My take on the oiling system crossover tube for the small block

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Marcohotrod said:
I have solid lifters, and I do not have a problem because of good lifter clearances and plugging the flow to the driver side. I did not change cam to bearing clearance, just checked it
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"the other thread said the cam bearing clearance basically closes the oil feed holes up to the galley which effectively restricts them."

This statement was said by you and quoted by procharged on the first page of this thread.
You made this statement in another oiling thread.
Checking your cam bearing clearance and your lifter bore clearance to make sure they are correct is good engine building practice as you said, but all cam bearings and lifter bores have some leakage by design. Solid lifters do not require pressurized oil. It is a waste of pump volume that is better sent to the crank. Solid lifters will survive on splash oiling.
Cam bearings leak just like rod or main bearings. The cam only sees half the rpm of the crankshaft. Unless you are using some really monster springs, cam bearings are over oiled and the volume to them can be restricted to cut down on pump volume that again is better sent to the crank. That is the basis of all performance oiling improvements on a sbm.Even if your lifter clearances are within tolerance, they still have some leakage, if you cut the flow to the drivers side, you have cut 50% of the lifter leakage. That oil volume is now available to make good oil pressure and send that extra volume to your crank. In a general rebuild it is usually cost prohibitive to bush lifter bores. If the bores have some wear, they will leak even more to the point that oil pressure could be a problem even with all the cam bearings and bottom end bearings in tolerance.
With a high volume, higher pressure pump combined with excessive lifter leakage you can develop the galley excess velocity problem that is the reason for tubing the block or running a crossover line to fix.
There is no way that I know of to restrict the flow of oil going to the cam bearings other than an inline screw with a smaller size feed hole or drilling new smaller holes in the cam bearings.
You claimed that you did this by adjusting the cam bearing clearance,
and I was asking how you do this.
You dismissed the need to restrict volume to the cam bearings completely in the other thread. You followed Dick Landys oiling mods
By cutting the flow to the drivers side, which was good, but that mod was half the reason for your problem free build, not that you checked your lifter bore clearance. Imho
 
Jadaharabi said:
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Did it make it back in?
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Not yet!! I'm lagging BIG time! To be honest, I kinda got burnt out for a second. So I switched gears and started working on an old Cletrac BGS Crawler I have. I bounce back and forth between tractors and cars. Lol

Got myself in the middle of a valve job :X

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Duane said:
The guy who said that never explained nor have I ever heard of anyone adjusting cam bearing clearance to restrict flow. A cam bearing works the same way as a rod or main bearing. If it has some clearance, it leaks. The amount of volume flowing to a cam bearing is excessive in relation to the load and rpm(half the crank) that the cam sees. That excessive oil is better restricted and sent to the crank.
I have never heard that there are .001 under or over size cam bearings to adjust clearance in a cam bearing, and because of the way cam bearings are installed, you would ruin a set just establishing what is needed. I say bs on that type of restriction imho.
Cam bearings leak huge, that's why people restrict them.
If I am wrong the guy who posted that should explain how it is done.
Not just make a blanket statement and disappear imho.
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Engine shop I worked in years ago fitted undersized cam bearings to every engine regardless of what it was and the engine assembly guy reemed them to suit.
 
Retroboy said:
Engine shop I worked in years ago fitted undersized cam bearings to every engine regardless of what it was and the engine assembly guy reemed them to suit.
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I have heard of that, but that is done to verify alignment more than to adjust clearance although you could do that too.
My point was that I have never heard of anyone saying that cam bearings are a natural restrictor. A bearing is a bearing and they leak oil under pressure. It is very common to restrict flow to the cam bearings to force more oil where it is needed at the crank and rod bearings. That guy was dismissing that. I am ok if someone doesn't agree, but come back to the thread and tell us why so maybe we can all learn something.
 
Retroboy said:
Engine shop I worked in years ago fitted undersized cam bearings to every engine regardless of what it was and the engine assembly guy reemed them to suit.
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FWIW..... That was standard assembly procedure for Opels, and probably Holdens, in that year range.... 60's-80's and maybe earlier in time. You could not buy cam bearings finished-to-proper ID from the factories for the Opel CIH engines of that era. So it had nothing to do with clearances or alignment in some cases... it was just what had to be done for standard replacement procedures.

Fiat's were the same way in that era for simple bearings like the oil pump shaft... really sucked if you did not have the tools. Since I did not have the tools, I let my Opel cam bearings wear to some pretty big clearances LOL
 
I don't know much detail about the oiling system itself, but the build was first done in the '70s following all the tips in the SA Books "Mopar Performance" including "X" heads with full port/polish by Bob Mullen. This guy (engineering student with access to money) from Roswell, NM ran a Challenger with an over cammed stock 340 and set up street races for big money, then came home and swapped this motor in for the races!!!

He unfortunately died young, and his mother, Juanita, gave me the engine after she'd stored it for many years. When I got it, it had "mountain" pistons in it. I had to rebuild it for street and tried to do it "with respect" with the best machine work I could find, etc. Full details in the thread "Help with 340 compression + cam change.

Does anyone have any information about the "A&W crossover"?????? I know who did the heads, but do not know who would have prepped the block. I remember the machine shop telling me the crank was full radius (?) and rods "side clearanced" among other things. I built it myself, but when I picked up the block and heads I remember the shop owner telling me, "Man, somebody broke the bank on these heads!!" He told me to sell the heads to buy some nice after market heads and finance the build! (.....I was given the motor, and in honor of that will not part with it. )

The block had been de-burred and was white inside (epoxy?) and they tanked it in the aluminum block tank to save the paint.

Any knowledge of this oiling system set-up and who did these would be very helpful.
 
midnight340 said:
I don't know much detail about the oiling system itself, but the build was first done in the '70s following all the tips in the SA Books "Mopar Performance" including "X" heads with full port/polish by Bob Mullen. This guy (engineering student with access to money) from Roswell, NM ran a Challenger with an over cammed stock 340 and set up street races for big money, then came home and swapped this motor in for the races!!!

He unfortunately died young, and his mother, Juanita, gave me the engine after she'd stored it for many years. When I got it, it had "mountain" pistons in it. I had to rebuild it for street and tried to do it "with respect" with the best machine work I could find, etc. Full details in the thread "Help with 340 compression + cam change.

Does anyone have any information about the "A&W crossover"?????? I know who did the heads, but do not know who would have prepped the block. I remember the machine shop telling me the crank was full radius (?) and rods "side clearanced" among other things. I built it myself, but when I picked up the block and heads I remember the shop owner telling me, "Man, somebody broke the bank on these heads!!" He told me to sell the heads to buy some nice after market heads and finance the build! (.....I was given the motor, and in honor of that will not part with it. )

The block had been de-burred and was white inside (epoxy?) and they tanked it in the aluminum block tank to save the paint.

Any knowledge of this oiling system set-up and who did these would be very helpful.
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$5 to a donut Bob Mullens or Larry Atherton did it. Atherton was A&W.
Post #3 I mention the A&W crossover.
Neat engine.
 
Well, that’s pretty interesting!!! I bought Atherton’s book when I did the build and was struck by how much similarity there was.

I remember reading that Bob Mullen and Co. we’re based in the LA area. Was Atherton in the same area?

Juanita told me she didn’t know much except the parts were sent to California and that it cost “a whole lot of money.”
...She helped her son “hide the amount” from his father. :)

I have long term plans to do a rebuild someday that’s more in line with the potential.
 
midnight340 said:
Well, that’s pretty interesting!!! I bought Atherton’s book when I did the build and was struck by how much similarity there was.

I remember reading that Bob Mullen and Co. we’re based in the LA area. Was Atherton in the same area?

Juanita told me she didn’t know much except the parts were sent to California and that it cost “a whole lot of money.”
...She helped her son “hide the amount” from his father. :)

I have long term plans to do a rebuild someday that’s more in line with the potential.
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I'm not sure where atherton's shop was. But the guy I used to work for in Phoenix used to go over to it and taking parts and get parts from him. Back in the seventies he took his 340 over to atherton's and they put the crossover on that 340 block.
My understanding was that Atherton's shop was in his garage at his house.
By the way his crossover tube looked just like yours but I don't remember the writing on it. Or maybe I do.
Yes I do believe I saw that on his crossover tube. Old memories long ago.
 
Jadaharabi said:
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Have you got it running yet? The car or the crawler either one? lol
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Neither! Before I install the engine, I need to cut a small piece out of the upper trans crossmember to make clearance for the Passon 5 speed. I *think* It’s a touch bigger than a stock 4 speed, as the top of the trans rubs against that member. Not a big deal, little cut and welding.
 
nm9stheham said:
FWIW..... That was standard assembly procedure for Opels, and probably Holdens, in that year range.... 60's-80's and maybe earlier in time. You could not buy cam bearings finished-to-proper ID from the factories for the Opel CIH engines of that era. So it had nothing to do with clearances or alignment in some cases... it was just what had to be done for standard replacement procedures.

Fiat's were the same way in that era for simple bearings like the oil pump shaft... really sucked if you did not have the tools. Since I did not have the tools, I let my Opel cam bearings wear to some pretty big clearances LOL
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My point was I have never heard of anyone intentionally adjusting there cam bearing clearances on the tight side to aid with better oiling to the main and rod bearings which is what was being implied.
Not sayin it's not done, just that I have never heard or read of that.
 
Have any of you seen or done this on a mopar? These are from high hp LS engines at a buddies shop. There is also a groove in the block going from the main oil hole going up to this second hole in the bearing.

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Correction. not YR but Duane posted pictures of this mod on one of the oiling system threads.
 
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