Commando Pushrod Tech

If you look back at the 70s Ed Iskenderian was up to his eyeballs in calculations too, however the E3134 type of cam appears very often in many motorcycles. So what are we looking at when we view a PW cam ? Was it computer designed or drummed up on a slide rule ?

How ever it was done by guess and by golly or critical calculations, it wasn't done very long after examples of Axtel and Woods cams showed up in the old country.

I shared the office in 1970. I'm not suggesting that the cam that PW was working on at that time was ever made, let alone made and sold. I just found the concept of somebody like Peter copying a 10 or 15 year old competitors design and passing it off as his own a bit unlikely. I know that he held his Fathers cam designing talents and integrity in very high regard. At the time I would imagine that he used a slide rule, nothing wrong with that, there not being too many 'puters about in 1970 and just about 100% of all calculations up to then being done the hard way or with a slip stick.
cheers
wakeup

Wakeup, I'm not implying that PW did anything different to what many others have done. Have a look at the timings at nil clearance that the E3134 are specified to be used at, by Triumph. Then compare them with the timings used in the SFC Laverda, and the two valve Jawa speedway motors. Also compare them with the inlet cam timings on a lot of the faster 70s four cylinder race bikes.
I think you will find them all fairly similar - there is a convergence ? The thing that intrigues me is that when I fitted the two into one pipe to my 850, and advanced the standard cam 12 degrees, I got a major increase in torque. So what timings give the best results from the standard commando cams - were they retarded to make the road bikes more tractable and sane to ride ?
I am never inclined to accept manufacturers' recommended cam timings at face value. Until you try advancing and retarding the cam ,how do you know what suits your exhaust system and your inlet length ?
With a standard road bike, it is usually pretty safe to assume you have something near the optimum. However I would point out that the steering geometry on the earlier commandos was race format, and a few inexperienced riders crashed, so it was changed to a safer setup on later models . The same sort of thing probably happens to the motors etc. as the models progress.
PW is probably a very nice guy, however if someone has found something which really works well in a race bike, do you think they are going to tell you about it ? When you look at the history of the Manx Norton, the works bikes always seemed to be much faster than the average punter could buy, and the commandos were not raced for such a long time. I'd love to see the notes on the tests done on the PW cams as they were developed.

Lash like air pressure and chain tension, each set up has some optimal setting but generally fall in same zone for everyone. I won a bet with V8 race engine shop building their first ever optimized for propane fueler by my parts picking, him telling me I told ya so on 3 prior runs... so I put up another $250 for one more dyno run but with cam advanced just 0.5' more than last run, and got another ~dozen hp to top out above what the LPG 'carb' was even rated for. Only way I know is old school, start loose then work up while hot > tighter till quiet as expected then check measures when cold.

please read your in box Ken