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when are 3/4 grooved main bearings needed for bbc ?

General engine tech -- Drag Racing to Circle Track

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Warp Speed
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Warp Speed » Tue Nov 26, 2019 12:14 pm

ClassAct wrote:
Tue Nov 26, 2019 11:20 am
Warp Speed wrote:
Tue Nov 26, 2019 10:16 am
I can't really go too much into the oiling strategy we use, but I know one thing for sure. If the theory Classact has on oil timing were true, none of our engines would make it through a single pull on the dyno.
As I've said all along, look elsewhere for the problem, because thats NOT it! :wink:

Once again, the OP didn't ask about what you do. The actual question was about a 3/4 groove main bearing for a BBC. He wasn't talking about the latest, greatest oiling system you use.

The sad thing is, the oil timing issue is well known. How it's done today at the NASCAR I can't say and really don't care. Most guys on here will never deal with it.

A hydraulics engineer, who wasn't indoctrinated in automotive engineering, developed the system needed o fix the oil timing on engines where it's off.

Again, I don't know anyone, not a single guy I can think of, who actually runs RPM's at 8k or more who hasn't had Rod bearing oiling issues with the OE type oiling system. I know that many guys claimed they did/do it, but data logging proved most of them never saw the high side of 7600.

The oiling system of an OE engine is essentially the same for every brand out there, with very small differences. Yet, the SBC was the ONLY one that oiled reliably at virtually any RPM you had the balls to pay for. And none of the rest of them would even get close and to do that took a bunch of modifications and even then, reliability was a big question mark.

So take two blocks and cranks, a SBC and for fun, let's use a BB MoPar which is just as bad and set them side by each and look at the differences. Virtually no differences, except where the oil feed hole is located.

I had the good fortune to work with a local Comp racer who eventually set and reset several times his National Record. I also looked at most of his runs right off the data logger. He shifted at 9800 and crossed at 10,200-10,400 depending on conditions and clutch tuning etc. Did that with a wet sump and an oiling system that was literally untouched. His blocks didn't even have priority main oiling until he had set and ready the record several times.

You're not going to do that with any other brand.

So figure out what the difference is.

To the OP, you don't need more than a half groove bearing for a BBC. Or a SBC. Anything else, use a half groove bearing at your own risk.
:lol:
Man, I'm really sorry if facts are getting in the way of your theory, but it is what it is.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Kevin Johnson » Tue Nov 26, 2019 2:48 pm

Straight-shot oiling just popped into my head versus one shot. Sorry about that!

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by swampbuggy » Tue Nov 26, 2019 10:28 pm

Warpspeed, once oil gets from the main bearing groove into the crankshaft oil passage way, does centrifugal force play a part in getting the oil to the rod bearing ? Mark H.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Warp Speed » Wed Nov 27, 2019 7:46 am

swampbuggy wrote:
Tue Nov 26, 2019 10:28 pm
Warpspeed, once oil gets from the main bearing groove into the crankshaft oil passage way, does centrifugal force play a part in getting the oil to the rod bearing ? Mark H.
Yes, it is called centrifugal force. It helps feed the rod bearing past the crank centerline. Unfortunately, prior to the oil crossing the centerline, this same force inhibits oil flow. That is one of the biggest challenges to overcome, and one of the big problems with a straight drilling. That, and the limitations to oiling timing and strategies. It is also one of the problems with cross drilled mains.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Kevin Johnson » Wed Nov 27, 2019 7:54 am

I know SAE papers are expensive. If you are really interested in oil flow in a crankshaft then I strongly suggest purchasing at least this one -- peer reviewed and written thirty-three years ago by a researcher at General Motors.
Meernik.jpg
Aside:
https://en.wikipedia.org/wiki/Centrifugal_force#History_of_conceptions_of_centrifugal_and_centripetal_forces wrote: In another instance the term refers to the reaction force to a centripetal force, or reactive centrifugal force. A body undergoing curved motion, such as circular motion, is accelerating toward a center at any particular point in time. This centripetal acceleration is provided by a centripetal force, which is exerted on the body in curved motion by some other body. In accordance with Newton's third law of motion, the body in curved motion exerts an equal and opposite force on the other body. This reactive force is exerted by the body in curved motion on the other body that provides the centripetal force and its direction is from that other body toward the body in curved motion.[35][36] [37][38]

This reaction force is sometimes described as a centrifugal inertial reaction,[39][40] that is, a force that is centrifugally directed, which is a reactive force equal and opposite to the centripetal force that is curving the path of the mass.

The concept of the reactive centrifugal force is sometimes used in mechanics and engineering. It is sometimes referred to as just centrifugal force rather than as reactive centrifugal force[41][42] although this usage is deprecated in elementary mechanics.[43]
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Warp Speed » Wed Nov 27, 2019 8:14 am

Kevin Johnson wrote:
Wed Nov 27, 2019 7:54 am
I know SAE papers are expensive. If you are really interested in oil flow in a crankshaft then I strongly suggest purchasing at least this one -- peer reviewed and written thirty-three years ago by a researcher at General Motors.

Meernik.jpg

Aside:
https://en.wikipedia.org/wiki/Centrifugal_force#History_of_conceptions_of_centrifugal_and_centripetal_forces wrote: In another instance the term refers to the reaction force to a centripetal force, or reactive centrifugal force. A body undergoing curved motion, such as circular motion, is accelerating toward a center at any particular point in time. This centripetal acceleration is provided by a centripetal force, which is exerted on the body in curved motion by some other body. In accordance with Newton's third law of motion, the body in curved motion exerts an equal and opposite force on the other body. This reactive force is exerted by the body in curved motion on the other body that provides the centripetal force and its direction is from that other body toward the body in curved motion.[35][36] [37][38]

This reaction force is sometimes described as a centrifugal inertial reaction,[39][40] that is, a force that is centrifugally directed, which is a reactive force equal and opposite to the centripetal force that is curving the path of the mass.

The concept of the reactive centrifugal force is sometimes used in mechanics and engineering. It is sometimes referred to as just centrifugal force rather than as reactive centrifugal force[41][42] although this usage is deprecated in elementary mechanics.[43]
This also answers Ptuomov's inquiries about oil acceleration.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by swampbuggy » Wed Nov 27, 2019 8:58 am

A thank you to Warpspeed and Kevin J. for your input on this oiling discussion !! =D>

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by ClassAct » Wed Nov 27, 2019 10:47 am

Warp Speed wrote:
Tue Nov 26, 2019 12:14 pm
ClassAct wrote:
Tue Nov 26, 2019 11:20 am
Warp Speed wrote:
Tue Nov 26, 2019 10:16 am
I can't really go too much into the oiling strategy we use, but I know one thing for sure. If the theory Classact has on oil timing were true, none of our engines would make it through a single pull on the dyno.
As I've said all along, look elsewhere for the problem, because thats NOT it! :wink:

Once again, the OP didn't ask about what you do. The actual question was about a 3/4 groove main bearing for a BBC. He wasn't talking about the latest, greatest oiling system you use.

The sad thing is, the oil timing issue is well known. How it's done today at the NASCAR I can't say and really don't care. Most guys on here will never deal with it.

A hydraulics engineer, who wasn't indoctrinated in automotive engineering, developed the system needed o fix the oil timing on engines where it's off.

Again, I don't know anyone, not a single guy I can think of, who actually runs RPM's at 8k or more who hasn't had Rod bearing oiling issues with the OE type oiling system. I know that many guys claimed they did/do it, but data logging proved most of them never saw the high side of 7600.

The oiling system of an OE engine is essentially the same for every brand out there, with very small differences. Yet, the SBC was the ONLY one that oiled reliably at virtually any RPM you had the balls to pay for. And none of the rest of them would even get close and to do that took a bunch of modifications and even then, reliability was a big question mark.

So take two blocks and cranks, a SBC and for fun, let's use a BB MoPar which is just as bad and set them side by each and look at the differences. Virtually no differences, except where the oil feed hole is located.

I had the good fortune to work with a local Comp racer who eventually set and reset several times his National Record. I also looked at most of his runs right off the data logger. He shifted at 9800 and crossed at 10,200-10,400 depending on conditions and clutch tuning etc. Did that with a wet sump and an oiling system that was literally untouched. His blocks didn't even have priority main oiling until he had set and ready the record several times.

You're not going to do that with any other brand.

So figure out what the difference is.

To the OP, you don't need more than a half groove bearing for a BBC. Or a SBC. Anything else, use a half groove bearing at your own risk.
:lol:
Man, I'm really sorry if facts are getting in the way of your theory, but it is what it is.
I'm sorry you can't comprehend what the facts are. I'd ask the simple question again, bu you've dodged the question enough that either you can't or won't answer it.

Everything you do is fogged by your experience. You look down your nose at anyone who doesn't work for some big dollar team or whatever. That's on you.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by mt-engines » Wed Nov 27, 2019 3:05 pm

ClassAct wrote:
Wed Nov 27, 2019 10:47 am
Warp Speed wrote:
Tue Nov 26, 2019 12:14 pm
ClassAct wrote:
Tue Nov 26, 2019 11:20 am



Once again, the OP didn't ask about what you do. The actual question was about a 3/4 groove main bearing for a BBC. He wasn't talking about the latest, greatest oiling system you use.

The sad thing is, the oil timing issue is well known. How it's done today at the NASCAR I can't say and really don't care. Most guys on here will never deal with it.

A hydraulics engineer, who wasn't indoctrinated in automotive engineering, developed the system needed o fix the oil timing on engines where it's off.

Again, I don't know anyone, not a single guy I can think of, who actually runs RPM's at 8k or more who hasn't had Rod bearing oiling issues with the OE type oiling system. I know that many guys claimed they did/do it, but data logging proved most of them never saw the high side of 7600.

The oiling system of an OE engine is essentially the same for every brand out there, with very small differences. Yet, the SBC was the ONLY one that oiled reliably at virtually any RPM you had the balls to pay for. And none of the rest of them would even get close and to do that took a bunch of modifications and even then, reliability was a big question mark.

So take two blocks and cranks, a SBC and for fun, let's use a BB MoPar which is just as bad and set them side by each and look at the differences. Virtually no differences, except where the oil feed hole is located.

I had the good fortune to work with a local Comp racer who eventually set and reset several times his National Record. I also looked at most of his runs right off the data logger. He shifted at 9800 and crossed at 10,200-10,400 depending on conditions and clutch tuning etc. Did that with a wet sump and an oiling system that was literally untouched. His blocks didn't even have priority main oiling until he had set and ready the record several times.

You're not going to do that with any other brand.

So figure out what the difference is.

To the OP, you don't need more than a half groove bearing for a BBC. Or a SBC. Anything else, use a half groove bearing at your own risk.
:lol:
Man, I'm really sorry if facts are getting in the way of your theory, but it is what it is.
I'm sorry you can't comprehend what the facts are. I'd ask the simple question again, bu you've dodged the question enough that either you can't or won't answer it.

Everything you do is fogged by your experience. You look down your nose at anyone who doesn't work for some big dollar team or whatever. That's on you.
Actually no.. I think the only person fogged is you. There are professionals giving advice and you have to contradict it due to your own theory.. It's like the kool-aid drinkers praising authors that have absolutely no data for themselves.

I stopped posting because people don't want to learn facts.. They just want hearsay from 40 years ago.

I may be speaking for myself, but it's amazing what even a stock wetsump is capable of when you understand what the losses are.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Warp Speed » Wed Nov 27, 2019 3:16 pm

ClassAct wrote:
Wed Nov 27, 2019 10:47 am
Warp Speed wrote:
Tue Nov 26, 2019 12:14 pm
ClassAct wrote:
Tue Nov 26, 2019 11:20 am



Once again, the OP didn't ask about what you do. The actual question was about a 3/4 groove main bearing for a BBC. He wasn't talking about the latest, greatest oiling system you use.

The sad thing is, the oil timing issue is well known. How it's done today at the NASCAR I can't say and really don't care. Most guys on here will never deal with it.

A hydraulics engineer, who wasn't indoctrinated in automotive engineering, developed the system needed o fix the oil timing on engines where it's off.

Again, I don't know anyone, not a single guy I can think of, who actually runs RPM's at 8k or more who hasn't had Rod bearing oiling issues with the OE type oiling system. I know that many guys claimed they did/do it, but data logging proved most of them never saw the high side of 7600.

The oiling system of an OE engine is essentially the same for every brand out there, with very small differences. Yet, the SBC was the ONLY one that oiled reliably at virtually any RPM you had the balls to pay for. And none of the rest of them would even get close and to do that took a bunch of modifications and even then, reliability was a big question mark.

So take two blocks and cranks, a SBC and for fun, let's use a BB MoPar which is just as bad and set them side by each and look at the differences. Virtually no differences, except where the oil feed hole is located.

I had the good fortune to work with a local Comp racer who eventually set and reset several times his National Record. I also looked at most of his runs right off the data logger. He shifted at 9800 and crossed at 10,200-10,400 depending on conditions and clutch tuning etc. Did that with a wet sump and an oiling system that was literally untouched. His blocks didn't even have priority main oiling until he had set and ready the record several times.

You're not going to do that with any other brand.

So figure out what the difference is.

To the OP, you don't need more than a half groove bearing for a BBC. Or a SBC. Anything else, use a half groove bearing at your own risk.
:lol:
Man, I'm really sorry if facts are getting in the way of your theory, but it is what it is.
I'm sorry you can't comprehend what the facts are. I'd ask the simple question again, bu you've dodged the question enough that either you can't or won't answer it.

Everything you do is fogged by your experience. You look down your nose at anyone who doesn't work for some big dollar team or whatever. That's on you.
Man, Im really sorry you feel that way.
I don't look down my nose at anyone, until they start arguing, with theories that don't hold water. I'm trying to teach you something, but you refuse to listen.
You say everything I do is "fogged by my experience ", and your correct. My opinions are based on facts and experience gained from 25+ years of scientific testing and development of high rpm race engines, with basically unlimited financial and technical resources, along with oem technical support, o conduct this testing with. Now you can say, like many do when they get frustrated, that the Nascar engines dont apply. So lets look at this for a moment. A Nascar v8 is a 90*, ohv pushrod engine, that not only does it need to make the most power possible, it has to do it, while living under some of the worst conditions imaginable rpm and temprature wise, for hours on end. We put more cycles on an engine getting it up to testing temperature, than a typical drag engine will see in 2 or 3 years of service. The things we do oiling system wise, are designed to live at extreme rpm and temp, for hours on end, while being the most efficient as possible.
Nascar engines are the same basic architecture, as most all american v8 engines. So how does this knowledge that I have gaines not apply?!?
Now you can point again to the placement of the main feed messing up the "timing", but as I mentiones before, this is maybe 10* different than that of a standard SBC. The angled vector that the feed passage meets the mains in a Cleveland isn't optimum, but it isn't the big problem either. So then we move to the supply. The main oil galley is also a lifter galley, and that is more than likely where the problem begins. Not only are there various pressure bleeds along the way, and they are all effected both by lifter position and movement. This is not conducive of supplying a steady pressure with low aeration.
I mentioned earlier how to break down an oiling system. It starts with the main feed to the bulkhead passages. Fix that, and you can move farther down the system.
Again, I'm just trying to help you. And while it is obvious your not some Joe blow of the street, your opinions of oiling systems, and this block and crank oil timing are greatly flawed. If you dont want to listen, that is fine. But quit trying to beat your point home, because it is incorrect!

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by ClassAct » Wed Nov 27, 2019 4:41 pm

Warp Speed wrote:
Wed Nov 27, 2019 3:16 pm
ClassAct wrote:
Wed Nov 27, 2019 10:47 am
Warp Speed wrote:
Tue Nov 26, 2019 12:14 pm


:lol:
Man, I'm really sorry if facts are getting in the way of your theory, but it is what it is.
I'm sorry you can't comprehend what the facts are. I'd ask the simple question again, bu you've dodged the question enough that either you can't or won't answer it.

Everything you do is fogged by your experience. You look down your nose at anyone who doesn't work for some big dollar team or whatever. That's on you.
Man, Im really sorry you feel that way.
I don't look down my nose at anyone, until they start arguing, with theories that don't hold water. I'm trying to teach you something, but you refuse to listen.
You say everything I do is "fogged by my experience ", and your correct. My opinions are based on facts and experience gained from 25+ years of scientific testing and development of high rpm race engines, with basically unlimited financial and technical resources, along with oem technical support, o conduct this testing with. Now you can say, like many do when they get frustrated, that the Nascar engines dont apply. So lets look at this for a moment. A Nascar v8 is a 90*, ohv pushrod engine, that not only does it need to make the most power possible, it has to do it, while living under some of the worst conditions imaginable rpm and temprature wise, for hours on end. We put more cycles on an engine getting it up to testing temperature, than a typical drag engine will see in 2 or 3 years of service. The things we do oiling system wise, are designed to live at extreme rpm and temp, for hours on end, while being the most efficient as possible.
Nascar engines are the same basic architecture, as most all american v8 engines. So how does this knowledge that I have gaines not apply?!?
Now you can point again to the placement of the main feed messing up the "timing", but as I mentiones before, this is maybe 10* different than that of a standard SBC. The angled vector that the feed passage meets the mains in a Cleveland isn't optimum, but it isn't the big problem either. So then we move to the supply. The main oil galley is also a lifter galley, and that is more than likely where the problem begins. Not only are there various pressure bleeds along the way, and they are all effected both by lifter position and movement. This is not conducive of supplying a steady pressure with low aeration.
I mentioned earlier how to break down an oiling system. It starts with the main feed to the bulkhead passages. Fix that, and you can move farther down the system.
Again, I'm just trying to help you. And while it is obvious your not some Joe blow of the street, your opinions of oiling systems, and this block and crank oil timing are greatly flawed. If you dont want to listen, that is fine. But quit trying to beat your point home, because it is incorrect!
TL;DR Can't help you Jay. You'd be wrong. The OP asked a simple question and it turned into this shit show because you THINK you know but you don't. I do, because I have lived it. Many guys with credential much greater than yours are wrong about it. And you propagating it is a bad thing.

I don't want or need your help if it's wrong. There is a REASON why Chrysler told everyone to use full groove mains to oil the rods. Unless you think they are stupid. But they weren't. The understood the issue.

Again, to the OP, for a BBC you done need more than a half groove bearing. Other engines, use a half groove at your own risk, and even then it will only help until you hit a higher RPM.

One last thing. The (for example) small block Chrysler and small block Chevy are so close in oiling systems when you get them side by side it's almost hard to tell them apart. Yet one will oil the rods and one won't. Go figure out what the difference is and then you'll have the answer.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Warp Speed » Wed Nov 27, 2019 7:38 pm

ClassAct wrote:
Wed Nov 27, 2019 4:41 pm
Warp Speed wrote:
Wed Nov 27, 2019 3:16 pm
ClassAct wrote:
Wed Nov 27, 2019 10:47 am


I'm sorry you can't comprehend what the facts are. I'd ask the simple question again, bu you've dodged the question enough that either you can't or won't answer it.

Everything you do is fogged by your experience. You look down your nose at anyone who doesn't work for some big dollar team or whatever. That's on you.
Man, Im really sorry you feel that way.
I don't look down my nose at anyone, until they start arguing, with theories that don't hold water. I'm trying to teach you something, but you refuse to listen.
You say everything I do is "fogged by my experience ", and your correct. My opinions are based on facts and experience gained from 25+ years of scientific testing and development of high rpm race engines, with basically unlimited financial and technical resources, along with oem technical support, o conduct this testing with. Now you can say, like many do when they get frustrated, that the Nascar engines dont apply. So lets look at this for a moment. A Nascar v8 is a 90*, ohv pushrod engine, that not only does it need to make the most power possible, it has to do it, while living under some of the worst conditions imaginable rpm and temprature wise, for hours on end. We put more cycles on an engine getting it up to testing temperature, than a typical drag engine will see in 2 or 3 years of service. The things we do oiling system wise, are designed to live at extreme rpm and temp, for hours on end, while being the most efficient as possible.
Nascar engines are the same basic architecture, as most all american v8 engines. So how does this knowledge that I have gaines not apply?!?
Now you can point again to the placement of the main feed messing up the "timing", but as I mentiones before, this is maybe 10* different than that of a standard SBC. The angled vector that the feed passage meets the mains in a Cleveland isn't optimum, but it isn't the big problem either. So then we move to the supply. The main oil galley is also a lifter galley, and that is more than likely where the problem begins. Not only are there various pressure bleeds along the way, and they are all effected both by lifter position and movement. This is not conducive of supplying a steady pressure with low aeration.
I mentioned earlier how to break down an oiling system. It starts with the main feed to the bulkhead passages. Fix that, and you can move farther down the system.
Again, I'm just trying to help you. And while it is obvious your not some Joe blow of the street, your opinions of oiling systems, and this block and crank oil timing are greatly flawed. If you dont want to listen, that is fine. But quit trying to beat your point home, because it is incorrect!
TL;DR Can't help you Jay. You'd be wrong. The OP asked a simple question and it turned into this shit show because you THINK you know but you don't. I do, because I have lived it. Many guys with credential much greater than yours are wrong about it. And you propagating it is a bad thing.

I don't want or need your help if it's wrong. There is a REASON why Chrysler told everyone to use full groove mains to oil the rods. Unless you think they are stupid. But they weren't. The understood the issue.

Again, to the OP, for a BBC you done need more than a half groove bearing. Other engines, use a half groove at your own risk, and even then it will only help until you hit a higher RPM.

One last thing. The (for example) small block Chrysler and small block Chevy are so close in oiling systems when you get them side by side it's almost hard to tell them apart. Yet one will oil the rods and one won't. Go figure out what the difference is and then you'll have the answer.
:lol: :wink:

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Little Mouse » Wed Nov 27, 2019 8:30 pm

Even though I'm certainly a chevy guy, I did not know my razzing of chevy folks about the hemi and it's full groove bearings that seemed to really make this thread take off. I do like telling chevy folks how the hemi destroyed everyone in nascar to the point the rules makers did everything to get rid of it. Lol rules makers did the same to the offy 4 when it dominated could not be beat.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by modok » Wed Nov 27, 2019 8:50 pm

And I don't have a clue!
Never thought hard about it, never had the opportunity.

I do appreciate the fact we can share what we DO know, it might result in something useful.

I need to point out that what direction the crank is loaded at any given point in time should be considered.
On the con-rod size, seems to be well accepted that it will get oil flow when the gap near the oil hole is opening up,
isn't the same true for the other end?
If the oil hole in the main is approaching the loaded area of the bearing I would think that would PUSH the oil into the hole, and it it was leaving the loaded zone then it might let the oil back out.

I had assumed, years ago, that that was the problem with cross-drilling, The oil would just be going back and forth in the cross-drilling.

BUT there are so many odd-ball design cranks that ALSO seem to work.... I know less all the time.

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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by modok » Wed Nov 27, 2019 9:03 pm

And BTW this is V8 ONly, right? and that's what makes it really a mind-bender.

You have two rods on one throw, and the END counterweights, which totally changes everything.

Two alternate possibilities in how the crank could be drilled.
It could be drilled like a VW crank, basically same both sides, not cross drilling....X drilling, for V8 that would be a crank drilled for normal or reverse roataion at the same time, and by covering any one or two of the four holes, you could have the oil go and out any spot, maybe the same side it came out, and I've NEVER seen that. i really wonder if that doesen't work or just nobody tried it.

AND there is no law saying you need ALL full groove or ALL half groove, you can mix and match. OE's do it, doesen't scare me in the least.

THIS main feeds two rods? ok I'll give this one a full groove.

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