square 4 - camshaft wear

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MARK.WALSH
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square 4 - camshaft wear

Postby MARK.WALSH » Fri Dec 28, 2012 6:25 pm

hi
the dismantaling of my 1951 ariel sqare 4 project continues.
I had the camshaft out the other day and there are ridges left on the lobes where wear has not occurred as it has not been in contact with the cam followers(I have not measured the amount though)
Anyone know how much wear (if at all) is permissable on a camshaft?
With the price of a new one im tempted to keep it unless someone advises utherwise. I must admit I have pulled a number of vehicles apart before and rebuilt them including many brit bikes, straight 6 Jags and even built a kit car from scratch - but the square 4 is somewhat of a fiddle compared to anything I have worked on in the past.
Many thanks
Mark

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simon.holyfield
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Postby simon.holyfield » Fri Dec 28, 2012 7:08 pm

My camshaft is like that too. I'll be interested to hear what the experts say.

My plan is to grind them smooth again, to reduce any noise.
cheers

Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
http://ariel-square-four.blogspot.com

chaz.wheeler
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Postby chaz.wheeler » Fri Dec 28, 2012 7:54 pm

just stripped a mk1 motor owner bought a new cam around £100, his old one has around a 20 thou high step and around 40 thou wide. I would have dressed off and re used, the other motor Im rebuilding has around twice as bad wear and a 1/16 wide step may still be useable but would need dressing again , obviously not set up right last time and needs seeing to or valve lift would wear quicker and need adusting often,

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simon.holyfield
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Postby simon.holyfield » Fri Dec 28, 2012 8:10 pm

My step is nothing like that high - its still in the cases, so I haven't had the mike on it yet, but by eye I'd guess 12-15 thou.

Thanks for the guidance - I'll post again when I have measured it.
cheers

Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
http://ariel-square-four.blogspot.com

MARK.WALSH
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Postby MARK.WALSH » Fri Dec 28, 2012 9:12 pm

chaz - £100 for a new cam - could you tell me who sells them, as at that price i woud renew it.
Thanks to all with your wear measrements I will see how bad mine is and report back
cheers
Mark

chaz.wheeler
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Postby chaz.wheeler » Fri Dec 28, 2012 9:56 pm

oops, looks like they must have had a new batch made. g0ne nearly double in a year, df do exchange for a bit less

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Postby nevhunter » Sat Dec 29, 2012 1:26 am

This wear is typical of many ( not Ariel) twins as well. If they were running in a channel they would get more oil at start up. The singles do it too on the exhaust cam in particular.. It is the most critically lubricated part on most of the engines. Cams and followers need to be made of good material amd heat treated well. A good oil is necessary too. Most modern oils have additives for anti scuffing, but I would still go to a bit of trouble to get something of a reliable quality. I have run Aeroshell W-100 plus as it is specially formulated for camshaft wear prevention. The metal particles don't help the rest of the engine either. I saw a BMW car engine absolutely ruined from steel particles from the valve gear. Nev

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brenton.roy
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Postby brenton.roy » Sat Dec 29, 2012 2:50 am

Hi blokes, it might be about the performance you hope for. I doubt a few thou would make much difference in either aspect.
Square four motors are expensive to rebuild, and you have to stop somewhere, but after all that money it would be nice to get performance that is as close to original as possible.
The followers could be as worn as the cam, so lift reduction at the valve might be double the numbers for your cam wear (more, if there is a clear ridge in the follower radius).
If you are going to have a cam reground, it's better to have it built up with something like stellite first, than to just grind the base circle away to regain lift. The followers may need doing too.
It's also worth measuring each lobe as a worn follower can cause damage to a lobe.
'51,'56 Squares, '48 VH, '27 Model C, R67/2, Mk IV Le Mans, '06 Super Duke and Ariel projects.

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fpassmore
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Postby fpassmore » Sat Dec 29, 2012 4:27 pm

Just as an added question on this subject. Does anyone have any experience with the cam oiling mod/kit offered offered by Bennet Longman
http://www.ironhorsespares.co.uk./Detai ... roductID=6

Looks a lot like the mod on my VF1000F which has extended the life of the cams considerably.

Happy New Year to All
Frank
'51 SQ4, '37 VH500 Red Hunter, '56 SQ4 (basket case), '49 Sq4 (basket case), '48 A7 BSA Twin, too many other BSA's, Norton's, Triumph's, Ducati's and Japanese to list. Just crazed is all my problem is.

chaz.wheeler
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Postby chaz.wheeler » Sat Dec 29, 2012 7:03 pm

wont show from link, just fitted one to a Mk1 and have one to fit to a mk2 if he wants it. Bruce does 14 pages with sketches on how to fit. must say fairly easy now Ive done one and even using an oil can it gets oil onto the cam, have also fitted the new morgo oil pump so customer shouldnt have any problems. only thing is sketches are ok but pictures would be useful. you know what its like , do I or dont I drill the crankcases?????
at least on the ironhorse site you do get 3 pictures to give you an idea usefull.


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