Starting off with the right engine oil.

don's 37

don's 37

Senior Member
I have heard so many people saying that they use 20W-50 motor oil in their Flatheads on this forum. I will be hopefully driving my '37 Ford in about a month and I have straight 30W in it right now. Is this okay to use breaking in the first 500 miles or should I start off with the 20W-50? Seems a little heavy to me. I live in NY and will be just driving the car in the spring and summer. Thanks!
 
Down here in the antipodes I use a straight 30 weight non detergent 'running in oil' for the intitial running in period. This is formulated to enable the rings to bed in correctly. After that 500 mile period change oil to whatever you want to run. Brian
 
Leaving it sit for 6 mths out of the yr. is no good for it. use it. The 30 is ok to break in then switch to 20-40 or 20-50 which ever you prefer. ken ct.
 
You can break-in your engine with the 30. Use a zink additive to protect the camshaft during break-in. Todays oils do not have zink.
 
laryh said:
You can break-in your engine with the 30. Use a zink additive to protect the camshaft during break-in. Todays oils do not have zink.
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Wrong any oil 40 weight or higher ( straight 40, 10-40, 20-50) has more than enough zinc. Never use an oil marked "for gasoline engines only" Rotella R 15-40 is also good. For breakin, use an addiitive. The GM EOS is good.
 
I started my NOS engine in my 39 over 30 years ago with Castrol 20/50 and it has over 106,000 miles on it now, is quiet and burns no oil. I pulled the pan to fix a leak at 85,000 miles and the bottom of the engine and pan looked like it had 3 or 4,000 miles on it with not a spot of sludge anywhere. G.M.
 
don you could use the brad penn break in oil.It has the correct amount of zinc and its recommended by crower cams,crane cams and schneider cams,so it will protect.Its a PA crude made in america and is more than suitable for flathead engines.I have had the same dilemma with oil for my flathead,i will use brad penn from now on as it has the zinc.Interesting to note that i read that the modern synthetics wont cause leaks in the flathead,it is true that the old sythetics would shrink the seals but i read that this has now changed anybody heard this?
 
When breaking in a rebuilt I go to Walmart and get the Acell oil.
It only comes in 10-40 and sometimes 30 non detergent.
The 10-40 is SF rated. That means it has zink like the old oils had.
After break in I use the same stuff, why not? It's $2.25 a Qt.
G.M. says he has used Castrol 20-50 for 30 years. Yup, Fine. But 30 years ago Castrop 20-50 had plenty of zink. It still did 4 years ago but not any more.
It is now rated SF. Look on the back of the can. Or bottle.
Sam for Rotell R. It is an SM oil. now No gottum much zink.
 
I always used Castrol but now it is owned by BP. That may be why it is not the same. Marv
 
aaron griffey said:
When breaking in a rebuilt I go to Walmart and get the Acell oil.
It only comes in 10-40 and sometimes 30 non detergent.
The 10-40 is SF rated. That means it has zink like the old oils had.
After break in I use the same stuff, why not? It's $2.25 a Qt.
G.M. says he has used Castrol 20-50 for 30 years. Yup, Fine. But 30 years ago Castrop 20-50 had plenty of zink. It still did 4 years ago but not any more.
It is now rated SF. Look on the back of the can. Or bottle.
Sam for Rotell R. It is an SM oil. now No gottum much zink.
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I agree ,tried to tell GM two or three years ago that Castrol is not the same it was at least I could not find any with zinc in it. I have used the Supertech from Walmart since I started up engine three years ago but it seems to be getting harder to find. Every Walmart store seems different some have gallons and quarts,some 5 quart containers,some no individual quarts at all.
 

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I use it and see no difference in rear main weep. No leaks anywhere else. Have used it in all my cars and trucks since 1979 with great results. The Mobil 1 15w50 is made for old cars with the extra zinc.
Don
 
Rotella has lost its zinc of late,its the parts per million that you need to pay attention to.I believe that you need 1200ppm of zinc for it to be effective on cams etc.If you dont have the zinc one bottle of zddp plus during the oil cahnge will fix that.
 
All of the crate engine guys, and a lot of speed shops are recommending Rotella. I asked about Royal Purple and they laughed and said to save my money and break in with Rotella.
 
Don, if the oil says, "SM" on th bottle I would not use it for break-in.
SL has a little more zinc.
Keep the SM oil for after break-in or use it in you modern cars.
Or get a lttle bottle of the additive like hombres ruin suggests.
If you are using stock valve springs in your pre '55 Ford I see no reason to worry about the lack of zinc after break-in.
The zinc has been removed from most oils to prevent damage to 3-way catalytic converters.
Those cars do not have flat cast iron tappets and they can get by just fine without all that zinc.
Cars with double and even tripple valve springs can tear up the cam and flat lifters in 20 minutes with SM oil. So if it aint a hiper hot rod don't worry.
 
Are you guys using cam break in lube and zinc elevated oil as well? If you're that worried about the zinc and need it, just add it to anything you use for break in. Better safe than sorry. I would think that with cam lube being used that the bearings and rings would be the parts to benefit most from the zinc.
 
If you go to internet and type in Walmart Super Tech oil,you will get a lot of information. One page shows that all grades of SuperTech are manufactured for Walmart by Specialty Oil Co. a Division of Pennzoil-Quaker State Shreveport ,La.
 
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