Undersize journals on flathead cam

[Bob Hoffmann CLC#96]

This was a NOS cam that I believe came out of a tank engine. Machine shop tells my friend that it's .010 undersize on the journals. Anyone ever have this situation???
Thanks, Bob

[Steve Passmore]

Yes Ive seen this before Bob, The military reconditioned these engines on an "Hours Run" basis, and as they were used extensively after the war many hours were put on them,   Of the tank engines here a few have been overhauled and have cams ground down with undersized bush's made up and fitted, I have one such engine myself

[Bob Hoffmann CLC#96]

Steve,
Thanks for the quick reply. I still don't understand why they would only turn the journals??? The lobes look new.
I guess the next question is: where do you get cam bearings?
Regards, Bob

[Steve Passmore]

I have always seen the bearing surfaces worn more than the lobes Bob, the bearings were shot in my 41 engine but not the lobes, I don't know why that is but its not peculiar to just Cadillac, I have seen other  engines with the same event. In the case of my tank engine it has plain bronze bearings turned up by a competent engineer, guess it must have worked?  it may have been possible to obtain undersized bearings at one time, who knows?

[Mike Simmons 938]

Bob- Interesting that you should have that problem- ypu post it and felllow travlelers come out of the woodwork. I had (have) that same siituation- went to repllace a cam with a beautiful used 40 cam- and found it wouldn't fit. Had to reuse the one I had just removed. It was the first time in 50 years  I  had ever heard of this situatiion. Now there are three of us at least. Could it have something to do with the oil supply to the journals??
Mike Simmons 938

[ederm]

Under size cam bearings:     IAm restoring a 1939 LaSalle conv.   It sat for about 50 years on a farm. Engine froze, mice went up the exhaust pipe, the inside of engine was junk.  Some one put bearings (rod and mains) but didnt go far enough. the cam bearings were not finished on # one and two bearings surface. It look like a very fine thread on them.  Most engines the oil pressure  is determed by good cam bearings. I send it to Berry Cams in Minn. for a work over. Not cheap, I believe they were ground to .   010  under, I got the last set of bearings Eddge had. The shaft was steel not cast. I found a NOS cam and bronze gear at Hersy in 2009. ALso take a very good look at your bronze gear it wears because of poor bearings in dist. towerbearings.  Thank you, Mike     P.s. am lokking for a vac. ant. for it.

[John Tozer #7946]

In view of these posts, why not replace the camshaft? Has anybody had experience of these?

http://cgi.ebay.com/ebaymotors/Cadillac-Lasalle-camshaft-322-346-1937-1938-1939-1940-_W0QQcmdZViewItemQQhashZitem2c4fda2599QQitemZ190318257561QQptZVintageQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Regards,


John Tozer
#7946

[Bob Hoffmann CLC#96]

Guys,
I appreciate everyones response but... please reread my post. The cam looked NOS. There was NO sign it had ever been used. I believe it came out of a new or rebuilt tank motor years ago. I'm trying to help a friend. He's going to double check what the machine shop said. I'll let you know when he advises me. If anyone has the journal diameter,not the tolerances, please post it. Thanks.
Bob

[Steve Passmore]

Number 1   Front    2.4076 - 2.4083
Number 2               2.4076 - 2.4083
Number 3               2.0014 - 2.0021

[Bob Hoffmann CLC#96]

Steve,
I just checked a NOS cam I have. 2.4075  on the big journal.  We'll see what my friend comes up with.
Thanks, Bob