what kind and grade oil to you use in these flathead motors

 

If it's a fresh rebuild, use what you'd use in any other engine. I run 10W40. Some guys run synthetics or syn-blends. I've got too many leaks to do that.

If it's an old engine that hasn't been disassembled and cleaned top to bottom, you'd best use a non-detergent. Operator's manual says 30W for summer and 10W for winter.

If you use a new detergent oil in an old cruddy engine you risk having chunks of sediment break up and plug the oil pump screen. Then your engine starves for oil and burns up bearings. Not cool.

 

thanks Tim

this truck was restored about 4 years ago, not by me so i don't know about the motor. the motor is spotless on the outside so i am guessing that it was rebuilt at that time.

 

It's always prudent to drop the pan and check. If it's clean then its probably been rebuilt. I prefer Castrol 20W50 for a warm weather flatty but have been reading threads recently about the oil companies continually reducing the percent of wear inhibitors; the current SL grade has the least. In that vein I am going to start using a grade designed for diesel trucks which maintains the additives. Use a C grade which stands for compression ignition; S is spark ignition.

As far as the do I or dont I use modern oil in and old dirty engine Ive used nothing but modern oils for decades and NEVER have had any problems in flattys or OHV's of any make.
I suspect its more of an oft repeated old wives tale than fact. The heat hardened mess inside a flatty isnt going to move for anything except acid or a sandblaster; the rest will be dissolved in the detergents and you should change oil and filter more often at first. A clean pan and pump screen is the most important step to keeping an old flatty running.

Also in a stock 49 the oil pump was still the old square cut gears unless it was replaced. Ford went to the Melling helical gear M19 in mid 50 and it dramatically improved flow. Speedway and others carry it as its still in production. Cheap insurance.

 

thanks Carl

what do you think of this new line of products for high milage motors

 

Im just starting with the diesel oils Dale, no real mileage on the 396 or 292 yet. Also going into a flatty and 85 Dodge 318 this weekend.
Since Im a Castrol freak here is a good link with lots of info and choices.

http://www.castrolhdl.com/products/F...ory=EngineOils