Camshaft Noise

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I think I know the answer but I thought I'd check first. I dry fit (with lube) the camshaft back into the crankcases. If I push the camshaft to the primary side it makes a horrible sound. I believe the camshaft gets pulled to the other side so this won't be an issue. I thought I'd share a short video of it.

 

Fast Eddie

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Swoosh, the cam gets pulled to the timing side until the lip, that mates to the rear of the cam sprocket, is flush with the end of the cam Bush.
 

Time Warp

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The noise is contact rubbing on the D/S cam bush until the T/S is secured.

Here is another Arthur C Clarke moment, I installed new cam bushes a while back, the cam shaft pulls to the D/S due to a vacuum in the engine case cavity behind the journal (until the T/S is set) ??
It made me wonder about the clearance but it turns very smoothly.
 
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Isn't there a thrust washer or is that only on certain models? If it had one didn't put it on for this test fit.
 

L.A.B.

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Also:
https://www.accessnorton.com/NortonCommando/camshaft-end-float.10512/#post-143609

As stated by dynodave, all 20M3S-on camshafts should have the 06-1086 thrust washer.


750 models that had the 06-2600 timing side bush also had the 06-2601 thrust washer in addition to 06-2600 06-1086.

http://www.oldbritts.com/cam_bush.html
"06-2601 -- NORTON, Washer, Thrust, Camshaft, Some 1972( $3.55 each). This tabbed thrust washer is only used when fitting the 06-2600 bushing and there is a locating hole for the tab in the crank case."

https://andover-norton.co.uk/en/sho...connecting-rods-pistons-camshaft-timing-gear#
Thrust washers, 24 & 25.

Correction: https://andover-norton.co.uk/en/sho...rankcases-crankcase-breather-tachometer-drive
Bush, item 4.
 
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I swear it's a SS cam with a scroll. According to Old Britts it should be plain. I'll look later tonight.
 

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Does it have a stamped T on the side of any lobe ?
 
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I swear it's a SS cam with a scroll. According to Old Britts it should be plain. I'll look later tonight.


Conical thrust washer. Which way does it go, thin side facing the tach drive?



You can see the SS stamping. And it's got scrolls. If original to the engine it's an early Combat. 200xxx.
 

L.A.B.

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I swear it's a SS cam with a scroll. According to Old Britts it should be plain. I'll look later tonight.
The "plain" Combat camshaft and scrolled 06-2600 TS bush were supposedly introduced from 204049.

The important thing is, if the timing-side bush which you haven't mentioned is a type other than 06-2600 then the additional 06-2601 tabbed thrust washer isn't used.
 
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The "plain" Combat camshaft and scrolled 06-2600 TS bush were supposedly introduced from 204049.

The important thing is, if the timing-side bush which you haven't mentioned is a type other than 06-2600 then the additional 06-2601 tabbed thrust washer isn't used.
Which one is this bush?



 

L.A.B.

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Since I don't have the scrolled bush it's simple, use the thrust washer I have.
Yes, although even allowing for the missing steel thrust washer the camshaft does seem to have a lot of end float in your video or perhaps others wouldn't agree and fitting the camshaft sprocket might reduce it?
 
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http://www.oldbritts.com/cam_bush.html



Possibly 06-7358.

"06-7538 -- NORTON, Bush, Camshaft, Pre* 72 R.H. ( $35.75 each). This bushing is only used on Atlas and Commando motors with the tachometer drive on the timing cover."

*(It seems likely this bush probably continued to early 1972?)
Correction
06-7538/39 were originally T2036/37 and "renamed" by ?AN.
Same bushes for twin and single chain engines.
They are thick sleeve bushes used through 20M3S... see the oil groove on the OD!

The fatal thin sleeve bushes06-2600/01/thrust washers started with 200000 series cases.
Ol brit article has several mistakes
 
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Correction
06-7538/39 were originally T2036/37 and "renamed" by ?AN.
Same bushes for twin and single chain engines.
They are thick sleeve bushes used through 20M3S... see the oil groove on the OD!

The fatal thin sleeve bushes06-2600/01/thrust washers started with 200000 series cases.
What is interesting is that this engine "appears" to have never been split it should have had the 06-2600 bush. But I'm not naive enough to think that I know everything that has happened to this engine in the last 47 yrs. All I know is that it sat in my friend's garage for most of that time.

Seems strange that someone would have changed out the cam bush but left the non-Superblend bearings. Strange but not impossible.

What explains the SS (2S) cam with scrolls? Fred's note was that the 2S cams were all plain.
 
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What is interesting is that this engine "appears" to have never been split it should have had the 06-2600 bush. But I'm not naive enough to think that I know everything that has happened to this engine in the last 47 yrs. All I know is that it sat in my friend's garage for most of that time.

Seems strange that someone would have changed out the cam bush but left the non-Superblend bearings. Strange but not impossible.

What explains the SS (2S) cam with scrolls? Fred's note was that the 2S cams were all plain.
Fred's a nice guy, but I do not send people for his "tech infomertials "
My 9.5k mile 202206 was a scrolled cam with the 2600/01bush.
My original 2S cam was bent from new and the Shenstone AN (factory) replacement was also scrolled 2S
ex 1.219" in 1.261" across the whole lobe. Both have drilled sling rings...ie timed breather prep.
All 1S cam lobes are equal 1.215". I have 2 that are not scrolled and are probably late 72 or 73 therfore also 750.
Both are also NOT drilled at the sling rings i.e. not prepped for timed brather.

ADDED: The name "SS" only refers to a cam used in twin chain motors therefore last used in 20M3 engines.
 

L.A.B.

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What is interesting is that this engine "appears" to have never been split it should have had the 06-2600 bush. But I'm not naive enough to think that I know everything that has happened to this engine in the last 47 yrs. All I know is that it sat in my friend's garage for most of that time.


What explains the SS (2S) cam with scrolls? Fred's note was that the 2S cams were all plain.
As stated previously, one modification list states:

"062807...Interim plain "Thinwall" camshaft bushes, interim "Scrolled" journal Combat camshaft & 062601 (thrust washer)" ....(Eng.No.)203959 (except 20396?)
062608....Final "Scrolled" steel backed bushes (062600) &....
062673....Plain journal standard and Combat camshafts......(Eng.No.)204049"


If accurate, and the camshaft is original it would explain the existence of scrolled Combat camshafts.

The oddity is that the 062601 tabbed washer would appear to have been introduced with the "interim" bush, whatever that was as there's no part number for it?

(062608 = standard camshaft, 062673 = 2S. Searching 06.2807 at AN leads to 062673)
 
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