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Re: Fixing Big Block Cam Bearings [Re: markz528] #2771567
05/05/20 07:58 PM
05/05/20 07:58 PM
Joined: Oct 2004
Posts: 3,097
back in Georgia
dthemi Offline
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dthemi  Offline
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back in Georgia
If you're using the same cam, here's something that happened on a BBC. Plenty of oil clearance, and straight. Ate bearings almost as soon as it fired up. The problem turned out to be tiny heat cracks in the cam you couldn't feel with your hand. Showed up in the polisher. New cam , no more instawipe bearings. I mean smoke coming up through the valve cover with almost. 003 oil clearance. Spun by hand like a top, but as soon as pressure and heat hit it,,,presto saw blade

Re: Fixing Big Block Cam Bearings [Re: dthemi] #2771656
05/05/20 11:24 PM
05/05/20 11:24 PM
Joined: Nov 2010
Posts: 1,397
Carson City, Nevada
Biginchmopar Offline OP
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Biginchmopar  Offline OP
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Posts: 1,397
Carson City, Nevada
Originally Posted by dthemi
If you're using the same cam, here's something that happened on a BBC. Plenty of oil clearance, and straight. Ate bearings almost as soon as it fired up. The problem turned out to be tiny heat cracks in the cam you couldn't feel with your hand. Showed up in the polisher. New cam , no more instawipe bearings. I mean smoke coming up through the valve cover with almost. 003 oil clearance. Spun by hand like a top, but as soon as pressure and heat hit it,,,presto saw blade


Thanks for the input, I really do appresiate all the replys.

I'm sure it is a possibilty, at this point it doesn't matter why. My OP was asking if anybody knew there was enough room to install 54mm or 55mm roller cam bearings not "What went wrong?"
I've been in touch with a good friend of mine that owns a real, real top notch shop and we have decidded to install 50mm roller cam bearings. He told me Bullit Cams has cam cores so that is another thing I don't have to find.

Al said I might have an oiling issue and I might, I don't know. This block has lifter bore bushings in all the lifter bores and that has been a topic in the past but that being said I had 50PSI at idle and 85PSI from 3500rpm through 7500rpm (Data logger).

I might make a tube bypass to help the oiling but once again the engine bearings looked wonderful.

Last edited by Biginchmopar; 05/05/20 11:25 PM.
Re: Fixing Big Block Cam Bearings [Re: Biginchmopar] #2771711
05/06/20 07:57 AM
05/06/20 07:57 AM
Joined: Oct 2004
Posts: 3,097
back in Georgia
dthemi Offline
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dthemi  Offline
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Posts: 3,097
back in Georgia
The condition I described was one of the weirdest ones I've seen. Plenty oil and clearance, and being able to spin it by hand and have it continue spinning like on rollers was just nuts. Had some bearing material not clung to the cam forcing a polish in the lathe, I dont know if it would have been discovered. That cam became a burr when hot.

If you have room to bore and hone the tunnel to 2.5 a ford roller bearing will get you to a 54.5mm core (BBF), or jesel sells a nice coated babbit for a 60 using that bore size.ive never done a factory block like that, so no idea about available material

Re: Fixing Big Block Cam Bearings [Re: dthemi] #2807141
08/10/20 03:00 AM
08/10/20 03:00 AM
Joined: Nov 2010
Posts: 1,397
Carson City, Nevada
Biginchmopar Offline OP
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Biginchmopar  Offline OP
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Carson City, Nevada
Well just wanted to let everybody know I went to a 50mm roller cam bearings to fix the problems I was having with cam bearings in this engine. The cam bores were off, when we cut it it really showed up. Nice and straight now! I got the new cam from Bullet Racing Cams.

IMG_1704.jpgIMG_1705.jpg
Re: Fixing Big Block Cam Bearings [Re: Biginchmopar] #2807182
08/10/20 09:47 AM
08/10/20 09:47 AM
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Clanton Offline
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Nice!


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Fixing Big Block Cam Bearings [Re: Clanton] #2807185
08/10/20 10:00 AM
08/10/20 10:00 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Romeo MI
I have the 50mm bearings in my 48* SB.. I had to do a slight bore job to get the bores right
I really like the 50mm on a SB
wave

Re: Fixing Big Block Cam Bearings [Re: MR_P_BODY] #2807366
08/10/20 04:53 PM
08/10/20 04:53 PM
Joined: Nov 2010
Posts: 1,397
Carson City, Nevada
Biginchmopar Offline OP
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Biginchmopar  Offline OP
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Originally Posted by MR_P_BODY
I have the 50mm bearings in my 48* SB.. I had to do a slight bore job to get the bores right
I really like the 50mm on a SB
wave


I have 60mm roller bearings in my Small Block

I really like them and the cam.

I was going to try 55mm but I didn’t want to weaken a stock block.

Re: Fixing Big Block Cam Bearings [Re: Clanton] #2807545
08/11/20 04:37 AM
08/11/20 04:37 AM
Joined: Jan 2003
Posts: 6,149
Melbourne , Australia
LA360 Offline
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Glad you got it sorted out!


Alan Jones
Re: Fixing Big Block Cam Bearings [Re: LA360] #2807574
08/11/20 08:24 AM
08/11/20 08:24 AM
Joined: Jan 2003
Posts: 13,385
Marion, South Carolina [><]
an8sec70cuda Offline
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Marion, South Carolina [><]
Originally Posted by LA360
Glad you got it sorted out!

iagree That looks awesome too! What would the machining to install these bearings in a block typically cost?


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Fixing Big Block Cam Bearings [Re: an8sec70cuda] #2807614
08/11/20 10:48 AM
08/11/20 10:48 AM
Joined: Jan 2003
Posts: 19,382
Las Vegas
Al_Alguire Offline
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Las Vegas
So now that that this hurdle has been cleared what is the plan for the block?


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Fixing Big Block Cam Bearings [Re: Al_Alguire] #2807657
08/11/20 12:41 PM
08/11/20 12:41 PM
Joined: Jan 2004
Posts: 8,337
fredericksburg,va
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cudaman1969 Offline
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fredericksburg,va
Are all the bearings the same size? Do you need a special cam or does it ride on the bearings?

Re: Fixing Big Block Cam Bearings [Re: Al_Alguire] #2807687
08/11/20 01:35 PM
08/11/20 01:35 PM
Joined: Nov 2010
Posts: 1,397
Carson City, Nevada
Biginchmopar Offline OP
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Carson City, Nevada
Originally Posted by Al_Alguire
So now that that this hurdle has been cleared what is the plan for the block?


Put the engine back together and sell it.

Re: Fixing Big Block Cam Bearings [Re: cudaman1969] #2807691
08/11/20 01:39 PM
08/11/20 01:39 PM
Joined: Nov 2010
Posts: 1,397
Carson City, Nevada
Biginchmopar Offline OP
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Posts: 1,397
Carson City, Nevada
Originally Posted by cudaman1969
Are all the bearings the same size? Do you need a special cam or does it ride on the bearings?


All the bearings are the same size (50mm)
I had to get a new cam from Bullet Cams. It's not anything real special just a 50mm cam core. Yes the cam rides on the bearings.

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