Further to some previous posts, my '66 650SS seems to be over oiling the rockers. Just to clarify, should the flats on the rocker spindles face in towards the centre of the engine, or out towards the rocker covers?
david.....the flat should face away from the centre of the head.i had the same issue as you some years ago.A favourite mod years gone by was to replace the [spiraled] dommi rocker spindles.
with atlas/commando [plain] spindles.and move the oil feed pipe from near the oiltank and have it feed from the timing cover as per commando just below the pressure release dome nut.
also check that you have three start oil pump gears.some poeple fitted six start gears as per the atlas/commando.and that can cause over oiling....
hello if your having over oiling issues this could be down to the small oil holes being blocked. As Most of the oil runs down the pushrod tunnels on the exhaust side and the rest runs down an oil hole at the inlet side that goes down the side of the right side inlet valve spring and down the back of the barrel and into the timing case, so something is blocked somewhere and needs a clean now have fun yours anna j
Hi David mine had the intermediate type plain rocker spindles with the no flat. Upgraded to the plain type with the flat which faces outward (away from the inside of the head) with the 6 start oil pump as per Commando. My issue was the spindles were turning in the head due to the interferance fit being lost over the years.
Actually got the same issue on my Commando when I came to strip it they were turning on that to and sat to deep on both bikes to engage with the tangs on the spindle covers.
If they arn't turning the book recommends heating the head, mine were spinning very freely on a cold engine hence the issues.
On my 650 SS some had worn into the head deeper as they had been turning so were all set at different positions ended up using a kit from RGM that stopped them spinning thanks to the adjustable allen keys. Norvil also do some with longer tangs.
Some video clips up on my youtube channel about when I did it with my 650SS. If you put norton.rider rocker spindles into the youtube search
Hope this helps,
Have checked flow through the head/barrel drain holes. All clear. Thank you for the tip Anna.
Just pulled the rocker spindlesout to check their positions (no heat required, somewhat alarmingly), and Lo! and behold, I have the unscrolled plainn spindles, but no flats, just a hole. I assume that the hole will face the rocker covers, the same as the other ones with flats on. Incidentally, did the new spindles fit tighter in the head? All my current ones had remained with the slots on the ends in the correct position.
Rocker shafts should be a tight fit in the head when cold, this is refered to as an interference fit , they should never be removed or replaced without first warming the head, removing and replacing them cold will gradually enlarge the locations untill they become loose.
Rocker shafts can move inwards from new when the engine is at working temperature, they then dislocate from the end plates and can rotate, this will cut the oil feed off. To overcome this a dummy shaft can be made, this can be used to determine the ammount by which the shaft is moving , a spacer is then made and placed behind the shaft bringing the outer end flush with the outside surface of the head.
Rocker shafts:- To turn or not to turn, this problem appears to have been caused in the past by an issue with an excess of oil in the head , brought on no doubt by the improved oil pump output and the now positive feed to the rockers.
The hole in the rocker shaft was always intended to feed oil directly into the rocker and thence to the pushrod cup. The flat is to allow an uninterupted flow into the rocker when it is moving. Turning the shaft will effectively turn the tap off making the pump improvement somewhat negative.
Someone decided when the oil problem arose that a quick fix could be made by turning the rocker shaft , it appears that it worked , the modification was put in "the book" and from then on it became the rule to be followed by owners and "experts" alike. This modification might have solved the problem but it raised another one which seems either to have not been recognised or has been totally ignored .
The answer to over oiling is not to turn the shaft round , but to increase the drainage from the head.
Turning the rocker shaft reduces the flow of oil through the rocker and to the cam and followers this results long term in severe damage to both of these components.
Currently, I'm told, these parts are in short supply, if you need to replace them you'll not get very much change out of £700 if and when you can get them.
So, read all the advise and the final decision about you shafts is your's.
On Dommies and Atlas the Inlet side does not drain well ,there is a hump in the middle of the head so oil has to find its way down the small drain hole, With the high pressure system and the shaft holes facing the pushrods there can be too much oil at the inlet valves and it gets drawn in.I would have thought that facing the holes away from the pushrods would increase the pressure and force oil along the rocker bushes giving better lubrication to them. The cam tunnel trough gives good lubrication to the cam (except for those silly enough to have removed it!) .I have fitted oil seals to our Atlas inlets which may solve the issue. I may have to do the same to the 99 which is also now getting a bit too much oil on the plugs since I "improved" it.
We seem to be talking about two systems here, the three start and the six start. With the three start system and the "hit and miss" feed to the rockers flooding was never a problem, but the oil trough was very important because without it the cam will wear out. Problems with flooding seemed to start with the enlargement of the pump gears and the addition of the six start drive gear. As already mentioned turning the shaft was a quick fix but not the answer. What's the point of increasing the oil flow and then cutting it down by turning the shaft round with the eventual result of damaging the cam. Why do they continue to put the flat on new rocker shafts? Turn the shaft round and the flat serves no further purpose.
No the flooding is not the problem, ineffective drainage which is causing the flooding is the problem.
The spindle flats serve as small reservoirs. Once the engine is running the camshaft then receives a combined splash, drip and oil mist feed. The motion of the pistons helps with lubrication of all the bottom end due to what is known as the 'bellows' effect. ie. the pushing of oily gases around the crankcases. This also works in the timing cover. If you look carefully you will note small feed holes that point at all the chains and gears. They look like drain holes but also serve as part of the oil feed system when the pistons descend. This arrangement worked fine for the early Dominators and only gives problems when people mess around with the breathing system.
The spindle flats may operate as a reservoir but that is not why they are there. They are so there is a continuous feed to the pushrod ends of the rockers arms. With them turned round, there is very little oil going that way.
Without this there is very little oil running down the pushrod tubes and hence on to the camshaft. The camshaft will be lubricated by splash and mist but the more oil you can get onto it the better.
The proper fix is to enable the oil to get out of the head, not stop it getting there in the first place.
I may expand on this when time allows.
Its amazing that such an obscure and almost irrelevant detail on some outdated old engine can occupy the thoughts of so many intelligent and creative people. We should all get out more, but not yet , crappy weather.
The trough that is mentioned may not add that much to the lubrication, but maybe more a function of other need for oil, heat removal. The nose of the lobe will be very hot as it has passed the tappet, and thus the cooling hit in the the trough helps keep the cam lobe cool. The lobe can get hot, I have a microscope photo of a tappet wearing molten cam, the tappet was not even affected by the heat, it could be refaced and reused.
One thing I have noticed is that standard cams fail more than performance cams, the higher the lobe the more chance of hitting oil.? Any oil that is hit in the trough by the lobe I suspect would be flung off, or splash / airborne oil takes over, so the trough may not add much to the lubrication.
Varying crankcases have varying troughs, and you can easily check this with the cases in a vice.
Having seen the build up of oil above the tappets and how slow it drains past them, I would prefer the oil to be doing a job and not just sat there.
Looking forward to Tony's expansion. I know a lot of thought and work will have gone into it.
Could it be that the current manufacturers of the "performance cams" pay more attention to the heat treating and materials than did the factory?
No, because they also make the standard cams as well.
My 60 year old cams and followers are still in perfect nick after a life of riley bathing in their trough.
Hi Team- New to the NOC- this is my first post.
I have a bone stock 1966 650ss that I just restored- Got it as a basket case- now she lives! No more than 50 gentle miles on it in several short trips. When she gets hot- we get a nasty metallic chafing sound developing in the left hand exhaust valve area- . Spray a little lube on the valve spring/stem and it goes away.... temporarily.... I'm watching in there while she runs, and I don't see whole lot of oil flowing down the pushrods- nor do I see whole lot of "mist" being generated in the front . A little oil oozing out the ends of the rockers/spindles where they meet the case and drooling down the sides but that's it. There doesnt seem to be much reaching the valve springs/stems Plenty of oil in the back , i.e. -the intake valves- its even pooling up a bit around the base of the valve guide and lots of "splash"- Three mins with it running with the cover off and it gets the tops of the carbs wet with oil. ... but none of that is happening in the front. Not sure what action would be generating the "mist" necessary to wet the exhaust valve stems in the first place. Seems like it should be a lot wetter up front there. Now, I didn't do the motor- I sent it to a chap who I know/ trust very much and he did the work. But I am guessing I should pull the rocker spindles and suss it out. Blow everything out clean and start again So -Here's my questions: -Can I pull them without removing the head?
And on a late 66 with ( I am guessing) the 6 start pump, what type of spindles should be in there? Are there any upgrades/tricks that you would suggest?
Sounds like the small oilways are pretty blocked ,if its a high pressure system there should be plenty of oil. You are going to have to see what you have. Its all accessible without removing the head.Its possible that just the inlet spindles are facing the wrong way and diverting the oil.
Hello Tristan, you say you have a problem once the engine is warm , to hear a scuffing sound above the sound of the engine suggests it might be something other than a tight unlubricated valve, and yet, as you say, the sound goes away with the addition of oil. Is it likely to be an assembly problem, how conversant with the Norton engine is your engine builder? There is an oil drain hole in the rear right hand side of the cylinder head that drains oil back to the timing case, if the cylinder base gasket were to be put on incorrectly the crankcase hole would be covered and the oil would build up in the head , not all gaskets are both left and right handed, there is a similar hole in the head gasket. The other end of this drain hole can be accessed from the rear of the timing chest, a low pressure air jet directed into this hole should tell you if it is clear. A lot of members seem to suffer over oiling within the cylinder head and follow the instructions in " the book" to rotate the rocker shaft so that the oil hole faces away from the pushrods. This will restrict the oil flow into the rocker arm and produce the effect you have seen of oil squeezing out of either end of the rocker. I think you definitely need to carefully dismantle the head, taking notes or pictures as you do so. I don't know when it was done, but later engines have oil drain holes in the exhaust valve pockets, these are so effectively masked by the spring seats as to be almost useless. I have within this thread a couple of posts which I had hoped might explain some of the problems with the valve gear and how to overcome them , it might be worth glancing through them again .
Good luck with the investigations, Cheers, Ian
PS:- Try and warm the head before withdrawing the rocker shafts, it's not good to remove or replace them cold, localised heating with a hot air gun usually works.
Thanks very much Robert. That's where I will start.
Thanks very much for the detailed reply Ian, much obliged.
One question to clarify: should the rocker spindles NOT have the hole facing away from the pushrod then?
Other threads imply that away from the pushrods is the correct positioning, or over oiling will occur, but are you saying that the book might be incorrect on this? ( wouldnt surprise me, I have seen incorrect stuff in "the books" on several bikes in the past!)
If the holes all line up with the high pressure system then a lot of oil will go through the head. This could overcome the valve seals (when fitted) and is too much for an Atlas (which has no seals). It could also reduce the oil pressure to the crank which on later engines had oil bleed holes in the rods for piston lubrication.
Hi Tristan, just read my previous post's and I think you'll find I've covered pretty much most questions asked. Further to that, in the past 5 years I have assisted my friend, a fellow member, in the building of half a dozen or so Norton engines, all twins, mainly Commando and one ATLAS . In all of these engines the rocker shafts were fitted with the oil hole facing the push rods because as far as we are concerned they were always intended to face that way. The reports from all the owners, one of whom was a member of the EC was that all engines were performing correctly with no sign of over oiling or exhaust smoke. Other answers to your questions will tell you that you must put the shafts in the other way because the "book" says so. I've explained all the reasons for not doing this in my other posts, the likely damage it can cause and the possible cost of repairing that damage. In the last few weeks while rebuilding a MkIII Commando engine my friend and I have carried out numerous tests to try and improve oil drainage past the cam followers and also made new spring platforms to do the same through the exhaust drain holes on the later engines. The results and videos of these tests were shown to A N who were interested enough to discuss them with us.
PS:--Don't worry it won't affect the oil pressure to the crank , unless 40+psi hot isn't sufficient.
Hi Ian. Sounds logical to me. I know I am not getting enough oil in front for certain. I have ordered the spindle puller tool, and am looking forward to seeing what I find. Again, thanks so much for your kind advice and the time you have taken to provide it.
Hi Tristan, any time and no problem. PM me any time if you feel the need. Its so pleasant to receive a positive response rather than being told my information is obscure and irrelevant. Thanks again, Ian.
Happy to, thankyou again. I will be pulling those spindles this weekend. See what we've got......
And I agree with your observation, it seems like chat forums, regardless of subject, are full of bored old buggers who delight in insulting one another over minutiae obscura. One wonders how brave their approach would be face to face!
It is physically impossible for the oil pump to cause over oiling, 3 start or 6 start. The way the pump is designed prevents it.
The oil circuit can cause over oiling. Considering that the feed to the scrolled rockers and 3 start pump worked for years, just why did they change to a 6 start pump. Did they need to, did they fully test the 3 start pump, I don't think so. The 6 start pump is very good, works at just over 50% of its capability and delivers a huge amount of oil per minute.
The reason to remove oil flow to the cam is a strange one, and goes against all the thinking then and now. Getting more oil to the cam by aligning the holes into the head makes sense, despite the hole in the rocket ball end being shut off in the cup of the pushrod for a long portion of cam rotation is the same no matter which way the hole faces, but when it has the opportunity to deliver oil to the pushrod tunnel it can't. Many other pushrods in the automotive world are hollow for a reason, to get oil to the cam.
There are two things that suggest that getting more oil to the cam is a good idea. First, the Domiracer tappet had double chamfers and two holes drilled in them to obviously allow oil past the tappet to the cam. Seems that the race shop was on the other side of the planet - why did they design them that way, and why not introduce it to road models. If they had then no over oiling in the head no matter which way your spindles were fitted or what style. Second, anyone with an optical thermometer just check out the temperature at the tappet tunnel area near the barrel flange. Then decide how you are going to fit your rocker spindles.
I noticed the temperature at the tunnel when the manufacturer of the one piece tappets asked about working temperature in this area. At the time thought it was quite high but there was little else out there to suggest it was either not normal or that it could be be made cooler.
When you break this whole thread apart and look at each part on its own, then what was considered the norm in the past, needs questioning, as it may have cured the result of the problem but not the cause.
I can agree that more oil to any cam is good,particularly for the Commando motor which has had far too many cam failures. I have not had any measurable cam wear over 60 years of "Dominating" with the 3 start low pressure system and a functioning cam trough. These motors get very little oil down the pushrod tunnels and the ex valve chambers usually look dry. The rocker spindles do wear though so I have recently arranged for them to get a little more oil. The Commando motor with its cutaway trough needs a good oil supply to the cam no doubt. But even the bigger pump and double speed gears do not deliver the oil where its needed.
Dominators had very substantial camshaft oil troughs which worked. When the engine stopped the trough retained oil so that when the engine was restarted there was oil immediately available. I have heard it mentioned that some owners tried for some reason to remove the trough, I feel the trough is so much part of the crankcase that this would render the crankcase useless if they managed to succeed.
Mention has been made of the damage to Commando cams and followers.
The Commando trough is not so pronounced as that in the Dominator, but is helped by the inclination of the engine, but not sufficiently to counteract other problems, some of these being badly cast cases. An example of this being a MkIII finished only last week. The right hand case on this engine had a fully machined trough, the left hand case had an unmachined ledge sloping down to the joint section of the case, this resulted in a 5/16" step down. With the case set up on the bench, oil poured into the trough remained in the r/hand side but ran off the l/hand side, the camshaft from this engine only had three lobes the fourth, on the l/hand side was 50% worn away, the other cams and all the followers were badly scuffed. The rocker shafts were facing away from the pushhrods which is why all the oil from the uprated pump is NOT going where you need it. On this engine a new trough was fabricated and welded into place exactly matching that in the right hand case. Further mod's were made to the cam followers to increase the oil flow past them and so avoid flooding the tunnel and head.
Ashley asks if it was required to fit a six start pump, it had been altered by fitting larger gears, but spinning the pump twice as fast doesn't necessarily mean it will deliver twice the ammount of oil. Do we know if the enlarged pump was tried with a three start drive, might this have been all it needed?
The higher capacity oil pump (marked 'S') came about with the arrival of the 650 and 750 engines. These having larger crankpins compared to the 500cc and 600cc motors. All the engines using low pressure rocker feeds. A couple of years down the road and high pressure rockers feeds and conrods with bleed holes turned up and a quick fix to keep the pressure up all round was to double the speed of the oil pump. Which as Ashley says was more than enough for the job. The drawback of doubling the speed of oil pump is the higher rate of internal wear. Fortunately, the excess of oil pressure covers this for a lot more engine miles but wet-sumping then becomes an issue.
I think that the 88SS had the higher capacity oil pump but kept the 3 start gears for all of its life. Fitting a 6 start gear would just be wasted as the pressure release valve would just be endlessly dumping excess oil in the timing cover.
I have not long joined the NOC although I have owned a 650SS for four and a half years. There is a painting of my bike (1965 model) by Ian Cater on the main page of the website.
Now twelve months ago, I carried out a full engine overhaul of my SS and the Bruce Main-Smith Norton manual stated that the flats on the rocker spindles should all face towards the centre of the engine. My Haynes manual stated the opposite.
I looked on the internet where I read in ‘access Norton’ that for Commandos, the flats should face out towards the rocker covers and for the Atlas and similar engines where the oil feed goes into the top of the cylinder head, the flats should face towards the centre.
I went with flats towards the centre. My bike has been running good and strong, but having read the debate here and you guys clearly know your stuff, I will be pulling out the rocker spindles this weekend and fitting them with the flats out. I do not want any nasty surprises with the cam or tappets or anything else for that matter wearing out prematurely.
I did notice the last time I checked the valve clearances that there was less oil under the valve covers than before the engine rebuild.
The Manuals are all correct depending on which type of Rocker Spindles they are referring to. Right from the first Dominator engines, up until Pressure Fed Plain Rockers arrived the system consisted of scrolled spindles fed by a Low Pressure Return Side Feed from a 3 Start Oil Pump. The spindle flats in all of these machines faced inwards towards the spark plug,acting as a small oil reservoir for cold engine starts.
However, just like crankshafts, when the engine was not run for some time the small oil reservoir drained away leaving metal on metal contact until the engine was next started and the return feed was able to, once again, dribble enough oil up to all 4 rockers. This could take some time, while the rocker turned on a reduced area, scrolled spindle. Inevitably the rocker spindle clearance grew to the point where the flat was colllecting the oil flow and then just dumping it onto the valves ends causing smoky engines.
This problem got worse when the SS headed engines arrived with stronger valve springs and higher lift camshafts. At which point somebody decided that turning the spindles 180* put the flats at the top, facing outwards, was a good idea to help with lubrication but not over-oiling of the rockers. A practice continued when the plain spindles and a pressure fed system arrived.
If your engine does not smoke then leave the spindles as they are. Early Maintenance Manuals will mention scrolled with spindle flats facing inwards and later books will suggest the opposite.
My Dommie has a 6 start pump and top feed from the low pressure return. I've never found the need to remove rocker spindles (they don't need to come out to remove valves or valve guides) so I have no idea which way the spindles face. But they've never given any problems...so far...
Thank you for clearing this up. My SS has the scrolled spindles and the engine does not smoke, so I will leave it alone. I had quite a job removing the spindles on the last occasion despite putting the cylinder head in the oven and getting it nice and hot.
I stripped the threads on two pullers, one of which I have now repaired as well as acquiring a slide hammer.
That has saved me a job. I appreciate the advice, I was starting to worry!