thread above, everything is as it should be with this 235. So I will continue to feed her what she needs when she needs it and she'll continue to take me where I want to go when I want to go there.

Thank you all,

An old Chevrolet mechanic once told me that they started tin-plating the cast iron pistons to keep them from rusting before they were installed in the mid-1930s, and during the break-in period, the tin would redeposit in the microscopic scratches left in the cylinder bores while they were being machined at the factory. When this happened, a near-perfect ring seal was achieved, hence the low to nil oil consumption on the "Cast Iron Wonder" engines. I seem to remember seeing this description of the pistons in sales catalogs even into the early 1950s as being "cast gray iron - tin plated." Can anyone else verify this story?

The tin plated pistons were "new" for 1935. The breaking -in part is correct. The rusting part is not.

What was the rationale behind tin-plating the pistons, then? Seems that the law of "Unintended Consequences" came into play and kept oil consumption low for the owners of the vehicles that used the tin-plated pistons.

For the breaking in period as you first mentioned.
To quote 1935 literature;
One of the most important refinements resulting in a smoother engine performance is the tinplating of the pistons. The piston skirts are ground to contour which provides a greater bearing area and they are plated with tin form .0005" to .001" thick.
The plating has several important advantages. The tin supplies an ideal bearing surface. It is hard enough to carry the load under all circumstances and yet soft enough to fill up any minute irregularities in the shirt. In addition the tin is deposited on the cylinder walls to fill up any irregularities. Therefore shortly after it goes into use , the tin plated piston presents an ideally smooth cylinder bore. As the tin is softer than the cyl. walls, the break-in peroid of the piston is materially shortened and there is little likelyhood of scoring oror scuffing or sticking.

From the book "The Cast Iron Wonder" written by a VCCA founder, he said the the 1935 engines would continue to use oil if they were driven too slowly during break-in. It was necessary to take the car out and drive it wide-open for a whiles to seat the rings.
Tin was in short supply and the 1942 Chevrolets did not have tin plated pistons. After the war a form of zinc as well as tin was used.
If you purchased a new genuine Chevrolet piston for a 1929-34 (after 1935) it would be tin plated. When you remove a tin plated piston you can see where the tin is worn away and it is more silver in that area, The tin made the entire piston appear black.Chevrolet said this is normal and the piston can be reused.
The aluminum pistons introduced on the 1953 Powe glide engines were also tin plated. I believe tha the V-8 pistons wer tin plated also but didn't take time to check it out.