quote:Originally posted by George P:
On the subject of oil pumps, I can show you Ford literature from the 1960s recommending 3/4" ID for the oil pump suction line of a high performance motor, yet the largest suction line you can screw into a 351C oil pump has an ID of 5/8". As Homer Simpson would say ... DOH!
That's interesting information George.
It doesn't sound like much to go from 5/8" to 3/4" but that small change in size would actually result in almost 50 percent reduction in resistance to the inflowing oil. A considerable improvement to alleviate possible pump cavitation.
I do say possible cavitation because as i said earlier you can't see caviation unless you had xray vision, and it is hard to hear in a engine, the castings are too massive and the engine makes too much noise, you can only imagine it based on experience of what similar systems of similar design have been know to do in other circumstances. The experience of the hydraulic engineers is paramount.
I do agree with you that the lifter bore issue is a far worse problem than the oil pump and i think if a motor is being built up from scratch that is the way to go.
I was looking at this with the perspective of what can be done to a motor that is in a car and does not at this stage require a rebuild but could benefit from simple bolt on modifications eg: while the sump is off changing the stock connecting rod nuts perhaps look into the oil pump and sump for possible improvements ??
I agree a high volume pump is not desirable in the 351c and likely to make things worse.
But a larger inlet to any pump makes sense in any application whether it is a oil pump in a engine or a hydraulic pump or a fuel pump. Like the ports in the cylinder heads the inlet needs to be bigger than the exhaust/outlet.
Most things are made to a price or for ease of manufacture or simply designed to be "good enough" it is rare that no improvement can possibly be made to a item or system and subtle improvements are made to every other aspect of the 351c often without a moments thought. I don't understand why the oil pump should be thought of as "untouchable" especially when it is a bolt on item and easily changed out.
Best regards to everyone on the forum
