Zinc, lead

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Wolfen
Technician 3rd Grade
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Location: Woodburn Oregon

Zinc, lead

Post by Wolfen »

I know this has probably come up before, but I was wondering, if the Zinc additive for motor oil is useful or is it a marketing gimmick? The same thing for the Lead substitute for gasoline?
Adam in Wa
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My garage: 48 Power Wagon
42 WC53
71 Dodge Challenger R/T
Location: Newport Washington

Re: Zinc, lead

Post by Adam in Wa »

Zinc (zddp) is very helpful in protecting the flat tappet cams on engines with high valve spring pressure. An additive is useful, but not needed if you choose the right motor oil. Brad Penn oil has it, also Delo 15-40 diesel oil.... there are others. I don’t know if it is needed on the flathead six, but it can’t hurt and is cheap insurance.
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Gordon_M
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Re: Zinc, lead

Post by Gordon_M »

I can venture an opinion here.

The pressures and duty of the engine oil in one of our trucks is such that any decent motor oil will do it, without additives.
Similarly, the lead-replacement additives for the fuel are unnecessary too, as our engines were designed before lead was added to fuel the first time.

So it is all good news? - nope. The ethanol in some modern fuels will kill all our gaskets and hoses - they need to be upgraded if you can't find ethanol-free, and many modern gear oils have a constituent that attacks yellow metals - basically brass, as found in our transmissions and particularly the differentials ( I'm told ). so the one thing you need to check is that any gear oil you buy will be suitable for older vehicles.
Gordon, in Scotland

( Now officially given up on any form of politics )
Kaegi
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Location: Allyn WA

Re: Zinc, lead

Post by Kaegi »

the lead additives like mentioned are not needed. all mopar flatheads from 33 on have hardened valves seats. but one advantage to additives like Bardahl insteadOlead is it makes the fuel burn better. its not a bad stabilizer for fuel that sits as well. And its made in my home state so I'm plugging the company. ;/)
Wolfen
Technician 3rd Grade
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Location: Woodburn Oregon

Re: Zinc, lead

Post by Wolfen »

Thank you for the answers. I

'm hoping to bring my WC63 home next weekend. If anyone wants to help me work on it, I'm in Woodburn Oregon. The truck will be in a heated shop with a bathroom. And I have plenty of hand tools. All helpers will be provided soft drinks and lunch. If someone is available to transport it from Woodland Washington to Woodburn Oregon. that would be great.
Kaegi
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Re: Zinc, lead

Post by Kaegi »

does it drive? doesn't look too far. not too warm out right now tho. ;/)
June J
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My garage: 1942 Dodge WC 53
1941 Willys MB
1960 M38A1 Nekaf
Location: New Zealand

Re: Zinc, lead

Post by June J »

Hi,
Lead was added to lower octane rated fuels (gasoline/petrol) to enhance ignition and to reduce knock or ping/pinking, more accurately known as detonation. Detonation can be very destructive particularly on 1st compression rings and ring lands. Bear in mind our engines were designed with 75 octane fuel in mind, and most low octane fuels are 90 octane or higher so no, there is no real benefit in adding lead to your fuel. Simply set your ignition timing at 4 to 6 degrees before TDC at warm idle and you should be fine.

I dont know if you have encountered a grey coloured sludge in your engines, particularly when washing your oil sumps etc when overhauling your engines? This is lead residue and is nasty stuff.

The zinc discussion has been ongoing for many years, but Gordon is right on the money. Buy the best quality 20w50 or similar engine oil you can reasonably afford and stick to that oil for the life of your engine.

If your engine is an unknown quantity as internal condition goes then try to find out what oil the previous owner used and stick to that. The reality for most of us is that we don't do enough milage to make a real difference to tappet wear so unless your fixing to do big milage (I did 11,000 miles in 11 years with my Command Car) dont worry about zinc.

Gordons comments on gear oil additives is quite timely for you northern hemisphere folks as you will be gearing up for the summer MV season.
Most extreme pressure gear lubricants contain sulphur as a film strength enhancer. The sulphur attacks yellow metals (copper, brass, bronze etc) but only in the presence of water. Trust me when I say there will be moisture in your differential, transfer case and gearbox oils. It may be a minute amount but it will be there, drawn into those compartments on air via the breathers as the day warms and cools. To my knowledge neither the transfer case (2 and single speed) or gearbox have any yellow metals so GL5 gear oil is fine in there, the (8.5") differentials have fibre thrust washers behind the side gears but the spider gears have bronze thrust faces. However given that the diffs are hypoid style you need a lube oil rated for hypoid type diffs but with low suplhur.

Hope this is useful.

Cheers
Ian
1942 Dodge WC 53
1941 Willys MB
1960 M-38A1 Nekaf