While we're on the subject...
The 948 race engine I'm rebuilding had 3 cam pearings installed when it was
first built up. After losing the center main bearing, small bits of metal
found there way to the rear cam bearing since that's where the oil pump is
situated. The cam required only minor polishing and while there was a
little roughness in the bearing, one shop suggested I clean up it with a
little enery cloth and continue to use it. The engine only has a couple
hours use on it, so the other two are fine.
I may have problems finding a prefit cam bearing, so I'm wondering what
others may think.
Gerard
At 9:45 PM -0500 10/8/00, Charley & Peggy Robinson wrote:
>Larry, et al,
>
> Hmm, I think thing need to be put into perspective here. Most
>engines have separate "cam bearings" (sleeves) installed into the block
>for the cam to spin within. Some don't. The Spridget 1500CC engine is
>a case in point; its cam spins within machined bores in the block. If
>the cam bores in the block get worn out of tolerance, the oil pressure
>could indeed suffer. Also, if the bores wear too much, the cam will
>flex under the valve spring pressure. The cam can break because of
>this, but the most frequent sign of this is that the valve lash won't be
>constant. I had a Fiat 128 Spyder DOHC engine that manifested worn cam
>bores in this way. The fix is, reputedly, to bore out the cam bores for
>bearings and run an XXX cam. Take your pick; I've been told of several
>different to use.
>
> My thought is that I'd have to see signs of real probs in the cam
>bearing area before I'd bother. By signs, I mean a real good going-over
>of the cam bearing journals on the cam for signs of loss of alignment,
>out-of-round, etc.
>
> Hope this clears it up a bit,
>
>
> CR
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