hard or soft copper line for a valley oil gallery bypass line?

[Newbomb Turk]

In the scenario we are discussing, why would there be a different pressure on each end of the gallery?

What makes you think it will be the same? Oil pressure isn't the same throughout the entire engine.

I put several gauges on my engine and the results were shocking to say the least. For example, you can have 80 pounds on the gauge and damn near nothing at the rocker shafts.

The length of the tube or gallery, the number of 90's, the surface finish of the tube all change the pressure in the tube.

So, thinking it through IF you pull oil from the filter or the back of the engine, run it to the front and then add some 90's or whatever to get the oil to the front you will have different pressure in that tube.

 

[92b]

What makes you think it will be the same? Oil pressure isn't the same throughout the entire engine.

I put several gauges on my engine and the results were shocking to say the least. For example, you can have 80 pounds on the gauge and damn near nothing at the rocker shafts.

The length of the tube or gallery, the number of 90's, the surface finish of the tube all change the pressure in the tube.

So, thinking it through IF you pull oil from the filter or the back of the engine, run it to the front and then add some 90's or whatever to get the oil to the front you will have different pressure in that tube.

Are you saying that if the oil pressure was the same on each end, that having opposing feeds in the gallery does not stop flow at some point?

 

[Newbomb Turk]

Are you saying that if the oil pressure was the same on each end, that having opposing feeds in the gallery does not stop flow at some point?

No, I'm saying even IF there is a pressure differential at some point you will have pressure and no flow. But you assumption that the pressure is equal throughout the engine is incorrect.

 

[92b]

No, I'm saying even IF there is a pressure differential at some point you will have pressure and no flow. But you assumption that the pressure is equal throughout the engine is incorrect.

That is not my assumption. I didn't say pressure was equal through out the engine. I'm trying to figure out how having opposing feeds in the gallery stops flow at some point in the system. Can this only happen if the pressure is different at each end of the feed? or will this still occur if the feed pressure is the same on each end?

 

[Duane]

What ever. I’m saying there is no reason to do the crossover if you think it’s going to save bearings.

I pulled out the other book and looked through it. The only thing that I see that he says differently is to block the oil feed from the cam by clocking the cam bearings to block the feed holes.

That’s a great idea but I wouldn’t pick up the oil to feed the rockers from the main oil feed down the passenger side. I have been looking at doing that on my junk especially when I do the W2 engine. But I would get the oil to feed the rockers from the feed to the oil pressure gauge. Then it doesn’t come off the main feed but I haven’t had a chance to look at it close to see if it would work.

Saying that, my ***** about this whole thing is guys are doing a mod that doesn’t do a damn bit of good as far as bearing life is concerned.

I went back and read the OP. I asked him why he wanted to do the crossover. He said to slow the oil down so it is evident he is looking for bearing life. As I have said many times it doesn’t.

It’s one thing to do a modification if it serves a purpose. For the OP the crossover doesn’t do that.

As for the mod to not feed any rockers off a main feed I did that in 2000 or so. Each shaft was fed from a separate feed that didn’t come off the main feed and it helped a ton.

The engine I’m getting ready to do won’t get all the modifications I did back then but I want to at least stop feeding the rockers off the main oil feed.

The block is already tubed on the passenger side and the oil to the drivers side is blocked with a set screw.

That’s my *****. Guys doing the crossover for the wrong reasons.

I went back and looked through my Sanborn notes. Two things I noticed. Yes indeed he used pushrod oiling. But he also had bushed lifter bores. So why run a crossover. You say it’s to feed the lifters. Sanborn says the crossover line was put in to reverse feed number 1 main bearing. I can repost his notes if you’d like. He says without that crossover, you are feeding all the drivers side
Lifters off #1 main leaving that bearing prone to failure. It is right in his notes.
So what do you think happens to the oil in the passenger side if you block it from feeding 1 main bearing,1cam bearing,and 8 lifter bores. What effect do you think that has. Where else can that oil and pressure go.
To the 2,3,and 4 mains. And if the oil only has 3 leaks instead of 13, that oil speed in the galley is not moving very fast.
Sanborn also feeds the galley front and back as well.

 

[Newbomb Turk]

I went back and looked through my Sanborn notes. Two things I noticed. Yes indeed he used pushrod oiling. But he also had bushed lifter bores. So why run a crossover. You say it’s to feed the lifters. Sanborn says the crossover line was put in to reverse feed number 1 main bearing. I can repost his notes if you’d like. He says without that crossover, you are feeding all the drivers side
Lifters off #1 main leaving that bearing prone to failure. It is right in his notes.
So what do you think happens to the oil in the passenger side if you block it from feeding 1 main bearing,1cam bearing,and 8 lifter bores. What effect do you think that has. Where else can that oil and pressure go.
To the 2,3,and 4 mains. And if the oil only has 3 leaks instead of 13, that oil speed in the galley is not moving very fast.
Sanborn also feeds the galley front and back as well.

Post his notes if you don’t mind. I haven’t read those in probably two decades. I’m sorry to say I can’t even remember when he passed.

And I just learned today a brilliant guy on another forum passed in December.

To that end, you are making my point. My memory was he was using pushrod oiling.

Once you block the oil to the drivers side lifters IF you are using pushrod oiling OR hydraulic lifters although I can’t reason why you would run a hydraulic lifter in a performance engine except for rules then you have to get oil there somehow.

To that end, the crossover tube works for that specific issue. It won’t save a main bearing.

I also get why he was back feeding the number one main.

I suggest there are better ways to get oil over there without the crossover, but the tube does that.

What it doesn’t do is fix the issue of oiling the bearings. It doesn’t slow down the oil.

That’s why I asked the OP why he’s was doing it. His answer had nothing to do with pushrod oiling. His answer was he was looking for more reliability concerning bearing oiling. The crossover doesn’t do that.

 

[Duane]

Post his notes if you don’t mind. I haven’t read those in probably two decades. I’m sorry to say I can’t even remember when he passed.

And I just learned today a brilliant guy on another forum passed in December.

To that end, you are making my point. My memory was he was using pushrod oiling.

Once you block the oil to the drivers side lifters IF you are using pushrod oiling OR hydraulic lifters although I can’t reason why you would run a hydraulic lifter in a performance engine except for rules then you have to get oil there somehow.

To that end, the crossover tube works for that specific issue. It won’t save a main bearing.

I also get why he was back feeding the number one main.

I suggest there are better ways to get oil over there without the crossover, but the tube does that.

What it doesn’t do is fix the issue of oiling the bearings. It doesn’t slow down the oil.

That’s why I asked the OP why he’s was doing it. His answer had nothing to do with pushrod oiling. His answer was he was looking for more reliability concerning bearing oiling. The crossover doesn’t do that.

And I am telling you that his notes specifically say it is done to reverse feed #1
main.i am pretty sure that I posted all his notes in the original oiling thread on this topic. My point to you is his vouching the crossover works just like Chrysler has, but it is a two part modification. Sleeving the galley and plugging with a set screw was also approved by Chrysler because both mods cut some or all oil to the lifters.

 

[Duane]

Post his notes if you don’t mind. I haven’t read those in probably two decades. I’m sorry to say I can’t even remember when he passed.

And I just learned today a brilliant guy on another forum passed in December.

To that end, you are making my point. My memory was he was using pushrod oiling.

Once you block the oil to the drivers side lifters IF you are using pushrod oiling OR hydraulic lifters although I can’t reason why you would run a hydraulic lifter in a performance engine except for rules then you have to get oil there somehow.

To that end, the crossover tube works for that specific issue. It won’t save a main bearing.

I also get why he was back feeding the number one main.

I suggest there are better ways to get oil over there without the crossover, but the tube does that.

What it doesn’t do is fix the issue of oiling the bearings. It doesn’t slow down the oil.

That’s why I asked the OP why he’s was doing it. His answer had nothing to do with pushrod oiling. His answer was he was looking for more reliability concerning bearing oiling. The crossover doesn’t do that.

I am not making your point. If his class rules required oil at the lifters, and you bushed lifter bores, you could restrict flow to your discretion with the bushing and leave the stocking method of oiling off #1 main as is. Sanborn claims this fails #1 main.
Just as you spoke about those old cams with a groove on # 2&4 cam journals robbing the mains of oil. I had one of those cams. Failed my 2&4 mains after 40 runs.
You cannot feed other areas of the motor off of a main bearing because you get a pressure drop at that bearing. The stock oiling feeds all the drivers side lifters from number one main.
So the fix is to block the feed on the passenger side. Then re-supply the oil to number one in the opposite side and direction of feed with a crossover tube.
The stroker small block book method goes even further and does not allow any cam bearings that are fed by the mains, to feed the rockers, re-enforcing the supply to 2&4 mains as well.

 

[Duane]

Post his notes if you don’t mind. I haven’t read those in probably two decades. I’m sorry to say I can’t even remember when he passed.

And I just learned today a brilliant guy on another forum passed in December.

To that end, you are making my point. My memory was he was using pushrod oiling.

Once you block the oil to the drivers side lifters IF you are using pushrod oiling OR hydraulic lifters although I can’t reason why you would run a hydraulic lifter in a performance engine except for rules then you have to get oil there somehow.

To that end, the crossover tube works for that specific issue. It won’t save a main bearing.

I also get why he was back feeding the number one main.

I suggest there are better ways to get oil over there without the crossover, but the tube does that.

What it doesn’t do is fix the issue of oiling the bearings. It doesn’t slow down the oil.

That’s why I asked the OP why he’s was doing it. His answer had nothing to do with pushrod oiling. His answer was he was looking for more reliability concerning bearing oiling. The crossover doesn’t do that.

 

[Newbomb Turk]

I am not making your point. If his class rules required oil at the lifters, and you bushed lifter bores, you could restrict flow to your discretion with the bushing and leave the stocking method of oiling off #1 main as is. Sanborn claims this fails #1 main.
Just as you spoke about those old cams with a groove on # 2&4 cam journals robbing the mains of oil. I had one of those cams. Failed my 2&4 mains after 40 runs.
You cannot feed other areas of the motor off of a main bearing because you get a pressure drop at that bearing. The stock oiling feeds all the drivers side lifters from number one main.
So the fix is to block the feed on the passenger side. Then re-supply the oil to number one in the opposite side and direction of feed with a crossover tube.
The stroker small block book method goes even further and does not allow any cam bearings that are fed by the mains, to feed the rockers, re-enforcing the supply to 2&4 mains as well.

Then we are in agreement. The crossover has zero to do with bearing life. It is a means to getting oil to the drivers side when you restrict the oil to the lifters.

Which is exactly why I asked the OP why he was doing it. I don’t know if he’s using pushrod oiling or not but if he’s not he is wasting his time with that modification.

Hopefully he’s running a rear sump pan and he spends some time getting the pick up side of the pump in shape.

He will have way more success doing that then the crossover.

 

[Newbomb Turk]

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Thanks. On my iPhone so I can’t read it and I have to go see my accountant this morning so I’ll look at them on my lap top when I get back.

 

[Duane]

Then we are in agreement. The crossover has zero to do with bearing life. It is a means to getting oil to the drivers side when you restrict the oil to the lifters.

Which is exactly why I asked the OP why he was doing it. I don’t know if he’s using pushrod oiling or not but if he’s not he is wasting his time with that modification.

Hopefully he’s running a rear sump pan and he spends some time getting the pick up side of the pump in shape.

He will have way more success doing that then the crossover.

Read what I wrote. We are not in agreement.
It has everything to do with bearing life.

 

[Jadaharabi]

I say it doesn't do what they say it does. And it doesn't. If you are using it to put oil back to the lifters for pushrod oiling that's one thing. But saying it slows the oil down defies ALL logic.

So you tell me what the OP will gain if he wastes his time and money doing it.

I'll tell you I called in a late night favor last night to a guy who knows things. Without me going out to the shop and taking some measurements he did some rough calculations. His math says it doesn't slow the oil down. It can't. He and I were looking at the oiling schematic and he thought the whole thing was retarded.

If you are trying to get more oil to the bearings, and by blocking oil off where its not needed why is it going right back to where you just took oil from? That makes no sense.

To that end, the oiling going to the top end, especially with a roller cam that has a groove in the 2 and 4 cam bearings to get full time oil to the rockers is what is taking oil from the bearings is what's causing oil loss to the bearings, not some fantasy about oil velocity too high.

Just because Chrysler developed it doesn't make it right.

For the OP its a giant waste of time and money. Why people ignorantly defend this modification is beyond me.

I agree with your last statement. It is beyond you. Deniers do not want to admit that it works so there's no sense in even trying to convince you otherwise. Just do the modifications and see what happens.

 

[92b]

@Newbomb Turk . This is a continuation of post #54. In this diagram representing an oil circuit being fed from two opposing ends. Where in the main oil gallery would oil stop flowing?

 

[Duane]

@Newbomb Turk . This is a continuation of post #54. In this diagram representing an oil circuit being fed from two opposing ends. Where in the main oil gallery would oil stop flowing?

View attachment 1716215850

I was going to post a drawing like that. It shows how ridiculous his understanding of hydraulics is. According to him, the oil will just sit in the galley going nowhere with 80psi pressure on both ends and not flow to the 4 leaks in the tube. He also denies that if you take away the front feed that there is no possibility of some of the oil running past those 4 leaks because there are 10 leaks at the end of the galley(lifters on the drivers side)
that are gushing oil and that number one main is the one that’s feeding 9 of those leaks.

 

[Newbomb Turk]

Read what I wrote. We are not in agreement.
It has everything to do with bearing life.

@Newbomb Turk . This is a continuation of post #54. In this diagram representing an oil circuit being fed from two opposing ends. Where in the main oil gallery would oil stop flowing?

View attachment 1716215850

I'll say it again because you love to argue. You can have pressure an no flow. Simple as that.

I'll say this again. Let's say I'm wrong. Let's say it doesn't happen. It still doesn't change the FACT that a crossover tube doesn't slow down the oil or do a damn thing that can't be done better.

My post was about helping a FABO member NOT waste his time and money on a modification that will do him ZERO good and not a single one of you has ANY proof that the crossover does what you think it does.

Now I have to go read the link that Duane so kindly posted from Sanborn.

 

[Newbomb Turk]

I agree with your last statement. It is beyond you. Deniers do not want to admit that it works so there's no sense in even trying to convince you otherwise. Just do the modifications and see what happens.

Jad, exactly what end user proof do you have that the crossover does anything? Your own personal experience please with some kind of industry (say SAE or similar technical paper) that shows the crossover slows down the oil to save the bearings.

 

[Newbomb Turk]

@Newbomb Turk . This is a continuation of post #54. In this diagram representing an oil circuit being fed from two opposing ends. Where in the main oil gallery would oil stop flowing?

View attachment 1716215850

BTW. your assumption that the pressure from each feed is the same. It's not. Also consider the FACT that somewhere in that pipe there are two different columns of oil meeting. That point can move back and forth in the pipe as the local pressure changes. Pressure and no flow. It happens.

 

[Newbomb Turk]

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Duane, I can't figure out how to make the notes big enough to read. would you mind sending them to my email? I'll PM you my address.

Thanks

 

[Newbomb Turk]

I was going to post a drawing like that. It shows how ridiculous his understanding of hydraulics is. According to him, the oil will just sit in the galley going nowhere with 80psi pressure on both ends and not flow to the 4 leaks in the tube. He also denies that if you take away the front feed that there is no possibility of some of the oil running past those 4 leaks because there are 10 leaks at the end of the galley(lifters on the drivers side)
that are gushing oil and that number one main is the one that’s feeding 9 of those leaks.

The very FIRST modification MUST be stopping oil leaks at the lifters. Or at least stopping 95% of the leaking. If you don't do that there is nothing else you do will help, with the exception of getting the suction side of the pump the very best you can.

 

[Jadaharabi]

BTW. your assumption that the pressure from each feed is the same. It's not. Also consider the FACT that somewhere in that pipe there are two different columns of oil meeting. That point can move back and forth in the pipe as the local pressure changes. Pressure and no flow. It happens.

Your very close on the column of oil. A column of oil has hundreds of columns within the column of oil going in different directions some going sideways some going back or forth some going up or down. It is not just all the oil gushing forward.

 

[Newbomb Turk]

the utube vid that described it said to use a hard copper (I forget the letter designation) but a utube pro plumber said to use soft copper (in his demo) because you would be flaring it. what do you guys think? thank you for your time. RR

Robert, let me ask you again what is your end goal. And before you can answer that, we should discuss what you are exactly doing. For example...

Are you running solid or hydraulic lifters?
Are you pushrod oiling?
How many RPM will the engine run?
What type of oil pan can you use?

Answering those questions should direct you to what modifications you need to make, if any.

Now lets play the the game. Keep in mind I'm assuming you have full groove mains, a HV pump and your pick up is well sorted out, or at least as good as you can do within the limits of the oil pan.

Hydraulic lifters? You are screwed. All you SHOULD do is tube the block, drill an .080 hole in the tube where it breaks through the lifter bore. For the passenger side use a set screw under the main bearing to restrict flow to the drivers side.

Solid lifters? Much better. Tube the block. Block the feed to the drivers side as above and go.

Pushrod oiling? Now its more work. Tube the block and drill the holes for lifter feed in the tube. Use a plug under the main bearing with about a hole in it to feed the lifters.

How many RPM? If you are under 7500 then worry about the inlet side of the pump and getting the pan in shape to go around corners. If you are going much higher than 7500 you need to address the elephant in the fridge and that's getting the oil to the rods. I'm not addressing that here.

What pan? Mid sump, rear sump, box style? The worst pan by far is a box pan, but I haven't done a wet sump circle track engine since the late 90's so I don't remember what you can do with a pan like that. I don't think I've ever seen what I call a box pan.

A mid sump is the second best option as far as oil control goes. Oil control is less problematic than a box pan, but the pickup tube will be longer than a rear sump and therefore as the length gets longer the cross section MUST get bigger and that's hard to do. As I said before, the biggest gains in increasing bearing life is a HV pump, full groove bearings, getting the suction side of the pump as big and short as possible and stopping the leaks at the lifter.

If you can use a rear sump pan, jump on that. Best oil control, shortest pick up tube and you can install the pick up in the cover and you can also if its done correctly will let you add a second pick up using the OE hole in the side of the pump. As engine speed goes up, getting the suction side of the pump as unrestricted as you can gets more critical.

To that end, your engine builder shouldn't be using 1970's and 1980's bearing clearances. .0025 on the rod and mains is the loosest I would use, and even at that I would spend money on a quality synthetic oil (not group III oil because its not really a true synthetic oil) because using a 20/50 oil makes it more difficult to get the oil into the pump. Or a single grade oil. Other than my compressor and the brake on my dyno I can't think of a reason to ever use a single grade oil.

Notice I didn't say use a crossover? But let's go there.

Lets say you are pushrod oiling and running right at 7500. Here's what you could do. Tube the block, put your holes in the tube to feed the lifters, plug the feed to the number 1 main at the front of the passenger side feed hole then install the crossover tube to feed the drivers side and put to the drivers side and let it get the oil to those lifters that way. That
s what the crossover does. It doesn't slow the oil down, it doesn't do anything other than get oil to the drivers side lifters. Bearing life is increased because you stopped the leaks and forced the oil to the mains rather than letting the oil leak all over the place.

Or, you could leave the crossover out and and rather than blocking the oil to the number 1 main at the front of the driver side gallery you block it under the main bearing of number 1. Then you can pick up the oil to feed the D side lifters by drilling and tapping a hole in the rear china wall where the pressure gauge feed goes up and take the oil from there to feed the lifters from that. That way it doesn't take oil off the main gallery.

If you are running a roller cam that has a groove around the 2 and 4 bearings then I would either install a set screw in the head where the oil gets to the shaft. For roller rockers a .0625 hole is plenty big. If you are running bushed rockers or any rocker that doesn't have needle bearings on the shaft you need to make the hole .080 or so.

If the engine is apart, you can clock the 2 and 4 cam bearings so you block the hole feeding the passage in the block so no oil gets through the cam to the heads. Then do the above modifications and rather than the crossover just feed the rockers by accessing the same oil gallery that feeds the pressure gauge. Then drill and tap the gallery that goes from the cam to the head that normally feeds the head and run a hose from the pressure gauge gallery to feed the rockers.

In post 4 you said you wanted to do the crossover to keep the bearings alive. It doesn't do that. All it does is allow you to feed the drivers side lifter IF you are running hydraulic lifters or pushrod oiling. Or both.

If you need to do that then you can do it, but there are better ways to do it than that. The biggest bearing savers are a HV pump, full grove mains and blocking the oil off to the lifters. And of course to get the pick up as big and short as you can.

 

[Jadaharabi]

Robert, let me ask you again what is your end goal. And before you can answer that, we should discuss what you are exactly doing. For example...

Are you running solid or hydraulic lifters?
Are you pushrod oiling?
How many RPM will the engine run?
What type of oil pan can you use?

Answering those questions should direct you to what modifications you need to make, if any.

Now lets play the the game. Keep in mind I'm assuming you have full groove mains, a HV pump and your pick up is well sorted out, or at least as good as you can do within the limits of the oil pan.

Hydraulic lifters? You are screwed. All you SHOULD do is tube the block, drill an .080 hole in the tube where it breaks through the lifter bore. For the passenger side use a set screw under the main bearing to restrict flow to the drivers side.

Solid lifters? Much better. Tube the block. Block the feed to the drivers side as above and go.

Pushrod oiling? Now its more work. Tube the block and drill the holes for lifter feed in the tube. Use a plug under the main bearing with about a hole in it to feed the lifters.

How many RPM? If you are under 7500 then worry about the inlet side of the pump and getting the pan in shape to go around corners. If you are going much higher than 7500 you need to address the elephant in the fridge and that's getting the oil to the rods. I'm not addressing that here.

What pan? Mid sump, rear sump, box style? The worst pan by far is a box pan, but I haven't done a wet sump circle track engine since the late 90's so I don't remember what you can do with a pan like that. I don't think I've ever seen what I call a box pan.

A mid sump is the second best option as far as oil control goes. Oil control is less problematic than a box pan, but the pickup tube will be longer than a rear sump and therefore as the length gets longer the cross section MUST get bigger and that's hard to do. As I said before, the biggest gains in increasing bearing life is a HV pump, full groove bearings, getting the suction side of the pump as big and short as possible and stopping the leaks at the lifter.

If you can use a rear sump pan, jump on that. Best oil control, shortest pick up tube and you can install the pick up in the cover and you can also if its done correctly will let you add a second pick up using the OE hole in the side of the pump. As engine speed goes up, getting the suction side of the pump as unrestricted as you can gets more critical.

To that end, your engine builder shouldn't be using 1970's and 1980's bearing clearances. .0025 on the rod and mains is the loosest I would use, and even at that I would spend money on a quality synthetic oil (not group III oil because its not really a true synthetic oil) because using a 20/50 oil makes it more difficult to get the oil into the pump. Or a single grade oil. Other than my compressor and the brake on my dyno I can't think of a reason to ever use a single grade oil.

Notice I didn't say use a crossover? But let's go there.

Lets say you are pushrod oiling and running right at 7500. Here's what you could do. Tube the block, put your holes in the tube to feed the lifters, plug the feed to the number 1 main at the front of the passenger side feed hole then install the crossover tube to feed the drivers side and put to the drivers side and let it get the oil to those lifters that way. That
s what the crossover does. It doesn't slow the oil down, it doesn't do anything other than get oil to the drivers side lifters. Bearing life is increased because you stopped the leaks and forced the oil to the mains rather than letting the oil leak all over the place.

Or, you could leave the crossover out and and rather than blocking the oil to the number 1 main at the front of the driver side gallery you block it under the main bearing of number 1. Then you can pick up the oil to feed the D side lifters by drilling and tapping a hole in the rear china wall where the pressure gauge feed goes up and take the oil from there to feed the lifters from that. That way it doesn't take oil off the main gallery.

If you are running a roller cam that has a groove around the 2 and 4 bearings then I would either install a set screw in the head where the oil gets to the shaft. For roller rockers a .0625 hole is plenty big. If you are running bushed rockers or any rocker that doesn't have needle bearings on the shaft you need to make the hole .080 or so.

If the engine is apart, you can clock the 2 and 4 cam bearings so you block the hole feeding the passage in the block so no oil gets through the cam to the heads. Then do the above modifications and rather than the crossover just feed the rockers by accessing the same oil gallery that feeds the pressure gauge. Then drill and tap the gallery that goes from the cam to the head that normally feeds the head and run a hose from the pressure gauge gallery to feed the rockers.

In post 4 you said you wanted to do the crossover to keep the bearings alive. It doesn't do that. All it does is allow you to feed the drivers side lifter IF you are running hydraulic lifters or pushrod oiling. Or both.

If you need to do that then you can do it, but there are better ways to do it than that. The biggest bearing savers are a HV pump, full grove mains and blocking the oil off to the lifters. And of course to get the pick up as big and short as you can.

I agree with some of what you say. But crossover does save bearings. How you say? You are restricting the oil to the number one main at the front of the block and feeding it from the oil passage at the rear of the passenger side to the front of the driver's side. This makes the number two main the front Main in the oiling on the passenger side. Therefore the oil is no longer having to make that 90° turn and then go on pass for the next Main bearing. Number two becomes the number one front feed. You are no longer going to take the chance of starving that bearing because the oil didn't want to make a 90° turn to feed it. So therefore the crossover tube does help save the number two and number four main bearings.
This is my humble opinion and I fully endorse it.

Remember I am talking hydraulic lifters here. If I was going solid I would tube the block and block the oil lifter Galley on the driver side.

 

[92b]

BTW. your assumption that the pressure from each feed is the same. It's not. Also consider the FACT that somewhere in that pipe there are two different columns of oil meeting. That point can move back and forth in the pipe as the local pressure changes. Pressure and no flow. It happens.

Your assumption about what you think I assume is incorrect. I will repost #54 with my question.

"That is not my assumption. I didn't say pressure was equal through out the engine. I'm trying to figure out how having opposing feeds in the gallery stops flow at some point in the system. Can this only happen if the pressure is different at each end of the feed? or will this still occur if the feed pressure is the same on each end?"

 

[92b]

BTW. your assumption that the pressure from each feed is the same. It's not. Also consider the FACT that somewhere in that pipe there are two different columns of oil meeting. That point can move back and forth in the pipe as the local pressure changes. Pressure and no flow. It happens.

You said you have a friend "who knows". Ask him which passage or passages from the main gallery 1-4 are going to receive no flow because the gallery is being fed from opposing ends. Maybe he can explain why this happens.