Lead additive in 1940s AC tractor ?

[94ranger55]

I am getting a 1940s AC tractor this weekend !! My question is, should a lead additive be used in the gas ???I figured since its from the 40s the engine was designed to run on leaded gas .What do you guys think ??? Thanks !

 

[jdemaris]

I am getting a 1940s AC tractor this weekend !! My question is, should a lead additive be used in the gas ???I figured since its from the 40s the engine was designed to run on leaded gas .What do you guys think ??? Thanks !

Not needed unless this a work tractor that's going to run 8 hours a day, 5-6 days a week. Even then, in the long run it would be more cost-effective to run it until the valves get too deep and leak. Then pull it apart and do a valve job with new hardened seat inserts. Overall that will be cheaper then buying any additive (which won't have lead in it).

The only issue with non-leaded gas in older engines is valve-seat recession during high RPMs, high heat, hard use and long hours. Not usually an issue with a part-time use collector's type of machine.

I'd be more concerned about what motor oil you use. Most motor oils sold since 2009 or highway use lack the ZDDP lube-additives needed for flat-tappet camshafts - like your AC has - along with just about all other cars and tractors made mid-1980s and back.

 

[94ranger55]

The tractor has been sitting for some time but she fires right up !Any recommendation for what motor oil to use ? I am a little rusty on my antique oil types...if i remember correctly non detergent is used for the older rigs ????Also what other things should I change ,check or add ie tranny fluid .Also i assume a regular grease that you would use on a modern day industrial tractor would be sufficient?

 

[Highbeam]

I have a tractor and sold an old international crawler that I had run the snot out of. These machines are owned and run by special people. They have their own forums, especially for something from the 1940s. I would seek that forum out.

Modern EP grease is fine for chassis grease.

 

[semipro]

I have a tractor and sold an old international crawler that I had run the snot out of. These machines are owned and run by special people. They have their own forums, especially for something from the 1940s. I would seek that forum out.

Modern EP grease is fine for chassis grease.

+1 Seek out the experts. I've heard you can really get into trouble running detergent oil in an engine that's only ever seen non-detergent oil.

If its ever had a valve job chances are that hardened seats were installed and lead is not needed. As was said earlier, its probably cheaper not to use the lead additive regardless.

I suspect just about any modern oil is much better that what was available in the 40s but again, the experts would know.

 

[jdemaris]

The tractor has been sitting for some time but she fires right up !Any recommendation for what motor oil to use ? I am a little rusty on my antique oil types...if i remember correctly non detergent is used for the older rigs ????Also what other things should I change ,check or add ie tranny fluid .Also i assume a regular grease that you would use on a modern day industrial tractor would be sufficient?

A 1940s AC tractor engine isn't much different then one built in the 1970s. Very little difference in technology.

The isssue of non-degergent oil versus degergent oil is this. If a tractor is old and wasn't maintained very well - it could have inches of sludge built up inside the engine. Especially in the oil pan and valve-cover (if an overhead-valve engine).

If you dump in high degergent oil into an engine that is that dirty inside, stuff starts coming loose. If that happens rapidly, it could damage the engine -but that's kind of rare.

If you have no past history of maintenance - and have no idea of the internal status of the engine - there are two simple approaches. 1st. Just use non-degergent oil and play it safe. 2nd. Put in a detergent oil and watch the dipstick closely for oil color. If it turns black real fast, you might want to put in non-degergent oil instead.

Note that even old tractors run for 50-60 years with non-detergent oil - can be fairly clean inside. All depends on how they were run and what sort of maintenance they got.

 

[jdemaris]

I suspect just about any modern oil is much better that what was available in the 40s but again, the experts would know.

Just about all motor oils made since 2009 that are intended for cars and trucks driven on highways have LESS anti-wear additives, not more - then older oils.

Thus the benefit of buying off-road, racing, or tractor oil for older machines.

 

[EKLawton]

got an old MM im working on, Went to mobil oil web site and they recommend 20-50 racing oil.

 

[jdemaris]

got an old MM im working on, Went to mobil oil web site and they recommend 20-50 racing oil.

Funny you mention a MM. The 2009 and newer highway oils cut back on the anti-wear ingredients that keep flat camshaft followers from wearing.

Out of the many brands of tractors I've worked on, built from the 1920s up to 1980s - the MMs are the only ones where I've found cam and lifter wear problems. If I had an MM engine with those wierd long rocker-type lifters that you access from the side - I would definately want off-road or racing oil with lots of ZDDP.

That's assuming your MM has a MM engine. A few have Hercules.

 

[Jags]

I run alot of old iron and don't use any additive with one exception and that is my generator. It simply has not had enough hours on it to even be broke in, so I add a touch of 2 stroke oil or the valves can seize (with the no-lead gas). Other than that, if the engine has some time on it, you should have no problems. I mow with a 1939 VC Case (big yard) and have used it for about 15 years. No issues.

 

[94ranger55]

thanks for all the great info ......tomorrow is the big big day 220 miles north bound here we go !