What oil to use in a flathead?

Need to change the oil in my `47 Ford....but what should I use in the flathead?

 

Where you live if you are going to drive it any this winter 15-40. If not 30 or 20-50 . Any decent brand NO non- detergent .

 

I use castrol 20-50.

Rich

 

Has the motor been rebuilt?

I use straight 30-weight, non-detergent. If the motor has never been rebuilt/cleaned then leave the sludge where it is.

 

If you've never used detergent oil, the first time you do the amount of garbage that will come loose will plug the filter very quickly. Count on changing the filter twice at least.

 

Buy oil with ZINC!
Valvolene makes a racing oil that still has the proper zinc additives as the old formulations.

 

Yep! I run Valvoline Racing Oil 20W-50......great oil....stareted using it when my flathead was fresh off the build......nice and clean inside and out, and it's staying that way......

CB

 

I use 15W-40 valvoline oil and Lucas Zinc additive. This is what I use in my 1947 Ford.

 

i use castrol hd 30 with a bottle of comp cams break in oil ( zink)

 

yes

 

What about us guys running flatheads in the south? I'm still a little confused on what weight to use.

 

Hey Pete....just as a side note.

Racing oil (good stuff btw) may have more zinc added for racing cams that use high valve spring loads - but it is not really an issue in a flatty. Even a strong street flathead would have no more than b/w 60-90lbs of spring pressure, unlike racing engines or strong OH street engines that may have 400+ valve spring psi "on the nose", in which case it can cause problems without the extra zinc.

Racing oil also does'nt have the additives needed (like a street car oil) to keep the oil cleaner longer because it is designed to be dumped and changed often. Dilution, fuels used and racing loads/engine clearances are different in racing engines, very different to a street FH.

Even in strong flatheads, use a quality 20-50W and if filtered, change it depending on usage and conditions for max cleanliness.

I use 20-50W non-synthetic oil in my blown 8BA, no probs. Is racing oil for a FH required or worth the $$$, you be the judge.

My 2c

Rat

 

If your zincphobic pour in a bottle of stp oil treatment...their MSDS states a good amount of zinc in it...and its cheap.

 

Go to AutoZone, find a gallon jug of Rotella straight 30 weight oil. It has the zinc in it everyon else has mentioned. It won't hurt to top it off with a quart of STP or Lucas.
My dad (MercDueceman) runs it in his flathead Merc, '56 Olds engine in El Tiki, and I run it in my '55 Desoto Hemi. Works good.

 

It said 20-50 in my manual and I seem to get good pressure.

 

I run 15w40 Rotella in both of mine.

 

Can anyone confirm the rumor that Shell is eliminating - or already has - the ZINC additive from their Rotella oil??

 

I ran Rotella in mine

 

I use 20-50 in my 59AB flathead. It helps keep the oi pressue up.

 

It makes little difference to the flathead what oil you use as long as you are prepared to keep putting new oil in it as it burns it. Use 20 weight in cold weather, 40 in hot weather, and when the oil consumption breaks your wallet, rebuild it . I have seen some with 90 weight in them, but that was long ago. But it made the oil pressure look good. And quieted things down a bit.

traderjack

 

90 weight... like gear oil? Thought about running that. Just bought 30w hd rotella and one quart of stp.

 

I'm in Tampa and I use Castrol 20/50 in all our Flatheads.

 

I live in Mesa Arizona, what weight of oil and maybe a cheaper brand that is good to throw in a 1950 Mercury with a flathead V8

 

Only time I've run 90 wt in an engine was an auction car I bought. Changed the oil and it started rattling bearings. Drained some off and added 3 qts of 90 wt, drove straight to my least favorite dealer and traded it in.
They asked why I was selling a car I just bought that week - "my girlfriend hates it"

 

Liquid, from a new container.

Mike

 

You my friend are a very wise man!!!!!

 

I’ve moved to Lucas Hot Rod oil for all my 50’s engines. It meets the specs of vintage flat tappet engines even with higher valve spring pressures than I use.

 

I currently have Brad Penn in my 40, not sure of the weight because I have a local machine shop with a vintage car repair shop in the back service the car because of the waste disposal problems. I just had a Flathead built and I do know they used Brad Penn 30 weight with high Zinc content for the break in.

 

OP from 2008.

 

cheap house brand diesel oil. 10 30 winter, 15 40 summer for me