Camshaft Problem

[sanborn]

We pulled down our oval track engine for a checkup (1000 laps). We found a camshaft problem. The cam was forced against the Milodon gear drive retainer plate hard enough that the camshaft was worn on the front of the cam journal about .050" and the retainer plate was worn about .050". Other than the wear, the cam looked good. The roller lifters looked good and the cam lobes looked good and the roller lifters were running centered on the lobe. The camshaft had the proper end play when we put it together (.004"). Has anyone seen this?

[sanborn]

I will definitely talk to several people tomorrow. We have used several setups like this in the past and I have never seen this problem. Since my earlier post I have noticed the radial bearings behind the cam gear also has had significant force applied to them as well. I am beginning to wonder if the lift(.700"), RPM(9000),spring pressure(600lbs) and tremendous deceleration forces are letting the cam float that much and the metal to metal contact of the cam and the Milodon retainer plate is leading to the excessive wear. I am sitting here wondering if I need to come up with a radial bearing system for the front of the cam gear to keep the cam centered. That would be like the roller bearing system used on GM and Ford.

[ChristianCuda]

There is a cam button made for Chrysler engines like the ones for the Phords and Shuvvys. I think Mildon makes it but dont quote me on that. It is recommended for use with roller and extreemely high lift cams.

Christian


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68 'Cuda 383 Working on adding EFI
69 'Cuda Race Parts Car
76 Duster 273 recent transplant
95 Neon 2.0 SOHC best of 16.96
84 Dodge Ram D50 transplanting 360

[DartGT66]

In a roller cam, there is nothing that keeps the cam in the rear. In flat tappets, the taper holds the cam back but in a roller you have to ahve somekind of a device to keep the cam in position. Usually this is done with a cam button; there are several different styles out there and according to my experience they all work. Wether it's a torrington set up or an aluminum or plastic spacer.

[sanborn]

Hey guys, I think I have determined what my problem is. I neglected to include two additional facts, we use needle bearing cam bearings and this is in an aluminum block. First, needle bearings run dry, no oiling at all. Second, on an aluminum block the cam is in a "tunnel". When using Milodon gear drives in the past, I have always depended upon splash lubrication to keep the cam/retainer plate lubricated. With this setup in the aluminum block, there is no lubrication thus cam/retainer plate wear occurs. I am going to fix the problem with a radial bearing cam button. We will run 200-300 laps, pull it down and see if the problem is fixed. I appreciate your comments and suggestions. Regards.