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Crank Bearings full grove or 3/4 ???
Posted By: JSR1485
Crank Bearings full grove or 3/4 ??? - 02/03/11 11:52 PM
What do you guys use 3/4 grove or full grove? I have heard that full grove is best for oiling but they can cause the crank to grove on thrust side-bottom and it is better to use 3/4 grove to give the crank more area on the bottom side. A friend of mine told that to also order the bearing -.001 also. This I have not heard of?
They do cost alot more
Also anybody use King Bearings? I see they are made right hear in NJ
Posted By: '72CudaRacer
Re: Crank Bearings what to use? - 02/04/11 01:52 AM
I use King bearings, but the're not made in NJ. they are made in Israel.
Brian Dunnigan
Posted By: Cab_Burge
Re: Crank Bearings what to use? - 02/04/11 06:32 AM
Which motor?
Posted By: JSR1485
Re: Crank Bearings what to use? - 02/04/11 02:02 PM
Small block 408 stroker
Posted By: JSR1485
Re: Crank Bearings what to use? - 02/04/11 09:45 PM
Anybody have any input on what bearings are best to use?
Posted By: jvcuda
Re: Crank Bearings what to use? - 02/05/11 12:00 AM
Old skool here,I always used full groove and on my race big block I even use the wide full groove.Never noticed any more wear on the cranks.
Posted By: CHAPPER
Re: Crank Bearings what to use? - 02/05/11 01:22 AM
Quote:
Small block 408 stroker
Over 10 years with the same crank,,,full groove bearings. 
Posted By: Stanton
Re: Crank Bearings what to use? - 02/05/11 01:42 AM
Ixnay on the full groove !!
From Clevite ...
First, it’s essential to understand that bearings
depend on a film of oil to keep them separated
from the shaft surface. This oil film is developed
by shaft rotation. As the shaft rotates it pulls oil
into the loaded area of the bearing and rides up
on this film much like a tire hydroplaning on wet
pavement. Grooving in a bearing acts like tread
in a tire to break up the oil film. While you want
your tires to grip the road, you don’t want your
bearings to grip the shaft.
The primary reason for having any grooving in a
main bearing is to provide oil to the connecting
rods. Without rod bearings to feed, a simple
oil hole would be sufficient to lubricate a main
bearing. Many early engines used full grooved
bearings and some even used multiple grooves.
As engine and bearing technology developed,
bearing grooving was removed from modern
lower main bearings. The result is in a thicker
film of oil for the shaft to ride on. This provides a
greater safety margin and improved bearing life.
Upper main shells, which see lower loads than
the lowers, have retained a groove to supply the
connecting rods with oil.
In an effort to develop the best possible main
bearing designs for performance engines, we’ve
investigated the effects of main bearing grooving
on bearing performance. The graphs on the next
page illustrate that a simple 180° groove in the
upper main shell is still the best overall design.
While a slightly shorter groove of 140° provides a
marginal gain, most of the benefit is to the upper
shell, which doesn’t need improvement. On the
other hand, extending the groove into the lower
half, even as little as 20° at each parting line
(220° in total), takes away from upper bearing
performance without providing any benefit to
the lower half. It’s also interesting to note that as
groove length increases so do Horsepower Loss
and Peak Oil Film Pressure which is transmitted
directly to the bearing.
Posted By: CHAPPER
Re: Crank Bearings what to use? - 02/05/11 01:48 AM
Quote:
Ixnay on the full groove !!
From Clevite ...
First, it’s essential to understand that bearings
depend on a film of oil to keep them separated
from the shaft surface. This oil film is developed
by shaft rotation. As the shaft rotates it pulls oil
into the loaded area of the bearing and rides up
on this film much like a tire hydroplaning on wet
pavement. Grooving in a bearing acts like tread
in a tire to break up the oil film. While you want
your tires to grip the road, you don’t want your
bearings to grip the shaft.
The primary reason for having any grooving in a
main bearing is to provide oil to the connecting
rods. Without rod bearings to feed, a simple
oil hole would be sufficient to lubricate a main
bearing. Many early engines used full grooved
bearings and some even used multiple grooves.
As engine and bearing technology developed,
bearing grooving was removed from modern
lower main bearings. The result is in a thicker
film of oil for the shaft to ride on. This provides a
greater safety margin and improved bearing life.
Upper main shells, which see lower loads than
the lowers, have retained a groove to supply the
connecting rods with oil.
In an effort to develop the best possible main
bearing designs for performance engines, we’ve
investigated the effects of main bearing grooving
on bearing performance. The graphs on the next
page illustrate that a simple 180° groove in the
upper main shell is still the best overall design.
While a slightly shorter groove of 140° provides a
marginal gain, most of the benefit is to the upper
shell, which doesn’t need improvement. On the
other hand, extending the groove into the lower
half, even as little as 20° at each parting line
(220° in total), takes away from upper bearing
performance without providing any benefit to
the lower half. It’s also interesting to note that as
groove length increases so do Horsepower Loss
and Peak Oil Film Pressure which is transmitted
directly to the bearing.
I use the Clevite full groove bearings....??? 
Posted By: Monte_Smith
Re: Crank Bearings what to use? - 02/05/11 02:01 AM
Clevite still makes them, because everyone thinks they need them. As with most things in an engine, most people really don't understand how it works. A healthy oiling system and proper clearances, you don't need a grooved bearing. If you insist, do as Clevite suggests and run a grooved upper, but you want the smallest groove you can find.
Monte
Posted By: dusturbd340W5
Re: Crank Bearings what to use? - 02/05/11 02:26 AM
I run the clevite H series in my 416 they are a half groove I spin this motor to 7500 on a regular basis and I looked at the mains after 125 passes and the bearings and crank still look new I see no reason to worry about having a full groove if everything else is correct.
Posted By: tjmarcus1
Re: Crank Bearings what to use? - 02/05/11 03:15 AM
i used to use full groove in race motors, but now i only use half groove. just make sure the clearances are right. oh, i also use a lot of 10w30 oil. sometimes spinning to 74 to 7500
Posted By: JSR1485
Re: Crank Bearings what to use? - 02/05/11 03:19 AM
Is it also good to use -.001 bearings for better clearance also? This is what a friend always uses.
Posted By: dOc …
Re: Crank Bearings what to use? - 02/05/11 03:33 AM
I beeez liken the NARROW full-groove. Michigan bearing ...I got them through JCW .... but I am getting real REAL low on them.
Posted By: MR_P_BODY
Re: Crank Bearings what to use? - 02/05/11 03:38 AM
Quote:
Is it also good to use -.001 bearings for better clearance also? This is what a friend always uses.
Maybe if your on the tighter side but if you set the
crank for the the looser side you wont need those...
I set everything at .003... and I've been running a
1/2 groove for a long time... just like that article
said... I want the larger load carrying area
Posted By: maximum entropy
Re: Crank Bearings what to use? - 02/05/11 04:27 AM
i've always used full groove, but, as usual, you guys got me thinking...
Posted By: POS Dakota
Re: Crank Bearings what to use? - 02/05/11 08:33 AM
1/2 groove king bearings here in my smallblock.
Posted By: 6PACMAC
Re: Crank Bearings what to use? - 02/05/11 01:46 PM
I run the full, narrow grooved on my big blocks. All has been well
Posted By: 440Jim
Re: Crank Bearings full grove or 3/4 ??? - 02/05/11 03:56 PM
As posted, there are a bunch of theoretical different characteristics. But from a practical point of view, this is my experience. My BB uses full groove main bearings to get the benefit of more oil to the rods. Even at my power level, I have not seen any main bearing issues from the reduction due to the groove in the lower half of the bearing. And I just took out my rod bearings after over 600 passes on them, so they are lasting a long time.
Now a top fuel may be different...
Posted By: 5spdcuda
Re: Crank Bearings full grove or 3/4 ??? - 02/05/11 04:46 PM
Lots of good engine builders have been successful in running either 1/2 or full groove mains. Obviously a full groove bearing reduces the amount of main bearing area at the point of greatest pressure or load. On the plus side a full groove bearing also provides full time oiling to the rod bearings. A 1/2 groove bearing provides full pressure to the rods only when they need it most, oil is restricted to the rods when loads are minimal. The real question in my mind is what does this mean in a practical sense. Personally I've yet to see a main bearing fail as a direct result of it being full grooved, I have seen rods fail due to insufficient oil. Now quite possibly these rod failures may have been due to some other flaw in the lube system, still I prefer to have more rather than less oil going to the rods. One downside to full grooves that hasn't been mentioned is that possibly and I emphasize possibly they may slightly increase oil consumption by allowing more oil to be splashed onto the cylinder walls.In the end I think it simply comes down to whatever you're comfortable with.
Posted By: justinp61
Re: Crank Bearings what to use? - 02/05/11 05:52 PM
Quote:
1/2 groove king bearings here in my smallblock.
318/340/416? When I built my 408 King didn't make a bearing for a 360 based crank. I do have Kings on the rods though, full groove Clevites on the mains. I've been using full grove for years and never had any issues .
Posted By: gregsdart
Re: Crank Bearings what to use? - 02/05/11 06:16 PM
"It’s also interesting to note that as
groove length increases so do Horsepower Loss
and Peak Oil Film Pressure which is transmitted
directly to the bearing."
I run 3/4 grove,but this post is getting my attention.
The only way I can figure there is power loss would be windage. On feeding the rod bearings, the exit hole for the rod bearing will have a window .003 times the circumferance of the feed hole, which isn't much of an opening. I can see where it may not be important to have full time oil feed to those openings.
Posted By: Sport440
Re: Crank Bearings what to use? - 02/06/11 07:00 AM
Quote:
Ixnay on the full groove !!
From Clevite ...
First, it’s essential to understand that bearings
depend on a film of oil to keep them separated
from the shaft surface. This oil film is developed
by shaft rotation. As the shaft rotates it pulls oil
into the loaded area of the bearing and rides up
on this film much like a tire hydroplaning on wet
pavement. Grooving in a bearing acts like tread
in a tire to break up the oil film. While you want
your tires to grip the road, you don’t want your
bearings to grip the shaft.
The primary reason for having any grooving in a
main bearing is to provide oil to the connecting
rods.
IMO, most oil failures or ineffeciencys show thier evidence first at the rod bearings. IMO ,rod bearings fail about 9 to 1 vs mains in such a situation.
The answer to this IMO is to have.???
IMO, you want as much bearing surface area as possible. Clevite concurs. But we need to feed these rod bearings. Id like to see a new narrow full groove design bearing. Or maybe we should stick with the 1/2 groove and just cross drill the cranks at a thinner diameter to retain journal strength. mike
Posted By: b1dartsport
Re: Crank Bearings what to use? - 02/06/11 02:35 PM
I've been running small blocks off and on for close to 40 yrs. The only bearing related failures I have ever had were rod failures while running half grooved mains. Since switching to full grove clevite mains in the late 80s I have not had one problem. I respect the info given here but I will continue to run full grove mains especially in a stroker which I believe has much greater side loads on the rods & pistons. Just my
-Randy
Posted By: Hot 340
Re: Crank Bearings what to use? - 02/06/11 02:40 PM
This stuff is fun to talk about but Id like to see proof that running a groove takes away HP. Especially when you consider the crank isnt riding on one bearing but five. I understand the thought that goes behind having more surface area. I am just skeptical that any hp is in it. As far as longevity, I believe alot of people have better or worse bearing experience based on their tune of the engine, which IMO is the biggest factor in bearing life aside from good clearances.
Posted By: 69Cuda340S
Re: Crank Bearings what to use? - 02/06/11 04:18 PM
When I bought my Scat stroker kit it came with Clevite full groove mains so that is what I run.
Posted By: Quicktree
Re: Crank Bearings what to use? - 02/06/11 04:22 PM
this is one of them posts you would think with all the builders we have on here they would be telling us their experience
sponsoring this site is great and I
to those that do. but a little info every now and then wont hurt either.
Posted By: cudabin
Re: Crank Bearings what to use? - 02/06/11 04:26 PM
I like the 3/4 groove bearings...
King makes great bearings in their allecular series, that are softer than the tri metal clevites if you are making big power or running nitrous (= big power).
I have unfortunately failed a few rod bearings in differrent motors though the years, but never a problem on the mains, so I agree the longer time oiling the rods with 3/4 or full groove seems more relevant than the increased support to the crank from a 1/2 groove design...
Good luck!
Arnie
Quote:
this is one of them posts you would think with all the builders we have on here they would be telling us their experience sponsoring this site is great and I to those that do. but a little info every now and then wont hurt either.
FWIW, here are my thoughts on the subject.
the debate about 1/2, 3/4 or full groove bearings will probably live on forever. based on my own experience, my conclusion is this. the full groove bearings aren't necessary but they can be more forgiving for the average do-it-yourselfer home engine builder. the average home builder typically doesn't haver the tools or the experience to accurately measure the bearing oil clearance. a full groove main will flood the rod bearing with oil full time. is it neccesary to do that? IMO no, it's not, as long as both sets of bearings (main and rod) have the proper oil clearance to begin with. rod bearings that have less than adequate clearance for the application can overheat, among other things. the extra oil not only lubricates but has a cooling effect too. a bearing with proper clearances doesn't need the extra lube or cooling to do its job.
some will argue that the full groove bearing doesn't have as much surface area to support the crankshaft. well, that's true, but it obviously has enough surface area to get the intended job done, so who really cares?, not me.
IMO most bearing related failures are the result of just a few simple things. improper clearance, a poor oiling system without the necessary modifications for the application, dirt and debris upon assembly, a bad tune or inadequate octane causing detonation, and possibly a few other things.
so, good machine work and attention to detail along with proper bearing clearance and a clean environment during assembly will always yield the best results, regardless of how far the groove extends around the bearing.
there are other little "tricks" that many professionals use to ensure success that i won't get into here. speaking for myself only, those are trade secrets that i just don't care to share.
now on with the debate. 
Posted By: blownzoom440
Re: Crank Bearings what to use? - 02/06/11 06:00 PM
Posted By: Quicktree
Re: Crank Bearings what to use? - 02/06/11 06:02 PM
Quote:
Quote:
this is one of them posts you would think with all the builders we have on here they would be telling us their experience sponsoring this site is great and I to those that do. but a little info every now and then wont hurt either.
FWIW, here are my thoughts on the subject.
the debate about 1/2, 3/4 or full groove bearings will probably live on forever. based on my own experience, my conclusion is this. the full groove bearings aren't necessary but they can be more forgiving for the average do-it-yourselfer home engine builder. the average home builder typically doesn't haver the tools or the experience to accurately measure the bearing oil clearance. a full groove main will flood the rod bearing with oil full time. is it neccesary to do that? IMO no, it's not, as long as both sets of bearings (main and rod) have the proper oil clearance to begin with. rod bearings that have less than adequate clearance for the application can overheat, among other things. the extra oil not only lubricates but has a cooling effect too. a bearing with proper clearances doesn't need the extra lube or cooling to do its job.
some will argue that the full groove bearing doesn't have as much surface area to support the crankshaft. well, that's true, but it obviously has enough surface area to get the intended job done, so who really cares?, not me.
IMO most bearing related failures are the result of just a few simple things. improper clearance, a poor oiling system without the necessary modifications for the application, dirt and debris upon assembly, a bad tune or inadequate octane causing detonation, and possibly a few other things.
so, good machine work and attention to detail along with proper bearing clearance and a clean environment during assembly will always yield the best results, regardless of how far the groove extends around the bearing.
there are other little "tricks" that many professionals use to ensure success that i won't get into here. speaking for myself only, those are trade secrets that i just don't care to share.
now on with the debate.
thats what I was talking about, thnaks Dan
Full groove is the only way to go.....there is plenty of load support on the full grooves! Rod bearings will live along time with a good supply of oil!
Posted By: Leon441
Re: Crank Bearings what to use? - 02/06/11 07:10 PM
If you look at the other differences in bearings you may find the length of the groove is not as important to you. I have ran full groove P bearings, half groove V bearings, and in all my aluminum rods HD bearings. The P bearing is much more forgiving with trash because it is softer. At the same time it should mushroom out easier if you did not have enough bearing in the bottom half. Never mushroomed a main bearing without detonation being the cause. I would venture to say the bearing surface is plenty on a 340 small block bearing. A 360 takes such a load of oil I may think about doing something different if turning any RPM. Something to think about.. The same engine mushroomed a couple rod bearings from an overdose of fuel but did not hurt the P bearing on the main at all. Until building an engine with an R3 block and Program caps I never realized how tight you can run the main clearances on a good block and crank combo. Problem is with alluminum rods you have a lot less control with oil clearance at the rod bearing and the deminsions change with temperature. When running a nitrous combo I prefered the full groove tried several different bearing combos. I ran .0025 for clearance for the best results. Just figured missing tuneups and hurting pistons ands the bearings always looked great something must have been working out. My current combo uses a 3/4 groove and I have tried the less than half groove. Never saw any real difference. If I could ever get enough restriction up top I may have a change of view on this subject. Every combo has different needs. I did notice a stock 360 in a Durango RT has a half groove bearing. The old 360's had full grooves if I remember correctly. Steel rod bearing clearances stay so stable I would say a full groove is unecessary.
Posted By: gregsdart
Re: Crank Bearings what to use? - 02/07/11 06:59 PM
Quote:
This stuff is fun to talk about but Id like to see proof that running a groove takes away HP. Especially when you consider the crank isnt riding on one bearing but five. I understand the thought that goes behind having more surface area. I am just skeptical that any hp is in it. As far as longevity, I believe alot of people have better or worse bearing experience based on their tune of the engine, which IMO is the biggest factor in bearing life aside from good clearances.
"On the
other hand, extending the groove into the lower
half, even as little as 20° at each parting line
(220° in total), takes away from upper bearing
performance without providing any benefit to
the lower half. It’s also interesting to note that as
groove length increases so do Horsepower Loss
and Peak Oil Film Pressure which is transmitted
directly to the bearing. "
These guys must have spent plenty of time testing to have put this out to the general public.
Also I appreciate your input Dan, great info.
Posted By: Monte_Smith
Re: Crank Bearings what to use? - 02/07/11 07:36 PM
Quote:
this is one of them posts you would think with all the builders we have on here they would be telling us their experience sponsoring this site is great and I to those that do. but a little info every now and then wont hurt either.
I personally, have never run a full groove main bearing in anything, unless that was all I could get, or all I had at the time. 99% of the time, rod bearing failure is more about clearance and preperation, than what kind of main bearing you run. If the oil system is right, the rods are round, the crank has no taper and the clearance is right, you will have no rod bearing issues.
Does the grooved main cost power, as Clevite says, probably, or they would not publish it. Is it enough power for the average guy to worry about, highly unlikely. But me personally, knowing that every motor is trying to push the crank out on the ground, I want all the oil film I can get on the force side, that means a half grooved bearing for me.
Monte
Posted By: Quicktree
Re: Crank Bearings what to use? - 02/07/11 10:14 PM
Quote:
Quote:
this is one of them posts you would think with all the builders we have on here they would be telling us their experience sponsoring this site is great and I to those that do. but a little info every now and then wont hurt either.
I personally, have never run a full groove main bearing in anything, unless that was all I could get, or all I had at the time. 99% of the time, rod bearing failure is more about clearance and preperation, than what kind of main bearing you run. If the oil system is right, the rods are round, the crank has no taper and the clearance is right, you will have no rod bearing issues.
Does the grooved main cost power, as Clevite says, probably, or they would not publish it. Is it enough power for the average guy to worry about, highly unlikely. But me personally, knowing that every motor is trying to push the crank out on the ground, I want all the oil film I can get on the force side, that means a half grooved bearing for me.
Monte
I have never used a grooved bearing either
Posted By: Stanton
Re: Crank Bearings what to use? - 02/07/11 10:38 PM
For anyone who wants to see more bearing tech stuff, here's the link:
http://www.engineparts.com/publications/EB-10-07.pdf
Posted By: 602heavy
Re: Crank Bearings what to use? - 02/07/11 10:57 PM
I use whatever i can get hold of , be it 1/2 groove or full groove.
.........................i always cut a 45 degree chamfer along parting line from rear of bearing to groove on both sides (thrust bearing) , after ballooning the convertor a few years ago & taking the calies crank out i find it cheap insurance , might not help in some instances but at least you know the rear thrust face is getting pressure fed.
Posted By: Sport440
Re: Crank Bearings what to use? - 02/07/11 11:03 PM
From that tech on the HP loss graph it shows over a 12% HP loss going from 180* to a 360* grooved bearing. It also shows a significant amount of oil film thickness loss too.
Theres no doubt in my mind from Clevites Tech and testing that they are pretty much Against a full groove bearing. IMO They are pretty much stating 1/2 groove only, and thats to oil the Rod bearings. If it werent for that, they implied a Simple hole would all thats needed or desired to oil the mains.
That makes me feel alot better about my 1/2 groove bearings. I was considering full grooving them myself or buying new FG,s. Not anymore 1/2 groove it is and Im keeping them. mike
FWIW; That 12%HP loss for full groove does seem high IMO. That % would also be dependit upon the bearing journals diameter.
Posted By: 69Cuda340S
Re: Crank Bearings what to use? - 02/08/11 03:10 AM
Quote:
Theres no doubt in my mind from Clevites Tech and testing that they are pretty much Against a full groove bearing.
But they still sell the full grooves?
Posted By: Monte_Smith
Re: Crank Bearings what to use? - 02/08/11 04:15 AM
Quote:
Quote:
Theres no doubt in my mind from Clevites Tech and testing that they are pretty much Against a full groove bearing.
But they still sell the full grooves?
Tobacco companies still sell cigarettes, even though they know they will kill you......jus sayin
Monte
Posted By: Stanton
Re: Crank Bearings what to use? - 02/08/11 04:53 AM
Quote:
But they still sell the full grooves?
That's because dispite all the research the bottom line is still "the customer is always right".