English French German Italian Spanish

Severe wear and galling on camshaft- mk3.

Submitted by ian_condy on Wed, 12/12/2018
Forums
Commando

Hi all,

Early last year I posted about poor running on my 1975 mk3 with the right cylinder misfiring and oiling the plug. I had parked the bike and only just got round to stripping the engine last week. Well I discovered the problem- the cam lobes for the right cylinder are badly worn,with severe galling particularly the exhaust lobe but it is only damaged across about 7/8 of its width. There is a lip of about 1/8â on the outermost edge of the cam lobe so the cam has not been running centrally on the tappet.

There is substantial end float on the camshaft which makes me wonder if the thrust washer is even fitted as the shaft needs to move more to the drive side to line up correctly with the tappets. There is no wire locking on the tappet plate fixing screws. The maintenance notes from the previous owner show that in 1983 a new camshaft was fitted and the right side tappets were dressed and one new exhaust valve fitted so there has been an issue and work done in the past. Iâll get the engine on the bench in the next week or two and investigate furtherââ-

meanwhile - a question- when fitting a new camshaft and the timing side thrust washer is it normal to use shims to adjust / correct end float so that the lobes run centrally on the cam followers?

Cheers,

Ian

Attachments 739336c4-4cf2-41df-8ca4-3349800495d9-jpeg

Submitted by katherine_scott on Wed, 12/12/2018

Permalink

Hi Ian

There was an interesting post on the accessnorton site recently, relating premature camshaft ware to a soft cam follower it may be worth getting your follower shore hardness checked if you are going to have them lapped when you fit a replacement camshaft.

Out of curiosity What oil have you been using ?

Best regards

Katherine Scott

Submitted by ian_condy on Thu, 06/12/2018

Permalink

Hi Katherine

Thanks for your reply

Iâm planning to fit new cam followers with the new camshaft and probably go with a standard cam from AN but still researching this.

Iâm using Motul 4T 20/50 at the moment but I think the damage was done just before I bought the bike a couple of years ago - - Bit of a story here- Iâd sold the bike in 2005 but in 2016 found the receipt when sorting out old paperwork so contacted the owner and bought the bike back again.It had lain in a shed for 11 years and only done 100 miles but he was planning to sell it and had been trying to start the engine. Iâd say there was no oil film inside the engine which probably caused the damage.

Iâm going to do a full rebuild now over the next couple of months as itâs a great machine which I always regretted selling but was lucky enough to find again!

cheers,

Ian

 


Norton Owners Club Website by 2Toucans