Oil recommendations for 1950 B-2-B flat head?

[John Zellmer]

I'm looking for a high-zinc oil for my recently built engine.  During break-in I'm using high-zinc break-in oil provided by my machinist to keep my cam and tappets happy.  Anybody know a source of good oil with the proper additives for old engines?

 

Thanks

 

John

[Don Coatney]

I'm looking for a high-zinc oil for my recently built engine.  

Thanks

 

John

Why? High zinc oil is not required unless it makes you feel good to spend extra money. Your engine will not care. This subject has been hammered into the ground many times on this forum. Do a forum search.

[ggdad1951]

if you want to do a zinc in your break in oil, I used Amsoil.

 

for my regular oil I run Amsoil Z-Rod.  

 

Regardless of opinions of people on the forum, it's what I did/do.

[John-T-53]

Zinc and Phosphorous are essential for older engines. The API grade SM oil you find on today's shelves has inadequate levels. You should shoot for 2500 ppm Z and 2000 ppm P.

 

Amsoil has a line with higher Z/P levels as stated above.

 

Joe Gibbs also has a line formulated for hot rods and old engines.

 

You could also go with API rating of "SF" if you can find any old stock.

 

Additives work well with new, non specialty oil. ZDDP Plus has little 4 oz bottles that does it for 5 quarts.

 

Crane cams and other MFRs also have break in additives with high zinc. but you usually have to add a whole quart to your crankcase. BUT...What other additives are in in that quart that you don't necessarily want in your engine?

[TodFitch]

Zinc levels in current, find it at any discount or auto supply store, oil are as high as they were in the mid 1950s and far higher than what was in oil when the L-6 engine that is in your vehicle was designed or manufactured.

 

You are starting with a newly rebuilt engine. In your position I'd simply use the cheapest multi-weight oil that meets current service levels for new cars you can find.

[DJ194950]

Zinc levels in current, find it at any discount or auto supply store, oil are as high as they were in the mid 1950s and far higher than what was in oil when the L-6 engine that is in your vehicle was designed or manufactured.

 

You are starting with a newly rebuilt engine. In your position I'd simply use the cheapest multi-weight oil that meets current service levels for new cars you can find.

 

 

If spending more makes you happy but without going overboard with price, just get diesel rated oil available at any auto parts store and probably Walmart!

[John-T-53]

Zinc levels in current, find it at any discount or auto supply store, oil are as high as they were in the mid 1950s and far higher than what was in oil when the L-6 engine that is in your vehicle was designed or manufactured.

 

You are starting with a newly rebuilt engine. In your position I'd simply use the cheapest multi-weight oil that meets current service levels for new cars you can find.

 

API        P    Zn     B

SJ     1301 1280 151

CI-4  1150 1374   83

SL      994 1182  133

CJ-4   819 1014   26

SM     770  939   127

Source: http://blog.hemmings.com/index.php/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/

[Htchevyii]

I use Eastwood's additive. http://www.eastwood.com/ew-zddp-oil-additive-4-oz.htmlYou might be able to skip it in an old flat head, but performance engines with stiff springs are wiping out cams with modern oils.

From Valvoline's site: Why is it important to have the zinc/phosphorus levels in motor oil changed?

With ever increasing limits on emissions, automobile manufacturers have tightened emission control systems on newer vehicles. This is one of several factors considered when the American Petroleum Institute (API) sets standards for motor oil with zinc. The current API standard is SM which replaced the previous SL classification. Because phosphorus can poison a vehicle's emission system, the level of zinc is lower for current motor oil.

Edited May 22, 2015 by Htchevyii

[TodFitch]

API        P    Zn     B

SJ     1301 1280 151

CI-4  1150 1374   83

SL      994 1182  133

CJ-4   819 1014   26

SM     770  939   127

Source: http://blog.hemmings.com/index.php/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/

 

I haven't yet come across the root or authoritative documents I'd like to see, just extracts and endless speculation.

 

But take a look at http://zddplus.com/TechBrief2%20-%20ZDDP%20and%20Cam%20Wear%20-%20Just%20Another%20Engine%20Oil%20Myth.pdf

And the first post at http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1040691/1

 

1. It appears that 1950 era equivalent of SB oil had about 0.08% ZDP which, if I am correctly interpreting things, is the same as the current SM oil.

 

2. 0.08% ZDP should provide scuff protection for up to 600 pounds of lifter load. Unclear to me as I would think we would be looking at a PSI rather than simply pounds number.

 

3. The spring loading on the valves for a 1946 through 1954 Plymouth L-6 engine should be 105 to 115 pounds. Unclear again what the contact area and thus the PSI would be. And there will be some components to the load to based on cam geometry and engine RPM. But it seems that the low valve spring compression numbers relatively low max RPM on our engines will keep us in a regime where scuff protection requires very little additive.

 

On the face of things it appears that SM rated oil should have at least as good anti-scuff protection from zinc as the oil that was available when your engine was new. Also, too much ZDP/ZDDP can actually damage the metal in your engine (increased wear at about 0.14% and spalling around or above 0.2%).

 

I am sticking to the on sale modern multi-viscosity SM rated oil that I find on sale at my local auto supply. If I had a 1960s high performance V8, I might make a different decision.

[Plymouthy Adams]

I have posted the Bob's the Oil Guy link a number of times..very good reading for those who have an inquiring mind...

[Don Coatney]

For those in the Zinc corner stating that Zinc is essential and required on these Mopar flathead 6 engines can someone show me the pile of engines that failed due to lack of Zinc? Or can anyone show just 1 Mopar flathead six engine that failed due to lack of Zinc? 

[NiftyFifty]

It's not a matter of complete failure of the engine, it's a case of premature wear on the cam and tappets, and a lack of what is needed for that style of engine. I'll never understand why someone would build an engine and put it in their truck and not run the best oil they can find that is suited to the engine. I was running a local Co-Op straight 30, because it was rated the highest levels of phos and zinc I could get, but since my last change they have discontinued it, so moving forward I will likely run straight 40 or 15w40 with a zinc/phos add. If you really want a great additive, just by Delco (GM) assembly lube, and add about 1/2-3/4 of a bottle every oil change, it's about the best levels of those additives, without all the other conditioners you get in other oil add on's. As for oil, I think unless your on a fresh rebuild, 10w30 is a bit too light, and if you only drive in the warm months, a bit thicker oil won't hurt.

[Don Coatney]

[TodFitch]

. . . so moving forward I will likely run straight 40 or 15w40 with a zinc/phos add. . .

Just don't add so much zinc that the total (what is in there plus what you add) is greater than 0.14% or you will be increasing your engine wear instead of decreasing it.

[John Zellmer]

Thanks to all for their recommendations. There seems to be a lot of opinions to sort through.

John