Cam Followers

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rvich

rvich

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I would like the experts to chime in here. The cam followers on my 850 look great in that the wear on the surface is very mild. When I put a straight edge across the face and shine a light from behind I cannot see any gap at all. However, I can see from the wear pattern that one of the followers (it would be the left side intake) doesn't contact the cam lobe across the entire surface.

Cam Followers


The cam shows a similar wear pattern. Should I be concerned about this? Obviously 100% contact would be better but for all I know they are all like this to a degree.

While we are at it, what is acceptable end play on the cam?

Thanks
Russ
 
Kind of hard to accurately judge that, and not wishing to inadvertantly give wrong advice I would otherwise recommend you pop them out and take them and the cam to a motor recon shop and get an expert opinion. (Keep them togther as matched pairs).

As to end play on the camshaft, there is no shimming, only the thrust washer. The cam chain pretty much pulls it into alignment. If its an early breather cam, the end spring more or less pushes it over to the timing side.

Mick
 
Grinding the cam followers at an angle is a pretty common problem. I have even seen some new ones that were not straight.
I would find someone to regrind it straight. Jim
 
Cam and their followers are mated. That is to say if you grind the cam you must gring the followers. If you choose not to gring or recondition them (this is what i advise) be sure not to mix them up, as in drive side to timing side and intake to exhaust.
 
I am going to have to decide how far to go with this build. I put one of the old rings in the bore and checked the gap with the ring at top, middle and bottom, there is less than .001 difference between top and bottom (bottom being where the cross-hatching is still visible). The motor has about 6000 miles on it.

The pistons are in good shape. I have not seen the crank journals yet but thanks to wet sumping the inside of the case looks terrific.

I had always thought that the followers being mated pairs were due to their interface with each other rather than the cam. Does it always follow that if you grind one (cam or followers) that you grind the other?

I suppose it would be FUBB to think that I could reface the follower using a piece of glass and some valve paste?

Russ
 
If you replace or regrind the cam then the lifters must be ground.

Normally I would not suggest re-grinding the lifters unless the cam was also replaced but it appears that your engine has low mileage on the cam. A straight lifter will be better than a crooked lifter.

If it were mine I would just regrind the one problem lifter. I don't think you could correct the angle with emory paper but if you want to mail me that lifter I will grind it straight for you and send it back. Jim
 
I may be in danger of hijacking my own thread, but how much can you take off that follower before you have to start worrying about valve geometry?

It has been commented often that Combats should have their pushrods shortened. Is there a reason that nobody talks about grinding the followers to change this?

As for this project...Assuming my son-in-law doesn't kidnap me for a day of fishing, I should have the cases apart this afternoon. I can get a look at the crank and a better look at the cam. It will give me a chance to think about how much stuff I need to send out. No point in sending a lifter and then deciding I have to ship a crank as well.

Thanks,
Russ
 
rvich said:
I may be in danger of hijacking my own thread, but how much can you take off that follower before you have to start worrying about valve geometry?

It has been commented often that Combats should have their pushrods shortened. Is there a reason that nobody talks about grinding the followers to change this?

As for this project...Assuming my son-in-law doesn't kidnap me for a day of fishing, I should have the cases apart this afternoon. I can get a look at the crank and a better look at the cam. It will give me a chance to think about how much stuff I need to send out. No point in sending a lifter and then deciding I have to ship a crank as well.

Thanks,
Russ
Click to expand...

I would remove no more than needed from the stellite pad although you could probably remove .040 safely. It would be a lot of work and a lot of wear on a green or diamond stone.
Pushrods are easy to shorten. Just pull the end off -cut the tube and push the end back on with a bit of JB weld.
Geometry changes with head or barrel cuts, valve regrinds, cam regrinds as well as lifter grinds. To make the geometry "correct" it needs to be checked and adjusted on an individual basis but the geometry is pretty forgiving and not usually a big issue on a streetbike. Jim
 
Interesting dilemma on mechanical choices. Anal way is replace to new. Cavalier way is just run till need to renew. Tricky way is square the lifter and hope cam remates with it for long life w/o undue skewing of forces. If trimming lifter and or cam, remember to break it in right.
 
Here are some photos of the cam.

Cam Followers


Cam Followers



Check this one out!

Cam Followers
 
Oh well, those tab washers don't help a bit with keeping the nut tight. I always throw them away. They are too soft to hold tension. Jim

PS That looks like one of those "soft MK3 cams" Jim
 
comnoz said:
Oh well, those tab washers don't help a bit with keeping the nut tight. I always throw them away. They are too soft to hold tension. Jim

PS That looks like one of those "soft MK3 cams" Jim
Click to expand...

Regarding the cam..

Yikes! To my untrainded eye, it looks like...a cam.

Well shite...I had expected the inside of this motor to look like it had been recovered from the Titanic. So was planning on a lot of new parts. Of course finding the inside to be pretty clean started forming new ideas in my little brain. I am probably better off to start saving my beer money toward parts again.

As always, all advice is welcome...particularly if it is good.

Russ
 
comnoz said:
PS That looks like one of those "soft MK3 cams" Jim
Click to expand...

rvich, he didn't say it was bad. Don't assume, find a machine shop and have it rockwelled.

The virtual can of worms you are opening is unrealistic. You are right that this unit looks good. If you feel you need to replace thing then do so, but wait for a better time, snowy, cold, rainy...you know, shitty out.

You are fixing something that ain't really broke, and for all practical purposes may run wonderfully for 10g to 20g miles or more. The wear and tear on that bottom, and top end for that matter, is minimal. And if I might add, motors that are run in, as yours seems to be, tend to be much more reliable than freshly built units that have yet to be proven.
What I see is that you have validated a good build and should be reassembled.
But if you must, you must.
My to cents.
 
It is not outside the realm of possibilites that I might reassemble and run this engine. It is out of my avatar bike. So there is lots to do as the bike sat untouched for 35 years in a lean-to type of storage in lovely S.E. Alaska weather.

So it isn't like I can put the motor back together and ride it either. I need to take some time to think about how I want this build to go and whether I want to do it all at once or as an evolution.

If nothing else this is the first phase of research.

Russ
 
comnoz said:
Oh well, those tab washers don't help a bit with keeping the nut tight. I always throw them away.
Click to expand...

True, but these tab washers are to keep the dowel in place so throwing them away I would not recommend :!:
 
I'm with pvisseriii.

Yeah, they're out of alignment but that slight misalignment has done no damage so far, and as they wear in the future, they will come into alignment, fixing themselves.

The benefit doesn't outweigh the risk and liability of the process.
 
rvich said:
I need to take some time to think about how I want this build to go and whether I want to do it all at once or as an evolution.


Russ
Click to expand...
"Evolution" Great word in the Norton world. Unfortunately an evolutionary process in rarely a luxury with these barn(lean to) finds. I was fortunate when i got mine that it was a running machine. Although little has not been touched (steering head bearings come to mind) I have had that fortunate luxury of an evolutionary process. Somethings did wait for the winter months (crankcase swap out) and the like.

Getting your Alaskan dream road worthy may not be so simple but it sound like the motor should not hold you up. I will be interested to hear and see what's next.
 
But it is already apart. It would be worth at least checking the cam hardness now. If it is a soft cam then even if it is put back together to ride this summer, a search could be underway to find a new cam to be put in during the winter. If it were me I would make it right now to avoid the double work. I wouldn't be happy riding something that was questionable either.
 
But the point is to not go through the thin hard layer on the cam. Once it breaks through then failure happens quickly. It looks to me like it would be better to even out the wear by straightening the lifter. Either way would likely live for a while. Which would last longest would be a crapshoot.

Locktite or JB weld will keep the center dowel in place. The crank studs hold their torque better without the tab washer. Jim
 
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