Oil in a 1936 Pontiac?? Help please

[Dauphinee]

Ok I am getting the oil changed in my 1936 Pontiac inline 8.

I believe I was told straight 40 weight oil.

Is that correct?

what about tranny oil and rear end oil??

[JFranklin]

You need to find an owners manual for your car, it would have all the right answers. I think 30 wt oil would be more like what it needs.

[jpage]

I would use a multiviscosity 10w-40 . If it hasn't been cleaned in a while I would suggest you drop the pan,clean out the sludge and double check the dipper tray specs. I would also clean out the valve lifter trays and clean any oil tubes and oil pickup strainer. I would also use 140 wt. oil in the tranny and rear end. It's about the same consistancy as the old 600w or heavy oil used in those cars.

[Rusty_OToole]

30s Pontiacs have an unusual feature, an oil filter inside the oil pan. I don't know if it needs to be changed or cleaned out periodically. Might be worth asking on the Pontiac board just in case it needs some special service.

[Guest]

30s Pontiacs have an unusual feature, an oil filter inside the oil pan. I don't know if it needs to be changed or cleaned out periodically. Might be worth asking on the Pontiac board just in case it needs some special service.

I have heard that this particular strainer needs to be done every 100,000 miles. I would be doing this much more frequently. The strainer system is almost identical to air cooled VW's and early Porsche's, except that in the VW & Porsche the engines have a simple cover plate that you remove to pull out and clean the strainer---EVERY oil change which is 1,500 miles or six months. There was a article in Hemmings Classic car magazine on Pontiac flatheads last year that mentions this strainer and oiling system.

The Pontiac service manuals actually call for 20W oil in summer, but I would run 30W. The trans and rear end need just 90W gear oil to be happy.

D.

[Guest Pete Woodruff]

SAE 40 is too heavy unless you live in a desert with temps over 90F all the time. SAE 20 or 20W was the recommended oil, and 10W-30 is the accepted replacement. These engines originally had cast steel pistons, if your engine has been rebuilt with aluminum pistons, SAE 30 would be acceptable as they have more piston to wall clearance when cold. The oil cleaner Pontiac used was a reverse-flow precipitation-type filter and exclusive to them, as far as I have ever known. The oil flow reversed direction abruptly within the unit causing any particulate matter to fall into a large sediment bowl. This unit was intalled in Pontaic six and eight cylinder engines beginning in 1941, and could be retro-fitted back to 1937. It works effectively with detergent or non-detergent oils and I don't belive any other auto manufacturer ever used such a system.

Your transmission calls for SAE 140 above 60F, although SAE 90 EP was also acceptable. This is a mild EP lube, not the current GL-5, which is not acceptable in early manual transmissions. It is corrorsive to yellow metals and is too slippery for proper synchronizer performance. You need to find a GL-1 equivalent gear lube, Pennrite is one source.

[Guest]

Pete, thanks for the information you provided. I have a question for you. Earlier this month I was allowed to participate in the Flathead reunion here on the west coast. My house is about twenty minutes from Morro Bay so I thought I would take a chance and ask if I could attend. These guys are great and it's refreshing to find a group with the attitude of keeping these cars stock and NOT hot rodded. During the tech session I asked the group about this strainer being cleaned and the general consensus I came away was 100,000 miles on the oil change or basically overhaul to overhaul. I also asked about valve adjustment interval remembering my dad adjusting valves on our 1950 eight and my dad saying how important this was. Most of the guys in the group said they never adjusted their valves with the exception of a couple who said to adjust them when they get noisy. Having grown up in a Pontiac, Oldsmobile, VW world and being in the automotive industry for over forty years I know first hand that it's not the noisy valves that are as critical as a tight valve. Just wondering what is the interval? Someday I plan on joining the ranks of a Pontiac owner of a Flathead Pontiac Eight again.

Don

[Guest Pete Woodruff]

Don, unfortunately my schedule did not permit me to attend the Flathead Reunion west. You are correct that the oil cleaner was intended to function for 100,000 miles, but the service maunal also advised cleaning the sediment bowl whenever the oil pan was removed for service; of if the vehicle was involved in a roll-over accident, as the sludge would fall back into the engine. As for valve adjustment; the Pontiac engine was pretty well designed for its day and many people that I have talked with over the years claimed that 30,000 to 50,000 miles was possible between adjustments. I have yet to adjust the valves on my '53 Chieftain, which is a survivor with 87,000+ showing on the odometer. I got it with 65,000+ and it still runs smoothly on all 8 cylinders. I do have a loose rod bearing though, it knocks when first started; so I am going to have to open the engine for service. I do keep the engine tuned and pay close attention to the idle quality. So far, there is no indication of any "tight" valves; including checking with a vacuum gauge. I personally service my cars based on apparent need, not by mileage interval; with the exception of anti-freeze. I do service the cooling system every other year.

Pete

[Guest Water Jacket]

Dauphine, Dr. Woodruff is right about 10W/30 for your Pontiac, or most any '30s, '40s automobile, assuming good repair, etc.

I'm a Packard man, and the above info about the Pontiac filter is new to me, but otherwise, there's nothing exotic about your or our cars, and 10W/30 flows quickly during start up, protects over the road.

I use Kendall GT-1 10W/30, but Consumers Reports ran exhaustive 60,000-mile testing of all the major oil corporations' motor oils, as well as independents like Valvoline, Quaker State, Castrol (but not Kendall) and found no discernible difference in wear in the NYC taxi fleet they used.

I use Kendall because they've a good name, i'm sentimental, and it smells nice. But Dr. Woodruff is right.

[PONTIAC1953]

I would use a multiviscosity 10w-40 . If it hasn't been cleaned in a while I would suggest you drop the pan,clean out the sludge and double check the dipper tray specs. I would also clean out the valve lifter trays and clean any oil tubes and oil pickup strainer. I would also use 140 wt. oil in the tranny and rear end. It's about the same consistancy as the old 600w or heavy oil used in those cars.

dipper tray specs ?, this pontiac engine should have full pressure lubrication, not dippers like the chevys would have. charles coker, 1953 pontiac tech advisor.

[Guest]

Hi Charles, you are correct about full pressure lubrication on Pontiac's. I would also add that when doing a oil change that zink and phosphate additive should be used to protect camshafts even though the Pontiac flathead has relatively low valve spring pressures.

D.

[Guest bofusmosby]

If I am not mistaken, the non-detergent oil that these Pontiac cars used when new is a bit different that the modern HD oil today. The old oil would have a tendency to have the "sludge" settle, in which case the filter inside on the oil pan would collect these impurities, to be cleaned when the oil pan was removed. The modern oils today (the high detergent oil) is designed to suspend these impurities (sludge) so that the oil filter can filter out this stuff. With modern oils being used today, wouldn't that have an effect on the efficiency of the original strainer's operation?

[Guest]

Jim, In my above thread I stated that VW-Porsche used this type of strainer and only difference is that their design allows you to remove the strainer with ease and the strainer is to be cleaned every oil change. when you pull the cover plate to get to the strainer there is always some sediment on the plate and when you remove the strainer itself you can get your pinkie into the bottom of the engine case where you will also find some sediment ( sludge if you prefer ) there. I have put many thousands of miles on these type of engines using high detergent oil, but I gotta tell ya the heavy stuff still accumulates at the bottom. The less often the oil changes the more sludge though, that's why with that type of system VW was calling for a oil change of 1500 miles. Even when I built a 455 Pontiac for my car that had been in another Pontiac with 96,000 miles and a full flow oil filtering system there was still sludge in that engine.

D.

[Guest bofusmosby]

Thank you for your insight "D". As a matter of fact, everything that I have learned about these old cars are because of members like yourself. In my car, I use 30 W HD, and since I have not installed an oil filter yet, I change my oil every 1000 miles, or 6 months, just to make sure that engine wear is reduced as much as possible.

Now to get my engine up and running good again......

[Guest]

Now to get my engine up and running good again......

Don't worry Jim, we will help if you need us. I just don't want you to end up like our friend here;

http://s1.hubimg.com/u/4922892_f520.jpg

Don

[Guest bofusmosby]

Don't worry Jim, we will help if you need us. I just don't want you to end up like our friend here;

http://s1.hubimg.com/u/4922892_f520.jpg

Don

Too late on that one my friend!

[Ben Bruce aka First Born]

Hey, I resemble that man, bed and all!! LOL.

Ben

[Guest Pete Woodruff]

The oil cleaner phsyically removes foreign matter large enough to cause damage to the engine bearings. The use of modern oil will not effect its operation, the ultra-fine matter that causes discoloration of the engine oil with use will be held in suspension by the dispersant additives and drained out when the oil is changed.

Since not all of the ZDDP has been removed for API-SM motor oil, the use of any reputable brand of 10W-30 oil should provide more then enough protect to any flathead 6 or 8 cylinder Pontiac engine. I make no claim for other brands of automobiles as I have no personal experience with them.