Camshaft Thrust washers

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olympus

olympus

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Hi Guys
A technical question please...
I have a engine number of 200918 on a 72 build. AN parts listing indicate a conical washer & a flat washer with a tab
Unfortunately I got the motor as a basket case .. in bits with neither of the washers So I ordered in both
Doing a dry fit of the cases with the conical washer (flat face out) and the flat washer tab located in the hole the cam locks solid and the casings don't contact each other.. several attempts thinking the tab may have jumped out its always the same.
Now without the flat washer I have clearance
Checking the on line shop manual it also states that between 200000 & 3000000 both washers should be fitted... so I'm confused.
Is the book right or do I just fit the conical washer .... if this is the case what is the max cam end float & are there shims to achieve the figure.
I am fitting an OE cam from AN

Thanks
 
The tab breaks off and with the pump unprotected by a filter guess where they end up, break it off now if you end up using them. You sound like you have a mix of parts, my combat has its original cam plus 1 conical and one tab less washer.
 
Camshaft Thrust washers
Is it possible that you have a shouldered bushing, replacing the tab-washer with the upgraded bush? I have engine [HASHTAG]#201182[/HASHTAG] 200 units away. When I broke mine down this was the case. No tab washer present. A picture of the timing side case?
 
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olympus said:
Hi Guys
A technical question please...
I have a engine number of 200918 on a 72 build. AN parts listing indicate a conical washer & a flat washer with a tab
Checking the on line shop manual it also states that between 200000 & 3000000 both washers should be fitted... so I'm confused.
Thanks
Click to expand...

The combat cam (I am assuming yours is) most had no scrolled oil-way groves at the journals, so they used two tab washers. One against the conical washer and one behind the cam shaft sprocket. But as others stated above these tabs would break off when the engine is running and get sucked up the oil pump, locking it and blowing up your motor shortly there after. So it is best to break them off prior to assembly because this series engine cases did not have the large filter plug to stop large bits of debris going into the O/P. Here is some information from Old Brits: https://www.oldbritts.com/cam_bush.html
Edit: Sorry I posted the website that L.A.B. linked you earlier.
While your are still in assembly why don't you ask DynoDave about his mod to relocate the oil pickup location and create a primitive yet effective filtration modification to your engine cases.

Cheers,
Thomas
 
Last edited:
olympus said:
Hi Guys
A technical question please...
I have a engine number of 200918 on a 72 build. AN parts listing indicate a conical washer & a flat washer with a tab
Unfortunately I got the motor as a basket case .. in bits with neither of the washers So I ordered in both
Doing a dry fit of the cases with the conical washer (flat face out) and the flat washer tab located in the hole the cam locks solid and the casings don't contact each other.. several attempts thinking the tab may have jumped out its always the same.
Now without the flat washer I have clearance
Checking the on line shop manual it also states that between 200000 & 3000000 both washers should be fitted... so I'm confused.
Is the book right or do I just fit the conical washer .... if this is the case what is the max cam end float & are there shims to achieve the figure.
I am fitting an OE cam from AN

Thanks
Click to expand...

It sounds like you are attempting to install the tab washer on the inside of the case along with the top hat bushing. The tab washer would only be used inside the case if there is no thrust washer built as part of the cam bushing. [the brim of the top hat bushing]

With the top hat bushing to the inside of the case you only use the conical washer.

You would install the tab washer from the outside -under the cam sprocket -after the tab is broken off. Once the sprocket is in place this will control the cam end play, nothing more will be needed.

And yes, the sump pump pickup needs to be moved back to the rear of the cases if you ever want to have a leak free engine. jim
 
Jim,
Good point.
Yes if he has the top hat bushing on the inside then the tab washer would be not used. I have seen this on one combat that gernaded, Pete Turners. No Pictures so I was assuming olympus has just the scrolled bush.
Cheers,
Thomas
 
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yes I see..
If I'd stripped the engine I would have had a point of reference.. but I didn't
I have the very same shouldered bush so were all good
Built the cam into the case with just conical washer & fitted the timing sprocket and nut . I have between 8-10 th end float
Only problem now is with crank dry fitted & new bearings I have 28 th end float ....so shimming is now required.

Thanks Guys
 
If the cam shaft bushings were being replaced on a Mk2 (A) 850 and you found both the stock type one piece 06-3020 T/S bush and a pair of the Mk3 06-5428 type in your spares, would there be any merit to fitting the Mk3 bushes ?
There would be less engagement for the same interference fit (might move) in the engine case over the one piece bush but being shorter the gap between the two bushes when installed might offer an improved oil supply ?
My stock camshaft lobes were fine but the T/S bush and cam journal showed corrugation perhaps from lack of oil.
Maybe the later bushes would improve the available oil supply ? or just use the stock one piece bush ?

Camshaft Thrust washers
 
olympus said:
Only problem now is with crank dry fitted & new bearings I have 28 th end float ....so shimming is now required.
Click to expand...

I don’t think it is required actually. You can if you want to of course, but if you do nothing, you will suffer no downside at all. In fact, if it’s an engine that’s gonna be put to hard use, a little more space is a good thing.
 
Time Warp said:
If the cam shaft bushings were being replaced on a Mk2 (A) 850 and you found both the stock type one piece 06-3020 T/S bush and a pair of the Mk3 06-5428 type in your spares, would there be any merit to fitting the Mk3 bushes ?
There would be less engagement for the same interference fit (might move) in the engine case over the one piece bush but being shorter the gap between the two bushes when installed might offer an improved oil supply ?
My stock camshaft lobes were fine but the T/S bush and cam journal showed corrugation perhaps from lack of oil.
Maybe the later bushes would improve the available oil supply ? or just use the stock one piece bush ?

View attachment 6020
Click to expand...


FWIW
When opening up my MKIII I found that the inner cam bush had spun in the case. I replaced it with the one piece bush, used the stock hardened shim/spacer on the inside and the tabbed washer ( with tab cut off ) under the cam gear. I also had to ream the bush to fit the cam. I believe there was enough meat on the case to use the two piece bush and not have a problem but I figured the one piece would definitely stay in place. I gotta thank Jim Comstock for the idea on using the one piece bush.
Pete
 
Thanks Pete, I will use the one piece 06-3020 T/S bush.
It looks like they need reaming to 7/8" after fitment but will double check when the new camshaft arrives and measure the journals.
 
I might have asked this before, I wonder why Norton did not use sintered bronze bushes.
 
Time Warp said:
I might have asked this before, I wonder why Norton did not use sintered bronze bushes.
Click to expand...

The benefit to sintered bushes is their self lubricating properties isn’t it?

If so, then as they run in the engine, in constant oil mist, there’s no point is there?
 
Fast Eddie said:
The benefit to sintered bushes is their self lubricating properties isn’t it?

If so, then as they run in the engine, in constant oil mist, there’s no point is there?
Click to expand...

I'm not sure they (Commando) get a constant oil mist but yes sintered is supposed to be a little more forgiving over non sintered bronze which is why I wondered why they were not used in the NVT Commando.
Bronze can't be ball sized as the sintered can be either (Triumph)

When I posted a pic of the USA made bronze (over the stock sintered bushes ) camshaft bushes for my 1957 TR6, John Healy who knows a thing or two about Triumph's said there was a risk of them galling and spinning in the case.

I was just curious and am not aware if that material was ever available even as an aftermarket part.
I guess if it was better or an improvement Jim Comstock would have done it long ago.
 
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