In the '74 8-bolt I just rebuilt, the only thing out of spec when I tore it down was a melted front cam bearing. I suspected that the cam had been changed at some point, there was RTV on the bottom of the cam cover, but that may have been to fix a leak. The engine had 250kmiles. It had very low idle oil pressure, but all the bearings were within spec, and it turned out that the leak was entirely through the front bearing, which had melted at least 50% away. There was just enough to keep it centered.

It turns out the engine, a '73 six-bolt I replaced had a similar condition, discovered when GaryL tore it down.

I can understand how this might occur in a low oil condition, But I'm wondering about other potential causes.

Could a clogged cam gear sprayer cause failure of the front bearing?
It had a fiber gear.

Could a worn thrust plate cause the failure?
The thrust plate has a ~couple thousandths ridge.

Anybody else seen this?


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MPergiel, Elmhurst, IL '74 145e T-5 'Orange Alert'