1951 Pontiac Chieftain 6cyl 3spd 2 door sedan

[Jhudds]

Picked up a 51 2 door with minimal body rust, floors shot, but otherwise in good condition. car has been off the road for 30 yrs, last ran about 5 or 6 yrs ago.

 

We got the engine running and the car rolling. I rebuilt the fuel pump and carb, and she purs like a kitten running off a remote tank. Right now I am running it off a remote tank filled w/ 89 gas and a little 2cyc oil. I put that in there on the first start running when bottlefed, poured that along with a gallon of 89 into a 1 gallon tank to run from. Fuel pump pulls good and the engine idles and revs great. 

 

Need to next tackle tank and brakes. I checked compression when the engine was cold and I had round 90# on all but one, no 3 cylinder was 70# I figure it may come around if it runs a little more. I read somewhere to check compression when warm, will do another compression test to see where we are at. Engine runs around 175 degrees idling, and the radiator hold water with a very slow leak, that will need to be addressed. all gauges and lights work, except radio. 

 

My question is I want to change the oil, this 6cyl has no filter so its just drop oil and refill. What oil do I use can I use a detergent oil in it to try and clean it up and then change right away, of just keep pouring in non detergent? My guess is I also will need to add in a lead additive to the fuel as well as zinc in the oil? please advise.

 

[Ben Bruce aka First Born]

Any good quality 10/w30 or even 15/w30 will be great. No additives needed .   I use 15/W40 in my 1950 Buick.  Pictures?

 

  Ben

[Rusty_OToole]

Detergent multigrade oils came on the market about the time your Pontiac was built. Default choice for oil changes in the fifties and sixties, 10W30 detergent oil, chances are your car never used anything else unless some Goober thought good ol' straight 30 weight was better (it isn't).

You don't need any lead additive today's gas is already too high octane for your motor. I would suggest you keep adding a little 2 stroke oil, or Marvel Mystery Oil, Redex, Bardahl or your favorite upper cylinder lube. Today's gas is too dry and not as oily as gas from the fifties. Some upper cylinder lube will double the life of rings and valves. Will also help prevent valves sticking if the car is not run for long periods, something flatheads are prone to.

[Roadmaster 70]

Look for an oil that has zinc in it. Zinc has good lubricating properties. I think Speed Way Motors had oil for older cars that could use the zinc additive. Diesel oil also has added zinc in it

[Jhudds]

[Jhudds]

So we picked,up a set of cheap cragars with nearly new 225/70 15 rims to replace the old bald bias ply tires. Rebuilt the master cylinder and picked up 4 wheel cylinders, set of front shoes but need to move it to a flat area to work on the brakes, cylinder and shoes. 

[Bloo]

On 4/25/2022 at 9:25 AM, Jhudds said:

My question is I want to change the oil, this 6cyl has no filter so its just drop oil and refill. What oil do I use can I use a detergent oil in it to try and clean it up and then change right away, of just keep pouring in non detergent? My guess is I also will need to add in a lead additive to the fuel as well as zinc in the oil? please advise.

 The non-detergent thing is sort of a myth with a tiny grain of truth in it. Anyhow, like Rusty, I wouldn't assume it has been running non-detergent oil all these years. I believed that myth fully when I was younger. My first car was made in 1953. I was asking about non-detergent oil. My boss at the gas station I was working at said something along the lines of "When this place opened in 55, we already had multiviscosity detergent oil. They called it "Heavy Duty" in those days and we put it in almost everything".

 

There is an oil filter of sorts on a 51 Pontiac six. It is a reversion type in the oil pickup that uses momentum to trap dirt rather than any sort of paper or filter medium. It isn't intended to need service until 100.000 miles. If you are really concerned about sludge, you could drop and clean out the oil pan. That is a good idea anyway, and you could take that filter apart and clean it out while you are in there.

 

Edited June 28, 2022 by Bloo (see edit history)