Unusual mag engine camshaft

[Tony Betts]

Found this earlier whilst sorting a cam for a customer.

The bottom cam is a standard XL cam for a mag engine.

Check out the width of the inlet loans on the top camshaft.

The loabs are a 1/3 wider.

The camshaft looks to be an original cast or forged cam, but I can't find any numbers on it. I've put a mic on it. The inlet loabs are 15 thou bigger across the lift and 10 thou bigger across the dwell.

What do you think. SPORTS.?

Thanks tony.

     

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A closer look.

I've never seen one of these before, so I'm hoping you experts know what it is.

Thanks tony.

   

[Zetomagneto]

Hi Tony, what’s the base circle, and lift of the 2 different cams?
If I understand correctly from what you said, the lift is only .005” higher.
You would need to check the opening, closing, and duration to know if this is anything 
special.
Can you be bothered to set it up and check with a degree wheel?

[Charles P]

It may be a trick of perspective but the nose profile looks different - more rounded. This could mean a number of interesting things

Best wishes

Charles

[Ian Williams]

Tony can you clock it? without knowing timing it is hard to say if it is special, however I do agree with Charles suggestion. Perhaps I need to have a rummage through my stock of parts and see if I can find any with wide flanks

[AustinWood]

Is the centre bearing larger diameter too?

[Tony Betts]

thanks guys.

im not able to set my own lathe up at a moment. due to sorting the sheds. and moving alot of stock about.

but ill see if i can get time to use a friends.

i know the lift and dwell difference isnt huge, but there must be a reason for it. and having the wider loabs.

i got a tray of mag cams, so ill check them against any other veriations.

[Ian Williams]

Might be just deceptive Charles the exhausts always have a more round nose than the inlets, we are not getting a good view of the inlet lobes in these pictures. I have also found to not uncommon to find a 5 thou difference in life heights of cams when you check a whole batch, so perhaps that not a fair indicator of anything either.

[Charles P]

Might be just deceptive Charles the exhausts always have a more round nose than the inlets, we are not getting a good view of the inlet lobes in these pictures. I have also found to not uncommon to find a 5 thou difference in life heights of cams when you check a whole batch, so perhaps that not a fair indicator of anything either.

Yes Ian, you're probably correct.
5 thou variation in camshafts is nothing compared to some of the frankly "hit and miss" machining I've seen in Austin crankcases

[Steve Bryant]

The camshaft seems to be a mirror image of the other one. Might it be for an engine designed to rotate in the opposite direction?
Stephen

[Tony Press]

Don't you have to just rotate one 180 degrees ?