I would like to here from people on what they are using today for bearing clearance in there race engine more towards circle track and why.And what kind of oil pressure are you using with the clearance and oil.I build circle track 2 bbl engines and i have found that .0025 on the mains and between .0018 and .0022 work good on the rods gives me good oil pressure and the bearings look good doring tare down at the end of the season.I use coated bearings also.
mike
Bearing clearance
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Skip Honaker
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bearing clearence
That is a good question I personally use .028 all the way rods and mains.
I have tried tighter but havn't had any luck with it. I use king bearings. I not a engine builder but have won alot of races with the engines I've built but there are alot of smart people on this board and can help out with anything.
I have tried tighter but havn't had any luck with it. I use king bearings. I not a engine builder but have won alot of races with the engines I've built but there are alot of smart people on this board and can help out with anything.
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learner
I've always run .002" on the mains and .002"-.0025" on the rods. One particular shop i worked for used King bearings in two motors and both sets were actually coming apart, flaking away. I personally have always used Clevite. After the King experience especially. I don't know if there was a batch problem on the King bearings or what. I have just always stuck with the Clevite because i feel they are the best and i'm sticking to what has worked for me.
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CNC BLOCKS
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On the circle track engines we build we run .0025 to .003 on the 2.100 crank pin and 350 mains and on the Honda rod and 283 main we run .002 to 0025 on rods and mains.
We use Clevite H series coated on the Honda rod and 283 main engines
and on my 2.100 crank pin and 350 mains I have always used the Clevite V-series bearings with great success.
We have SBC 2 blower engines we build and maintain they both have 8-71 blowers on them, Buick heads both aluminum raised cam tunnel blocks 370 cubic inch on alky bearing clearances are .004 to .0043 on rods and mains and have the run the V-series bearings for years and when we tear them down they look great.
I have some pics of those bearings and crank if any bodys interested in see them.
And I have heard the same thing about the King bearings flaking or coming apart.
We use Clevite H series coated on the Honda rod and 283 main engines
and on my 2.100 crank pin and 350 mains I have always used the Clevite V-series bearings with great success.
We have SBC 2 blower engines we build and maintain they both have 8-71 blowers on them, Buick heads both aluminum raised cam tunnel blocks 370 cubic inch on alky bearing clearances are .004 to .0043 on rods and mains and have the run the V-series bearings for years and when we tear them down they look great.
I have some pics of those bearings and crank if any bodys interested in see them.
And I have heard the same thing about the King bearings flaking or coming apart.
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user-z68766209
bearing
The key to getting the correct bearing clearance is first to know
how good of a rod you are using. What I mean is how much
"meat" there is around the bolt for clamping.
Just to cover the base> the big end of the rod goes egg shape
under a load, take a plastic coffee squeeze across the center
that is what the rod does under a load some more than others.
Look at some of your bearings after running them do they look
like they have been "wipe" from parting line to parting line?
Or chunking with a King bearing.
If so the bearing does not have enought eccentricity in it (I call
it not enought taper in the bearing from the center of the bearing
to the parting line)
Yes bearing have some eccentricity built in but not enough in most
cases. Also it makes a difference where you set your big end size at.
Using a stock SBC rod 2bbl motor flat top piston 7000 rpm Melling M55HV
Rod Vertical clearance .0013 and then at about .300 up from the parting
line .004-.0045 the bearings come out looking like new! Warning>>>
.004-.0045 is the most you can set up for because at an idle you will have
under 20psi but just off of idle you will have 60 psi.
H. Elloitt told me a few years back, cup rods are set up @.0023-.0025
vertical, .007 just up from the parting line but that is with a dry sump.
It comes back to how good of a rod you use on how to set bearing clearance.
Brian B
Dakota Parts Warehouse
Distributor of Ferrea Valves
how good of a rod you are using. What I mean is how much
"meat" there is around the bolt for clamping.
Just to cover the base> the big end of the rod goes egg shape
under a load, take a plastic coffee squeeze across the center
that is what the rod does under a load some more than others.
Look at some of your bearings after running them do they look
like they have been "wipe" from parting line to parting line?
Or chunking with a King bearing.
If so the bearing does not have enought eccentricity in it (I call
it not enought taper in the bearing from the center of the bearing
to the parting line)
Yes bearing have some eccentricity built in but not enough in most
cases. Also it makes a difference where you set your big end size at.
Using a stock SBC rod 2bbl motor flat top piston 7000 rpm Melling M55HV
Rod Vertical clearance .0013 and then at about .300 up from the parting
line .004-.0045 the bearings come out looking like new! Warning>>>
.004-.0045 is the most you can set up for because at an idle you will have
under 20psi but just off of idle you will have 60 psi.
H. Elloitt told me a few years back, cup rods are set up @.0023-.0025
vertical, .007 just up from the parting line but that is with a dry sump.
It comes back to how good of a rod you use on how to set bearing clearance.
Brian B
Dakota Parts Warehouse
Distributor of Ferrea Valves
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Guest
Speed talk,
I have looked at your charts and to me it would look like that between .002 to .003 would be the best place for a small block chevy for circle track.But i have questions on what oil temp was this based on and also what vescosity was the oil.Also would we lose HP if we went to a qualfying oil based on these clearances.Based on the oil flow vers. clearance chart could we adsume that if a small block chevy ran .0025 clearance mains and rods side clearance of .020 and a dry sump system and used 4 gal a min that we would need no more than 40 to 45 psi of oil @ a straight 30 w syntetec and 800HP.How can we determen what is needed. I talked to Johnson oil pumps for a breif moment at PRI last year on this.I have heard that this is what they use in winston cup but could not get a firm answer on it.How i.am i wrong in this thinking.Or am i wrong.
mike
I have looked at your charts and to me it would look like that between .002 to .003 would be the best place for a small block chevy for circle track.But i have questions on what oil temp was this based on and also what vescosity was the oil.Also would we lose HP if we went to a qualfying oil based on these clearances.Based on the oil flow vers. clearance chart could we adsume that if a small block chevy ran .0025 clearance mains and rods side clearance of .020 and a dry sump system and used 4 gal a min that we would need no more than 40 to 45 psi of oil @ a straight 30 w syntetec and 800HP.How can we determen what is needed. I talked to Johnson oil pumps for a breif moment at PRI last year on this.I have heard that this is what they use in winston cup but could not get a firm answer on it.How i.am i wrong in this thinking.Or am i wrong.
mike