lifter galley crossover tube
I think we've gotten a little off course. Duane, I believe your 2&4 failure was from little things that added up to the failure. Your full groove cam without a restriction in the rocker pedestal played a part. I'm not sure about the rest of your combo like the pump, oil type, bearing clearances, etc.
Now, the oil tube mod and plug has one purpose, to take pre#4 and dump it into the other galley. Some say, as in the guitar jones oil mod write-up, that this slows down the velocity of the oil flowing by the main 4,3,2,1 ports. This will allow the oil to take the 90* turn towards the mains easier. The entire oil galley will now dead-end at #1 and the oil pressure will allow oil flow out the leakage areas in the crank/rod. The more oil leakage you have that is connected to anything that feeds the crank will drop the pressure at the crank. Full time, unrestricted oil to the head is a bigger leak compared to the crank leakage. this induces a greater pressure drop for the crank oil supply at #4,2. Not to mention, the lower pressure that the full time head oiling creates, will allow the oil to flow to the lowest pressure area, the head. This seems to be a problem when you want to rev higher and higher. Even tho you did the tube mod, the head oiling screwed you over, IMO. A restricted head would lower the pressure drop seen at the crank/head oil port intersection. That, and/or make the crank/rod bearing clearances larger. This will allow more flow past them, in turn changing the pressure drop at the head/crank intersection in your favor.
What I was pondering about using an oil cooler had nothing to do with using the tube mod/plug at all. My theory was that if the sole problem is the velocity of the oil flowing past 4,3,2,1 is great enough that it is difficult to make the 90* turn, why not slow down this velocity by dropping the pressure/flow by running a line to an oil cooler coming from the oil pressure sending unit connection. Dump this line into the pan. No tube, no plug. On second thought, the plug creating the dead end at #1 is equally important (if not more important than the tube) to this mod because the oil flow becomes much slower since it doesn't have to feed the other lifter bank at #1. The tube simply helps slow down the oil by feeding the other lifter bank before #4 as well as provide lube since its passage is now blocked by the plug in 1.
T56. Yes I agree we have gotten off course.
It occurred to me that we may be confusing each other with some of out terminology. From now on when I say the words tube mod, I am referring to the mod where you ream out the drivers side oil galley and install copper tubes. I call this the Chrysler method.
Instead of saying just tube I will now call it the cross over line.
When I say mains I mean the main bearings not main oil galley. Lol
Having cleared that up yes T56 I totally accept your explanation.
As I was trying to explain to B3, I have never personally used the cross over line on any of my engines including the one that had the failure. That block had the "Copper tube mod" in it along with the drilled passages to the main bearings.Hv pump. You are correct that there were no restrictors at the rocker gear feed.
I am only talking about the cross over line mod for the sake of discussing it validity. I did not ever say that velocity caused the failure because my block was already modified to address that issue.
When I posted to you about putting a line into the pan I was assuming you were referring to the cross over line mod being done,
I assumed you had forgotten that the cross over line reverse feeds the #1 main bearing.
Regarding your proposed method at the sending unit, what size line would you propose. I would be worried about reducing the total system pressure to unacceptable amounts.
B3 apparently is either not convinced that there is a velocity problem with this engine,or is not convinced of the crossover lines effectiveness.
I do not have his educational background and I believe his dilemma
Is that the recommended cross over line method does not match what he has been taught.
I do not think I am the one that could provide that scientific explanation.
But this crossover line modification has been around for like 40 years. It is not new and many racers swear by it.
If we are to only go by our physics of pressures always moving to a low pressure area, then there should not even be a problem with the oil making the turns to the mains. That is probably why there are so many non believers. Incidentally I have the original Larry Atherton book here and it says that only #4&3 main bearings are affected. It also claims that the angle the fittings enter the block are critical to how much oil is diverted to the drivers side but does not tell you what the angles are.
B3 claims that using the crossover line would reduce the pressure
At the main bearings. That sounds like what your are proposing.
Maybe that's how it works. Reduce the pressure to reduce the velocity. I do not know.
Very good post by you though.
