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Old 07-19-2020, 09:14 AM
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Default rollmaster cam sprocket

So I am into my 3rd tear down on my 505 pro port deal. First cam thrust plate from Butler went 12 passes and it was galled beyond using. 2nd set was rollmaster red series with Simms roller thrust plate and sprocket deal. I did not put the short together because of working long hours. Tore it down a month ago only to find the thrust plate wasn't centred and it cut into the plate. Also the cam sprocket was galled up. I use 50mm roller cam bearing set up. In all my years of racing and building my own engines,I have never seen this kind of damage with so little runs on the motor.I hope the oil feed hole near the transition slot is feeding proper oil to the thrust plate. I don't get the Sprocket going south. Am I missing something with oil feed to the thrust? I have never used 50mm roller cam bearings before. Is there a Mod that I am missing here? Thanks if anyone has some answers to this problem would be appreciated.

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Old 07-19-2020, 09:35 AM
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The roller bearing block the oil feed to the cam. Imo you have two options, install 55mm babbit bearing (they're the same od as the 50mm roller bearing, you'll need to get a 55mm cam but that's a good thing imo) or knock out the front roller bearing put a groove from the oil feed oil to the plate so oil can get to it. The other thing to check is make sure the interface between dist and cam is good. The dist might be pushing cam forward in block.

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Old 07-19-2020, 11:58 AM
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The Sims plate comes with a plastic alignment tool to center the thrust plate and roller bearings. It sounds like the plate might not have been centered during the installation.

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Old 07-19-2020, 12:31 PM
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There is a 035 thou oil feed hole near the transition slot. Is that sufficient size feed hole.?

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Old 07-19-2020, 12:46 PM
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check cam end play with distributor in engine
also prime engine with cover off and see if oil comes out of feed hole to thrust plate

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Old 07-19-2020, 02:13 PM
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The roller bearing in the #1 journal blocks the cam feed hole, so there is no spillage to go out the small hole in any cam retainer plate. What I have been doing is using a very small dremel to put a small groove under the cam bearing. This allows some oil to escape and feed the thrust area......Bill

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Old 07-19-2020, 04:34 PM
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Thanks Bill. There is a feed oil hole drilled into the transition slot.it measures .035 thou. I sprayed some brake clean through the main saddle to make sure it wasn't plugged up. Do you need to remove the front roller bearing to add slot. I am assuming you do.

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Old 07-19-2020, 07:40 PM
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Quote:
Originally Posted by Richie Hoffman View Post
check cam end play with distributor in engine
also prime engine with cover off and see if oil comes out of feed hole to thrust plate
My cam had an end play of 0.006" with the Sims plate. I wasn't concerned since it was riding on a roller bearing both sides.

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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule.
  #9  
Old 07-20-2020, 08:08 AM
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Quote:
Originally Posted by slowbird View Post
The roller bearing block the oil feed to the cam. Imo you have two options, install 55mm babbit bearing (they're the same od as the 50mm roller bearing, you'll need to get a 55mm cam but that's a good thing imo) or knock out the front roller bearing put a groove from the oil feed oil to the plate so oil can get to it. The other thing to check is make sure the interface between dist and cam is good. The dist might be pushing cam forward in block.

So is this just an issue with the Cam Roller Bearings, and not the Babbit Bearings.?
I'm having a 505 IA2 built with 55mm Cam and Babbit Bearings.



Thanks

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Old 07-22-2020, 06:58 AM
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Nobody knows?

Thanks

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Old 07-22-2020, 07:36 AM
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No experience on this, but if it's a babbit, it should have a hole in the bearing to line up with the block oil hole?
(which should make it OK to use)



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  #12  
Old 07-22-2020, 07:41 AM
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Quote:
Originally Posted by johnta1 View Post
No experience on this, but if it's a babbit, it should have a hole in the bearing to line up with the block oil hole?
(which should make it OK to use)



Thank you John.

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