Noisy exhaust valve tip

Rohan · Jul 20, 2013

Bernhard said:
You could, just to double the oil flow, fit a 6 start worm, but check that you have from the timing case that the bolt connecting the oil pipe has a hole that is clear and not blocked.
.

The timing cover of most dommies doesn't even have the port for the pressure oil feed to the rockers.
That would have to be changed, for starters.
And its likely to suffer considerable over-oiling if all the rocker shafts aren't changed to the pressure feed type too.
Otherwise, your oil pressure to the big ends will be somewhat diminished. Not good...

Its odd that the existing feed oil doesn't work its way down this rocker and flow onto the valve tip.
The rocker action usually propels the oil along the rocker.
Why is is different to the others, we wonder....

Bernhard · Jul 23, 2013

Rohan said:
Bernhard said:

You could, just to double the oil flow, fit a 6 start worm, but check that you have from the timing case that the bolt connecting the oil pipe has a hole that is clear and not blocked.
.

Click to expand...

The timing cover of most dommies doesn't even have the port for the pressure oil feed to the rockers.
That would have to be changed, for starters.
And its likely to suffer considerable over-oiling if all the rocker shafts aren't changed to the pressure feed type too.
Otherwise, your oil pressure to the big ends will be somewhat diminished. Not good... quote]

6 start worm will drive oil pump at twice the speed as 3 start, so your quote “Otherwise, your oil pressure to the big ends will be somewhat diminished” Quote; somehow doesn’t make any sense as the oil will be pumped to the big end even quicker, further it will very likely blow off the pipe to the metal Y piece to the cylinder head.
Check the timing cover/oil pump rubber seal, as these will be some aging of these materials, and make sure the all the rocker connector pipe bolts are/have clear oilways in them :!: :shock:

http://www.ebay.co.uk/itm/Norton-Rocker ... 348wt_1170

http://www.nortonclub.com/docs/NortonValveSealTests.pdf

Rohan · Jul 23, 2013

If you don't fit the restricted flow shafts into the top end, all the 'extra' oil will simply gush into the top end.
Thus starving the big ends of PRESSURE.
Since its unrestricted, there will no pressure on the y-branch rocker feed tube either.
With pressure rocker feed, its recommended to fit something like the commando plastic feed line - which is rated for something like 60 psi ?

The timing cover will need changing too, to one that has a pressure feed outlet.

Ever actually played with or owned dommies ??

yasser_fernandez · Jul 24, 2013

What do you mean about "y-branch rocker feed tube". I have fitted a T instead of a Y....Could this be a cause of the problem?

Hobot · Jul 24, 2013

Y or a T fitting is all the same to head oil supply. Its proven well known over a century our type heads just don't need much oil beyond enough to keep things wet and not over heat hanging around cook to carbon. Getting high pressure small hoses in Cuba may be a problem so still seems best solution is tiny hole in the rocker placed to oil dribbles on rocker enough to splash on valve stem. Its well known for over a century that Nortons don't really need at oil pump to feed the big ends just enough oil flow to replace what's slung out. Norton stopped putting oil pressure gauages on big twins when reports soon flooded shops with Zero pressure showing at high way speed, yet nothing bad happened to engine.
Heck thinking back a century they had hand pumps to oil head a few pumps every 10-15 miles depending on loads and mood and memory of pilot.

yasser_fernandez · Jul 24, 2013

It would be impossible for me to open the drill!

Rohan · Jul 24, 2013

hobot said:
Y or a T fitting is all the same to head oil supply.

Yes this is right - and Nortons fitted the T branch type anyway, its just Bernhard used wrong choice of words to call it a Y branch.

Have you tried taking off the oil feeds to the head, one at a time maybe, and check just how much oil comes out each side ?
Each rocker should get a similar amount of oil, and the rocker action works it down the shaft onto the valves.
Doing that fingertip over the outlet into the oil tank to force more oil to the rockers.
It is most odd that one is different to the others....

You don't have ONE restricted flow rocker shaft fitted to your head, do you ??
The standard type is scrolled, for MORE oil flow, for the oil return type oiling system.
You have to actually remove them to see this.
(Head has to be HOT to do this).

Rohan · Jul 24, 2013

Isn't a Nomad head intended for pressure lubrication ??

Could simply be not enough oil is being supplied.
And what little is getting there, from the dribble-feed return system is simply then being restricted - intended as it is for pressure feed.

??

Bernhard · Jul 25, 2013

yasser_fernandez said:
What do you mean about "y-branch rocker feed tube". I have fitted a T instead of a Y....Could this be a cause of the problem?

will make no differance.
I have seen Domis with soldered Y pieces and T pieces, I cannot tell you which fitted which year, -Norton appeared to change the oiling system according to any announcement that it was a new/improved model.

I suggest you remove the top cylinder head oil feeds, put them into a container, start the engine briefly and see if there is oil flowing out of them if yes there is no problem from the oil feed.
The rockers /rocker shaft may have rusted up and blocked the spiral oilways on the rocker shaft, one method that might work is to remove the oval side plates and use a 120psi airline jet on them and observe the air coming out of the other end of the rocker. You will need to remove the rocker/tappet covers for this.
Without the benefit of knowing your bikes history, there is no way of knowing what has happened to it during the last 50+Years. :shock:

Hobot · Jul 26, 2013

from British Iron email listee..

Early Norton twins take the rocker feed off the return side of the oil pump (three start drive worm gear rather than later six start = double speed and volume). Oil is forced up to the rockers by a restriction in the oil pipe inside the tank - basically the end of the return pipe is squeezed flat, forcing the returning oil to spray out to each side, and in turn creating back pressure that forces oil up to the rockers.

If Yasser has modified or changed his oil tank, there may be no restriction in the return, and thus no oil to the rockers.

First thing to check, IMHO.

Mike Randell randell@shaw.ca
supplier of the c*ban nomad head lo these many years ago...

Rohan · Jul 26, 2013

It has been mentioned above that it is quite possible here that the Nomad head involved is required to have pressure feed oiling, and the bike here is set up with dribble feed oiling off the return line.

It has also been suggested to pull the rocker shaft out of the problem valve, and see what is going on in there.
And if its the restricted flow type rocker shaft, or free flow type.

Otherwise, we are just going around in circles ?

Hobot · Jul 26, 2013

references state the 3 start pump was changed to 6 start in 1966. Also came across a reference on model 99's using a rocker misting method to oil valve stem.

Rohan · Jul 26, 2013

Nomads oiling system was not like other Nortons.
He still needs to pull out a rocker shaft, and see if its scrolled or oil restricting type.
AND measure oil flow out of the oil lines to each side of head...

BTW, what makes owner say this is a Nomad head ?

Tomato man · Jul 27, 2013

Rohan, his Nomad head was donated by a Norton owner in BC. The Nomad head was shipped to him to replace his much worn Dommie 99 head.
TM

Tomato man · Jul 27, 2013

COuld it be that this valve oiling problem is as simple as..... a very poor hole alignment of the access hole in banjo bolt to the inlet hole in the encircling banjo fitting ... where the oil is provided?

Would it help to open up the entry hole in the banjo bolt for less oil restriction?

ANd could copper crush washers be replaced on the banjo bolt to position the hole in the banjo bolt ...closer to the entry hole from the banjo fitting?

Every time the inflowing oil hits some obstruction through its passage into the banjo bolt to the head ..oil flow is going to slow going to the rockers.

Perhaps it could be enough of a pressure change to alter the flow path of the oil to the valve stem.

Ed

Rohan · Jul 27, 2013

Tomato man said:
COuld it be that this valve oiling problem is as simple as..... a very poor hole alignment of the access hole in banjo bolt to the inlet hole in the encircling banjo fitting ... where the oil is provided?
Would it help to open up the entry hole in the banjo bolt for less oil restriction?
ANd could copper crush washers be replaced on the banjo bolt to position the hole in the banjo bolt ...closer to the entry hole from the banjo fitting?
Every time the inflowing oil hits some obstruction through its passage into the banjo bolt to the head ..oil flow is going to slow going to the rockers.
Perhaps it could be enough of a pressure change to alter the flow path of the oil to the valve stem.
Ed

Good suggestions.
But sufficient ?? oil flow to 3 valves, and poor flow to one valve suggests something else is going on ?

We have not heard back if he has actually measured or eyballed the flow out of each side of the T pipes up to the head.
Or pulled that rocker spindle to look at.

Thanks TM for the nomad head supply update.

Chris_van_p · Feb 1, 2014

check shaft alignment of the troubled valve, if rockershaft is turned the shaft itself blocks oilpassagehole. The oval plate should have 2 little stubs that fixates the shaft from turning. These stubs do break of sometimes making it possible for the shaft to turn from its indexed position

Noisy exhaust valve tip

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