@Triedaq, I just got a call from a friend telling me he bought a “very nice” 1955 Pontiac Star Chief last weekend, and since he knows I have more than a passing familiarity with early automatic transmissions, asked if he could come over Sunday for me to provide my opinion on the condition of the hydramatic. I said ok. Since I know he’s a pretty poor mechanic, I’m going to wind up with more than his transmission on my mind. I recall you had a 1955 Pontiac with engine issues. What were they? I reached into my memory bank, and I remember Pontiac’s first year V8 had issues with rod bearings and the stud mounted rocker arms slipping off their studs. Anything you could share would be a great help, thanks.
@old_mopar_guy My problem with the 1955; Pontiac that I bought in 1962 and got rid of in 1963 was with the stud mounted rocker arms. The oil was pumped up through the studs and lubricated the stamped steel rocker arms. The studs would plug up with sludge and the rocker arms would chirp. One mechanic pulled the studs, soaked them in solvent, blew them out with compressed air. That helped for a while. However, when I would go out on the highway, after about 100 miles, the rocker arms would start chirping. I had the hydraulic valve lifters replaced because the oil to the rocker arms came from the valve lifters. That didn’t solve the problem. There were plugs in the cylinder heads. The Pontiac dealer pulled these plugs out and.swabbed out the oil galley. The problem still persisted.
I bought the 1955 Pontiac from the Rambler dealer. His service department had overhauled the engine before I bought the car. I think the overhaul was really just a sloppy patch that consisted of new rings and a valve grind.
The V-8 overhead valve engine was new in 1955 for the Pontiac. The previous Pontiacs had either an inline flathead 8 or an inline flathead 6. An oil filter on the 1955 Pontiac was an option and my 1955 Pontiac did not have that option. After I bought the Pontiac, I did go to a wrecking yard and bought the oil filter mounting from a wrecked 1955 Pontiac. I removed a plate from the engine and installed the filter. I think some of the problem may have been caused by the lack of an oil filter. To me, it seems strange that an oil filter would be an option because the engines had hydraulic valve lifters and detergent oil was required. I changed the oil every 1000 miles. However, I have no.idea how regularly the previous owners changed the oil. I thought the overhaul done by the Rambler dealer should have taken care of any previous lack of maintenance. While I owned the car, it didn’t use any oil between changes. The engine started reliably, even in freezing weather.
I can’t speak for the Hydramatic transmission. My 1955 Pontiac had the three speed column shift manual transmission. The shift linkage did not work smoothly. I also had to.have the front bearing replaced in the transmission. By 1955, the Hydramatic transmission was reliable and dependable. The manual.transmission was not popular and I don’t think GM cared much about how well it worked.
The 1955 Pontiac did handle well compared to other makes in that time period. However, it did still have the master cylinder for the brakes under the floor rather than the suspended brake pedal and the master cylinder under the hood.
Despite Consumer Reports giving the 1955 Pontiac a high reliability rating, I should have run away from that car. A mechanic that I had done mowing around his home and shop advised me to stick with Fords and Chevrolets. I should have taken.his advice. The problem with oil not getting to.the rocker arms with the shaft mounted rocker arms on the Ford and Chevrolet 6 engines could be solved with bypass oil lines. Kits were available from J. C. Whitney and most auto parts stores. Outside oil lines weren’t possible with stud mounted rocker arms.
By 1957, Pontiac had the bugs worked out of the engines and the engines were really good. In the early 1960s, Fireball Roberts was winning stock car races with Pontiac. The engines had increased in displacement from 287 cubic engines in 1955 to 389 cubic inches in the 1960s.
This is my knowledge of the 1955 Pontiac.
Thank you very much!!
@old_mopar_guy Your welcome! In the spirit of some of the people that post on this site, I may file a lawsuit against GM on all the grief that 1955 Pontiac caused me back in 1962.
The other thing I remember about the 1955 Pontiac engine is that it had some kind of reverse coolant flow through the engine. I am not certain how it worked or how it differed from the cooling system on other engines.
There were three Pontiac models in 1955. The lowest trimline was the 860, the midline was the 870!and the top of the line was the Star Chief. The Star Chief was on a longer wheelbase.
The star chief had a rear deck about the length of my wife’s Hyundai!
Can’t forget the Canadian versions, Pathfinder, Sedan Delivery
I think Pontiac retained the reverse cooling through 1960. If I had one and had the $$$$ I would drop in a later model motor. The early motors had short coolant tubes from the water pump to the heads, if one blew you had to remove the WP to replace the tube.
That’s a lot of work on a car that you owned for only a year. I can’t imagine anyone wanting to buy it except for scrap.
@RandomTroll The 1955 Pontiac was the worst car I ever owned. I was able to dump.it back on the Rambler dealer. My parents had purchased a new Rambler from the dealer in 1960. In 1963, the Rambler was rear ended by a semi and totaled. The insurance company of the trucking company located a similar 1960 Rambler at the Rambler and got a guaranteed price. My dad could either accept the car or a check in the amount. My dad had a 1954:Buick he wanted to sell. He got a price on the Buick in trade for the replacement Rambler and a price on my 1955 Pontiac in a trade in. The Rambler dealer offered more on the trade-in for the Pontiac. I traded my Pontiac to my dad for the Buick and the Rambler dealer got the Pontiac back.
I learned some important lessons on the purchase of the Pontiac. The dealer had installed new piston rings and ground the valves. That is not a real engine overhaul. The hydraulic valve lifters should have been replaced and were not. 1955 was the first year of the V-8 in the Pontiac. There were some problems that needed to be shaken out. As I said in an earlier comment, an oil filter was an option on the 1955 Pontiac and the Pontiac I bought didn’t have that option. In 1955, detergent oil was a recent development. Detergent oil and hydraulic lifters requires an oil filter. I thought that a manual transmission was the way to go. By 1955, a manual transmission on a Pontiac wasn’t common. In fact, when Pontiac first offered the Hydramatic transmission in 1948, 85% of the inline flathead 8 cylinder engines and 50% of the inline flathead 6 cylinder engines were sold with Hydramatic. By 1955, the GM Hydramatic was a very reliable transmission.
I also learned that Consumer Reports is not always right. CR listed the 1955 Pontiac as a model with good reliability. I talked to other owners of 1955 Pontiacs that had problems with that engine.
In 1955, each division of GM had its own V8 engine. I had looked at a 1956 Mercury, but it didn’t have as good a reliability record as the Pontiac. However, it may have been a better purchase. The engine was the Y block V8 used in the Ford. Parts were more readily available. With a rocker arm shaft rather than stud mounted rocker arms, outside bypass oil lines could be fitted if the internal oil lines got plugged with sludge.
Some years later, I owned a Ford Maverick. The Maverick didn’t have a very good reliability record according to Consumer Reports, but parts were cheap and repairs were easy to do.
I learned a valuable lesson from the 1955 Pontiac. I thought a V8! engine with a manual transmission would be cool. It became apparent that a reliable common car with an easily serviced engine made more sense for my transportation needs.
Don’t forget that Chevy had those same cheap stamped steel stud mounted rocker arms on its 1955 V8
@old_mopar_guy The Chevrolet engineers borrowed the stamped steel stud mounted rocker arms from Pontiac. The 1955 Chevrolet 265 V8 also had some problems in its early production. By 1956, the problems with that Chevrolet engine and with the Pontiac engine had been resolved.
Actually, the stud mounted stamped steel rocker arm is.an efficient design. Other manufacturers adopted this design.