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Catastrophic camshaft and follower failure - any ideas?

BlackLightning998

Well Known and Active Forum Website User
VOC Member
Evening All,

Oh dear - isn't Vincent ownership fun......

I wondered if any members have any ideas on what caused pretty catastrophic camshaft and follower failure on my 4000 mile old engine. Pictures embedded below.

The story is that I came to re-start the bike after re-fitting my refurbished dynamo, only to find it fire on the rear cylinder and not on the front. I traced it to a stuck open exhaust valve and suspected the valve lifter mechanism.

On stripping the timing side today, sure enough the front and rear linkage had become seperated and the front had stuck open the exhaust valve.

However, then things get worse. On checking for other damage/issues we found that all four cam lobes were heavily worn/scored and all four followers were deeply scored and worn - see the pictures.

Everything was invoiced as new in the top end and timing side before I bought the bike. More new parts than would sink a Battleship.

The work was done in Australia - I don't yet know the origin of the new parts which were fitted, but we have narrowed down the problem to one of three causes, I'd be very grateful for any other ideas, comments or advice from members on what to check/look for in advance of fitting the new parts I ordered today (ouch!):

1 - Parts failure
Perhaps the cams or followers weren't properly hardened

2 - Oil Failure
I have been meticulous in checking the oil return immediately on firing the bike, changing oil and cartridge filter at 500 mile intervals including priming the cartridge and keeping to recommended running in speeds and loads. The timing case is lovely and oily throughout, the valve caps have always had a good covering of oil in them when I have removed them and the new stainless rocker feed bolts are all clear and running through when you blow them - no metering wires fitted. So whilst of course it is always a possibility - I just can't see it myself.

3 - High Lift Cams
The lower valve guide is visible in the picture attached - we were wondering whether such damage could have been caused by a mechanical problem, perhaps the valve collar is bottoming out on the top of the lower guide before full cam lift and this is causing the damage. The cams which have come out are stamped "3" but the profile does not look anything like some spare old "3"'s I've compared them to.

Have we missed something?

Regards

Stuart
 

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BlackLightning998

Well Known and Active Forum Website User
VOC Member
Greg - what valve springs are you running.

Hi Greg,

Thanks for your interest and reply. Still trying to get to the bottom of it all.

Can I ask what valve springs are you running with these cams please?

Cheers

Stuart

Stuart
On the face of it I would be getting the oil checked(chemist)
There is a few of us running these cams,( 4 of us in my area) and to my Knowledge No Problems .
My Mk2s have had one adjustment in 10500 mls and that was at 500mls( sorry for using the term tappets)(I also use 10w-60 full synthetic)that is just my choice, another word use a good quality and Brand oil castrol ,Valveline etc
I had an experience with a Mazda 3500 Deisel some years ago,it ran out of go ,on stripping, the cam shaft , followers and oil pump were (well like yours)the rest of the Engine was ok . I figured the oil pump was the problem with all the hardening off the teeth and pump shaft , rebuilt the problem area , filled it with Mobil Delvac and No problems for 5000 ks , the owner did his own oil change with his own oil , 1200ks later same problem, had the oil tested, the chemists report read may be used externally for warding off moister (Low grade)similar to WD40. I know this doesnt soften the blow for you it just had a similar ring to it ( thats why I was asking so many Questions).
Stuart I have NO affiliation with the said supplier.
Will be very interested with the out come . GOOD LUCK
Greg
 

ossie

Well Known and Active Forum Website User
VOC Member
STUART.
do come to the annual rally and bring your cams as there will be wide range of owners from all parts who will be only to pleased to give valid input to your problem.
and im sure we can have a whip round for you barbeque meal?
OSSIE
 

ossie

Well Known and Active Forum Website User
VOC Member
nothing to do with the wear on your cams but i did have the split pin come out of the valve lifter on my shadow and the loose lifter rod went into the cam gears and took off part of a tooth on the large idler i had it welded up and it sat in my spares box for years.
i then put in about three ally gears but they all wore their teeth to points after a while.
so i dressed up the steel one and took it up to a club night and asked for the views of the assembled mob?
mr chapman said it looked like a good repair so i replaced it and its been in place for ages with no problems only half of one tooth was missing so i filed it to match that profile.
ps i am a precission engineer by trade but did not want to wreck my engine.
after 42 years of ownership replaced tyres and chains had 1 rebore and the heads serviced at conways gold hawk rd but have never split the cases to check the flywheel assembly etc cant do that or i cant ride it .
it might rattle but it gets used.
must get everything ready for hever and then the annual its a busy month ?[off to visit freinds in sarasota fl. for a rest] then the annual dinner at stevanage..
 

biggles

Forum Website User
Non-VOC Member
camshaft failure

Hi Stuart.
One thing I have found over the years that when installing camshafts and crankshafts (plain bearings) for the first time is that you need to allow for the lack of oil on the initial start up some cranks and camshafts are supplied coated in an assembly and running in compound with warnings attached not to remove it I personally use Rocol assembly and running in spray and never had a cam or crank failure yet.It is also supplied as a paste so that you can apply small amounts to small critical areas.Sometimes just squirting oil at the parts is not enough.
Hope this may be of assistance in the future.
Cheers
Biggles
 

BlackLightning998

Well Known and Active Forum Website User
VOC Member
Update - I made it to the Manx......

Evening All,

Thanks to everyone for their support on my trials and tribulations of Vincent Ownership.

Thought I'd post an update to my "cam and follower" failure.

I've just returned from the Manx GP - 1000 miles in total. A wonderful trip, a great week and I felt priviliged to be there at all on the Vincent bearing in mind that just two weeks before setting off my engine, having been expensively re-built just 4000 miles ago, ate it's cams and followers and required a few other bits and pieces too.

I was lucky to fall on my feet and find an experienced and capable Vincent man to re-build it for me, and we were supported by Patrick Godet who let me have a set of cams, Maughans who supplied followers and other odds and ends.

Russ at VinParts was his usual wow self and supplied all the bits and pieces in stock, and in double quick time - this included some standard valve springs to replace the ones we found to be ten thou oversize. Also, trying to look on the bright side we took the opportunity to fit the VinParts Exhaust valve lifter oil seal modification - 1000 miles and not a drop through there (although I'm still chasing on or two other leaks though!).

We also fitted a set of Neil Videan V3 seals that I'd bought through Vince Farrell - I hadn't expected to fit the top and bottom pushrod seals quite so soon though. Again - no oil problems with them in 1000 miles.

Not sure we'll ever get to the real bottom of my problem, perhaps poor parts in either the cams or followers contributed, although the oversize valve springs that were fitted I think may have been unhelpful, particularly as they didn't appear to sit comfortably/at all in the upper guide and in one case I suspect had been sitting at an angle and caused noticeable wear in the upper valve guide in just 4000 miles. There have been a few little engineering adjustments which have been completed (which I am sure are well known to those in the know, but new to me) whilst putting it all back together again too. There were some interesting mixes of new and old parts - it would have seemed sensible tome to replace the valve caps, collets and ring when fitting new valves, pistons and overhauling the heads with new valve seats. So, some lessons learned, lots more money spent - but it all moves to the background (a bit!) as I was riding round the Isle of Man on such a wonderful bike.

There is certainly no sign of any oil starvation anywhere in the engine to be found.

I'll get the spelling wrong I'm sure, but "caveator emptor" I think is the phrase most appropriate, oh - and "all that glisters is not gold" is another.

The engine is quite a bit quieter now too (surprise, surprise). She started first or second kick all week (after I sheared the shear pin on my electric start) and ran superbly, all after a two week re-build and just two short shakedown runs in the two days before I left.

I plan to have a word with Gary Robinson and see whether there is any merit/way of having the cams and followers tested to see if they can tell a tale.

I'll post the link to Jtan too - as quite a few Jtaners had been helpful along the way too.

Thanks again to Forum members for words of encouragement, suggestions and offers of assistance and spare bikes - great guys.

Stuart
 

pifinch

Well Known and Active Forum Website User
VOC Member
Glad its fixed,your enthusiasm might kick me back into gear, (I've been a bit low on "get up and go" this year) I hope you are through the worst of your learning curve!!
 

BlackLightning998

Well Known and Active Forum Website User
VOC Member
The wonder of riding a Vincent around the IOM

Hi Steve,

Sorry to hear that - I can thoroughly recommend riding a well running Vincent around the Isle of Man as a great tonic - I just felt so privileged to be there at all on the bike given all that had happened. Just so lucky to have had all the help and encouragement to get it all sorted too.

If you can't make the IOM, why not try any local "A" road on a quiet, sunny afternoon and go for a spin - it makes you feel better.

I'm crossing my fingers too on the learning curve - but don't hold your breath.

Cheers

Stuart

Glad its fixed,your enthusiasm might kick me back into gear, (I've been a bit low on "get up and go" this year) I hope you are through the worst of your learning curve!!
 

timetraveller

Well Known and Active Forum Website User
VOC Member
Hi Chaps. This is a very delayed reply to this thread as I have been away until three days ago. The following remarks are specific to a posting by Martinamotor on the 8th August where he states that loading on the valve gear is very high when turning over at low revs and recommends taking a handfull of throttle one started. I am not sure how to respond to this without seeming to be over rude but what a load of ****. For those of you with an interest in this please work out the 'maximum G' force on the valves etc at 6,000 rpm and at 1,000 rpm. If you cannot work it our then guess and after a few days I will tell you what the correct answer is. You are likely to be in for a surprise!

Going back to the original problem of rapid cam and follower wear; assuming that nothing was binding then with any type of oil at all nothing should have worn like that in 4,000 miles. If the cams and followers were both of compatible material, ie both stellited or both case hardened or nitrided then it has got to be inadequate hardening. If the cams or followers will mark with a file then they are not hard enough and Maughans have a hardness tester if you can talk to them.

Sorry if this seems a little harsh but I sometimes wonder where some of these ideas come from.

Cheers
 

macvette

Well Known and Active Forum Website User
Non-VOC Member
Hi, This thing about slow idle speed and kicking the engine over without running it rang a bell with me
Some years ago I rebuilt the engine in my old car (see avatar). It's V8 ohv pushrod so there are some similarities although the cr is 11.25 to 1!
I put an Edelbrock camshaft in and I just dug out the instructions (no I'm not an anorak). They are very adamant on two points. You MUST use the special start up lubricant supplied with the cam, I think it's MOS2 by what's left of it and you MUST NOT allow the engine to run below 2000 rpm for the first half an hour. The instructions contain the warning that slow idle speed on first start up will cause severe cam and lifter wear. They don't give any explanation of why this is so. Edelbrocks are well known and unlikely to suffer from manufacturing/ metallurgical inconsistency so whilst this doesn't rule out these factors in the case of the Vincent engine here, it does point up the possiblity that lubrication and slow running on start up were contributing factors.
Regards Mac
 
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