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January 29, 2025
Camshaft
Back in my 70s engine work, I bought a "Competition Camshaft, for
midrange increase" from Moss Motors for the princely sum of
$30.00. With only a few hundred miles on it since then, it showed
no signs of wear beyond some polishing on the lobes. So I wanted
to re-use it.
I don't really know much about the characteristics of this cam, and
there are no markings on it except "4J9" stamped on the front end.
I guess it will be a bit of a guessing game when it comes to cam
timing.
When I stripped the block for thorough cleaning, I removed the cam bearings to improve access to oil passages.
Even though the bearings I took out were still in excellent shape, I
opted to buy a new set. They are relatively cheap. To
install them, I used the same bespoke adapters that I used to pull the
previous bearings.
And in they went.
All want well, except the front bearing seemed to take a lot more force
than the others. I attributed this to tolerances, but when trying
to test fit the camshaft, the front journal would not go into that
bearing. I couldn't check the fit of the other bearings at that
point because the front journal engages first, and has to be part way in
its bearing before the other journals will engage.
Mystified, I checked the ID of the bearing with a bore gauge and
compared it with the journal OD. The bearing was actually about
0.0015" smaller than the journal. I wondered if the other bearings
were off, too.
Then I remembered that I still had the old set, which I knew fit, and
were still in good shape, in part due to the low stress removal
process. I pulled the new front bearing and replaced it with the
old one. The cam fit like a glove--silky rotation with slight
resistance and no play.
The cause remains a mystery.
This was all done in parallel with the crankshaft work, which is why
there is a seeming time warp in the chronology. Here's what it
looks like right now.
This was a fairly quick job, even with the front bearing unpleasantness. Cost was only around $30 for the bearing set.
Comments to Ed at elhollin1@yahoo.com
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