Demon Camshaft

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Mick Knights

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Hi. All. My little Demon is coming on, but I've now reached the camshaft, something I've been putting off for a while. As I only have a Myford Super7 using the turning fixture described might be a bit of an ask. I've fabricated four throw camshafts before but the angular positions of the individual cam lobes was always supplied. I can't see any way of establishing the individual cam lobe positions from the spread sheet with the plans and as maths was never my strong point I would be grateful if there's a member who can check my calculations for the angular positions each lobe. I've taken Exhaust #1 as zero (360 degrees) with #1 being the first lobe to load and bond, the angular positions follow in cylinder order rather that firing order. Firing order: 1 8 4 3 6 5 7 2 Lobe separation of exh. and inlet is 110 degrees. #1 ex 0 inlet 250. #2 ex 240 in 130. #3 ex 60 in 310. #4 ex 280 in 170. #5 ex 340 in 210. #6 ex 200 in 90. #7 ex 100 in 350. #8 ex 240 in 130. Thanks. Mick.
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retailer

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Don't make the same mistake I did when working out the cam lobe positions the cylinder banks are 90deg apart so you need to factor in that 90deg, I haven't machined my cam yet but I did draw it in cad and it took me a few hours of head scratching before the penny finally dropped. I can't help with the Demon cam, that is a design by Steve Huck, from what I have seen he is a very knowledgeable and helpful guy I'm sure he will be along to help. BTW your build looks great.
 

Mick Knights

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Hi. Steve. I'll check that out tomorrow. I've already fabricated the crankshaft using the crankcase as an assembly fixture. The crank journals are cross drilled, pinned and then bonded in position. As every journal is supported between a bearing or bush there is very little chance of any movement. The advantage is that small adjustments can easily made to ensure smooth rotation and should a bearing bush fail the whole crank can be disassembled. I'm really enjoying machining this engine and what with the current global situation it should be completed sooner rather that later!
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Mick Knights

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Hi. All. I've checked out the chart and now I can see how to read all the cam lobe angular orientations to #Exh 1. Thanks. One question, why are the positions for the exhaust and inlet on cylinders 6 & 7 identicial? Meanwhile I'm having fun assembling the radiator.
 

Mick Knights

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Finially finished the camshaft, thanks to Steve's input. I took the bonding approach as I have a little cnc mill and so the individual lobes weren't a problem to produce, just got to finish off the valves and I'll have a look to see if everything works as it should!!
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Mick Knights

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I've never experienced any problems with bonding, but once the positions are verified then pinning would be the belt and braces approach.
 

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