My take on the oiling system crossover tube for the small block
Boy, lots of opinions/different ways of trying to keep the rods in these things. If your way works for you, that's great.
IMHO...
Chevrolets are very different from Chryslers - they have a main galley that feeds the crank exclusively and auxiliary galleys to feed the lifters and heads. These auxiliary galleys are easily restricted and controlled at the back of the block as to the amount of oil going to these areas, which in turn makes it easier for the system to keep up with the crank oiling. I tried to duplicate this with what I was doing.
A separate auxiliary line, rear to front and feeding the front of the right galley provides a source for oil to the left side in the event I want to provide oil pressure to the lifters. That is the ONLY reason to put oil in the left galley.
I like bushing the lifters. It corrects the sloppy original machining, seals the galleys, wears better than the iron bores especially in a 59* deal and allows for precise control of oil to the lifters if needed. There are different ways of doing that.
I prefer to oil all 4 mains from the right side and do what it takes to seal those mains at the saddle and keep all the oil on the crank.
None of these fixes require or would benefit from running a crossover. In fact, putting oil in the left galley would be counter-productive to what I was doing. Front oiling eliminates that need. #1 main has the benefit of only having to oil one rod. #1 main and rod were always happy.
I do not agree that the mains are the first thing to show problems due to lack of oil. The rods are at the end of the line and the first to run dry when the flow stops or pressure drops. Typically in my experience the rods would show signs of lose of lube while the mains were happy.
Timing can be an issue. Full groove mains should fix that IF the problem is entirely how the crank is drilled. Changing that had zero benefit for me. Eliminating that big pressure dump at the cam journal every revolution of the cam did make a difference.
My steel crank 340s were mostly happy to 8000 with few modifications to the oil system. The iron crank 360s were awful. That is where I was forced to figure all of this out.
I agree with about everything you posted Cole.
A couple of interesting observations on your post.
You seem to feel that the advantage of the Chev is its dedicated galley for the separate oiling of the lifters and the cam,crank/rods.
I agree. It's as if you are spreading the duties around to the 3 galleys. If you were to view it that way, sending a large volume of oil over to the drivers side on the Chrysler leaves the passenger galley with less responsibilities. The drivers side is still being used to
Oil a main bearing, cam and rod journal.
With number 5 main having its own separate passage, this leaves the right side to only feed 3 bearings. I wonder if this is why the crossover is claimed to work. Everything you said about keeping the oil at the bearings would still apply to number one main. It would just be supplied from the other side.
I found it interesting that you mention rod bearing trouble with the 360 crank but not so much with the 340. Do you think that is because of the longer stroke?
Your comment reminds me of an article I read by David Reher in which he claimed that stroker motors were much harder to oil the rods. His belief was that the cavity inside the crankshaft on a stroker is larger and more difficult to fill and that because of this, stroker motors required more oiling mods.
In the Sanborn thread Charles claimed that slotting the bearing shells increased the dwell time and gave more time for the rod passage to fill up with oil. He also never ran full groove bearings.
He claimed his motors were reliable to 8000 rpm lap after lap not just a quarter mile pass. I often wonder if the rods partially get pressurized oil just from centrifugal force provided that there is oil in the passage in the crank.
I have never lost a rod bearing shifting at a maximum of 7000 rpm,
But have had main bearing trouble twice. I do not know how to explain that other than possibly lack of pressure at the mains, but the rod bearing cavity had oil in it and still fed the rod bearings.