Hot Rods Motor oil for a Mercury flathead

Cute. But in my world, correcting misinformation, presenting facts, and dispelling willful ignorance has nothing to do with dead horses.

 

I see this a lot. And it's not correct. Modern passenger car motor oils carry ~800 ppm of zinc. The reason for reduced levels of zinc was to protect the catalytic converters, as the zinc that gets past the piston rings and into the combustion chamber will get blown out with the exhaust and end up in the cat where it will plate out on the interior surfaces rendering the cat inoperable. 800 ppm is still a relatively healthy dose of zinc, and is more than was in the oils available when the flathead V8 was in production. Probably not enough for higher lift flat tappet cams in OHV V8's, but enough for a 3/4 race flathead cam.

 

Re detergents in oils, detergents clean the interior surfaces of an engine by competing with polymers, varnish, and lacquers from oxidized hydrocarbons for space. They also neutralize acids that develop in the oil to reduce corrosive wear. The additives that keep particulate suspended in the oil are actually dispersants. Dispersants encircle particulates and not only keep them afloat in the oil where they can be removed by the filter, they also keep them from agglomerating together and forming larger clumps of particulate matter. The two additives work together to keep an engine clean internally. When the particulates are filtered out of the oil by the oil filter, the dispersants go out with the particulate. Eventually the dispersants are used up, one of the reasons why the oil needs to be changed periodically, and why not changing the oil results in sludge.

And that's another reason why modern diesel engine oils work so well in old gas engines, the higher level of detergents and dispersants do a better job of keeping them clean, and free of metallic wear metal particles that can cause additional 3-body abrasive wear if not removed from the oil. They also neutralize acids that form in the oil that can attack soft metals like main & rod bearings. And the higher level of zinc provides added resistance to wear. Good stuff. Those who say otherwise are ill-informed.

 

Thank you
We have certified authorities on various subjects on the HAMB. @Blues4U is one such person, why we don’t take such experts advice I’ll never know!
Too have a slightly differing opinion or experience is fine and dandy usually not a big deal, but when said opinion is 180• out of phase it my be or become a big deal.
Dan

 

That old non detergent could probably be used for chainsaw bar oil.

 

Use my used oil for the chain saw

 

And the Bleat goes on...

 

Thank you @Blues4U !! Always the voice of reason. Those who say that modern diesel oil doesn’t have ZDDP in it don’t know anything about modern diesel engines. The largest selling medium duty diesel engine today STILL uses a flat tappet camshaft and modern diesel oil still has to be formulated to support that engine.

 

Thanks for the info. I watched all the vids on removing valve springs on YouTube, it looked real easy. E
ven with a flathead valve spring tool I had a helluva time. A big screwdriver got the job done, but I'm wondering if that stiff spring had anything to do with the broken valve. Or somebody tried to race the car? (It has a bit of a lopey cam and dual carbs.) Hope my cam lobes don't wear because of the stiff springs.

 

I used a gm door spring removal tool on a FH once

 

Oil is needed and it’s fun to talk about. I believe its how you drive and use your older or even newer cars should be a large factor or dictate on your decision.
My old car has a Y-block with its known problems so I change the oil more often because it gets very few long drives and runs cooler than newer cars. 1000 or so miles between changes. I’ve had the car for 13 years and put 16,000 miles on it. The engine had about 50 miles on it when I bought it. Lucas 10-30 Hot Rod oil.
My wife’s 10 year old Honda has 19,000 mile and has had 10 oil changes. It sees no hyway driving so once a year at the dealership because I’m 81 and the car is low to the ground. Oh it has a catch can.
My pickup is the dreaded 2018 F-150 with a 5.0 with 41,000 mile and has been thru the Ford 5.0 excessive oil test twice but didn’t qualify for an engine change. I solved its oil use by stopping 5-20 and going to 5-30 both semisynthetic Motorcraft. It also has an oil separator. Its oil is changed between 3-4000 miles.

 

Here is a nerdy guy that knows way more about motor oil than probably all of us and he is talking about zinc in motor oil. For the record I have never met the guy I don't know anything about him I came across him on YouTube a year or two ago and I have learned a lot about motor oil from him.

 

So to pour more oil on the discussion:
I also have a 50 Merc with flathead and I am using SAE 50 non-detergent oil.
Engine has been rebuilt 20 years ago and has run on that oil ever since. I am changing oil every year.

 

If what you say is true, it's probably not to late to switch to the proper oil for you car.

 

How dare you question people with real world experience

 

I think it's time to revisit the original post :

"Whoever built my '50 Merc 8CM installed a cam with a bit of a lope, along with (2) 94's. I do not know if it has hardened valve seats. When I replaced a broken valve, I noticed the valve springs were very stiff. (There was no damage to cylinder or combustion chamber, thank God.)
I will never race this car. Just want to cruise.
So, what oil do you folks run? Something with ZDDP(?)? I'm currently running 15-40 diesel oil because of the additive package. I need to change it because of contamination caused by leaky power valves.
Any thoughts or references are appreciated.
Matt"

Here is a guy that is asking for a recommendation of what oil he should be using in his particular case. So first of all this is not a discussion of oil types and qualities, but a request for information. I would bet my life that 90% of the members of this forum and 100% of the professional petroleum engineers in this world are of the opinion that a non-detergent should not be used in his engine. The fact that there are two of you out there even mentioning using non-detergent oil is doing this person a disservice. You guys are absolutely free to use tmproper oil in your engines and suffer the results down the road.. but to come on here and even mentioning non-detergent oil in a positive manner is doing the O/P and this forum itself a disservice.

The consensus would be to use a modern detergent oil intended for spark or diesel engines of 10-30 or 10-40 weight. There will be minor differences of opinion on the amount of ZDDP, the proper weight, or the fact that oil intended for diesel engines only may have an additive package incompatible with spark engines, but that's to be expected. What is not in doubt is that non-detergent oil should not be used in anything but air compressors or the oldest antique engines.

 

He has no reason to change anything

if someone has used non detergent for 20-50-70 years in the same engine,that person has no reason to change either.
Rule of thumb growing up was non detergent for no filter. Change more often. Detergent for the rest.




oil is good. Use it

 

I'm sorry, I know a lot of guys around here really like this guy and think he know's what he's talking about. I'm here to tell you that he says a lot of things that are not correct. He does say some things that are correct, but too much of what he says is just flat wrong. He is not the expert you think he is, and yes, I have more experience in the business and have held my CLS certification longer than he has. Just please be careful what you take away from this guy's videos, a lot of it is wrong. Case in point, where he says too much zddp can cause accelerated wear. That is flat wrong. Does not happen. Period. I have posted an SAE technical paper here in the past that explains the mechanism of zddp and how it plates out on wear surfaces in an engine. The fact is that no matter how much zddp is in the oil the tribo film that is developed on wear surfaces by the zddp will only develop to a certain thickness and will not build any thicker no matter how much zddp is in the oil. What happens once that thickness is achieved is the tribo film wears off as the engine operates and the mating parts come into contact with each other. This is why it is known as a self sacrificial material, the plated out zddp wears, givers up it's life so to speak, to protect the metal underneath. As the tribo film wears, additional zddp in the oil will replace the zddp that has worn off, and in this way maintains the tribo film thickness. There is a balance between wearing and plating, as long as there is fresh zddp in the oil available to plate out on the surface. This is another reason why we have to periodically change the oil, not only do dispersants deplete over time, as I described earlier, but zddp will also be depleted eventually. And other additives in the oil will deplete as well. The goal is to change the oil before the additives are all depleted. But, the bottom line is his comments about too much zddp being harmful are simply wrong, because he is unaware of the mechanics of zddp and how it works. Like I said, be careful what you take away from his videos. Got questions, ask me.

 

Well, this has gone on long enough that we need an entertainment break.

In about 64 or so, I stole a quart of 10-30 Pennzoil from my old mans case, for my 1 1/2 horse briggs motor on my crude home made go kart. It blew up within an hour.

The old man always said it was because the Briggs needed non detergent, and the detergent oil killed it. Well...he was a dentist not a pro mechanic, and I, the dumb kid, perhaps added oil too late? we'll never know

 

I have a question, does oil go bad from setting? If the vehicle is parked in a climate controlled garage or low humidity climate, and is driven on nice days, does the oil go bad? Even in an outdoor storage area, if driven enough to " dry out any moisture " , will the oil go bad over time?

 

I was taught in A&P school that petroleum oil will begin to degrade after 12 months.
We did oil changes by hours or once a year.

I have never seen an expiration date on a quart of aviation oil.

most all jet engines use synthetic oil and most follow the old standard of so many hours or every 12 months.
Although there are several manufacturers that require oil change at overhaul.

I have seen an expiration date on a full synthetic aviation oil, what’s up with that!

 

I've known a couple of different people who back in the day read that oil doesn't wear out, it just gets contaminated. Siezing on that, they both just changed oil filters at the designated time & added a quart.....

 

We usually tell customers that the oil has about a 1 year shelf life, but I've seen/used it older than that myself. What can go "bad" is settlement of some of the polymeric additives that are not fully solubilized into the base oil; as well there can be ingress of moisture into the container as air enters and exits the package due to temperature changes, and condensation can build in the oil, and that moisture then can cause degradation of the oil depending on the severity. This kind of depends on how much exposure there is, how humid the area is (would be worse in FL than in AZ for instance), how severe the temperature changes are from night to day, and where the oil is stored. If stored out in the wash rack it could get contaminated rather quickly. We're dealing with that very issue right now with a waste hauling shop and a drum of very expensive synthetic transmission fluid they're claiming came to them contaminated with water. Even a brand new unopened drum will pull water past the bungs. On bulk tanks we like to have them sealed up tight with a desiccant filled breather to filter air in/out of the tank. And finally, oxidation of the oil can start to occur. The process is natural due to exposure to oxygen, which is pretty common right? (#1 common element on Earth). The process is accelerated by heat, and water or moisture acts as a catalyst. It may look fine, but if the process has started and there are precursors present in the oil when you pour it into your engine, the life in the engine could be short before it starts to turn bad. If you aren't having it analyzed, how would you know? That's why we recommend a shelf life. Sitting in the sump of an engine that's just parked, all the same things would apply.

 

Yeah, one of the more common fallacies out there. It's unfortunate.

 

“Bad Horse, Bad Horse, listen to the experts we are not going down this road again!!!!!!

 

Thanks for information, I will change my schedule to one year.