Yes and no. True that when measuring clearances you are dealing with the un-worn, un-touched heal of the cam but also the follower which will be worn to a degree by a "south going" cam lobe. My MK3 was running fine when I took it down to investigate fine metal filings on the magnetic sump plug. I was also needing to adjust one intake valve down way too often even as the others remained OK. It did have lobe on the way out and a corresponding pitted follower.SteveBorland said:
Metal shavings in oil after first 100 miles
- Thread starter ag12680
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Thanks everyone for weighing in here. I wrote this post while waiting to hear back from my engine builder who is at Daytona this week. In the meantime, I found a local builder with 56 years of Brit and Norton experience.
I am writing this so it will show up in the Google search results for anyone else who wants to avoid my mistakes and the angst from seeing metal shavings.
First, despite searches here and elsewhere I put high quality non synthetic 20/50 to break the motor in. Both builders told me to drain it and put in straight non detergent 30 weight. When I finally found this oil it was covered with dust in a completely different section of the auto parts store. Then; run it 60-100 miles in 5 heat cycles staying below 4K RPM while interval loading the motor to build cylinder pressure. This is why I found the swarf at 100 miles in the first place.
Perhaps with more miles the motor would have broken in with the heavier weight oil, but both guys said that in the early days when these bikes were new and some would burn oil the factory would tell them to run 30ND.
Second, both told me to check the compression for even readings (with and without oil in the cylinders). Check that the valve lash was not too tight. If good, then put in the 30 weight and run for one heat cycle (20 miles) and drop the plug to inspect the strainer. I did that and found no remaining swarf at all. Also, on the MkIII there is an additional drain plug beside the large strainer plug that has a factory magnet. The compression was 70/90 without oil and 130/130 with oil so basically the rings were not seated. Possibly the piston to cylinder wall clearance is too much and/or the end gaps too wide. Did not get these number from the builder.
So, my plan is to leave the 30 weight in for four more heat cycles, drop the oil and inspect the strainer. If clear then go back to the 20/50. I will also check the compression which I was told should be around 145 with seated rings. If low and no more shavings, smoke or losing oil I'm just going to run it with more frequent oil changes to monitor the situation.
There was no way to clean the bottom end with it not being pulled apart so in all likelihood the metal was already there trapped on the magnet that I overlooked or elsewhere.
Jim C. called it when he told me not to worry about it (albeit the cam issue).
Thanks,
Andy --
I am writing this so it will show up in the Google search results for anyone else who wants to avoid my mistakes and the angst from seeing metal shavings.
First, despite searches here and elsewhere I put high quality non synthetic 20/50 to break the motor in. Both builders told me to drain it and put in straight non detergent 30 weight. When I finally found this oil it was covered with dust in a completely different section of the auto parts store. Then; run it 60-100 miles in 5 heat cycles staying below 4K RPM while interval loading the motor to build cylinder pressure. This is why I found the swarf at 100 miles in the first place.
Perhaps with more miles the motor would have broken in with the heavier weight oil, but both guys said that in the early days when these bikes were new and some would burn oil the factory would tell them to run 30ND.
Second, both told me to check the compression for even readings (with and without oil in the cylinders). Check that the valve lash was not too tight. If good, then put in the 30 weight and run for one heat cycle (20 miles) and drop the plug to inspect the strainer. I did that and found no remaining swarf at all. Also, on the MkIII there is an additional drain plug beside the large strainer plug that has a factory magnet. The compression was 70/90 without oil and 130/130 with oil so basically the rings were not seated. Possibly the piston to cylinder wall clearance is too much and/or the end gaps too wide. Did not get these number from the builder.
So, my plan is to leave the 30 weight in for four more heat cycles, drop the oil and inspect the strainer. If clear then go back to the 20/50. I will also check the compression which I was told should be around 145 with seated rings. If low and no more shavings, smoke or losing oil I'm just going to run it with more frequent oil changes to monitor the situation.
There was no way to clean the bottom end with it not being pulled apart so in all likelihood the metal was already there trapped on the magnet that I overlooked or elsewhere.
Jim C. called it when he told me not to worry about it (albeit the cam issue).
Thanks,
Andy --
Fast Eddie
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If its not smoking, and not rattling, and is running well, and especially if its a bike that you intend to use fairly easily and fairly lightly, I would certainly not strip it.
If you're building a serious racer or high mileage tourer then its a different story and needs stripping and rebuilding with a high degree of care.
But I would venture to gamble that you could leave this bike alone and enjoy many more thousands of miles from it.
I would however use a high quality oil with a high zinc content in order to protect the cam and followers as much as possible. Lots of opinions on the best oil. My personal preference is Red Line (but you must buy the specific motorcycle oil to ensure the high zinc content).
If you're building a serious racer or high mileage tourer then its a different story and needs stripping and rebuilding with a high degree of care.
But I would venture to gamble that you could leave this bike alone and enjoy many more thousands of miles from it.
I would however use a high quality oil with a high zinc content in order to protect the cam and followers as much as possible. Lots of opinions on the best oil. My personal preference is Red Line (but you must buy the specific motorcycle oil to ensure the high zinc content).
Fast Eddie
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DogT said:
One needs to check before buying / assuming. Last time I checked the oil you mention, it did have high zinc and looked good. However, oil by the exact same name in UK had very low zinc, I have no idea why, but it goes to show its best to check.
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DogT said:
That is what John Favill recommended to me at the rally in Asheville, it is Series SJ oil, full synthetic.
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Personally I expect to find a few bits and pieces in the piston ring catching oil so called filter in the crank cases whose only real purpose is to stoplarge bits getting back to the pump to damage it ....this filter being a feature some expert (exspurt) removed on Combat motors......let us not forget!1
As for the cam wear.... At one time the clever souls at NVT somehow managed to manufacture soft / incorrectly hardened cams. Without going up into my cold loft to retrieve one still with its GENUINE NORTON SPARES wrapping to read the label attached to it from memory its surface hardness was around 320 ish Vickers while the new 4s can on a shelf behind me has a surface hardness of ..turning around and looking at the attached label...626 Vickers.
However everyone is missing the major cause of cam and follower wear and personally I am rather ****** off telling Norton owners / people the following tale....
When Mr Hopwood and friends designed the original Dominator engine they knew that cams require CORRECT lubrication if they are to give satisfactory service. They also knew that the major problem is ensuring the cam and followers received correct lubrication from the very first moment of rotation otherwise galling takes place and once galling has occured premature cam failure is ensured....SO.....Mr Hopwood and friends designed into the crankcases a camshaft oil bath to ensure the lobes of the cam dipped into the RETAINED oil from the very first moment of rotation thus ensuring correct lubrication between the cams and followers from the very firstmoment of rotation. It was NOT rocket science and was cheap and easy to include at the design stage. For all those who do NOT believe I will now quote Mr Hopwoods letter to me on the subject dated 21st July 1981 and I quote.....
'The camshaft tunnel of the Dominator was designed to retain as much oil as possible and in fact collected oil from the flywheel rim. i would suggest that you make your fabricated elements from sheet aluminium of fairly substancial guage , say 14g (0.080) and also let the flywheel rim run within about 3/32 to 1/8 inch of the flywheel face.'
HINT. On later motors with the 1 3/4 big ends the rods can foul the tunnel so remember this as you play replacing it rather than finding outafter replacing it!
Of course the tunnel would also collect AND RETAIN oil flowing back down past the cam followers. .....tThus the very first time the cam rotates the lobes collect oil from the oil bath ensuring correct lubrication between the cam and follower. As the Piper Cams tuning notes book states and once again I quote.....Page 36 ....
Research indicates that most cams that wear out start to fail during the first few momements of operation. We have found that many cams are irrepairably damaged before the engine is started because basic rules of camshaft break-in have not been followed. The cause of premature caqm and tappet failures is metal to metal contact between the tappet and cam lobe. Should this contact occur due to lack of proper lubrication or excessive ly high pressure due to valve train interference shearing the oil film, galling takes place. When galling takes place, metal is tranferred from the cam to the tappet or from the tappet to the cam in a process comparable to welding . Small areas (microscopic high spots present on all machined parts) become over heated due to friction and over pressure and bond together, tearing section loose from the tappet or cam lobe. These pieces of metal remain attached to the face of the tappet or cam lobe and create further local overheating during further revolutions of the camshaft and lead to ultimate failure of the effected cam and tappet'.
Now the Dominator engine , designed as a 500 twin, underwent lots of rebirths as a 600, then a 650 then a 750 then an 820 lump and all required new crankcases which required new patterns and the people in charge by that time forget or were totally unaware as to the reason for the camshaft oil bath tunnel and so it was slowly removed with each new version of crankcase patterm made...It is an interesting exercise to lay out unmodified various editions of crankcase and watch the tunnel vanish rather like the talew we once had ...if you look at your Mk3 cases you will find a lump of useless alloy beneath the cam which was originally part of the camshaft oil RETAINING tunnel !
It wasnt just Nortons who cocked it up..at one time 25% or so of all 650 Triumph twins were having their exhaust cams changed for free under the warrenty period due to lack of lubrication. The triumph bodge was to nitride the cams making them as hard as glass and if you are careless enough to drop one you can, so I have been told on a few occasions over the years, flake off a bit of the surface. Unfortunately with the exhaust cam at the fromt of the motor most of the oil being flung off the crank lubricates the inlet can in the rear and the bores leaving little to lubricate the exhaust cam or in the case of Nortons THE CAM which is probably why the BSA lumps had the cam in the rear and why Mr Hopwood included the camshaft oil bath into his Norton crankcases in the first place!!!
I can see NO reason why a correctly manufactured installed and lubricated Norton cam should not last 50,000 miles PLUS with zero problems although I am talking STANDARD cams and not those rediculous go faster, or often slower, high lift versions which increase the loadings on the cam and followers somewhat .... even a 650SS profile cam works very well for racing when combined with correctly designed inlet and exaust systems etc......
Of course in my young days we had as many Norton tuning expertts and exspurts around as there are now and in the Paul Dunstall tuning guide (Chapter IV) there is a picture of someone armed with a rotary file removing meat from the remains of the camshaft tunnel to allow for a higher lift cam to fit and in so doing was removing any of the oil retaining the tunnel might possibly of had by that time. Observant readers will note the in the CAMWSHAFT DESIGN chapter a picture of a cqam with holes in each lobe allowing positive pressure fed lubrication of the cam which required the 6 start worm gear set to double the speed of the pump so as to maintain correct crank oil supply on the Domirace motors....the 6 start worm becoming a tuning go faster modification every one had to have!! Jeoff Monty and Dudly ward on their Triumph engined MONARD race motors also included a positive oil supply to the cams which required a new gear oil pump (Norton) and a new timing cover. all manufactured by an ex AMC race mechanic (Tommy Mortimer). On later motors attacking the tunnel with a rotary file was not required because the idiots had totally removed the oil retaining tunnel by then and funnily enough cam problems only really began as the tunnel was being reduced I bet the more it was reduce4d the greater the cam problems....NOT that anyone cared because that way they sold more cams and followers.........AND ARE STILL DOING SO. if the info a friend gave me as to the numbers still being produced is to be believed.
The pictures of that cam showing wear. I have seen high mileage cams out of olde 500cc motors (with camshaft oil baths) that look as good as new. In fact it was in taking the head and barrel off of a friends vintage chamionship winning 77 motor many decades ago and UNEXPECTIDLY finding the cam and followers in perfect condition and upon wondering / investigating why and finding the cam was picking up oil from the tunnel even thnough the motor had sat on the floor for years with the oil filter / plug removed that had me thinking about the oil bath which resulted in my consulting Mr Hopwood.
One friend 'in the trade' of repairing and preparing road and race Nortons for customers has been known to replace the oil bath but as he does not enjoy doing the job and I have been told NOT to mention his name or company. Personally I do not understand why someone with a mill and welding gear has not set up a little business replacing the oil bath but I guess there would have to be various versions depending upon the cam to be used......However having the oil bath replaced must be a lot cheaper than a couple of new cams and especially followers......
So now another one or two owners might possibly know a bit more about Norton twins and one of the many cock ups Norton / AMC / NVT made.
A great many years ago when visiting NVT at Shenstone or was it Andover?? Mr Negus showed us the first off new Commando crank cases made using the new patterns they had had produced (the old ones having been scrapped on the orders of previous mismanagement under the impression that they would never be producing such old crap in the future.... BSA mismanagement ordered all Gold Star drawings be burnt in a skip..luckily others had different ideas and saved many of them and they still reside in Birmingham some not yet sorted some being linen drawings!!). I looked at these new super dooper crankcases and asked Mr Negus ' OK so where is the camshaft tunnel?' . I was then asked to explain so I did quoting Mr Hopwoods letter. On another visit I was told it was far too expensive to modify the patterns to include it so I assume new crank cases do not include this rather important design feature?? Not that old farts like me can afford new crank cases BUT the camshaft tunnel is most certainly included in the rather modified crankcases destined for the 68 x 68 500cc short stroke 90 degree crank motor sitting in my garage in bits awaiting my shoving it all together OR my death in which case it will never get shoved together.. by me anyway!! And YES the better half does know how much the one piece 90 degree crank etc etc cost me....... I even have some new old stock lumps of blown Dommy alloy pushrods for use in the motor and was told by a friend the other week that they are lighter than titanium ones.....
And while you have the crank in bits dont forget to check the drive side half by looking inside it to ensure that the sharp edge of the drill they employed to clean it out has NOT left its sharp outer edge diredctly beneath the big ends outer 90 thou stress reducing radius thus introducing into the crank a stress raiser directly beneath the stress REDUCING 90 thou radius.......If it is directly beneath get the D.S. half X rayed because it could well be on its way to failure and from personal experience 4 piece cranks make rather a mess of the moror. Oh yes the crankshaft drawings were correct and put the stress raiser well into the web where it would do no harm as can be seen on the drawing of the 650 unit construction Dommy motor shown in Classic Bike (September 2004 page 33) but my money is on the workers being on piece work rates and it took longer to do the job to drawing so it was not done to drawing plus of course quality control and inspection were probably as good at AMC and NVT as in the British defence industry (In my experience that is)....Mr Negus had the drawings checked and found them correct but had them modified to show in larger print or something the importance of correctly machining the inside of the D.S. crank.....Not that they were going to produce any as the small batch they had Wonder what happened to the bins full of forgings?? my money woupld be they went into the scrap.... I was told that in putting the stress raiser into the web and thus removing a bit more metal had not effected them balancing the crank correctly.....
Nortons are an Engineering learning curve and one has learnt a bit but by that time you are usually old and past riding the lumps.....as a friend advises older owners asking which Norton they should next buy.....Go out and buy a good low mileage 650 Kwaka or Suzuki twin. It will go faster, stop quicker, handle as well, require a lot less maintenance AND start on the button every time.......... not as pretty as a black and silver wideline or even slimline Dommy mind you.......in my opinion that is but I am biased.
No spell or grammer checks done its time to watch the Moto GPS for the next 4 hours!!!
As for the cam wear.... At one time the clever souls at NVT somehow managed to manufacture soft / incorrectly hardened cams. Without going up into my cold loft to retrieve one still with its GENUINE NORTON SPARES wrapping to read the label attached to it from memory its surface hardness was around 320 ish Vickers while the new 4s can on a shelf behind me has a surface hardness of ..turning around and looking at the attached label...626 Vickers.
However everyone is missing the major cause of cam and follower wear and personally I am rather ****** off telling Norton owners / people the following tale....
When Mr Hopwood and friends designed the original Dominator engine they knew that cams require CORRECT lubrication if they are to give satisfactory service. They also knew that the major problem is ensuring the cam and followers received correct lubrication from the very first moment of rotation otherwise galling takes place and once galling has occured premature cam failure is ensured....SO.....Mr Hopwood and friends designed into the crankcases a camshaft oil bath to ensure the lobes of the cam dipped into the RETAINED oil from the very first moment of rotation thus ensuring correct lubrication between the cams and followers from the very firstmoment of rotation. It was NOT rocket science and was cheap and easy to include at the design stage. For all those who do NOT believe I will now quote Mr Hopwoods letter to me on the subject dated 21st July 1981 and I quote.....
'The camshaft tunnel of the Dominator was designed to retain as much oil as possible and in fact collected oil from the flywheel rim. i would suggest that you make your fabricated elements from sheet aluminium of fairly substancial guage , say 14g (0.080) and also let the flywheel rim run within about 3/32 to 1/8 inch of the flywheel face.'
HINT. On later motors with the 1 3/4 big ends the rods can foul the tunnel so remember this as you play replacing it rather than finding outafter replacing it!
Of course the tunnel would also collect AND RETAIN oil flowing back down past the cam followers. .....tThus the very first time the cam rotates the lobes collect oil from the oil bath ensuring correct lubrication between the cam and follower. As the Piper Cams tuning notes book states and once again I quote.....Page 36 ....
Research indicates that most cams that wear out start to fail during the first few momements of operation. We have found that many cams are irrepairably damaged before the engine is started because basic rules of camshaft break-in have not been followed. The cause of premature caqm and tappet failures is metal to metal contact between the tappet and cam lobe. Should this contact occur due to lack of proper lubrication or excessive ly high pressure due to valve train interference shearing the oil film, galling takes place. When galling takes place, metal is tranferred from the cam to the tappet or from the tappet to the cam in a process comparable to welding . Small areas (microscopic high spots present on all machined parts) become over heated due to friction and over pressure and bond together, tearing section loose from the tappet or cam lobe. These pieces of metal remain attached to the face of the tappet or cam lobe and create further local overheating during further revolutions of the camshaft and lead to ultimate failure of the effected cam and tappet'.
Now the Dominator engine , designed as a 500 twin, underwent lots of rebirths as a 600, then a 650 then a 750 then an 820 lump and all required new crankcases which required new patterns and the people in charge by that time forget or were totally unaware as to the reason for the camshaft oil bath tunnel and so it was slowly removed with each new version of crankcase patterm made...It is an interesting exercise to lay out unmodified various editions of crankcase and watch the tunnel vanish rather like the talew we once had ...if you look at your Mk3 cases you will find a lump of useless alloy beneath the cam which was originally part of the camshaft oil RETAINING tunnel !
It wasnt just Nortons who cocked it up..at one time 25% or so of all 650 Triumph twins were having their exhaust cams changed for free under the warrenty period due to lack of lubrication. The triumph bodge was to nitride the cams making them as hard as glass and if you are careless enough to drop one you can, so I have been told on a few occasions over the years, flake off a bit of the surface. Unfortunately with the exhaust cam at the fromt of the motor most of the oil being flung off the crank lubricates the inlet can in the rear and the bores leaving little to lubricate the exhaust cam or in the case of Nortons THE CAM which is probably why the BSA lumps had the cam in the rear and why Mr Hopwood included the camshaft oil bath into his Norton crankcases in the first place!!!
I can see NO reason why a correctly manufactured installed and lubricated Norton cam should not last 50,000 miles PLUS with zero problems although I am talking STANDARD cams and not those rediculous go faster, or often slower, high lift versions which increase the loadings on the cam and followers somewhat .... even a 650SS profile cam works very well for racing when combined with correctly designed inlet and exaust systems etc......
Of course in my young days we had as many Norton tuning expertts and exspurts around as there are now and in the Paul Dunstall tuning guide (Chapter IV) there is a picture of someone armed with a rotary file removing meat from the remains of the camshaft tunnel to allow for a higher lift cam to fit and in so doing was removing any of the oil retaining the tunnel might possibly of had by that time. Observant readers will note the in the CAMWSHAFT DESIGN chapter a picture of a cqam with holes in each lobe allowing positive pressure fed lubrication of the cam which required the 6 start worm gear set to double the speed of the pump so as to maintain correct crank oil supply on the Domirace motors....the 6 start worm becoming a tuning go faster modification every one had to have!! Jeoff Monty and Dudly ward on their Triumph engined MONARD race motors also included a positive oil supply to the cams which required a new gear oil pump (Norton) and a new timing cover. all manufactured by an ex AMC race mechanic (Tommy Mortimer). On later motors attacking the tunnel with a rotary file was not required because the idiots had totally removed the oil retaining tunnel by then and funnily enough cam problems only really began as the tunnel was being reduced I bet the more it was reduce4d the greater the cam problems....NOT that anyone cared because that way they sold more cams and followers.........AND ARE STILL DOING SO. if the info a friend gave me as to the numbers still being produced is to be believed.
The pictures of that cam showing wear. I have seen high mileage cams out of olde 500cc motors (with camshaft oil baths) that look as good as new. In fact it was in taking the head and barrel off of a friends vintage chamionship winning 77 motor many decades ago and UNEXPECTIDLY finding the cam and followers in perfect condition and upon wondering / investigating why and finding the cam was picking up oil from the tunnel even thnough the motor had sat on the floor for years with the oil filter / plug removed that had me thinking about the oil bath which resulted in my consulting Mr Hopwood.
One friend 'in the trade' of repairing and preparing road and race Nortons for customers has been known to replace the oil bath but as he does not enjoy doing the job and I have been told NOT to mention his name or company. Personally I do not understand why someone with a mill and welding gear has not set up a little business replacing the oil bath but I guess there would have to be various versions depending upon the cam to be used......However having the oil bath replaced must be a lot cheaper than a couple of new cams and especially followers......
So now another one or two owners might possibly know a bit more about Norton twins and one of the many cock ups Norton / AMC / NVT made.
A great many years ago when visiting NVT at Shenstone or was it Andover?? Mr Negus showed us the first off new Commando crank cases made using the new patterns they had had produced (the old ones having been scrapped on the orders of previous mismanagement under the impression that they would never be producing such old crap in the future.... BSA mismanagement ordered all Gold Star drawings be burnt in a skip..luckily others had different ideas and saved many of them and they still reside in Birmingham some not yet sorted some being linen drawings!!). I looked at these new super dooper crankcases and asked Mr Negus ' OK so where is the camshaft tunnel?' . I was then asked to explain so I did quoting Mr Hopwoods letter. On another visit I was told it was far too expensive to modify the patterns to include it so I assume new crank cases do not include this rather important design feature?? Not that old farts like me can afford new crank cases BUT the camshaft tunnel is most certainly included in the rather modified crankcases destined for the 68 x 68 500cc short stroke 90 degree crank motor sitting in my garage in bits awaiting my shoving it all together OR my death in which case it will never get shoved together.. by me anyway!! And YES the better half does know how much the one piece 90 degree crank etc etc cost me....... I even have some new old stock lumps of blown Dommy alloy pushrods for use in the motor and was told by a friend the other week that they are lighter than titanium ones.....
And while you have the crank in bits dont forget to check the drive side half by looking inside it to ensure that the sharp edge of the drill they employed to clean it out has NOT left its sharp outer edge diredctly beneath the big ends outer 90 thou stress reducing radius thus introducing into the crank a stress raiser directly beneath the stress REDUCING 90 thou radius.......If it is directly beneath get the D.S. half X rayed because it could well be on its way to failure and from personal experience 4 piece cranks make rather a mess of the moror. Oh yes the crankshaft drawings were correct and put the stress raiser well into the web where it would do no harm as can be seen on the drawing of the 650 unit construction Dommy motor shown in Classic Bike (September 2004 page 33) but my money is on the workers being on piece work rates and it took longer to do the job to drawing so it was not done to drawing plus of course quality control and inspection were probably as good at AMC and NVT as in the British defence industry (In my experience that is)....Mr Negus had the drawings checked and found them correct but had them modified to show in larger print or something the importance of correctly machining the inside of the D.S. crank.....Not that they were going to produce any as the small batch they had Wonder what happened to the bins full of forgings?? my money woupld be they went into the scrap.... I was told that in putting the stress raiser into the web and thus removing a bit more metal had not effected them balancing the crank correctly.....
Nortons are an Engineering learning curve and one has learnt a bit but by that time you are usually old and past riding the lumps.....as a friend advises older owners asking which Norton they should next buy.....Go out and buy a good low mileage 650 Kwaka or Suzuki twin. It will go faster, stop quicker, handle as well, require a lot less maintenance AND start on the button every time.......... not as pretty as a black and silver wideline or even slimline Dommy mind you.......in my opinion that is but I am biased.
No spell or grammer checks done its time to watch the Moto GPS for the next 4 hours!!!
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