Gear lube as a high-pressure engine oil additive?

Schurkey · Jan 20, 2007

FNG here. I've run some searches, but I haven't found the answer to my question.

With the reduction in zinc high-pressure additives in motor oil, flat-tappet cam/lifter failure has become more common. I understand that certain dual-rated (Compression and Spark ignition) oils have additional high-pressure additives.

I was wandering the chemical isle at the local NAPA, looking for a less-expensive substitute for GM's EOS which is hatefully expensive here. (I think the dealer is charging more than MSRP!) I got to looking at the 80W90 gear lube--it seems to be loaded with high-pressure anti-wear additives, and it wouldn't affect engine oil viscosity nearly as much as a can of STP. It's dirt cheap and readily available. I envision dumping in a cup or a pint during new-engine break in (flat tappet cam only) and perhaps in the future when the EPA has eliminated the zinc in all motor oil, perhaps adding some with each oil change.

Is gear lube suitable for use as a high-pressure additive in motor oil?

Thanks, all.

forcedtalon · Jan 20, 2007

Gear lube has additives that break down soft bearing materials that would be found in your engine. Not a good Idea.
I would not put anything in a good engine oil.

Fordiesel69 · Jan 20, 2007

I had an old 3.5 HP techumseh lawn mower that would burn its entire crankcase in about 30 minutes. So I used old wolfs head 80w-140 and it virually stopped smoking, however the exhaust smelled horrific and the engine had no power. I never did tear it down though.

Wrehch · Jan 20, 2007

Short answer, NO.

Quest · Jan 21, 2007

No offense but just like the leaded gas/unleaded gas changeover during the 70s in da States, it would be the manufacturer's fault if they keep on using soft metal/improperly treated(hardened) valves and seats for unleaded gas.

Similarly, unless you are running some radical profile ultra high-lift aftermarket cams in your engine, why would you need such a heavy dosage of ZDDP in your motor oil???

The best way to find out if you need more AW/EP protection on your engine is to submit a used oil analysis to Terry Dyson and then go from there.

Hint: ZDDP is not the "Be all, end all" additives in modern motor oil chemistry you know...just the cheapest and most widely used.

JohnBrowning · Jan 21, 2007

NO!!! It is a 30 weight at engine temps, has the wrong PH and chemistry! If you want to stick your rings together and ruin the oil then go for it!

boxcartommie22 · Jan 21, 2007

torco's assembly lube is what i use at each oil change..i add the whole bottle i think its 16 oz.

toocrazy2yoo · Jan 21, 2007

What kinda car, Box?

boxcartommie22 · Jan 21, 2007

in all my 3 98's expy,conti and vic...this stuff mixes very good and it doesn't inc. the vis. index..i consulted torco before doing this 2 yrs ago..they said alot of the high performance people do this..they are working on changing the bottle to say you can use as an oil additive...works great!!!

Schurkey · Jan 21, 2007

Thanks for the replies; I hope others will also chime in.

Quote:

Gear lube has additives that break down soft bearing materials that would be found in your engine. Not a good Idea.
I would not put anything in a good engine oil.

Thanks for telling me about the bearing issue. One of my concerns is "what are flat-tappet-owners going to do when "good engine oil" has been regulated out of existence. Other oil additives may also be regulated into uselessness. Gear lube will--probably--always be available.

eljefino · Jan 21, 2007

I found a tube of STP "gear oil treatment" that's chock full of zinc at big lots for 40 cents a few years ago. The tube said it was also good for assembly lube on the bearings etc.

As said above most assmembly lube is full of AW adds and once it dissolves in the oil continues to make a great break-in oil.

Schurkey · Jan 21, 2007

Quote:

No offense but just like the leaded gas/unleaded gas changeover during the 70s in da States, it would be the manufacturer's fault if they keep on using soft metal/improperly treated(hardened) valves and seats for unleaded gas.

I don't understand. Which manufacturer are you talking about? GM, Ford, etc. are going to carry zero liability for the old legacy engines that use flat tappets. Therefore they couldn't care less. Cam manufacturers are already blaming the oil rather than switch to better (more expensive) material for the cam cores. In short, unless I switch to roller tappets, it's up to me to assure the engine I put together survives. I just want to make educated selections and--hopefully--save some bucks in the process. Hence the gear oil vs. GM EOS.

Quote:

Similarly, unless you are running some radical profile ultra high-lift aftermarket cams in your engine, why would you need such a heavy dosage of ZDDP in your motor oil???

Would a cup of gear oil in 5 qts motor oil provide THAT MUCH ZDDP? I'd be happy to add half-a-cup, which would mean even less of the bearing-eating additives.

Quote:

The best way to find out if you need more AW/EP protection on your engine is to submit a used oil analysis to Terry Dyson and then go from there.

Hint: ZDDP is not the "Be all, end all" additives in modern motor oil chemistry you know...just the cheapest and most widely used.

I already do some oil sampling--is his service more extensive than my current source? (Detroit Diesel test kits) What would I be looking for in the report?

Thanks for the reply!

Schurkey · Jan 21, 2007

Quote:

NO!!! It is a 30 weight at engine temps,...

Perfect!

Quote:

...has the wrong PH and chemistry! If you want to stick your rings together and ruin the oil then go for it!

No. Not my first choice. But we are talking a fairly small amount of gear lube mixed in with the oil--not a half-gallon. Is the gear lube chemistry that far off for use in engines? (I'm willing to accept that it might be--which is why I asked the question in the first place--but I admit that's not what I was expecting or hoping for!)

Thanks for the reply!

Schurkey · Jan 21, 2007

Quote:

torco's assembly lube is what i use at each oil change..i add the whole bottle i think its 16 oz.

How much is a bottle of Torco? Where are you buying it?

Thanks!

Quest · Jan 21, 2007

YOu just not getting it Schurkey!

Gear oil is not meant to be used inside an internal combustion engine as lubricant, period. IT shouldn't mix and go with it simply because of different chemistry and intended use, period.

gear oils are meant to be used inside a gearbox where minimal moisture and combustion by-products. You mix gear oils with moisture and that spells disaster. Consquences mainly to do with corrosion and elevated metal counts in oil analysis, which infer that something is being "eaten" away. (mainly bearing allow materials).

Cam manufacturers blame oil chemistry for faults simply because they figure that's the easiest way to "get away" scott-free. If you happen to have one of those engines with soft, improperly hardened cams w/ flat tappets, get some HDEO instead. Why bother being your own chemist/engineer?

Ultimatly, if elevated cam/tappet wear is your concern, consider getting your engine rebuild or get something better.

IMHO. YMMV

cmhj · Jan 21, 2007

Gary Allan · Jan 22, 2007

I don't know about current formulas ..but 90 weight hypoid would FOAM when mixed with motor oil. This is exclusive of any of the nasty additives that could play havoc with metals and whatnot.

There are plenty of additives that are compatible with motor oil that will protect your cam.

Look here What current oils must meet.

Quote:

GM, Ford, etc. are going to carry zero liability for the old legacy engines that use flat tappets. Therefore they couldn't care less.

True ..but the oil companies DO care. The current spec ..back spec's all the others.

Quote:

Cam manufacturers are already blaming the oil rather than switch to better (more expensive) material for the cam cores.

Note the operative word.

Most of the ruckus, IIRC, is due to improper break in ...or if you have some real high pressure spring rates. There are plenty of pushrod engines that use contemporary oils without any issues. Look at what they use for the sequence IIIG test for an engine. It's not some roller valve train engine.

boxcartommie22 · Jan 22, 2007

hi schurkey,i use torco mpz engine assembly lube much, much better then gm's eos...i get here at on track performance couple miles from my home..you can also order it from torco...feel free to speak to tech support very honest and knowledgeable people...it is 12 oz.not 16 oz.cost me 9 bucks..totaly miscible with any oil..also it is a synthetic formula...i wouldn't use gear oil in the oil.

toocrazy2yoo · Jan 22, 2007

Someone awhile back was talking about the SLOB (which has a ton of zinc, as any BITOG schoolboy knows) in the manual tranny. Extra EP. Is SLOB EP?

MolaKule · Jan 22, 2007

"Is gear lube suitable for use as a high-pressure additive in motor oil?"

No way should you use this in a PCMO. An EP additive is a different animal than the Anti-Wear (AW) agent fouind in motor oils.

An EP compound in a gear lube usually contains high levels of sulfur, phosphorus, and/or boron, and potassium. In addition, the TBN is usually lower and the TAN much higher than PCMO's. Gear oils and PCMO's have different types of anti-oxidant packages as well.

It is the AW agents in PCMO's that reduce most wear. See Technology threads below for more info on AW and friction modifiers and how they work.

Gear lube as a high-pressure engine oil additive?

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