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toasted cam bearings on new build
#1041510
07/27/11 05:41 PM
07/27/11 05:41 PM
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Joined: Aug 2005
Posts: 697
Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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Hoping someone here can shed some light on this problem. I just completed the build on my stroker motor it’s a 440, 0.60 over bore, 4.15 stroke crank and new rotating assembly,cam, roller rocker valevetrain etc… no apparent assembly issues, engine was pre-lubed with Joe Gibbs break in oil and assembled with assembly lube on all bearings. The engine fired right up and ran for 25 minutes at 2,000 – 2,5000 RPM to break in the cam before the valvetrain stared seizing. Now it’s torn back down and we have a mystery. The valve spring seat pressure was not out of line, the cam broke in well, but 4 out of the five cam bearings are toast. One spun and three are severely “wiped “ including the #4 cam bearing that feeds the heads. The mains and rods look great, so there was no lack of oil or pressure, the engine had 70 PSI from the get-go. Since the mains and cam bearings feed from the same source, there would not be any reason oil was not reaching the cam bearings. New cam bearings were installed as part of the block prep and the cam turned freely in the bearings prior to final assembly. You can still see the oil hole (although mostly wiped) on the 3 bearings still in the block from the feed hole under the mains, so the hole was lined up correctly. Any ideas? 
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Re: toasted cam bearings on new build
[Re: 70Sbird]
#1041513
07/27/11 07:06 PM
07/27/11 07:06 PM
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Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
Performance Only
top fuel
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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take a good close look to see if it there's debris embedded in the bearings. did any of the bearings have to be reamed or scraped to make the cam turn freely? that raises another question, if the cam didn't turn easily with 2 fingers during the assembly process, it was too tight.
can you take a picture of the cam bearings and the main bearings to post here? obviously, main bearings installed wrong could keep oil from the cam bearings too.
machine shop owner and engine builder
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Re: toasted cam bearings on new build
[Re: Performance Only]
#1041516
07/27/11 07:45 PM
07/27/11 07:45 PM
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Joined: Oct 2006
Posts: 527
alaska,usa
9secondsatellite
mopar
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mopar
Joined: Oct 2006
Posts: 527
alaska,usa
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did you prime the engine after final assembly? debris in cam? cam walk to far? what does the intermediate shaft look like? also mentioned 1 brg spun. could it have spun on start up? cam brg installer too tight when installing brgs?
Last edited by 9secondsatellite; 07/27/11 07:48 PM.
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Re: toasted cam bearings on new build
[Re: 85_Ram_4speed]
#1041519
07/28/11 06:10 PM
07/28/11 06:10 PM
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Joined: Aug 2005
Posts: 697
Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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Thanks for the replies everyone, I couldn't get back to my computer yesterday night so here are answers to some of your questions. The cam fit well and turned freely with 2 fingers, the block was prepped by a knowledgeable Mopar only engine builder and was checked for cracks and machined before the cam bearings were installed. The main and rod bearings are still in great shape, no excessive wear and no evidence of debris. The engine block was cleaned and prepped by the engine machinist, then I cleaned it again "just to be sure",including all the oil pasages from the lifter galley to the mains and cam bearings. The mains were installed correctly, with the groovs in the top, and the cam would still get oil regardless of the mains orientation and since the mains are good, I know this to be true. The engine was primed for about 10 minutes before ignition and I was turning the crank over by hand for about 5 minutes of that to be sure everything got oil. It looks like the bearings began "wiping" and closing off the oil holes that feed the rockers and heads at some point of the 25 minutes it was running. The part that makes no sense is how can the cam bearings be destroyed if they had oil going to them, there was 70 psi of oil at startup and during the break-in. Here is a pic of the cam bearings smearing themselves out of the bottom of their bores 
Last edited by 70Sbird; 07/28/11 06:17 PM.
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Re: toasted cam bearings on new build
[Re: 70Sbird]
#1041521
07/28/11 06:19 PM
07/28/11 06:19 PM
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Joined: Aug 2005
Posts: 697
Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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cam bearing closer up:
Last edited by 70Sbird; 07/28/11 06:19 PM.
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Re: toasted cam bearings on new build
[Re: 70Sbird]
#1041524
07/28/11 06:30 PM
07/28/11 06:30 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
cam bearing closer up:
It looks like the cam bearing is tipped partly sideways
in there... are you sure its smeared as in turned to
a putty state... it would have to get very hot to do that
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Re: toasted cam bearings on new build
[Re: 70Sbird]
#1041525
07/28/11 08:55 PM
07/28/11 08:55 PM
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Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
Performance Only
top fuel
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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you know, perhaps the best way to approach this is by using just a smidgen of logic. there's really only two basic things that will cause what happened to your cam bearings. it's either lack of oil, or it's lack of clearance. of course lack of clearance can be for a large variety of reasons, but it's still a lack therof. not to be too critical, but based on your pictures and the fact that you only have 25 minutes of run time on the engine. i think i'd go back and check the clearance on those mains as well. you really shouldn't have shiny edges and shiny wear spots like what the pictures show. basically they should look like brand new still if the clearances are correct. so anyway, are you sure all the holes in the cam bearings were lined up with the oiling holes? one can't really see much of the cam bearings from the pictures you posted. best of luck with it. i'm sure you'll get it figured out. 
Last edited by Performance Only; 07/28/11 08:58 PM.
machine shop owner and engine builder
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Re: toasted cam bearings on new build
[Re: Performance Only]
#1041526
07/28/11 10:36 PM
07/28/11 10:36 PM
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Joined: Jul 2004
Posts: 19,317
State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,317
State of confusion
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Quote:
you know, perhaps the best way to approach this is by using just a smidgen of logic. there's really only two basic things that will cause what happened to your cam bearings. it's either lack of oil, or it's lack of clearance. of course lack of clearance can be for a large variety of reasons, but it's still a lack therof.
not to be too critical, but based on your pictures and the fact that you only have 25 minutes of run time on the engine. i think i'd go back and check the clearance on those mains as well. you really shouldn't have shiny edges and shiny wear spots like what the pictures show. basically they should look like brand new still if the clearances are correct.
so anyway, are you sure all the holes in the cam bearings were lined up with the oiling holes? one can't really see much of the cam bearings from the pictures you posted. best of luck with it. i'm sure you'll get it figured out.
Makes good sense plus,in the one photo of the cyl., that seems like a lot of verticle scratches for such a short run time suggesting maybe it wasn`t perfectly clean or, as stated it passed some crud. 
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: toasted cam bearings on new build
[Re: crsnles]
#1041528
08/24/11 02:21 PM
08/24/11 02:21 PM
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Joined: Nov 2003
Posts: 6,293
Rock Springs
Bob_Coomer
master
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master
Joined: Nov 2003
Posts: 6,293
Rock Springs
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Never had a issue with cam bearings. I always check to make sure that the oil holes are lined up.. Even this if they are off a little bit will NOT hurt anything. Are the oil holes still lined up?
The engine looks trashy to me... whats all the pieces of blue and orange paint.
Cylinder walls look scored too. I have run engines for thousands of miles that look better. Bearings also dont look good IMO. They shouldnt even look like the crank has rolled over on them.
Pull the filter cut it apart, and the oil pump see what you find!
Good luck
[color:"red"]65 Hemi Belvedere coming soon [/color]
[color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: toasted cam bearings on new build
[Re: Bob_Coomer]
#1041529
08/24/11 03:01 PM
08/24/11 03:01 PM
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Joined: Feb 2007
Posts: 6,295
U.S.
moparniac
master
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master
Joined: Feb 2007
Posts: 6,295
U.S.
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Several years ago had the same thing happen to me! not sure what happened but the machine shop that installed the cam bearings bought me a brand new set of gold cranes cause the first set welded to the shaft....
Mopar Performance
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