Am i missing something here?

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john robert bould

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Sep 26, 2009
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Cam shaft lube;
I have not been out on the Commando for 4 weeks [House Improvements]
So i recon when i start the bike ,For oil to get to the camshaf this is the norm; On starting oil is pumped up to the rockers,drips through the spindle's, then drips down the push rod tunnel untill it drips onto the cam...some hundreds of "dry turns" later..or doe's the cam get instant oil from another supply?
 
john robert bould said:
I have not been out on the Commando for 4 weeks [House Improvements]
Click to expand...

Would you expect the cam lobes to be completely bone dry after four weeks?



john robert bould said:
So i recon when i start the bike ,For oil to get to the camshaf this is the norm; On starting oil is pumped up to the rockers,drips through the spindle's, then drips down the push rod tunnel untill it drips onto the cam...some hundreds of "dry turns" later..or doe's the cam get instant oil from another supply?
Click to expand...

What about the oil splash from the crankshaft?
 
L.A.B. said:
Would you expect the cam lobes to be completely bone dry after four weeks?
Click to expand...
Not if you use SAE50 honey.

Dave
69S
 
L.A.B. said:
john robert bould said:
I have not been out on the Commando for 4 weeks [House Improvements]
Click to expand...

Would you expect the cam lobes to be completely bone dry after four weeks?



john robert bould said:
So i recon when i start the bike ,For oil to get to the camshaf this is the norm; On starting oil is pumped up to the rockers,drips through the spindle's, then drips down the push rod tunnel untill it drips onto the cam...some hundreds of "dry turns" later..or doe's the cam get instant oil from another supply?
Click to expand...

What about the oil splash from the crankshaft?
Click to expand...

Bone dry? Well yes, Lubrication law states oil will produce a wedge of oil thats forces the parts apart,[aqua-planeing] if oil is there all the time no wear will take place. I thought only dry start ups caused wear ie metal to metal.......metal-oil-metal...no.
At school we drilled and reamed a hole, poured in a little hole then spun a dowl in it under great load .hours later it was hot ..but no end wear on the peg....metal-oil-metal.
 
john robert bould said:
Bone dry? Well yes,
Click to expand...

So you are saying that if a camshaft was dipped in oil then left for 4 weeks there would be no trace of oil on the lobes?

And what about the splash from the crank? The camshaft is directly in the path of any oil thrown off the crankshaft.
 
Hi all,
I remember reading something by John Hudson where he said that on earlier (Dominator) engines the crank case casting formed a well under the camshaft which always held a puddle of oil so as soon as the cams rotated they picked up oil & therefore never started up dry & cam wear was never a problem, certainly this is the case with my 99. On the Commando engines this well was done away with which meant that if left for a while there was insufficient lubrication on start up untill enough oil had been pumped arround the system, this is when cam wear became an issue. Not sure I'd like to argue with Mr Hudson !
Regards, Tim
 
L.A.B. said:
And what about the splash from the crank? The camshaft is directly in the path of any oil thrown off the crankshaft.
Click to expand...


So whoever designed the wet sumping issue into the oil pump was actually doing us all a favour.
If you leave the bike for four weeks, the cam gets dry ( ish) but the problem is cured by the wet sump splashing oil onto it as soon as the engine starts.
That's called integated design :)
 
john robert bould said:
L.A.B. said:
john robert bould said:
I have not been out on the Commando for 4 weeks [House Improvements]
Click to expand...

Would you expect the cam lobes to be completely bone dry after four weeks?



john robert bould said:
So i recon when i start the bike ,For oil to get to the camshaf this is the norm; On starting oil is pumped up to the rockers,drips through the spindle's, then drips down the push rod tunnel untill it drips onto the cam...some hundreds of "dry turns" later..or doe's the cam get instant oil from another supply?
Click to expand...

What about the oil splash from the crankshaft?
Click to expand...

Bone dry? Well yes, Lubrication law states oil will produce a wedge of oil thats forces the parts apart,[aqua-planeing] if oil is there all the time no wear will take place. I thought only dry start ups caused wear ie metal to metal.......metal-oil-metal...no.
At school we drilled and reamed a hole, poured in a little hole then spun a dowl in it under great load .hours later it was hot ..but no end wear on the peg....metal-oil-metal.
Click to expand...


Thats not quite the whole story, it would be the case if the cam and follower was in a hydrodynamic lubrication regime, the problem is that they are not, without doing the math at start up it is either boundary of mixed lubrication in which case there will not be a complete 'film' of oil separating the two faces, this is where ZDDP and other anti wear/EP additives come into the picture
 
The real problem appears to be "house improvements" cutting into the short driving season . Perhaps winter ?
 
No oil surfing wedge in our cam/lifter contacts, ugh was afraid of that. ZDDP protection comes from the depositing of what's called nano zinc-phosphorous pads, its a thin layer that gets wiped off pretty fast then lube depends on the oil flim or wedge and the nano pads don't reform till in 200'F oil temp range. i assume if it gets to that temp on the metal surfaces then temp of oil coming out of engine can be ignored unless too cold.

Here's dry friction coat i think helped past Peel and will again
http://www.professionalmotorsport-expo. ... 3/pohl.pdf
 
L.A.B. said:
john robert bould said:
Bone dry? Well yes,
Click to expand...

So you are saying that if a camshaft was dipped in oil then left for 4 weeks there would be no trace of oil on the lobes?

And what about the splash from the crank? The camshaft is directly in the path of any oil thrown off the crankshaft.
Click to expand...

Les, I am right in thinking the cam spins towards the crank? thus throwing off the "crank spray"


Also ,Yes i would expect very little oil to be present after a 4 week dip. remember the oil is 50 degress when the engine stops and remains hot for quite a while

My personal opinion is a drip and splash system is never going to do the most important job of OIL COOLING ,the camshaft lobes [as you know ]are the most pressurized surface...heat from friction will be very high..a Spray jet system from the front would ensure the cam is pulling oil into the surface's { NOT THROWING IT BACK} and a good supply ie from the "dump"would COOL it ...
 
john robert bould said:
I am right in thinking the cam spins towards the crank? thus throwing off the "crank spray"
Click to expand...

I honestly don't know.

It would be interesting to observe exactly what was going on inside the crankcase?
Anyone feel like motoring up a Commando crank with the barrels off?
 
L.A.B. said:
john robert bould said:
I am right in thinking the cam spins towards the crank? thus throwing off the "crank spray"
Click to expand...

I honestly don't know.

It would be interesting to observe exactly what was going on inside the crankcase?
Anyone feel like motoring up a Commando crank with the barrels off?
Click to expand...

I have looked into the hole in a 70 fast back crankcase, where a rod had decided it had had enough! must admit the engine was'nt running :lol:
But when the time is right i will make my MK 3 into a pressure feed cam spray...just for the HELL OF IT :twisted:
 
The Olde knorton Knowners Klub in England's recomendation of whipping a bit off the end of the Crankcase Oil Pick up Pipe ,
was said to be to allow an ammout of lubricant to be pressent on Start Up , to fling at akll and sundry components , such as these.
Another recomendation was to face followers smooth , on a good stone , wet & dry on Glass , or lapping paste on glass .
Steady Hand required. NO Tilting . Motion for and aft , i.e. direction of cam lobe travle . At any dismantling to acess .

Combined with efficent Air Filtration & impossing a 6.000 r.p.m.,cieling ( one had the slotted pistons still) Continental
touring had a couple of machines exceeding 100.000 miles without the head being removed . :shock: :D
 
Any Norton I know of- even a MK3 - will have collected enough oil in the sump in 4 weeks time to dip the crank and provide lots of lubrication for start up.
The cam on my Norton is rifle drilled with holes drilled in each lobe. I have an oil line connected to the left end of the cam with a .010 orfice to limit the oil. Seems to work as I have not seen any cam wear since I did this over 20 years ago. I did it after I had two cam failures in one year but I have no doubt they were caused by a poor choice of oil. Jim
 
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