Roller cam bearings

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Roller cam bearings

Post  kjett on May 17th 2013, 4:57 pm

Long story short. Had to pull my brand new motor apart again after we found some bearing material in the filter. The 1st time we found the coated cam bearing were starting to eat themselves on 1 journal. Cleaned everything up and put in an uncoated set. Finding its doing it again on the same journal. My engine builder doesn't have a way to line bore the cam tunnel on a 460 block. So, long story short, anyone know of and can recommend a reputable shop within a reasonable driving distance to Washington DC that can open my cam tunnel? Figure if I have to get it bored, might as well go with roller bearings. And before anyone asks, this is a standard d1ve block, with all of the other machine work done so I'd hate to waste the money I just spent and start all over on another block.

Is the benefit of going with the roller cam bearings noticeable or should I just get and oversize set put in?
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Re: Roller cam bearings

Post  Lem Evans on May 17th 2013, 8:21 pm

It doesn't sound like you spun the bearing....if that is the case you do not need to bore the cam tunnel.

Did you use the FP-30 460 bearing or the FP-26-1 wider bearings? The FP-26 have more clearance also.

Most of the time cam bearing issues are the result of too little oil clearance. The usual suspects are [1] Camshaft journal at or above the high side of the o.d. spec. [2] Camshaft bearing bore at or below the low side of i.d. spec. [3] Bend camshaft. [4] Some or all of the above.

I fail to see an advantage to using coated cam bearings. Unlike their harder rod and main brothers, the softer cam bearings seem not to retain the coating at the load area if any thing gets weird. Money for little or nothing i.m.o.

If your cam tunnels are small...you gotta find a shop that has a small mandrel that'll fit the cam tunnel....maybe a shop that does a lot of 4 cyls. etc.

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Re: Roller cam bearings

Post  kjett on May 17th 2013, 8:54 pm

Thanks Lem. I've always had issues with the 3rd journal being too tight. We made up a jig using an old shaft to "scuff" the bearing some and then it fits. After finding metal in the oil filter afte the dyno, we pulled the whole thing down and the only place we can see an issue is with that bearing. It went in and spun fine with the correct clearances prior to the dyno, but after when everything moved and was warmed up, not so much on disassembly. Not really having the right tooling for the 460 block, but trying something anyway, we chucked the block up and tried to hone the bad journal, well something wasn't right, and we ended up opening the other journals too much in the process. I know, dumb idea, but it was my call and I said WTF. Long story short, I either trash the block and start all over on another block, or fix what I have. Pricing out all the work to get back to this point vs going to oversized or roller cam bearings, I think the latter would be less costly. Just need to fins a shop within reasonable distance that has the correct tooling
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Re: Roller cam bearings

Post  Lem Evans on May 17th 2013, 9:13 pm

kjett wrote:Thanks Lem. I've always had issues with the 3rd journal being too tight. We made up a jig using an old shaft to "scuff" the bearing some and then it fits. After finding metal in the oil filter afte the dyno, we pulled the whole thing down and the only place we can see an issue is with that bearing. It went in and spun fine with the correct clearances prior to the dyno, but after when everything moved and was warmed up, not so much on disassembly. Not really having the right tooling for the 460 block, but trying something anyway, we chucked the block up and tried to hone the bad journal, well something wasn't right, and we ended up opening the other journals too much in the process. I know, dumb idea, but it was my call and I said WTF. Long story short, I either trash the block and start all over on another block, or fix what I have. Pricing out all the work to get back to this point vs going to oversized or roller cam bearings, I think the latter would be less costly. Just need to fins a shop within reasonable distance that has the correct tooling

I'm confussed...were you guys working on the cam, cam bearings as install in the block or the cam tunnel?

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Re: Roller cam bearings

Post  kjett on May 17th 2013, 9:43 pm

using the wide set of durabond cam bearings, the #3 journal had always been tight. This has been the case with this block on the last cam I got from you and the new cam I just got from Comp. In measuring the journals, the #3 journal is on the small side the minimum spec. So we did this to try to fix this tightnes issue so I don't have to basically shave some material off a new bearing everytime I refresh the motor. I came up with the idea to try using the Sunnen line hone machine. My machinist said it probably wouldn't work but as long as I was ok, he'd give it a shot. So we took an old hone setup and tried to limit the pressure on the other bearings and keep pressure on #3. Well that failed miserably and I ended up opening the first 2 journals to past the large spec on the cam journal sizes. The only options from there was bore the tunnel or scrap the block. He doesn't have the correct tooling to bore it properly, so I have to go elsewere.

Long story short, I'm a tard and should have left well enough alone and all would have been good once I shaved the #3 bearing to the proper clearance. Embarassed
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Re: Roller cam bearings

Post  c.evans on May 17th 2013, 10:14 pm

Run over to Carroll Carter's in Manasas VA and see if he can't repair the block. Hwy 28, Centreville Rd.

Charlie

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Re: Roller cam bearings

Post  cool40 on May 17th 2013, 10:37 pm

look at that block real good and make sure it aint cracked! they like to crack from the #2 or #3 main to the cam. Suspect
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Re: Roller cam bearings

Post  460pulling on May 17th 2013, 10:58 pm

I'm pretty sure Maryland performance center in Frederick or C&C can hook u up.

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Re: Roller cam bearings

Post  kjett on May 18th 2013, 1:09 pm

c.evans wrote:Run over to Carroll Carter's in Manasas VA and see if he can't repair the block. Hwy 28, Centreville Rd.

Charlie

I thought about him too being he's right around the corner. Talked to Chris (Carrol's son) and he said they farm the line boring on the cam tunnels to a shop in PA. Kind of surprised me when he said that.

Maryland Performance Center sends their blocks to the same shop in PA.

Made a trip to Frederick this morning to a shop that said they might be able to do it. I was a little reluctant, but figured it was worth a shot. Turns out I was in the right place when I walked in and saw 2 premier blocks, an A460 block, 3 sets of TFS A heads, and a pair or C heads ready to be assembled to tractor pull motors. Turns out the guy knew what I wanted, just wasn't sure what I was talking about. So for future reference, all the guys around here, Gunther's machine shop can bore and install the roller cam bearings. I pick my block back up next Friday Smile
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