Oil change 170 gas

That will work. Keep it simple. If it is a wintertime tractor, I'd be using 10W-30 or 5W-30 unless in heated shed.

Guys, I posted about this a couple years back as did Don(Mo) and we both got grief over it.Your synthetics and modern day gas engine oils are mostly low zinc and sulfer oils now days do to the epa.In these old flat tappet tratcors you need higher zinc than what these oils provide.Don was seeing a lot of cam failures in many of the engines he was overhauling do to this change in oils. Your best bet is a diesel grade that will have this. The two most common are rotella 10w-30/15w-40 or motorcraft 10w-30/15w-40(10w-30 for winter for sure).Valvoline VR1 is another choice but pricey. Rotella straight 30 wt is a low zinc oil now as are Delo and Delvac which are not what you want for flat tappet engines..This info is available on the Pqia site and the manufactures web sit in thier PDSs(product data sheet). I personaly use the motorcraft superduty 10w-30 diesel grade in all my gas tractors.It has a bit more zinc than the rotella.  It,s your cam shaft, do as you see fit.  http://pqia.org/heavy-duty-diesel-engine-oil/                                                                                                                                                                                                                                                     

Edited by ac45dave - 01 Feb 2021 at 2:07pm

Is there a good oil additive to add to the oil to boost zinc levels in most any oil one chooses to use, or an oil that has a good level of zinc still in it?

Yes, there are many oil additives to raise your zinc levels. I've used ZDDP brand and felt it was a good product. Any good Auto Parts store should have something on the shelf.

I use valvoline VR1 in my 170....it has a lot of sink in it for the older motors with regular (flat tappet) lifters

It might be a little expensive... But its better than putting a cam and lifters in it

My .02
Ocharry

Zinc levels have slowly been reduced over the years to help diesel engines meet emissions specs. Most modern engines have roller lifters/camshafts, which don't require the high zinc levels.