stp has zinc and phosphorus in it like oil used to has anyone used this in a T
Don't waste your money putting STP in your Model T. It's not needed.
5W-30, 10W-30 or even SAE 30 motor oil will suffice.
I prefer 10W-30.
STP is a friction modifier. I wouldn't use it with wet clutches and bands. There's times when you want friction.
STP is thick as honey. It is probably fine in a rear axle but I would not run it in an engine I cared anything about.
If you want an ZDDP additive this is a good one.
https://www.pegasusautoracing.com/productselection.asp?Product=1678
A friend uses straight STP in his Model T rearend.
STP is great in gear boxes on tractor or mowing equipment. Rear axles it would be great.
I used it to put engines together with. Such as bearings and journals. Just a very thin coat is fine. Hotrodders in this area have used it for years for that purpose.
Like John says, an excellent assembly lube. Not expensive, easy to find.
On diesel truck engines( Cummins and Mack)on the
mains and rod brgs, we used White grease, can't remember the brand.
Put STP in a 26 T years ago. After running a few miles, it had soaked into the bands so bad that I barely made it home after adjusting the low gear and brake bands several times. Had to put new bands in. That was back when we used original type band material. Don't know if it could be run with Kevlar or wood bands. No body could catch me when I had STP in there. The engine really ran great.
The only additive I have faith in is Rislone for stuck hydraulic lifters. Most additives, I believe are not needed.