Excellent Article on Oil...
 

Too much ZDDP can be corrosive...

https://www.hemmings.com/stories/wha...9b1bcf9b99e50a

Re: Excellent Article on Oil...
 

WOW! Thanks Pete for posting that oil article.

Re: Excellent Article on Oil...
 

I find the ZDDP excitement of the last few years confusing. The stuff was added to oil in 1958. Flat tappet cam wear is very much a concern with high revving overhead valve V8s with a lot of spring pressure. Flat tappet cam wear was never a concern with a lightweight flathead valve system. I don't use ZDDP addative in any of my old Fords, including my 53 with the overhead valve 215 six (the 215 is low revving with light spring pressures). I have driven tens of thousands of miles, many at 70 mph or faster, with no camshaft or lifter problems. Any of us flathead era folks don't need to worry about it, except maybe the few Bonneville racing masters among us.

Re: Excellent Article on Oil...
 

I'm with 38 coupe ......

Re: Excellent Article on Oil...
 

On a side note, if you ever have your cam out, never degrease or solvent wash the cam.

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Re: Excellent Article on Oil...
 

Amen, Fred. .

Re: Excellent Article on Oil...
 

One other thing to remember is that overhead valve engines use rocker arms with a ratio of 1.5 to 1.8. So not only are flathead valve trains significantly lighter than their overhead counterparts, but the rocker arms increase that extra weight by 1.5 to 1.8 times, depending on their ratio. Given normal circumstances, this will at least triple the pressure on the cam.

Re: Excellent Article on Oil...
 

Garbage. I have washed hundreds of cams of many manufacturers (&many flatheads) reused and never ever an issue.

Re: Excellent Article on Oil...
 

Agreed. Curious of the logic of that.

Re: Excellent Article on Oil...
 

Waboom: I sat and thought about that. Let's hear it.

Re: Excellent Article on Oil...
 

Same. Why would you want to put a contaminated part back into your motor?

Re: Excellent Article on Oil...
 

This is an article posted by Ted Eaton who is an engine builder, specializing in Y Blocks. His take on diesel oil and ZDDP. He has a lengthier article on this subject which is too long to post here.


Diesel Oil and ZDDP
Use only oil rated for gasoline engines and not an engine oil rated only for diesel engines. The amount of detergent in diesel oil accelerates engine bearing wear on gasoline engines.

Depending upon the bearing clearances, I’ll use 10W-30 or 10W-40 oil for most stock type engine builds. I’m partial to the Valvoline brand but I’ve used others without issue. I’ll use conventional oil only for the break in and no synthetic or synthetic blend oil ever for engines with flat tappet camshafts like the Ford Y. The shear property of the oil is important so don’t use any oil with less than 30 in its viscosity designation on an engine with a flat tappet camshaft. When in doubt about the amount of ZDDP in a given oil, look up the manufacturers MSDS (material data safety sheet) and see what’s there. I prefer a minimum of 700-750 ppm of zinc phosphorus. A 4oz bottle of ZDDPlus supplements the first charge of oil just to insure that there is adequate ZDDP during that first run in period. With engines that leave this shop, I recommend the first oil and filter change at the 2000 mile mark. Changing the oil sooner than this can have you adding additional ZDDP additive that would not normally be needed after the 2000 mile mark.

As a side note to the ZDDP amount in the oil, an oil with reduced amounts of ZDDP simply means that the oil must be changed more frequently as the ZDDP does get used up over time. On the flip side of this, having too much zinc phosphorus in the oil can create a situation known as zinc overloading and over time, this will have the negative effect of accelerated wear or chipping of the cam lobe flanks. There is a balancing act here in having the right amount and not too much. New engines have a lot of metal to metal contact going on so having an additional amount of ZDDP during that break in time is okay.