VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc "Full Pressure" Meaning

What is the consensus regarding the term "full pressure" mean?

a. Prior to 235 engines, I don"t think the term applies.

b. Some use it when it is in reference to any 235s. Are those engines really fully oil pressurized when not to the filter also? t

c. The 261 had full pressure to the oil filter. The 216 and thee 235 doesn't. How about a that difference? Is that what we mean when we think of full pressure i.e, to include the filter?

What is the consensus here. I think we use it too loosely and that it would be helpful and less misleading to nail this term down when we refer to it here on the Chat.

It is obvious that the poster just before me on this forum wants to know also.

Thanks,

Charlie

I think most people use the term "full pressure" to refer to the engines with crankshafts drilled to supply oil to the rod bearings from the main bearings... with or without a filter. These engines have higher volume oil pumps than earlier ones and run at higher pressures.
Some people are fussier in their terminology and only use the term "full pressure" for those engines where the connecting rod is also drilled to supply oil from the big end of the rod to the wrist pin. Usually these are diesel and industrial people.
On full pressure engines of either sort, filters can be either "full flow" or "bypass" depending on whether all of the oil going to the engine runs through the filter, or only part of the oil runs through it.

Just as an interesting aside...
Chevrolet referred to the 216's as being "pressure stream" oiled. Not "splash" oiled. And they technically weren't any more splash oiled than the later engines. All 216's and 235's oil the pistons, cylinder walls and camshaft with oil splashed or thrown off other parts.
And technically the rods on 216's were "pressure" lubricated by the inertia of the oil struck by the dippers... which actually supplied oil at much higher pressures than later engines... albeit more sporadically, as in only during an arc at the bottom of the stroke.
Interestingly, at least one of the top hotrodders of Chevrolet 6's in the 1950's said the "pressure stream" system was perfectly adequate and reliable for all purposes.
The only issues were the thickness of the babbit in the rod bearings, and the weight of the cast iron pistons.

Okay, OSO,

Please ignore my comment about Canadians on the thread regarding oil filters. You seem smarter than most.

Best,

Charlie

No offense taken :-)

"full pressure" means direct oil pressure to a bearing rather than oil splashed to the bearing.
In 1929 there was no full pressure to any bearing. In 1930 the was full prssure to just the center main bearing.1932 and up pressure to all main bearings. 1953 Power Glide the pressure to the main bearings was directed to the connecting rods bearings via oil passages in the crankshaft. The old dipper system say in 1952 was sufficent up to 4000 RPM and more suited to 3500 RPM and less.

the 1958-1962 261 had a full flow oil filter whch meant all oil was passed through the oil filter after it left the oil pump and before it got to the bearings.

Thanks Gene,

Good and knowledgeable comments in both threads.

Best,

Charlie