Widening valve clearances

Sounds like you have a cam or follower wearing out. You are going to have to take the head and barrel off to check.

Previously robert_tuck wrote:

Sounds like you have a cam or follower wearing out. You are going to have to take the head and barrel off to check.

ER the cam can wear out to 'round' but the gap will stay where you set it! As you set the gap on the 'back' of the cam. On the other hand the cam follower having lost its stellite tip would give a much greater gap which would then increase with considerable metal rushing around your engine!. One reason I had such a problem of an increasing tappet gap was using a solid alloy push rod, which had picked up on the end of the rocker which had blocked the rocker oil flow from the end of the rocker hence the push rod shortened as fast as a carrot given to a donkey!

Sounds like a top end removal and searching deeper, oh dear.

Al Osborn.

As Al says could be other reasons, Tappet locknuts not tight?, Head/barrel fixings loose?( you would see oil leaks or blowing head gasket).Soft valves indenting from the rockers?,All possibles ,but not usual. I did once have a similar situation where a push rod was not engaged in the rocker but was still able to operate the valve ,and it ran!!.

I would not be to hasty in dismissing the camshaft as the root of the problem. Once the hardened layer starts to wear through, any pieces, that break off the lobes, rapidly cut through the rest of the metal. You need to check this problem out fast. If it is the camshaft and/or followers falling apart then the particles are going to very quickly take out all the bearings, pistons and rockers. The oil pump has probably lost a lot of its omph already if it has swallowed and passed on the junk. Has your engine got an oil filter in its system?

Hi Ian

Just to let you know you're not alone.

I've the same problem on my 99. 2,000 miles after rebuild.

Phil,

Surely the tappets are set when the follower is on the base circle oft he cam. Here there is no contact between cam and follower. Wear occurs in the area around max lift.This can cause reduced valve lift and lots of noise but not excessive tappet clearance. Rapid follower wear can occur if the followers have been reground excessivly, but my money would be on the pushrods.

Grinding the followers prior to fitting a new camshaft is the recommended process so they bed in together, however todays oils do not have the correct amount of Zinc for protection of followers bearing down on camshafts and sliding. So have a look at the oils you used, API SG or earlier is good, later than SG can give problems.

Hi Ian

I've got the problem with the offside inlet rocker.

Neither the followers or cam were new or re-ground as they looked good.

The pushrods were new. Iuse a spin off filter and a quality 20/50 oil.

The bike was going well, but I won't get around to stripping it for some time, as I have other things apart also.

Shame I was loving it.

Good luck, let us know how you get on.

Keith

Until now it has had mineral 15W 50 API SL, and I have just changed it to Silkolene Super 4 semi-synthetic 20W 50, API SF & SG.

I would not have used a SL oil for bedding in, a 20w/50 mineral API SG is best for bedding rings in, no synthetics until rings bed in and then the oil you have gone to is fine. At this stage only a strip down is going to tell you what'sgoing on.

Halfords do a classic oil that appears to have minimal additives , i would steer clear of that one.

I'm finding this discussion very interesting as I near the end if my 1960 99 restoration. At this stage I have no intention of fitting an external oil filter, such is on my Mk 3 Commando.

I intend to run the first 50-100 miles on Millers mineral Piston ease SAE40 with light detergent they recommend for running in a fully rebuilt clean engine. No additional filter, hence the low initial mileage before change.

What to do after that is interesting but it looks like anything with synthetics is out for quite a while.

I started up my Mk 3 Commando yesterday for the first time after a month with nothing more than a battery charge (1989 Boyer) a few days before. It started first kick. This would never have happened on SAE 40 without draining the sump first but the Millers mineral 20/50 did the trick.

There may be a connection with the above issues on my 650 and likewise will come back to the topic after the 99 is finished so the problem(s) can be investigated.

I know that Miller, amongst others provide a service to examine oil for particles but for this to be of any significanceyou need the full oil spec as it is what is not in the oil they are looking for.

Good thread.

Point 1/ the issue of the proper amount of ZDDP is a red herring. a) the structure of the ZDDP used is more important, for the chemists among you,short chain branched alkyl groups are best. b) although some oils for engines with modern catalytic converters have lower ZDDP concentrations (ACEA C category), they still must pass the same cam and follower wear tests as those for which do not meet the latest Euro emission standards, (ACEA A category. Most oil companies have tested oils at 1/2 of current concentrations without wear problems.

Point 2/ Ideally replace cam and followers at the same time. If the followers are refaced by grinding, then you need to have them checked for hardness before installation.

For gods sake steer clear of antique oils even if you have an antique engine. When they were current, 10,000 miles between total rebuilds was considered good. Modern oils undergo rigorous, independently supervised development engine testing, obsolete specification oils are formulated largely by guesswork.

Good point Charles but do they test modern oils on old engines?

Sometimes it is a case of the devil you know. If so called modern fuels are anything to go by then give me the old stuff.

My Commandos original recommended oil was mineral 20/50 and I'm waiting for long term reports on Semi 15/50 some riders are now using.

All of this is of course relevant to the engine wear in the thread and it is Norton twins specific BUT Charles, are you suggesting something better that SAE 40 in my ex WD 16H. I think Mile Pemberton came to the conclusion that due to tolerances, that there was still a place for the good old oil.

Previously neil_wyatt wrote:

Good point Charles but do they test modern oils on old engines?

Sometimes it is a case of the devil you know. If so called modern fuels are anything to go by then give me the old stuff.

My Commandos original recommended oil was mineral 20/50 and I'm waiting for long term reports on Semi 15/50 some riders are now using.

All of this is of course relevant to the engine wear in the thread and it is Norton twins specific BUT Charles, are you suggesting something better that SAE 40 in my ex WD 16H. I think Mile Pemberton came to the conclusion that due to tolerances, that there was still a place for the good old oil.

With regard to the 'do they test modern oils in old engines? ' the answer is obviously, no they do not. But continuity of performance standards from one specification to the next is required. So todays spec. oils are required to be at least as good and in specific performance areas, better than their predecessors.

The big problem with very obsolete spec. oils like SG etc is that there is no guarantee that they are of that quality since the engines used in test methods at that time are long gone.

With regard to your 16H, lucky you, if it is worn to the state where oil consumption is high, then stick to a 40W monograde, If, on the other hand, it is in fine fettle use a 20W50. If I were lucky enough to own one of Mike Pemberton's motors, I would feed it on Mobil 15W50 .

OK Charles, I'll try Mobil 15/50 in one of my OHV singles, still low mileage after either rebore or new sleeve and piston in both cases but with the rings now bedded in. I will report back but this will be next year, God Willing.

As for my 16H, I think I'll stick with the SAE 40. Though interested to hear from anyone who tried anything other than straight oil in a Norton side valve with success?

After the new rings are bedded in I'll try the Mobil 15/50 in my 99 restoration. Still waiting to hear how the 15/50 is going in the riders that are trying this out.

Looking FWD to hearing how the guys with the valve clearance problems are doing.

A quick check of the internet shows that good quality 20W50 oils are readily available. Opie oils shows a range of 20W50 oils including Motul SL quality HD approved oil+Sikolene and Valvolene offer good quality oils at reasonable prices. Valvolene offer an SL quality racing 20W50 available from Eurocar parts.

Other products are also available, as they say.

For what my opinion is worth I dont think this rate of wear is a type of oil related problem.

When a new camshaft is fitted shouldnt it be initially coated with a special camshafft grease? Did you do this ? Did you make sure oil was getting to the head by cranking the engine over before you started it?

I run my B31, model 19 and Commando on 15/40 semi with so far no problems and they have all done fairly hefty mileages on it. But I do change it very regularly.

Previously ian_cordes wrote:

Let us de-bunk some of the myths here.... I don't think it is related to the quality of the oil either! I do not believe that my engine has been damaged by the use of a good quality, 15W 50 oil of a y2k specification, over 1000 miles. If it is good enough for 1,000,000 or 10 engines throughout the World, it is good enough for mine.

Yes, of course I coated the camshaft with the special grease which comes with it when new. Why wouldn't I? Yes, of course I made sure that the oil system was primed, that oil was getting everywhere, and on start-up, is returning properly. Yes, my tappet locknuts are tight. The oil gets changed regularly, 3 times in 1100 miles. No lumps are flicking off my camshaft and destroying everything in sight.

Forgive my flippancy, but the head and barrels are now off, and all looks good; camshaft, followers all look as they should. The inside of the crankcases are clean and shiny. The pushrods; steel ones; are straight and not crumbling at the ends, the oil is clean with no debris, or even fine particles that I can see.

The only problem that I can see, is that when I removed the rocker shaft end covers, there was a bit of sludge in there, and 3 of the 4 covers were missing the tabs which locate into the ends of the rocker shafts, to prevent them from rotating. This they have done, which will cover the oil holes, and restrict the oil flow through the shafts, and the rockers. All the broken tabs were present, and easily hooked out. These covers were all new 1200 miles ago.

Chicken and egg? Did the rocker spindles seize, causing them to turn with the rocker arms, thus breaking the tabs off? Or did the breaking of the tabs allow the spindles to turn, thus cutting off oil flow? The rocker shafts were not seized, and pulled out normally with the extractor. Fortunately, this problem has not gone long enough to cause wear in the spindles or rockers.

When I set this engine up, I tried a 6-start oil pump, supplied by, and in discussion with, Dale Middlehurst. Way too much oil pressure. Back to a 3-start, which still needed adjusting the shims in order to get the pressure right. I tried his suggestion of restricting the flow of the return pipe, in order to supply more oil to the rockers, but again, too much oil, and smoke. Removing the restriction restored the status quo. Also on recommendation I fitted plain inlet rocker shafts and scrolled exhaust items.

It may be that adding the Commando type oil filter has reduced the flow to the rockers, sufficiently to cause this situation. There is oil in the rocker boxes, but maybe not enough.

And - I am still not sure how this would cause the tappet clearances to increase.

Time to sleep on it....

Cheers!

Ian

Ian,

You sound like you know what you are talking about. If the rocker spindles have turned with sufficient force to break the tabs there is something not right, they must have seized, you will have to find out why, pressure feed to rocker gear is ok if you do it right you MUST fit inlet valve seals.

Think about why one rocker clearance increases, if the push rod, cam follower and camshaft / camshaft bushes are ok and you have checked the top of the valve stem and the adjuster is ok then what else can it be? The answer most likely is the rocker spindle, if it has broken the tabs (even though it came out ok) it has seized in the rocker and will be turning in the head which is aluminium which will be the source of the sludge, you dont need me or anyone else to tell you that you will have rapid wear.

Tony

The evidence presented does tend to indicate seized rockers. The chances are that lack of top end lubrication has also caused damage to the pushrods ends. Check the length of each one.

Previously ian_cordes wrote:

Hi Phil. Sorry, I have just seen your post, which must have gone up whilst I was tapping out my last missive.

Yes, I will certainly measure the pushrods, although they do look ok. For them to be shortened by lack of oil, it would have to have worn right through the hardened ball at the follower end, or cup at the rocker end, wouldn't it? I am not sure if I can measure inside the cup, but can check it visually, and it's fit on the ball of the rocker.

I have a bit of work to clear out of the way (what a nuisance work is!), then I can get back out there. I need to check valve guides and stems, as they could have suffered too. It is not that oil was not getting up there, because oil is laying around in there, more that the feed has been restricted by the rockers turning, perhaps? It is that chicken and egg situation, where maybe weak tabs on the end plate broke, possibly due to poor manufacture, allowing the spindles to turn and restrict the flow? Or, the lack of oil flow caused the spindles to pick up.....

Had I checked the rocker gear without removing the head, I could have reassembled and started the engine with the rocker inspection covers off, to see what oil flow there is. I felt it necessary to check the cam and followers, though.

Ian

Ian,

My 650SS was convereted by me to pressure fed rocker gear and spin on oil filter. Oil feed comes off from a union at the rear of the timing cover, I fitted plan rocker spindles exhaust and inlet, Commando oil seals to both inlet valve stems no need to fit them to the exhaust valves, 6 start oil pump. I use Halfords green classic 20/50 oil.

Spin on filter kit ex Paul Goff is on the scavange side of the oil pump with return to the tower on top of the oil tank.

I get a lot of oil to the rocker gear the engine does not smoke, I have done a many miles since completing the modification the longest from Aberdeen to Morpeth and back last year without any issue.

Sort your rocker gear and lubrication and you will have a great motor which will see off the best of the Meridian equivalents.

Tony

Plain spindle may have caused the problem, Worth blowing through the oilway in the head ,My 99 used to run very dry on the exhaust side ,probably the simplest solution is the one Norton proposed ,fit a Jubilee part.I have also tried the six start gears, too much oil!.

When this happened to me as a spotty youth back in 1970, the cause turned out to be that the boss in the head (which holds the rocker shaft) had cracked. As the crack opened up, so the valve clearance opened up until the boss failed. In these days, the local bike breaker was able to supply a Domi cylinder head over the counter for a modest sum. Check your bosses!

Hi Ian, sorry to hear about this. If it were me I'd try to get near Mk 3 spec or take out the filter so you are in a position you know works.

It is very helpful and an excellent point of reference that you are giving a detailed description of your findings. Hope you sort it out.

The Norton handbook used to reccomend occasional blocking of the return in the tank with a finger to flush through the oilway,this works as a smoky exhaust is a temporary result!. They also said to fit a tank fitting from a jubilee which has a more restricted outlet which will push more oil to the head, A soldered in sleeve could do the same thing.More oil to the head will mean that inlet seals will be helpfull.I always use a little 2 stroke oil in the fuel,lubes the carb,valve guides and rings on start up and helps to stop tank rust. Rotating spindles would affect clearances if there is any wear in the parts.

The pushrod lengths, for your engine, will depend on the barrel and head. Spigotless parts, fitted from 1966 on used shorter pushrods. Valve lengths were also changed on some later models. It is possible to mix and match these items and then fit the wrong length pushrods in error.

Attached sheet gives pushrod model/year details.

The advice given about checking the oilways is good. It does not take much to obstruct the oil flow. eg. Poor drillings or sludge in the oil.

I don't think that the oil filter is the root of your flow problem as many owners have fitted these and you do not often hear of such issues with them. I am wondering if you have a pump or flow problem on the return side. A John Hudson recommended mod was to open up the return oil way from the sump to the pump from 1/4" to 5/16" as done on post 1966 engines. He also suggested restricting the oil tank return union internal diameter to just 2.78mm (7/64") by fitting a drilled grub screw. Paul Dunstall used to sell a jetted oil union which allowed early engines to benefit from a pressure feed without having to change the rocker spindles to plain.

Your oil pump should give a feed flow of 13 gallons per hour at about 3000rpm. The low pressure return rocker feed should be at least 1 gallon per hour. Check this if you can.

I don't know what Charles means by 'antique' oils and engines. Norton twins are pretty old fashioned but 30,000 miles on rings, 50,000 on bores and 80,000 on a bottom end was not uncommon with monograde oils. Sadly there are engines running on oils designed by computer simulation which are giving far worse results than this...

But I also don't think that this sounds like an oil problem. Something this drastic sounds like something loose to me...Rocker ball ends or pushrod cups not seated on assembly or valve seat inserts dropping in use ?

The rocker spindle retaining plates are a worry. I've never heard of this, although some badly made plates can turn a fraction in use.

Side Valves are nice !

I don't know if this helps but another deviation from standard on my 1960 99 is that I have fitted the RGM rocker spindle kit. Not got the engine in the frame yet so I can't tell you how well it works but you can see the bits for yourself if new to you. Hope the link works..

http://www.rgmnorton.co.uk/buy/rocker-spindle-outer-plates-modified-to-lock-spindles_91.htm

Previously richard_payne wrote:

I don't know what Charles means by 'antique' oils and engines. Norton twins are pretty old fashioned but 30,000 miles on rings, 50,000 on bores and 80,000 on a bottom end was not uncommon with monograde oils. Sadly there are engines running on oils designed by computer simulation which are giving far worse results than this...

But I also don't think that this sounds like an oil problem. Something this drastic sounds like something loose to me...Rocker ball ends or pushrod cups not seated on assembly or valve seat inserts dropping in use ?

The rocker spindle retaining plates are a worry. I've never heard of this, although some badly made plates can turn a fraction in use.

Side Valves are nice !

This really is not ' an oil thread', but to clarify my earlier contribution.

I have two problems with the use monograde oils with either obsolete claims of performance specification or none at all. With monograde oils the issues are ease of starting and warm up and the fact that at low/normal temperatures most of the oil put out by the pump is dumped in the timing case instead of going to the bearings.

The other issue is guarantee of performance quality. The classic oil market is a nice little earner but products offered cannot be tested against the obsolete specifications which are claimed for them. The test methods, engines, fuels and reference oils disappeared long ago when specification upgrades occurred. Even when these methods were current standards of testing were poor by comparison with those applied to modern oils. It is unlikely that the additives used in the original formulations are still available, so all They can do is use later additives and guess. Usually they will use a low treat rate of their current additive package.

I am unsure as to what you mean by oils designed by computer simulation. I worked on the development of many oils for many oil companies. Our engine and field testing costs to bring a product to the market were eye watering. No computer simulation!

The return oil pressure should not be affected by the bleed hole rods, however its possible that when hot and working hard at low revs there could be a lack of supply pressure at the big ends if you are using the 3 start gears.There is a school of thought that the bleed holes are an attempt to solve problems unrelated to oil supply,IE unbalanced ignition timings and engineering missalignments.You could fit a grub screw adjuster to the uprated low pressure supply to the head and experiment till an acceptable flow is achieved.I would block off the flow to the timing side bleed hole if keeping the 3 start gear,and fit seals to the inlet v/guides.Using the six start gears and pressure feed would need seals all round,unscrolled shafts and good oil control rings.

How would you block off the bleed hole in the timing side rod? I can get at it, but the bottom end is still intact, and in the frame.

You would normaly do this by placing the shell bearing in the wrong way round so the undrilled bottom shell is on top, best done on a rebuild when fitting new shells even without a regrind if its not needed.

Ian, hope this link works and helps. No good me giving opinion on the new kit because the rebuilt cylinder head is not yet on the rebuilt engine but I'll let you know after a reasonable mileage.

http://www.rgmnorton.co.uk/csi/1245184/f/pdf/067579m_rocker_spindle_instructions.pdf

Charles, I recognisethat you know more than most with regard to todays lubrication but I have to back up Richard in favouring 'antique' oil in antiqueengines, especially old side valvers. It was because of your advice that I changed back to 20/50 in my Commando with good results to date. I may also try something more modern, as previously said, in my OHV singles.inc 15/50 But until someone can prove that there is something better than SAE 40 in my standard bore 16H I'll stick with what I know works.

Seems a shame to pull appart the bottom end, so a six start set, sea;s on the valves ,high pressure head feed unscrolled spindles ,later oil control rings ?,Nah ! I would just go with what you have ,fit the scrolled spindles ,and experiment with the low pressure head feed,and cross my fingers on the big end life.I always was a chancer.