Need info on 251 engine

[Bob Carriere]

Bonjour Michel

All oil is thicker when cold and the oil pressure will be high. Once the oil gets hot and thinner and water like it will leak from every bearing on the crank and on the camshaft. You may have just one or two worn bearing but it is enough to drop the oil pressure...... some sludge circulating in the oil system could explain the fluctuation or you have a worn bearing that may be moving...spinning on the lower end of a rod and drip more and somethimes less.

Old M37 would run well on 20 to 25 pounds warm..... below that I would get scared of doing damage.......

If you care about saving the engine before you get real bad damage..... don't drive it..... tear it down before you need a major regrind or score a cylinder wall...... if everything is worn loose you will never find oil thick enough to bring the pressure up......

Parts are readily available check out......www.vintagepowerwagons.com make sure you look at the Canadian 251 engine parts

Another excellent source of information is.....http://www.dodgepowerwagon.com

Like Gilles offered I may also have parts also....... you might be able to get away with just flipping the engine over and doing crank main and rod bearings
....... I even polished cranks by hand with progressively finer emery paper.... not a good job but the darn thing ran good..... they are fairly forgiving compared to modern thight clearance engine.....

Do you have a Dodge military shop manual for the engine..? Dodge flat heads are not hard to work on...... except you have to take the whole darn block to the machine shop to get a valve grind job.

Boob