Whats wrong with SAE 30?

Seems like the more I look into refreshing the engine on the
46 A, I keep seeing people talk about using oil weights other
than SAE 30. Whats the scoop? Dave

Modern multi grade oils are far superior to anything made in the 1940s. 30 wt was required for hard work for long hours. Modern oils can lube at high temperatures and low temps with one oil.

Not much choice for straight 30 weight these days. A good 10W-30 will do everything the straight weight oil will do, plus it will flow in sub-zero temperatures. I remember one particularly cold day when I drove my car couple of miles before the SAE 30 oil started to show any pressure. That taught me the value of multi-grade oil.

The multi grade oils have a better additive package. Reduces carbon build up in the piston ring pack area. For a parade tractor I would not worry about it.

Not a thing wrong with it.

I'm sure this will turn into an oil debate. Here is my 2 cents. Any oil today is far better than what these old tractors have used in the past 40 plus years. Most guys I know use 15W-40 because tgey buy it in bulk for their diesel tractors. And its said to have zinc which is supposed to be good for these old engines. There is also a ZDDP zinc additive that some people use. I use 15W-40 in most of mine and non detergent SAE 50 in some of my oldest ones. Using SAE 30 won't harm a thing. Everyone will have an opinion on what is best to use. This is just my thoughts and opinions and what I use in mine

Our 1987 Cub Cadet 1811 loves it's pennzoil SAE 30, we bought it in 2003 and that's all we use....it's been a great lawn tractor.

There's nothing wrong with 30wt.

I run 30 wt detergent oil in all my old tractors. I do buy small engine 30 wt. oil. It still has the zinc in it that flat tappet cams like. I have been told that most automobile oils don't have zinc in them because it causes problems with the catylist in catylitic convertors.

Now is you are thinking of using non-detergent 30 wt. that is a different story. Stay away from non-detergent oil unless you are afraid that your old engine has lots of sludge in it that you would prefer for it to stay right where it is inside the engine. The detergent holds sludge in the oil until it can be removed by the oil filter. Non detergent oil lets sludge collect anywhere in the engine that the oil is not moving briskly.

If you can't find 30wt anywhere, I suggest you use 10w40 or some thicker viscosity oil in you vintage International. I don't think Wal-Mart has 30 wt. anymore. I didn't see any at AutoZone last time I was there either. But then I was looking for 20w50.

USED to be... sae 30 was a very plain oil and low rated... BUT NOW... you can buy hd 30wt oil full of robust additives rated for diesel compression AND for gas spark use. So... with that sae30 hd oil, I no long have an objection to using the HD version with all the great stuff added to the very plain base oil. IRONICALLY, its almost twice as much$$$$$ for it as it is for the 15w-40 oil... of which in my mind is actually a much better base oil than the hd 30w..I want oil that has the cling properties to prevent dry starting that damages cam shafts (GM), the anti piston coking at the ring lands(cummins), the anti friction additives that stop the tappet and cam follower wear(cummins and cat), the modifier that stops the piston scuffing, the high alkali additives that neutralize the the acids, The anti clump additives that stop sludge from forming. All is part of the hd additive package... And then there is... the initial cold flow and starting of the 5w-xx but the high temp protection of the xw-40 oil. But now... for more money$$$$, you can run the hd sae30 and come quit a bit closer, if you take away cold starting and high temperature... again at a higher cost. Saw the hd sae30 in the diesel section of wallyworld... But there's nothing wrong with it. IIRC a quart of it was about same$$ as half of a gallon of the 15w-40. from the department of redundancy department.

I think I can buy 15-40 Delvac for about the same price, and I use it in many engines, both old and new.

I know that when they built the gas 656's; they weren't set up for unleaded fuel and IH has oil that keep the valves from burning up. learned firsthand what happened when you didn't use it!

Thanks for the responses, everyone. Great insight.

IN A NUTSHELL Nothing wrong with SAE 30, it will work fine, its just that in extreme cold temps 10W30 may allow an engine to crank over better yet still provide all the same protection.

John T

Here's an experiment:

Put a small container of 30 weight and a container of 15w 40 in the freezer overnight, then compare them.

Now imagine pumping that through several feet of 1/8 inch tubing to get to the rocker arms!

The multi grade oil is just a superior oil when it comes to cold weather. Synthetic is even better as it conforms to an even wider temperature range!

A lot of improvements in lubricants since 1946 that have made 30W outdated and not the best choice.

I allus use 30wt non detergent for running in a rebuilt engine!!! just a ,,,Family tradition....!!!!!!!!!!!!!!!

But if you use a 10W30 & straight 10, the 10 will be thinner at cold temps.

(quoted from post at 21:07:17 06/11/22) Seems like the more I look into refreshing the engine on the
46 A, I keep seeing people talk about using oil weights other
than SAE 30. Whats the scoop? Dave
<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto128016.jpg>

Click to expand...

There is viscosity and there is additive package . Two separate but important items .
Q

Aircraft use straight weight oils today, but they should be pre-heated up to 45F before starting.

If you keep the tractor in a 45F or higher temp, you can use straight 30wt oil up to 100F. All 30wt oils are rated are 111CTs @ 100.

The best straight weight oil is AeroShell 65, which is 30wt oil with additive package to help tappets keep lubed. It also is a detergent and will suspend carbon until changing with the filter.

The only downside to multi-vis is their lower ability to transfer heat away from the engine components, which is simply a function of their ability to tolerate a wide temp span.

I use a lot of straight weight oil because I'm rarely in very cold conditions. If heat rejection is a problem, stick with straight weight. If the tractor is regularly used below 40F, multi-vis will be better. It's all about temp gradients.