[Fot] Cam Bearings expansion

[Diesel Performance Parts - Info]

Scott,

I doubt if they can straighten the cam they are usually too brittle as compared to a crankshaft etc.
The old timers used to have a shaving tool for the poured babbit  bearing engine of days long gone. You could use one of those to "trim" a little off.

I would pull the cam bearings double check the cam bores for alignment, and diameter. If they are OK then make sure the cam bearings are all consistent in thickness.  If they are then it's the cam, it is either oversize or undersize on the nearing journals or bent.

Mark Craig
Diesel Performance Parts, INC.
411 Allied Drive
Nashville, TN 37211
866-455-7788 Phone
615-834-9923 Fax

www.dieselperformanceparts.com
From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of Scott Janzen via Fot
Sent: Monday, January 05, 2015 8:41 PM
To: 'Friends of Triumph' Triumph
Subject: [Fot] Cam Bearings expansion

I've got a bit of cam bind in a new cam I'm installing in the GT6.  It appears to be a combination of slight run-out (i.e., the cam is slightly bent, 1/1000 of runout in the middle), journal size right at the factory maximum spec, and installed bearing I.D. that is at or below the factory minimum I.D.

It's also possible that the block is not bored perfectly straight as the binding is not consistent around the rotation, but another cam I have, with journal diameters 5/10,000 smaller, turns freely.  I have not checked that cam for run-out.

Question is, is there a tool to "expand" the bearings into the block and possibly gain a bit of clearance?  I'm told the factory manual for one of those Octagon cars calls for such a tool.  I'm using the typical Spitfire bearings.

Next stop is a machine shop with a crank straightening machine to see if they can use it to straighten a cam.




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