STP additive

[Peter J]

I hope I'm not opening up a can of worms but here goes. I've heard a lot of discussion of adding STP straight to the trans. and as an additive to 600W to the rear end. Some folks swear by it and some seem to swear at it. Also using it in the two tooth steering gear. Any thoughts?

[Mike V. Florida]

Originally Posted by Peter J

I hope I'm not opening up a can of worms but here goes. I've heard a lot of discussion of adding STP straight to the trans. and as an additive to 600W to the rear end. Some folks swear by it and some seem to swear at it. Also using it in the two tooth steering gear. Any thoughts?

Not to be snotty but you answered the question yourself "Some folks swear by it and some seem to swear at it."

[cars56]

Tried straight STP in the gear box but did not feel any difference. Switched back to 600.
But Mike's does sell 600 wt with an additive that is worth taking a look at.
Running 50/50 STP and 600 in the steering box.

[Patrick L.]

I swear at it ! There should much much reading on the subject in the archives,, if there are archives..

[Terry, NJ]

Originally Posted by Peter J

I hope I'm not opening up a can of worms but here goes. I've heard a lot of discussion of adding STP straight to the trans. and as an additive to 600W to the rear end. Some folks swear by it and some seem to swear at it. Also using it in the two tooth steering gear. Any thoughts?

I used to use some STP in my cars and trucks (Modern) I was satisfied that it was "protecting" my drive trains. I had read somewhere that STP was a "stickier" lubricant and it adhered to surfaces bettter than just oil. As an aside, I owned a plane with a notorius engine (Lyc. 0-320 H2AD) and the reason it was notorius had to do with lubrication or lack of. In the north, they were slow to pick up oil when you started. I'd always pull the prop thru a couple of blades by hand when I started cold to pick up the oil, I never had a problem with it. I ran it to 2600 hrs . 2000 was the "time out". So being concious of the problems of the lack of oil at start could make, I welcomed the stickier oil on the crank journals. On the flip side, I really can't say the STP did anything any good either. However, I think it ruined a Ford/Mazda 5 speed trans in my 88 E-150. I would never put it in a modern Trans again. A Mod A trans, who knows? But there are good Dependable lubricants out there, why screw around?
Terry

[RonC]

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per STP, STP is a oil additive and was not designed to be used as a sole lubricant. I don't use it because if it was needed I am sure the multi billion dollar oil corporations would sell it in their oil.

[Chris in CT]

Hi Peter, The fellas above have said it all. Mike's A fordable sells a formulated 1500 non-compounded that is a shoe-in for the original 600W. I use this myself and am completely happy with it. Note of interest - the original 600W contained LEAD as an anti-galling agent. You are not going to find that anywhere! Additional note: you can buy the stuff from Mike's in quarts, so you don't have to buy more than you actually need for your car. Happy Motoring!

[Preacher]

To add to and reaffirm as Ron stated above, our club had a chemical engineer from a refinery come in and give a presentation on oils. Many many questions, but regarding STP he stated that STP is an additive that should NEVER be used alone.

[Peter J]

Thanks guys, I think I know how to proceed. Why take the chance.

Pete

[Old182]

Ron and Preacher are right: STP Oil Treatment is an additive, not a fully-formulated anything. It is largely a viscosity index (VI) improver used by oil companies to make multi-grade oils from straight grades. The long chain polymers in STP have the ability to coil up as temperatures rise resulting in a thickening of the oil, but when cold they stay uncoiled and the viscosity of the oil remains at the lower number. Without running tests, adding STP to your 30 weight oil will create a multi-grade oil of unknown viscosity. There's a lot of chemistry that goes into designing VI improvers. Andy Granatelli hit a home run with his famous "slippery screwdriver" ad back in the 1960s, and every kid on the block had an STP decal on his car window. Roger Kaufman mentioned in the Model A News awhile back that he uses it in his transmission with good success. I like to coat bearing and lifter surfaces with it when rebuilding engines. Other than that, I can see no useful purpose for it.

[Peter J]

Sounds good to me. Any good gear oil out there other than 600W? I hear that the "600W" was just a name rather than the weight. Is that correct? I would like to get something locally rather than pay for shipping from Mac's or Snyders.

[Purdy Swoft]

Originally Posted by Peter J

I hope I'm not opening up a can of worms but here goes. I've heard a lot of discussion of adding STP straight to the trans. and as an additive to 600W to the rear end. Some folks swear by it and some seem to swear at it. Also using it in the two tooth steering gear. Any thoughts?

It is Ok to add some STP as a viscosity booster but never straight. I ran straight STP in the transmission of my 31 tudor for a while and noticed that it did not shift nearly as well as our other model A's. When I removed the drain plug from the transmission the STP wouldn't drain out. I ended up having to heat the transmission with a heat gun to get any of the STP to drain. I sort of learned the hard way. I just hope that it didn't do any long term damage to the bearings and shafts.

[roccaas]

Originally Posted by Peter J

Sounds good to me. Any good gear oil out there other than 600W? I hear that the "600W" was just a name rather than the weight. Is that correct? I would like to get something locally rather than pay for shipping from Mac's or Snyders.

600 wt was an old viscosity calculation. Didn't it run to something like 90-180 gear lube? It is used in steam engines, and it does foam. I think the STP added on top keeps my transmission quieter and when double clutching the gear sets slow down much faster to avoid grinding.

Somebody had a method of mixing a bunch of modern stuff in his wife's blender that was like cold syrup on the transmission. Seemed like a lot of work.

[FL&WVMIKE]

I have had very good results, using STP straight, in the steering box. I would not use it straight in the transmission or rear end. In the steering box, it is a very slow moving action and I feel that you would want that "Stickyness". I have used it in the antique cars for decades. It works for me !
MIKE

[Ron in Quincy]

I have used only STP in my transmission for a number of years; the gears continually move it out of the bottom of the case into the gears. I use a 50/50 mixture of STP and 600W in the rear differential; the ring gear continually moves the mixture up to the top of the case. I don't use STP in the engine as it is so heavy that it will end up in the bottom of the pan and I would be concerned that it could foul the oil pump ?

Ron

[mrtexas]

I searched for an MSDS(material safety data sheet) for STP and found the following:

http://www.sheedycrane.com/pdf_files...%20RM-3579.pdf


Heavy naphthenic petroleum distillates 15-40%
Hmm, interesting, naphthenic petroleum distillates are not a lube oil

Solvent dewaxed paraffinic petroleum distillates 60-80%
This is a what a lube oil is

Zinc Disalkydthiophosphate 1-4%
Anti wear agent added to lube oils

Calcium sulfonate 1-4%
A thickener used to make grease

Amine grafted ethylene/propylene copolymer 4-11%
Lube oil VI(viscosity index) improver that helps to make sure the oil stays thick when hot but doesn't get too thick when cold.

It seems STP actually is 60-80% lube oil but has up to 40% of non lube oil naphthenic hydrocarbons(think hydraulic oil). The rest 6-19% are lube oil additives.

The fact that it does contain up to 80% lube oil and up to 19% lube oil additives explains the success some have had using it in Model A transmissions. The other probably is that the Model A doesn't demand an especially good lube oil as STP can have up to 40% of what is not a lube oil.

BTW I am a chemical engineer recently retired from an oil refinery.

[Russ/40]

mrtexas, Thanks for that! That is the most valuable information I have ever seen on the controversy of weather or not it is a lubricant.

[Ron in Quincy]

mrtexas,

Thanks for the detailed information on STP.

My oldest son was a mechanic on a dragster team, he was the one that suggested, a number of years ago, for me to use STP in the tranney and rear end, however, he was very positive about not using in the engine.

Ron

[aaron griffey]

The Horsless Carriage Club guys have a formula that they like to use in transmissions of old cars.
5 lbs. 140 gear oil
1 lb. long fiber wheel bearing grease
1 can STP
mix with a double beater mixer for 20 minutes.

I know guys who run STP straight in the rear end ot their T. I wouldn't.
I also know of a T that ran for years with just a bit of chassis grease on the ring & pinion and bearings too.
When you are out there pushing it along at 40 MPH for 3 or 4 hours at a time you'd better have some lube that can flow!
140 with 10% STP is heavy enough.

[hardtimes]

Originally Posted by mrtexas

I searched for an MSDS(material safety data sheet) for STP and found the following:

http://www.sheedycrane.com/pdf_files...%20RM-3579.pdf


Heavy naphthenic petroleum distillates 15-40%
Hmm, interesting, naphthenic petroleum distillates are not a lube oil

Solvent dewaxed paraffinic petroleum distillates 60-80%
This is a what a lube oil is

Zinc Disalkydthiophosphate 1-4%
Anti wear agent added to lube oils

Calcium sulfonate 1-4%
A thickener used to make grease

Amine grafted ethylene/propylene copolymer 4-11%
Lube oil VI(viscosity index) improver that helps to make sure the oil stays thick when hot but doesn't get too thick when cold.

It seems STP actually is 60-80% lube oil but has up to 40% of non lube oil naphthenic hydrocarbons(think hydraulic oil). The rest 6-19% are lube oil additives.

The fact that it does contain up to 80% lube oil and up to 19% lube oil additives explains the success some have had using it in Model A transmissions. The other probably is that the Model A doesn't demand an especially good lube oil as STP can have up to 40% of what is not a lube oil.

BTW I am a chemical engineer recently retired from an oil refinery.

Mr. Texas,
Ok, it's excellent to hear from a chemical engineer on this, but you haven't said whether you would use the stp for anything and/or if you would use it in a Model A...where/how??

[mrtexas]

Originally Posted by hardtimes

Mr. Texas,
Ok, it's excellent to hear from a chemical engineer on this, but you haven't said whether you would use the stp for anything and/or if you would use it in a Model A...where/how??

Nah, STP is for clunkers to stop burning oil. I bought some 680 steam cylinder oil and am using that. A more modern oil would probably be better.