Restoring a steel cam lobe

[Tim StevensParticipant @timstevens64731]

Expert needed – please

[Tim StevensParticipant @timstevens64731]

I need to restore one lobe on a steel camshaft (for a 1928 Car). Stellite and grinding have been suggested, but I am finding it difficult to get the work done.

Do you know of a sound craftsman in the West Midland to Wales area who is known to be good at this sort of work? Or two, as welding and cam grinding are distinct.

Many Thanks

Tim (10 miles west of Ludlow, UK)

[Chris Evans 6Participant @chrisevans6]

I have had motorcycle cams done by. Newman Cams in I believe Farnborough ? Worth a google ? They did a good job on my 1929 BSA cams. Don't expect them back in a couple of days though.

Edited By Chris Evans 6 on 17/08/2018 17:14:16

[Howard LewisParticipant @howardlewis46836]

Hope fully there may be a little enough area, unworn, to know the original form. Departing too far from it could set up some damaging forces within the vale train; although 1928 it is likely to be side valve rather than push rod or OHC.

A broken, or later worn, cam follower would be another unwanted problem.

Howard

[pgk pgkParticipant @pgkpgk17461]

I doubt they'd do it themselves but if you give Billcar in Shrewsbury a call (their car division) then I'd guess they'd know anyone reasonably local who could do it

pgk

[Tim StevensParticipant @timstevens64731]

There are three other cams on the shaft to provide a 'master' for copying, Howard. And one of them is exactly at 180 degrees to the worn one (as you might expect).

And Bill Car was my first visit and the nice man said 'no way, sorry'. Which did rather contradict the phone call when I made the appointment, but there you go.

Cheers, Tim

[KWILParticipant @kwil]

Try these people as a source of information, if they do not know then no one will. Look at their project Binky for a good intro to their skills.

Home

[Ian PParticipant @ianp]

Tim, it might be worth giving Chase Engines a ring. I have not used them (yet) but they do have a good reputation and I have seen their work at some classic car shows.

https://www.chaseengines.co.uk/

Ian P

[Jeff DaymanParticipant @jeffdayman43397]

One other option although not cheap would be to have a new cam made by one of the US cam firms. If the old one can be accurately measured and a drawing / 3D CAD file made, they will quote it. If new of course it could be made in modern spec steel as used in 1000+ HP race engine cams, with no risk by doing a weld / grind repair to the original cam. If the original cam is forged steel the weld would be relatively easy. If cam is cast iron the weld could be very tricky depending on the type of CI. I've had a couple of CI cams and connecting rods from pre 1930 engines melt and fall apart during welding despite extreme care in prep and weld technique- it can happen. That may be why BillCar said no way.

Couple of good US cam firms, Lunati and Iskenderian:

http://www.lunatipower.com/

http://www.iskycams.com

[thaiguzziParticipant @thaiguzzi]

+1 on on David Newman Camshafts. Used them before, excellent results.

Certainly better than sending to the States & using Megacycle or Isky.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by thaiguzzi on 18/08/2018 07:57:00:

+1 on on David Newman Camshafts.

.

They certainly tell a good story

The website is very well presented and informative. **LINK**

Prototype & Vintage

MichaelG.

[ just browsing ]

[Chris Evans 6Participant @chrisevans6]

I hope this isn't hijacking the thread but I have a question re steel for cams. I am soon going to be making a pair of cams for a 1930s bike and was going to use EN32 and case harden. Any other or better suggestions ? I have chosen the EN32 because I can buy a gear blank in that materiel.

[HopperParticipant @hopper]

ON the other hand, any good local welding shop could build the lobe up with common hard-facing rod. You could then grind the profile on it on a slightly modified bench grinder. All it takes is a simple rocking frame, pivoted at the bottom with two a chuck and centre or similar to hold the camshaft. If there is same profile cam 180 degrees out, an adjustable bolt bearing on this will provide the necessary movement. Cam is then rotated by by hand, back and forth over the welded area as the welding is ground down. Screwing in the bolt puts the cut on until the ground section comes down to meet the unground part.

This video shows the principle, but it can be done a lot simpler for a one-off.

 

PS, here's a simpler homemade rig, although he's only grinding the base circle to create higher lift in this example, you can see from the previous vid how another cam lobe can be used as the master to control the rocking and shape the cam lobe.

Edited By Hopper on 18/08/2018 09:32:21

[Mick B1Participant @mickb1]

If there's enough left of the original cam, you can measure the rise and make a good estimate of the dwell, then grind the profile by hand with a sharpening stone.

That's what I did in '74 for my BSA A10, and when I next looked at it 25k miles later it and the follower were fine and mirror-polished. There'd been scare stories about grinding through the case-hardening, but I was too poor for any other solution, and they turned out to be old bikers' tales anyway.

It took me 16 hours with an India oilstone, but hey, I was young and carefree then…

[Tim StevensParticipant @timstevens64731]

Thanks, chaps. A selection of firms recommended, and I have sent messages asking them – and you added a few ideas, too.

To clarify the case, the shaft is steel, not cast-iron, and there are three other exhaust cams on it to act as a pattern for grinding. And the car is not expected to break speed records, just to keep up with ordinary traffic as a touring car should. Max rpm is around 4000.

And – new camshafts are available – yes, for a 1928 car – but at £500 and I know I also need pistons, crankshaft, etc … So, if I can save a bit here and there I might be able to afford the rest of the bits.

Cheers, Tim

[Jon LawesParticipant @jonlawes51698]

I'd like to know more about the car if you have a link to some info about it, Thanks

[Tim StevensParticipant @timstevens64731]

Not a link exactly, but – Lea Francis (Coventry) model P, with coupe-cabriolet body* by Cross & Ellis. Meadows (Wolverhampton) 4ED engine, 1500cc, about 38 BHP. A good solid vintage car, a bit heavy but not ponderous (like some are), with nearly OK performance and inadequate electrics. The Magneto is no problem, but the dynamo offers 8 amps max at 3000rpm, less either side of this, and control by switching the dynamo on or off. IE: too much or not enough until it is dark, and then not enough.
* this means an open touring car with two seats but not low like a sports car, and a hood which includes proper glass windows rather than the (lighter) celluloid type. And a dicky-seat at the back, which means that the extra passenger (traditionally the mother-in-law) gets no benefit from protection when it rains.

Any more info – just ask

Cheers, Tim

[Barnaby WildeParticipant @barnabywilde70941]

SEP at Kegworth have an excellent reputation http://www.sep-kegworth.co.uk/page1.htm

[Chris Evans 6Participant @chrisevans6]

Tim, my first ever car was a 1929 Leaf. At 17 I soon got fed up with the tinkering and sold it on for £75. The stupidity of a youth !

[ronan walshParticipant @ronanwalsh98054]

Posted by Mick B1 on 18/08/2018 09:40:50:

If there's enough left of the original cam, you can measure the rise and make a good estimate of the dwell, then grind the profile by hand with a sharpening stone.

That's what I did in '74 for my BSA A10, and when I next looked at it 25k miles later it and the follower were fine and mirror-polished. There'd been scare stories about grinding through the case-hardening, but I was too poor for any other solution, and they turned out to be old bikers' tales anyway.

It took me 16 hours with an India oilstone, but hey, I was young and carefree then…

The problem with the A7/A10 cam wear, is a symptom of wear in the timing side bush, the oil pressure drops to a point where the pressure relief valve does not open, or open often enough to give the cam a shot of oil. Great engines apart from that though, and an end feed conversion to the crank see's this problem off.

[Mick B1Participant @mickb1]

Posted by ronan walsh on 19/08/2018 22:03:39:

…

The problem with the A7/A10 cam wear, is a symptom of wear in the timing side bush, the oil pressure drops to a point where the pressure relief valve does not open, or open often enough to give the cam a shot of oil. Great engines apart from that though, and an end feed conversion to the crank see's this problem off.

What was more serious was the timing side main bearing bush (turned and bored by a friend) seizing on the journal and starving the crankshaft of oil. Eventually it broke inside the timing side big end. Still got me home. It was the resulting rebuild that had me regrinding the 'spitfire' (?) camshaft I'd got from somewhere. The timing side bush seemed fine IIRC – it was well supplied with helical oil grooves.

Edited By Mick B1 on 19/08/2018 22:41:49

[thaiguzziParticipant @thaiguzzi]

Posted by Michael Gilligan on 18/08/2018 08:56:34:

Posted by thaiguzzi on 18/08/2018 07:57:00:

+1 on on David Newman Camshafts.

.

They certainly tell a good story

The website is very well presented and informative. **LINK**

Prototype & Vintage

MichaelG.

[ just browsing ]

Thanx for that, good to catch up with what they now do. Moved on a bit since i last used them in 02-03…

[ronan walshParticipant @ronanwalsh98054]

I had a pair of Newman cams for a triumph twin a few years ago, and they appeared well made to me, no machining marks , nicely polished and nitrided. Other people i know have been critical of their products, one in particular had a problem with dimensions of a hole in the end of a cam for a japanese car, reckoned they did not want to know when he raised the issue with them.

[thaiguzziParticipant @thaiguzzi]

Posted by ronan walsh on 21/08/2018 01:02:39:

I had a pair of Newman cams for a triumph twin a few years ago, and they appeared well made to me, no machining marks , nicely polished and nitrided. Other people i know have been critical of their products, one in particular had a problem with dimensions of a hole in the end of a cam for a japanese car, reckoned they did not want to know when he raised the issue with them.

Funnily enough, Triumph 650-750 twins is all we used them for.

The last set done by them were welded up and refaced on a set of Megacycle cores. These for some reason did'nt last that long, shot by 5-6000 miles. But they were also pretty ridiculous in duration & lift so if we classed them as "racing cams" they did pretty well (in a road bike).

[pmm1Participant @pmm1]

The veteran car club Welsh rally will be held in Presteigne the weekend 13th October, when the town will be awash with veteran cars and and a number of experts who maintain them. I suggest you buttonhole the stewards, etc. and, if you are lucky, you might get directed to someone who can help.

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