E: Engine Interesting big end...

[oexing]

My rods are one piece, case hardened, ground and lapped after heat treatment. The mainshafts and crank webs are one piece as well, no Mills pin there and main roller bearings i.d. is 30 mm , 62 mm o.d. so crank cases were alu bushed for 62mm bearings, shrink fit of about 0.06mm undersize. That will grip the outer lipped races up to 120 degrees C - normal practice with old sixties BMWs and the like.
Trueing up the pressed up crank is one thing, got them all right at 0 to 0.02mm runout at the outer ends of the mains, set up in V-blocks. I do not accept ways of taking the lot between centres, that masks flaws I believe.
A friend had some desire for dynamically balancing cranks so I set up a machine and belt drive to the crank with acceleration sensors at each main shaft. The crank halves were statically balanced before with dummy weights, then a dummy crank pin and central dummy weight were loctited in to have a temporary "complete" crank assy. for runs on my machine for fine balancing up to almost 3000 rpm . There is an Australian low price software and electronics for balancing propellers etc. but in the end I could not get conclusive results from these calculations so I used some oscilloscope app for trial and error testing by adding small magnets in various places and seeing improvements. Anyway it pays - hopefully - to look into this closer. I did a few Yam SR 500 cranks as they come and found dramatic off-centre balance defects . These mass production crank webs are forged type and not machined all over like Vincent so there is a lot to be gained with these.
Allright, I am a retired toolmaker so can use my time for fooling around as long as I like so it will be quite some time to get any of the bikes on the road.

Vic
Link to balancing app:
Dynex hobby

 

[Oldhaven]

Brilliant work! Still I can't the picture out of my head of a Vin crank assembly flying out of there at 3000 RPM.

 

[royrobertson]

The crank I made in 2000 to John Renwicks design has Ina needle rollers (silver plated?) mounted on a pressed in 40mm pin. The rods are Carrillos 5mm shorter for the 100mm stroke (90mm bore) of my race motor. The flywheels, pin and mainshafts were all deep hardened locally. My very good friend and ex-Vincent owner John Barrett (no longer with us and much missed) Jig-ground all the holes in the crank at work so some could be used for "line up pins" on assembly. I ground the rest on my little bench mounted grinder.
Eighteen years later, after many racing and sprint miles, it is still going strong. Cheers Roy

 

[vibrac]

Glad to see you here Roy. That crank you passed to me for the Egli did play a large part in Ben winning of the BHR championships

 

[royrobertson]

I was only too happy to be able to help. Shame its not being raced now. As you know the 100mm stroke crank you had was my Mk 1 version made out of EN24. The Mk 2 in my motor does not require the spacers under the muffs, longer push rods etc. because it has the shorter rods. All the Mk 2 parts were made of EN36 and case hardened to a depth of 40 thou. Having my own little bench cylindrical grinder has been a "godsend" Its a proper manufactured item with a heavy base casting but the actual manufacturers label is missing so I don't know who made it. If you go to Brighton Speed Trials 2018 YouTube you will see the bike runs including mine.
I won the regularity trophy this year with runs of 11.76 and 11.74 secs.

 

[Vincent Brake]

And on top of that a shorter rod will put out more tork on the main, due to the effect of the combustion paek being more "fully"used to create power at the longest "armlenght" of the pin from the center of crank.
look up Dan Smiths bike, amazing. i got it from him and than did some graphics.

 

[royrobertson]

I noticed that the splines on your mainshaft are machined with an end mill which gives a flat bottom. I was so lucky years ago, when rooting through some side and face cutters in my local second hand tool shop, to actually find the correct spline cutter for the one inch BS shallow spline. It has made this operation so easy.
Cheers Roy

 

[oexing]

Roy,
I did the splines with an 4 mm end mill radiused at the corner a bit. But there are no flat faces here , did the correct radii in small steps with the dividing head and went for perfect fits in all corresponding faces within the splines - in all splines and there are a few in a Vincent engine and gear box. So I did not get new spares mostly but chose to laser weld all splines and do them up with a hf spindle on the manual mill. I must have spent minmum a whole day at the laser machine to build up all susceptible faces - not to speak of time to finish grind them. I am terrible at fits when it comes to splines so did not have much trust in new reproductions from the Spares Co to provide that kind of fit I´d accept. Most of you will know the effects a poor fit on splines does to components so no compromises for me.
I did not even think about looking for obsolete tools for doing these crank splines easily, not the faintest chance to find anything in my country. In that regard I did try to avoid any imperial sizes if I could help it, lots of Helicoils, metric bearings in most places, even modifying them for imperial shafts. Life is too short to mess around with finding imperial sizes at funny costs today. And I believe to be the last owner ever to repair these engines as I think all street use will be banned in a few decades, all political activities seem to confirm my view. So I feel very free to do as I like. I do my bikes as I like and don´t care much what others say but try to keep the "spirit" of the bike and time.
As to silver plated cages, a few days ago I looked at a replacement set of conrod and big end for a Yam SR 500 . Same type of steel caged INA needle bearing, silver plated. Can´t see much benefit in a four stroke engine, must be more of a two stroke thing I believe. There is a lot of oil supply in a SR big end for keeping the light cage floating on its oil film fighting the centrifugal forces there. Silver being a competent bearing material is pretty new to me ?? INA did silver plating on request for big companies long time ago, was not standard. But big needle bearings are no longer available since many years from INA . You´d have to look into China to find their supplier - as I did.

Vic

INA KZK big end bearings. The one at left is an older INA type, next right is last I got from INA here, 20 years ago. The two at the right side are from Chinese supplier, sizes 40/48/20 and 35/42/20 mm .

 

[Flo]

Roy,
I did the splines with an 4 mm end mill radiused at the corner a bit. But there are no flat faces here , did the correct radii in small steps with the dividing head and went for perfect fits in all corresponding faces within the splines - in all splines and there are a few in a Vincent engine and gear box. So I did not get new spares mostly but chose to laser weld all splines and do them up with a hf spindle on the manual mill. I must have spent minmum a whole day at the laser machine to build up all susceptible faces - not to speak of time to finish grind them. I am terrible at fits when it comes to splines so did not have much trust in new reproductions from the Spares Co to provide that kind of fit I´d accept. Most of you will know the effects a poor fit on splines does to components so no compromises for me.
I did not even think about looking for obsolete tools for doing these crank splines easily, not the faintest chance to find anything in my country. In that regard I did try to avoid any imperial sizes if I could help it, lots of Helicoils, metric bearings in most places, even modifying them for imperial shafts. Life is too short to mess around with finding imperial sizes at funny costs today. And I believe to be the last owner ever to repair these engines as I think all street use will be banned in a few decades, all political activities seem to confirm my view. So I feel very free to do as I like. I do my bikes as I like and don´t care much what others say but try to keep the "spirit" of the bike and time.
As to silver plated cages, a few days ago I looked at a replacement set of conrod and big end for a Yam SR 500 . Same type of steel caged INA needle bearing, silver plated. Can´t see much benefit in a four stroke engine, must be more of a two stroke thing I believe. There is a lot of oil supply in a SR big end for keeping the light cage floating on its oil film fighting the centrifugal forces there. Silver being a competent bearing material is pretty new to me ?? INA did silver plating on request for big companies long time ago, was not standard. But big needle bearings are no longer available since many years from INA . You´d have to look into China to find their supplier - as I did.

Vic
View attachment 23677View attachment 23678

INA KZK big end bearings. The one at left is an older INA type, next right is last I got from INA here, 20 years ago. The two at the right side are from Chinese supplier, sizes 40/48/20 and 35/42/20 mm .
View attachment 23679

Hi Vic,

Have looked at Nadella: https://www.nadella.de/ ? They offer the relevant sizes with a cage made in hardened and tempered steel - no Silver though.

PF

 

[vibrac]

" I think all street use will be banned in a few decades, all political activities seem to confirm my view."
Wow giving up without a fight!, Nobody has banned the Horse from public roads yet, And in the UK you only have to see the type of person with money and influence coming to events like Goodwood and filling the car parks with exotica to know the greens will have a hard fight. Once the majority of the public who care nothing for vehicles except getting the latest electronic filled tin bucket are 'greened', 'automated' and 'regimented' then I think we the last vocal 5% will join the horse riders, Dog carts, steam engines and other antique means of transport,