Commando Crankshaft Porn

Status
Not open for further replies.
Nice video. The youtube DJ's should try remixing the audio from that sucker.
 
Mercury is nasty stuff to say the least!!
Oil leaks are a pain but I would not want to worry about leaking mercury! ! :D
 
Yeah I posted this to mc-engine list as toxic metal flywheel balancing subject line. Best I can glean we are past the point of no return into an extinction event, at least as concerns multi cellular life forms over next few decades and as all combustion and electrical power is deadly polluting might as well live it up to the end smooth as can be.
 
Snotzo said:
billet said:
jseng1 said:
Why go to all the trouble when I already have a cam with PW3 profile for BSA lifters - the JS stage 2. Plus it as two improvements - slightly more duration and closer lobe centers. The lobe centers are too wide on the PW3 at 107 degrees resulting in performance loss. The lobe centers on the JS2 are much better at 105 degrees. You want tho lobe centers to be close as possible without causing valve clash - to about 102 degrees but that would cause valve clash on any stock head unless the cam was very mild such as a stock cam (stock cams are at about 102 degrees).
Click to expand...
Click to expand...

I have noted comments made in earlier posts about variations in the lobe centers of the PW3 camshaft, but had not an opportunity to measure one. The chance to do so came up recently, and using Cam Pro Plus equipment I was surprised to find the separation of the lobes based on the points of maximum lift was for the left cylinder lobes 109.28 deg, and 109.77 deg. for the right. I have noted that Jim Schmidt has given a figure of 107 degrees, and has indicated that in his opinion somewhere in the region of 102 ~ 103 degrees would be near ideal. My enquiries with the camshaft manufacturer in the UK brought forth the comment that they have made no variations to the lobe centers for this camshaft. If that is the case , then where does such variation come from, and are there any examples that are even wider than the 109 degrees I measured.
Is Jim's figure correct, or is the camshaft I measured correct ? The question has been put to Peter Williams for a definitive answer, but thus far he has declined to comment
Click to expand...


How does Cam Pro Plus work? Does it measure the cam by itself or in the motor? I've found 2 or 3 degrees variation in cam measurements (on other motors) by changing to very light springs on the valves to remove distortion from stiff springs. Stiff springs cause closing valves to pull slack in wrong direction. If a bench test how does Cam Pro Plus account for different geometry in intake and exhaust pushrod length and angle, rocker arm ratios and the like?
 
Edge,

You make a relevant point regarding how spring strength may affect valve motion of pushrod/rocker arm engines. Below is an example (obviously not a Norton) of a system evaluated with a very light spring (just enough to assure mechanical contact) and with a heavy racing spring. As the data show, mechanical deflection of the system in the presence of the heavy spring causes both lift and duration, as measured via valve motion, to be altered significantly over the light spring analog, accounting for a loss in curve area of ~ 6%.

I don't know how Snotzo measured the subject cam, but if he was measuring directly off the lifter or in some test fixture, the LSA he reported should be correct as mechanical deflection of such a system would be minimal.

Anybody have any light spring vs heavy spring data for a Norton? I'd be curious to see the extent of deflection the Norton valve train has. Is it solid or is it a "swingset"?

Commando Crankshaft Porn
 
Getting back on topic, I just noticed in Classic Racer that Mick Hemmings is now selling a billet crankshaft. "Made by a well-known company in the car racing world to the highest specification." No other info yet.

Commando Crankshaft Porn


Ken
 
Arrow Precision in Hinckley?
I worked just round the corner, Triumph same distance the other way.
 
nickguzzi said:
Arrow Precision in Hinckley?
I worked just round the corner, Triumph same distance the other way.
Click to expand...

Could be. I guess we'll have to wait for someone to ask Mick.

Looks like it is more "pork chopped" than the Nourish crankshafts, and maybe has bolt-on flywheel weights. I'm guessing it is lighter than the Nourish items.

The interesting questions are going to be if it is available in other strokes, or in MK III dimensions, and, of course, what the price is.

Ken
 
Thats right..check out this months classic bike mag...£1200 quid..or there abouts.
lcrken said:
Getting back on topic, I just noticed in Classic Racer that Mick Hemmings is now selling a billet crankshaft. "Made by a well-known company in the car racing world to the highest specification." No other info yet.

Commando Crankshaft Porn


Ken
Click to expand...
 
If you buy a Dozen , youll save twelve times as much . :oops:

Outside of that , must save a lot of problems , running straighter would keep all the bits on the ends aligned better ,
and not set up a harmonic trampoline effect in the cases . :shock: Will have to have a word to him , if he's not doing
them for Mk IIIs . :wink: Selling off the E S & all the gubins would help pay for one ! . :p :)
 
Early Ed Geoff Collins stroker crank. Geoff's Canada crew did Peels Frantelli crank with some correction in Calif crank shop plus Left Coast Racing.

Commando Crankshaft Porn
 
im using a ' modified ' one like this . STEEL , like a Holden 186S & Falcon 221 / 3.6 pursuit , for our less familiar Australian friends , thyre STEEL too , amougst others . pity its been sold down the river .
now its nuclear waste dumps - progress indeed . :roll: :shock: :x .

Commando Crankshaft Porn
 
hobot said:
Moderator please change the sexual suggestive subject line. Also watch must our lingo of matching plumbing fittings terms as already had complaints its offensive.

Just change the Pee to a Bee . :!: :mrgreen:
Click to expand...
 
comnoz said:
It has normally been found that a featherbed frame/engine assembly would resonate somewhere over 5000 rpm with the stock balance factor of around 65%. Jim
Click to expand...


With my lightweight pistons and longer rods and the crank balanced at 65% there is barely a noticeable vibration frequency thing happening at about 3500 RPM in top gear only. Its so slight that I can't tell if its from the motor or from my chain whipping at that speed (you can watch it happen) or if its just the pulses of the motor interacting with the drive train etc. It disappears 100 RPM either way and is not enough to worry about - usually I don't notice. But the bike is smoother when up at 4000 RPM when the cam comes on but by then I'm doing 80 mph (4 to 1 gearing). 3000 RPM seems like a lazy putt at 60 mph. Heavier pistons and shorter stock rods would probably behave completely different - there being more stress at TDC when the pistons reverses more quickly.

The vibes just seem to get more intense no matter what when revving higher and higher. An exponential thing about the crank imbalance.

I'm with you on balancing so the motor vibrates in an orbital motion instead of being overbalanced so it shakes more up and down or front to rear. With the lightweight pistons and longer rods there is no benefit in overbalancing in any direction that I can tell. A big hint is to look at the single speedway motors and they balance in the low 60s or high 50s depending on inclination of the cylinder (vertical using the higher BFs). But since a higher balance factor shakes less up and down I prefer to err that direction just a little until I learn some more and know better.
 
lcrken said:
nickguzzi said:
Arrow Precision in Hinckley?
I worked just round the corner, Triumph same distance the other way.
Click to expand...

Could be. I guess we'll have to wait for someone to ask Mick.

Looks like it is more "pork chopped" than the Nourish crankshafts, and maybe has bolt-on flywheel weights. I'm guessing it is lighter than the Nourish items.

The interesting questions are going to be if it is available in other strokes, or in MK III dimensions, and, of course, what the price is.

Ken
Click to expand...


Hi Ken,

yes, available in other strokes, configurations (90 degree etc) lighter than Nourish.

Rods to suit also available

That's my next project sorted then :)
 
Status
Not open for further replies.
Back
Top