8BA Oil

On a fresh engine, I would use whatever 10/30 detergent that suits your fancy. Contrary to what others say, you don't need heavier weights or diesel oil. Stick with automotive oil and get the proper additive package for your engine. If it has been properly rebuilt, it should have the maximum pressure regulated to 55-57 psi by the relief spring in the oil pump. This is why you don't need 10/40, 20/50 etc. All they do is make the engine work harder and produce a little more heat.

Don't overthink this. Contemporary motor oil is head and shoulders above what was available when these cars were new and everything available is better than back then.

I will further editorialize and recommend running the stock bypass oil filter system unless you are planning on some serious racing or off-roading. The way the vast majority of these cars are used and maintained these days, the finer filtration provided is a real benefit. One last thing; if anyone recommends non-detergent oil, quit listening to anything they say.
 
52flthed said:
VR-1 valvoline 20/50 has been recommended to me on my new rebuilt engine.
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I am curious about this. Do they possibly think their rebuild won't pull full oil pressure with 10/30? It is my position that you should use the lowest viscosity that will supply factory specified pressure.

There was a thread on the H.A,M.B. about a week ago about a guy who had a fresh rebuilt 8BA that didn't want to supply initial oil pressure on start-up. When he finally got it running it would only run at 45 psi. Factory specified oil pressure on an 8BA is 55-57 psi. It turned out that the builder had installed an imported oil pump obtained by one of the major "Hot Rod" suppliers. Several years ago, because it was "new", I made the same mistake and installed the same pump from the same supplier in a fresh built 8BA. I had the same results : 45 psi maximum oil pressure. This bothered me, so I installed a known good tested Ford pump. The oil pressure came right back up to the factory specification.

I suggest that you ask your builder what kind of oil pump was installed in your engine.
 
In the 59AB in my '46 Coupe, I get 60 PSI at operating temp, whether I run 10-30 or 20-50, so I settled on 10-30
 

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When I was a kid in the 60s my dad ran 30W oil in warm CA in everything. He changed the oil every 3000 miles. The 30W oil was for the temperature of the area we lived in. Still, the engines weren't clean inside like they are today when you open one up. Maybe that was because the oils did not have the cleaning additives they do today, I don't really know. If an engine lasted a 100K miles before a rebuild you were really lucky. Today they last until the rest of the car falls apart and the engines are still clean inside, so it has to be that the oil is better than it used to be.

When I was 18, I went to work at the phone company fleet, first as a garage helper and then as mechanic. We had 400 vehicles; on the under-hood decals the manufacturers used all different kinds of viscosity oils. But at the phone company they didn't care about what the manufacturer recommended. We used overhead lube guns for servicing them and bought the oil in bulk, 500 gallons at a time, only one weight of oil as used. A national study had been done to figure out the best choice. They talked with the oil manufacturers, and it was suggested that since diesel engines were included in the fleet, they had to have the oil with the anti-wear additives and viscosity rating to protects them. They went with the Chevron 20W-50W diesel oil, we used it in in everything. At the time you still could get other weight engine oils with the anti-wear additives. But as the manufacturers switched to engines with roller lifters those additives were removed from the oil. They probably eliminated the additives to prevent damage to the oxygen sensors and catalytic convertors. It just takes a tiny amount of something to destroy an oxygen sensor. Then they started running lighter oil supposedly for fuel mileage, my 2014 pickup recommends a 0W-20W oil, the only oil recommended on the oil fill cap. They've done the testing so that's what I use.

What I do know, is no matter what engine it was at the phone company they all ran forever with the 20W-50W Chevron diesel oil in them, millions and millions of miles of inhouse testing. We rarely went inside an engine, and we kept the vehicles until the bodies fell apart. Since that diesel oil is the only oil left with those anti-wear additives many engine builders are recommending it for the old school engines with flat tappet cams. I don't know for a fact that lifters are going flat with modern oils, maybe on some engines with heavy valve spring rates they are failing. Probably 10W-30W oil would be just fine on a flathead but I really don't know. I doubt these days anyone has driven one far enough to know whcih oil will make your flathead last the longest.

It seems that no matter what brand the diesel oil is with the anti-wear additives it's only available in 20W-50W so that's what you're stuck with if you decide to go that route. if you don't have any oil pressure problems using it, I would try the diesel oil just because it has the anti-wear additives in it.
 
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wickcopland said:
Called the shop and he installed a new oil pump and said to run 10W30.

Thank you for the replies
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In this era when "New does not mean better" with vintage parts, this raises a red flag to me. Not mentioning the brand or source is troubling.

You will probably never notice any operational difference if the engine runs at 45 psi rather than 55 psi, but in my book, a quality rebuild should be back to factory specifications.
 
Flathead Fever:

My father worked for Ma Bell for over 35 years as a lineman. He also only used Castrol 20W/50 in all of our cars, many Volkswagens. He bought a new '85 Jetta GLI and used 20W/50 in that. I bought the car from him with 100K on the odometer and I drove that car to the junk yard with over 375K on the odometer. Never once did the motor come apart.

Sorry, I digress but your story reminded me of my father.
 
Flathead engines have a low power output compared to a modern engine. I JWL book he said the stock engine made 79.4 HP not running a fan or orator gen. These engines didn't need much pressure and 10lbs at idle 20 cruising the city and 40 on the road. I use 10\30 year round with a good filter system. In the stockcar we ran a 40 wt racing oil at 50lbs, which usually dropped to 30 at the end of the race. Never had a problem with this system Thw bigest oroblem with an IC entine is a rich fuel mixture. And a bad cooling system. The pistons we use today are not made for street use, only a Hyper u tectec piston can keep the crap out of the oil, but only OFFY males them, but with a 75 year lod ring pack. Be nice if someone would make a set with modern rings and we'd hae a 2--K engine..
OH !!! And by the way the 239 flathead never made 100 hp nomater what you did thoit as long at you kept the stock cam JWL
Gramps
 
1948F-1Pickup said:
Valvoline VR-1 20W-50 is what H&H runs in them.
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I would like to hear their reasoning for their choice. As I understand it, a properly rebuilt engine should not need oil that viscous, as it will only make it harder to turn, increasing heat and friction.
 
Get hold of the shop and get their recommendation - you may void any warranty if you use anything else, especially for the break-in.
 
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