Oil for MD

My '47 MD is my snow plow and it sits outside in the cold under a tarp, so it has to start reliably. I buy ATI 5W-30 for my vehicles in bulk from the local big truck supply place. It says "meets or exceeds manufacturer's specifications for all new cars, trucks, SUVs, etc." I've heard the stories about flat tappet damage when using oil meant for modern day engines in older engines due to the low zinc issue. I've been using this for the last ten years or so and it doesn't seem to have hurt it any. Should I be using something else instead? I don't want to use 15W-40 diesel oil since it is a lot heavier than what I'm using now. The book says to run 10W oil thinned with diesel fuel in subzero temps, but that would have to be changed annually since the summers are 90 degrees plus here. I'd been running the 5W-30 all year round and it always carries good oil pressure and starts easily. Any recommendations? Maybe use this stuff with a zinc additive?

If it were mine I would stick with a diesel oil. They do make 5w-40 that a lot of guys prefer to run in their trucks in the winter.

(quoted from post at 17:02:45 07/20/14) My '47 MD is my snow plow and it sits outside in the cold under a tarp, so it has to start reliably. I buy ATI 5W-30 for my vehicles in bulk from the local big truck supply place. It says "meets or exceeds manufacturer's specifications for all new cars, trucks, SUVs, etc." I've heard the stories about flat tappet damage when using oil meant for modern day engines in older engines due to the low zinc issue. I've been using this for the last ten years or so and it doesn't seem to have hurt it any. Should I be using something else instead? I don't want to use 15W-40 diesel oil since it is a lot heavier than what I'm using now. The book says to run 10W oil thinned with diesel fuel in subzero temps, but that would have to be changed annually since the summers are 90 degrees plus here. I'd been running the 5W-30 all year round and it always carries good oil pressure and starts easily. Any recommendations? Maybe use this stuff with a zinc additive?

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From what I read and hear at the local machine shops most of the damage from non zddp oils comes at break in. Most shops use a good break in oil and additive, then say run regular oil. I still am on the fence on the ZDDP thing. My buddy does NOT run any additives and regular 10/40 in his 67 390 Ford since rebuild and has had no issues. I run Rottella 15/40 and additive in my 72 455 Pontiac since rebuild and have had no issues. If she is pretty tight I would run synthetic 5/40 Rotella, that really helped on the cold start of our Farmtrac with no glow plugs.

I run 15w40 in my M year round, original 248 and turbocharged. Last winter was a cold one, -30's and I never had a problem.

Operators manual says sae30 oil for mds. I run sae30 in mine and use it throughout winter for odds and ends and haven't had a problem. Mine sits outside and I hand start it because im to cheap to buy a new battery. I personally do not like these new synthetic oil in my opinion the only thing its good for is a leak detector. My gf dad runs it in his stuff and everything he puts synthetic in starts to leak. Jim.

Zinc is not an issue with a 60 year old MD.

My understanding is there are two designations to check,
I understand that a spark-ignition engine ought to get the latest API code, which I bleieve is "SN". If you check on the back of the oil can, you ought to see a circular API rating, and I believe "SN" is the latest.
Similar, for compression-ignition, I believe the latest API designation is "CH-4", maybe "CG-4". You can check various cans and see the latest C-letter.
After you get the latest designation, then check about viscosity. For diesel, I"d use 10W-30. For extremely hot weather I"d use 15W-40.

I wouldn't get worried about the zinc issue. When these tractors were new, oil was fairly simple. When the MD was designed they were still distilling crude oil to get the different weight products. That's why back then the type of crude made a huge difference. Ever see all the old ads that mention Pennsylvania crude? Now they can take garbage and turn it into gold with molecular cracking.

These tractors have low valve spring pressure and relatively wide contact surfaces for the rockers and lifters. There's not that much unit loading.

Shoot, even with new springs you can open the valves with your palm. Try that the LS-6 in your '70 Chevelle! Ain't gonna happen. That LS-6 really _needs_ the zinc to help with boundary lubrication.

You definately do not need an additive!

The oil you've been using hasn't hurt because technology wise it's way better than anything available when the tractor was new.

That said, you _do_ want the detergent in a "made for" diesel oil (or fleet type oil). The latest spec I think is CI-4, made for the new low sulphur diesel. It generally has lower ZDDP but the function of the zinc has been replaced by newer tech chemistry that doesn't affect the catalytic converters. The key is the "CI-4" or "CJ-4" somewhere on the label. The "C" is for compression ignition and "S" is for spark ignition. Both will be on there for fleet type oils (such as Delo 400 or Rotella). If there's a "C" something on your current label then keep on truckin'!

could you give me a little info on how you did your turbo setup? I have considered doing that to mine......

Thanks to all that took the time to write. I"m going to stick with what has been working for me for the last 10 years! Brian

Oil is like a religion. Use what works for you. 5w30 should be ok.