Cam followers - Andover to the rescue?

olympus said:

Pity they don't have a coffee machine.... commented on this to them yesterday

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Makes me wonder what they put in those cups.
Do they have a Lucas refrigerator?

Just to make it clear. I think the cause of the broken parts was the ability of the spring retainers to deal with a large cam -more than a problem with the cam it'self.

I used the retainers because I had them laying around and was not wanting to use up my expensive spring kits. In hindsight I should have just used the expensive parts to begin with.

There is no question, the PW3 is not a cam I would put in my engine which usually sees 10,000 miles a year at some pretty high RPMs.

But for race use and occasional street use it is a cam that can make good power.

Of course I am still not a fan of any iron cam....Jim

The problem with harsh closing ramps on the PW3 cam has been solved for nearly two years now with one brand of aftermarket cam (not iron) with improved ramps.

comnoz said:

Well, never mind.

When I cleaned up the machine after the last failure I found one of the four oil squirters was plugged. It still should have had plenty of lube but, I though there was a chance it caused the failure at 20 to 30 minutes with the NOS cam.
So I cleaned it out good and changed the oil and filter. I resurfaced the followers and moved them to the other side of the cam that was still untouched. This time I filled it with Castrol GTX instead of Mobil 1 v-twin oil.

This time it failed in 10 minutes. The cam to follower seizure was bad enough to actually stop the spintron.

Definitely not compatible.

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As you may remember, I always have questions.... but I'll be patient because you always seem to answer the relavent questions even when they aren't yet asked..

GTX...typical. Trying to save a few bob instead of the pricey stuff!

Just kidding!

It was decided to use common average performing oil as that is most probably what most owners would use.

Pete Williams has recently calculated data and had us produce a PW4. I've been using it for over 16K miles, no rasp on the overrun. A little harder to fit as it needs clearance in the tunnel and valve stem collet recess ground higher up the stem and it needs radiused followers. It seems that with another mm of lift the ramps have been redesigned. The LSA is far wider than the PW3, some said it would not be possible to start the bike with the kickstart, hey ho, first kick nearly all the time.
The days of chill cast Norton cams are nearly over, the cost of chills and the MOQ, makes it a non starter. Case hardened cams will return when companies have the equipment to harden them without distortion - it is available now, and the beauty is that no final grind would be needed, but they can't see how to do it, and their preferred option seems to be nitrided.
Another cam grinder actually came up with what they thought was a real daft idea, they have asked to price it up!! It was not so daft, and makes perfect sense.

I have had a few questions concerning the oiling system on my spintron. So I made this video to answer them.

When starting from cold the oil is preheated to somewhere in the 100 to 150 F. range.
From that point normal friction will heat the oil to ~ 200 to 250. On long runs I use a cooling fan to keep the oil from overheating.

And the motor drive I am using is a quill drive so it has the ability to sense the load and shut down if the load changes more than a preset amount. So when the load increased by 10% with the follower failure that is what stopped the motor. Without that the motor is plenty powerful enough to destroy lots of parts.

I think I see a "Comstock roller follower" somewhere in the future...

Maybe, but not on a Commando - think about it. I did and even thought about scaling down the 961 ones and fitting them in an insert, it would not work. Basically, that bloody Norton cam says otherwise. Rolling follower is just in very simplistic terms a radiused follower, now you see the issue. Someone would have done it by now as it seems that easy.

Yeah, I have looked at a roller also. Maybe with a custom tappet, barrel and cam it could be done, but then rollers, particularly small diameter rollers, have a whole new list of problems...

I suspect that the answer is going to lie with the tappet that is howling away at 6000 rpm on Andover's PW3 right now....

Interesting reading being in the market for a new cam and lifters which is not a cheap outlay.
Maybe a lifter could have a ball and camshaft lobe face to match.

Roller lifter's in Nortons has already been done.





Westlake speed way roller lifters work but require perfect alignment and are still problematic.

Best solution for wear is BSA lifters or Norton lifters with a 1-1/8" radius as shown below:

Time Warp said:

Interesting reading being in the market for a new cam and lifters which is not a cheap outlay.
Maybe a lifter could have a ball and camshaft lobe face to match.

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Now that would be a trick to make work!

It's nice to see someone (Andover) putting in the time and money to try to come up with a better lifter design. If they end up with a material that is compatible with all the different cam materials, it would seem like grinding them to a radius and using a suitable cam profile would work for most of us. At the really high performance end of the spectrum, I still like the BSA lifters for their lighter weight. A really nice product would be new BSA lifters ground from solid in the newer material. Getting rid of the brazed-on foot is clearly the way to go, if it can be made to work.

I've seen a couple of roller lifter setups for Commandos, and used to think that would be the way to go. But now it looks like the limits in roller diameter, along with the small lobe size and unsupported cam center, really make it hard to design a drop-in conversion that is reliable.

Looking forward to seeing where the results of this project.

Ken

The BSA style lifter was also looked at. It is great for racing, but as yet I've not seen any with any serious mileage on them.
The radius idea is great, but its advantages are to be balanced against the issue it introduces. The smaller the radius the more the side motion imparted on the follower increases, yes, as I hear some say, it can be mitigated by cam design, but the Norton cam tunnel limits it.
When Jim has finished trying to destroy them, any failure evident should be relatively easy to identify and tweak. When you consider the Dr's and experts involved along with the modern alloys, for what looked an easy solution, they all now have some massive respect for this design.

I fitted JS cam and followers in 2013.

Since then the engine has needed another head rebuild, 2 sets pistons and rebore. In its last tear down it transpired it needs a crank regrind. It also needs new cam bushes (I hardly ever need to replace these on engine I build) but mine were seriously worn. The cases also had some small cracks starting.

What am I getting at here? Well, whilst my bike hasn’t been used for huge touring miles, it has been used hard enough to indict the above mentioned ‘wear and tear’ yet... the JS cam and followers do still look (almost) like new!

The journals only need polishing (even the bushes they were running in are now shot) and yes, as Ashley points out, there is evidence of side thrust wear in the lifter block. It’s not a lot though and I will re-use as is. Note though that even if the lifter blocks do get shot, they’re easy to replace without removing or splitting the engine.

In the 920 motor now I’m running a Maney cam (iron) and AN followers so it’ll be interesting to see how they fair.

If you want feedback from someone who’s done lots of touring miles on a JS cam and follower kit ask Ludwig.

Bottom line: cam and lifter wear is is regular hot topic on this and other forums, with ma y engines having to be torn down do to very premature failures. My own experience has clearly shown the JS cam and lifter combo to be excellent in this regard. So, I do genuinely hope you make this work out Ashley and applaud you and AN for taking the task on. But until you do, I’d steer clear of criticising the JS kit given the failure rate of other cams and followers out there!

On the subject of retro fitting roller followers in these type of engines. Nourish fitted them in his K spec engines.

Their increased weight meant that stronger valves springs were required.

The stronger valve springs took revs and power off of the top end.

To my mind this also reinforces the arguments for valve train weight reduction, even on the cam side of the rocker.

FE,
Not criticising them, as for miles, there are many bikes out that have done 100K plus, several have done well over double this with the same tappets though I suspect refaced. The BSA style lifters would need to see 30K miles at least to be a viable option. This sort of mileage seems to be the distance most standard engines either get looked at or removed for other work.
There has been no real issue using AN tappets and nitrided cams, I have sent new UK made nitrided cams to test for case depth to establish why. The results were surprising, that is why we have some on order.

I really like the spiggotted tappets that have been available from AN for years.

The only problem I have seen has been the same as the presently manufactured tappets available for the BSA, one in every so many is not the correct hardness and the cam to tappet interface fails.

Other than that, either design works great.

Welding hard material onto the steel lifter seems like one of the best ideas. This is what SRM decided to do instead of brazing on a stellite pad. The same welding process (not brazing on a pad) could be used with Norton lifters (if made of steel). I bought as many of these as SRM would sell me, sent them out to customers and haven't heard of a single complaint.



The Norton lifter is a complicated shape and expensive to machine - that's its main drawback (and its weight). The BSA lifter is nearly the same design as the Triumph lifter and the longevity is pretty much established in high mileage bikes (compared to Norton lifters). But the overall shape or design isn't the biggest problem. Whether its a Norton, Triumph or BSA lifter - the main issue is the pad material. So why aren't lifters with welded on cam contact surfaces being made at this time? Seems like a no brainer.

Hint:
SRM used stellite #6 hardweld - approx 50 HRC - softer than Hero 56 or 60 that is used on cam lobes by people like Web Cam (I think), So it should be compatible. BSA used 5 to 10 hardness difference between cam and lobe.