School me - Do modern flat tappet cams/lifters need high-zinc oil?

[Done Swimmin]

I have stroker planned based on a 400 block and with adjustable rockers, aluminum heads and i have reservations about rollers lifters. My engine builder wants to use mechanical or hydraulic flat tappets. Will I have to use a high zinc content oil even with modern cams/metalurgy and heat treating?

 

[Kern Dog]

Absolutely. There are few things that you can do to increase the odds of success, the proper oil is at the top of that list.

 

[Professor Fate]

"Even with modern cams and Metallurgy"?
Especially with modern cams and metallurgy, you must use high-zinc oil.
"Modern metallurgy" has gotten significantly more inconsistent.
Reconsider your reservations on using a roller cam- but whatever you do, do not compromise on the oil.

 

[dadsbee]

 

[Newbomb Turk]

Zinc is in every engine oil. It has to be or it’s not engine oil.

Excess zinc is BAD.

Buying an oil and then adding zinc is BAD.

Very smart dudes (chics I’m sure so no one gets offended) spend decades learning tribology. They understand what happens to an oil when you add another ingredient which makes that ingredient out of proportion to the rest of the oil.

Buy a QUALITY engine oil designed to do what you need.

I don’t run “modern” oils in these older engines. I don’t run cats.

You can reduce your clearances and eliminate as many needless leaks as you can and use a “modern” grade of oil (notice I didn’t say weight) and I encourage that.

My rod bearing clearance is .0019-.0021 and my mains are .0021-.0024.

I’m going to use a racing 0w20 and it has detergents and other additives that make the oil streetable.

 

[RustyRatRod]

Zinc content is important but so is low or NO detergent.

 

[Newbomb Turk]

Zinc content is important but so is low or NO detergent.

All Torco oils have detergent and dispersant packages.

When I bought my piston rings Lake Speed and I were emailing and we were both struggling to get our thoughts together.

So he had me call him. We had two areas where there were questions.

One was why I am running full groove bearings and running Torco SR5r 0w20.

My bearing choice meant I needed more oil ring to deal with the rods slinging oil on the cylinder walls all the time. And BTW they are throwing oil on the camshaft too.

His other concern was running a “racing” oil on the street because most racing oils don’t have detergents in them and the dispersant packages aren’t as effective in his definition of racing oils.

Torco oil has a full detergent package. I told him that and he was a bit skeptical. He said I’ll call you back.

About 40 minutes later he called back and said it does have detergents so run it.

I was going to anyway because I already knew what he didn’t.

 

[Kern Dog]

Zinc content is important but so is low or NO detergent.

NO Tide for my ride.

 

[Newbomb Turk]

Zinc content is important but so is low or NO detergent.

Why no detergent?

 

[RustyRatRod]

Why no detergent?

It's been shown that too much can wash the oil right off. Plus, low or no detergent is what I want.

 

[RustyRatRod]

NO Tide for my ride.

You posted pictures I think pretty much proves it for me.

 

[Newbomb Turk]

It's been shown that too much can wash the oil right off. Plus, low or no detergent is what I want.

Ok. It’s not the detergents fault. It’s the tribologist who built the oil.

I’ve never seen any evidence of detergent killing ring seal.

 

[RustyRatRod]

Ok. It’s not the detergents fault. It’s the tribologist who built the oil.

I’ve never seen any evidence of detergent killing ring seal.

I wasn't necessarily talking about ring seal. But I don't think it's impossible.