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Worn oil pump worm gear

Discussion in 'Norton Commando Motorcycles (Classic)' started by SteveA, Mar 15, 2017.

  1. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    I have just examined my oil pump and noted wear marks on the drive gear, so I checked the worm, and sure enought that is very worn also.

    Has anyone seen this kind of wear before?

    Possible causes?
     
    Yakatak likes this.
  2. Danno

    Danno

    Joined:
    Feb 7, 2010
    Old age (wait, that's MY excuse) wear and tear and irregular oil changes. If you don't have an oil filter, fit one.
     
  3. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    I have an oil filter, and I am guessing I change it more often than most.

    They are both new AN parts purchased in 2014.

    24 races later.....
     
  4. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    worrying
     
  5. Brooking 850

    Brooking 850 VIP MEMBER

    Joined:
    Oct 3, 2011
    Hi Steve A , I have noticed this on my race bike also, although only after using a one piece crank, it never did this with my standard Commando crank.
    Maney cases.
    The machined specs are identical though???
    I am in the middle of a re assembly so will check on why, it seems to have loaded from timing side towards the drive side, going by the wear witness marks.
    I may have to put a shim under the the worm nut to get it centred or maybe just remove the gasket from under the oil pump and use a bit of sealant.
    Last night during dry fit up , initially I had 0.017" crank end float, shimmed the drive side bearing between the case and the bearing with a 0.010" shim , this was identical setup using the Commando crank.
    Hope you find an answer to your problem and be keen to see which way yours has loaded.
    Regards Mike
     
  6. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    The solution should have been to replace the worm and the pump gear! It has done 5 race meetings in 2017/2018 since new parts went in, most of the race metings curtailed for one reason or another, so not heavy use like in the 26 race 2015 season I know I said 24 earlier in the thread but I am pretty sure it was actually 26! Shimming is exactly as it was from original build. I have changed to a synthetic oil.

    But I am planning to pop the timing cover off in the next two weeks before my next race meeting in Southern France. I am going to fit a new oil pump with gear. Not because I have seen a problem, more because I want to have a look. I had felt it was taking time to get oil back to the tank from a cold start after standing a while. Maybe just worrying more than I need. It is a bit difficult to see what is going on with the Rickman Oil in Frame. After running and settling for a short while, and standing it on the rear stand, it is only 200ml between showing correct on the sight tube and being out of sight! I think I am a bit fussier about draining the catch tank and topping up the oil tank between races in the more leisurely environment of France! Fewer races but longer.

    I tested the oil pressure before last weekend's races and it was good.

    Will check again with new pump. and look at the state of the worm etc. whilst apart. I didn't really check the wear 'pattern' on the original worm. It is still in a box, may dig it out.

    To be honest I cannot see how moving the pump in or out slightly on the studs would affect the wear, has someone suggested this to you?

    BTW I always understood it was best to shim the crank on the timing side! whether you choose to shim the bearing outer or inner.
     
  7. Brooking 850

    Brooking 850 VIP MEMBER

    Joined:
    Oct 3, 2011
    Hi SteveA , I have always shimmed on the drive side between the case and the bearing.
    Have decided to take the 0.010" shim out in this case, as by the time the bike is back in the frame and all bolts torqued up, will probably lose a thou, so it will be close to 0.015" end float (without the shim)which is pretty optimum according to the likes of JC.
    With the shim in, it would be close to 0.005" and thats with it cold.
    The thicker Maney cases probably dont grow as much as a standard set of cases.
    Also there is every reason to believe my one piece crank could grow more that a standard crank when hot.
    Once my dyno is up and running, I will test the end float between hot and cold running.

    It turns out there could be difference in hardness levels on the oil pump gear set depending on manufacturer.
    Worth looking into.

    Regards Mike
     
  8. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    Maney Cases and Crank. No one else seems to have reported issues with that set up. Based on improved materials I would have expected the Maney crank to remain nearer to size than an original Norton item! Surely if your one piece was going to expand more the supplier would issue shimming advice to suit? 0.015" is no way excessive.

    As far as the worm and gear supply, one source, AN, originals via Norman White.

    When I ordered a replacement worm and gear direct from AN the first worm I got was not acceptable to me. I could not run it onto the crank thread and the gear faces and finish were not to expected standard. I sent it back and AN apologised and replaced it with a part that passed my visual inspection. On assembly the pump and gear slid on and off with no resistance. But it also did so with the original worm and gear.
     
  9. Brooking 850

    Brooking 850 VIP MEMBER

    Joined:
    Oct 3, 2011
    Thanks SteveA, just so we are clear, the cases are Maney, the crank is a high spec one piece made here in New Zealand fabricated by Graeme Martin, highly respected crank fabricator especially amongst the classic guys.

    The worm drive nut was a NOS item and the oil pump gear was a new item with new drive gear.
    The pump was stripped from new to and each tooth on gears hand honed as it felt a bit 'ropey' when turned by hand.

    It couldve been that I did have the end float too tight .Not sure at this stage.
    Regards Mike
     
  10. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    Welll I opened it up today, not a lot of oil drained from inside the timing cover, but it had been sitting and I had just drained about one and a quarter litres from the sump.

    Before removing the pump I tried the backlash at the pump gear. Certainly not tight, several degrees of movement. Undid the two retaining nuts and the pump slid right off. There is wear showing on worm and pump gear, worse on the pump gear. Perhaps neither is catastrophic but I don't recall seeing wear after several seasons of racing in the past.

    At this point it is getting a new pump gear with the new pump, but not worm. Pump gears are £20, worms £80. By the looks I would need to change the pair for a modest season of racing. Not good.

    I am concerned the problem stems from insufficient oil in the timing cover rather than alignment. But on the other hand the timing chain tension is good with no obvious wear! Intermediate gears look fine too. Previous advice from Jim Comstock is not to have too much oil in the timing cover anyway. I have drilled one drain hole timing to main crankcase, but it is higher than shown in photos that were on this site once!

    I have an upright engine with plugs in the case to support the reed valve breather fitted at the lower rear of the cases (Combat breather location).
     
  11. Mr. Rick

    Mr. Rick VIP MEMBER

    Joined:
    Feb 6, 2009
    Insufficient oil maybe, or mis-alignment maybe. What about surface hardness of the gears themselves? I thought we were headed for a component problem...
     
  12. Brooking 850

    Brooking 850 VIP MEMBER

    Joined:
    Oct 3, 2011
    SteveA, I have my new oil pump gear installed and the new worm drive nut arrived so going to install both and will check to see if there is any load on the gear once it is mated to the nut.(Motor is on the bench)
    Hopefully not, there should be a few thou play (backlash)before the load comes on .
    If not I may have to slot one of the oil pump holes (the ones the studs pass through) to unload the gear set.
    Should have an update tomorrow.
    My Maney cases have all the oil way holes plugged and a 1/4 " hole under the pump drilled all the way through and a JC reed Vv breather screwed into the bottom of the case.
    It could be that my 10W50 Joe Gibbs oil is just to heavy at the 50 end of the range and making the pump stay loaded all the time?
    Regards Mike
     
  13. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Lube to the head is drained either down the pushrod channels or down the drain bore at the rear of the barrels, ending at the c/case top flange and further channelled to the timing case. Please make sure the drain bore is open (verify by using compressed air). The drained oil + the amount leaking out of the oil pump shaft is sufficient lubrication of the timing gears and the worm drive.

    -Knut
     
  14. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Was the oil pump new when you put it in? Wear on pump gear is a well-known observation, most likely due to metallic debris in the oil.
    Does your oil circuit include a filter and magnets to catch steel shavings? With these in place, please note this observation:
    https://www.nortonownersclub.org/noc-chat/technical4-commando-forum/192261477

    -Knut
     
  15. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    Similar setup then really, except my 1/4" hole is drilled above the pump! 2 reasons, Honestly I didn't have the confidence to drill below the pump and miss oilways and, since the motor is mounted uprigh like an Atlas, I though that location may be too low to leave enough lube for the gears. What this does mean is that the oil return feed from the inlet valve area enters directly over this hole, some 4" away. The hole should have negative pressure due to the read valve, I guess just maybe oil is drawn in. But looking where oil collects in small places inside the cases and cover, there must be a fair mist around most of the time.
     
  16. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011

    I know where the oil drains back from, checked it last time I rebuilt the motor, which isn't long. But I confess I hadn't considered the oil pump leaking oil out like that. Maybe alignment is more the issue. I have 3 pumps to compare including an unused old stock item.
     
  17. kommando

    kommando

    Joined:
    May 7, 2005
    It could be that my 10W50 Joe Gibbs oil is just to heavy at the 50 end of the range and making the pump stay loaded all the time?

    I use 10W60 oil and when fully warmed up the oil is thinner than when cold, still thicker than a 50 would be but as the oil warms up it thins out but not just as fast.
     
  18. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011

    Overal the pump has dome some 35 or so races plus another 20 or so track test sessions. It was re-installed with a new worm and pump gear last year, with little use since. Wear is not as bad as before so likely proportional to use. AsI said, I have a new pump and pump gear to go in. For my liking the oil drains down to fast even though a pressure guage shows over the 45lb pressure release. I don't ride with this guage fitted.

    Yes I have a return line filter, and in the spares box....one of those combination sump plugs. Maney cases also have the separate magnetic plug. Haven't generally found much on it. Typically more debris gets to the sump plug gauze and stops. Force feeding the magnet seems a good idea, but I have to check clearance to fairing lower/catch tank....and will have to drill and wire twice! maybe wintertime.
     
  19. SteveA

    SteveA VIP MEMBER

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    Dec 20, 2011
    I am using a 15W50 fully synthetic. It is possible this oil drains down faster than previous oils I have used. I am not inclined to think it is an oil spec issue.
     
  20. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    More likely a combination factor I think, unless more people report issues. The two things you quote, 'insufficient oil maybe, or mis-alignment maybe' need to be addressed first. These are not standard installations, even if they are quite common in racing.