Billet cylinder head

Dr_C · Aug 27, 2014

bushmechanic said:
that's interesting ! I found the same wear inside the crank with even 0.55mm big end axial play, the factory spec is 0.4.

since then I aim for 0.7 - 0.8mm and have not seen any odd marks, quick look on KTMtalk found thew same spec used for 35mm big ends

the prox piston i got seemed a tad large to me so i heated the liner and piston to 400F and checked if the piston still dropped through freely,

easy test although you would think the piston would in practice be hotter than the liner.

if the pins are higher modulus and lighter than OEM im definitely interested

I will increase the axial play for the big end and since I'm using ball bearing mains, they can cope with a smaller axial play for the whole crank.

Due to the time concern, the pins will this time not be of any peculiar mtrl. They will be of 2511 (see attached spec). Different steel alloys have very similar value on Youngs modulus, so I need to find some Harry Parkinson drag bike builder knowledge, as they struggle with the same crank spread problem.

spanner · Aug 27, 2014

Different steel alloys have very similar value on Youngs modulus

Yes I thought that was the case.

Hardening technique would be as important ( if not more important ) than slight material composition differences.
If I was making a pin I would consider increasing the internal bore diameter ( to save weight ) and offsetting it to the outside of the flywheel, like some car cranks have.

We know the pin fit in the flywheel is the problem, I want to get my crankshaft laser welded, but the welder guy can only penetrate 3mm deep, 10 would be better

so still looking.
BMW cars have the crown wheel laser welded directly to
the carrier, Crown wheels are made of material very similar to a Husaberg`s flywheel.

I posted the bearing yesterday so it should leave Australia by the end of the month,

hope you get it in time.

bushmechanic · Aug 27, 2014

what about a very light crank with big muthafudger mains and "zero" crank axial play?

if the cases don't break then they together with the bearings should limit the crank spread , the cases will flex a bit of course but the lighter crank will reduce the axial loading too

im trying it but not with as much stress

Dr_C · Aug 27, 2014

spanner said:
Yes I thought that was the case.

Hardening technique would be as important ( if not more important ) than slight material composition differences.
If I was making a pin I would consider increasing the internal bore diameter ( to save weight ) and offsetting it to the outside of the flywheel, like some car cranks have.

We know the pin fit in the flywheel is the problem, I want to get my crankshaft laser welded, but the welder guy can only penetrate 3mm deep, 10 would be better so still looking.
BMW cars have the crown wheel laser welded directly to
the carrier, Crown wheels are made of material very similar to a Husaberg`s flywheel.

I posted the bearing yesterday so it should leave Australia by the end of the month, hope you get it in time.

Thanks, Spanner! We did some stress analyze (Ansys) on the web/pin connection. It showed that the main problem was that the hole in the web is deformed, and not holding the pin in place. A larger diameter pin didn't help much. IMHO the webs need to be thicker in the area surrounding the hole to lower the pressure from the pin. An offset of the hole in the pin, sounds like a good idea! Without enlarging the hole, I would propably gain some stiffness!

bushmechanic said:
what about a very light crank with big muthafudger mains and "zero" crank axial play?

if the cases don't break then they together with the bearings should limit the crank spread , the cases will flex a bit of course but the lighter crank will reduce the axial loading too

im trying it but not with as much stress

Sure you're not a split personality, Bushie, where the other you is a Harry Parkinson drag bike mechanic?

In HD´s they sometimes install axial bearings between the crank and the case, with "zero" play, to help limit the crank spread. The skinny Husaberg cases would probably dislike this idea...

fdracing · Aug 27, 2014

on my big engine i use to run about 0.1mm to 0.2 mm axial big end conrod clearance , the more clearance you have the less oïl pressure you get , especialy with these engine that have low oïl pressure .

as you said at full torque your crankshaft is bending and the clearance is reducing a lot , crankshat over 90 ps is a big issue !!!

for me nickasil it's not a choice for that kind power, its just obvious .

anyway you've made a very nice bike and a bloddy big hard job ;-)

spanner · Aug 27, 2014

I doubt the itself pin flexes much. Just flywheels moving on the pin itself. IMO

fdracing · Aug 27, 2014

sure , not the pin , but the wheels ;-)

bushmechanic · Aug 27, 2014

spanner said:
I doubt the itself pin flexes much. Just flywheels moving on the pin itself. IMO

yes and welding the outer edge of the pin to the crank doesn't even reduce the movement by all that much

maybe with yours you could grind out a 2-3mm fillet, laser weld 3mm in from there then fill the rest in with a TIG. more laser penetration would be better though

hey Dr_C how did you know I tinker with harleys?

this is me on the way down to the shops to get some milk.

in the husaberg yes i agree the cases are not such a good prison for the crank spread. I made the steel sleeves to spread the axial load and for my machine i think it is enough.

if the cases protest violently I have in mind to make 2 flat plates from 4mm thick bisalloy bolted together either side of the main bearings with 4 high tensile bolts, the 2 outside the cases at the front (the engine mounting bolts) and another 2 through the cases in the middle.

I think it would add enough strength to make the idea viable.

spanner · Aug 28, 2014

That is a work of art Bushie

Ghost · Aug 28, 2014

Dr_C said:
I need to find some Harry Parkinson drag bike builder knowledge, as they struggle with the same crank spread problem.

Guess Jörgen Karlsson over at sporthoj.com might be able to help you. Otherwise you could always pop an e-mail to Charley Karling (karling racing) he knows a thing or two about racing Harry Motor shakers... :giggle:

regards

/Nick

bushmechanic · Aug 28, 2014

what do we think about the tapered harley pin ?

kerry peterson the hillclimbing ledgend used a crank in one of their bergs that had the drive side and pin machined out of the same block of steel (no join), class was 700cc plus and nitrous fuel.

Dr_C · Aug 28, 2014

Ghost said:
Guess Jörgen Karlsson over at sporthoj.com might be able to help you. Otherwise you could always pop an e-mail to Charley Karling (karling racing) he knows a thing or two about racing Harry Motor shakers... :giggle:

regards

/Nick

Yes, thanks, Charley would be my first choice! But as this application is more about the crank webs, I'm not sure an effort with the pin will pay off.

Dr_C · Aug 28, 2014

bushmechanic said:
what do we think about the tapered harley pin ?

kerry peterson the hillclimbing ledgend used a crank in one of their bergs that had the drive side and pin machined out of the same block of steel (no join), class was 700cc plus and nitrous fuel.

The Folan engine has an ordinary 3 piece crank, but the drive side web is much thicker than the other. Maybe loosing the counter balancer and make such a crank, together with another bearing where I used to have a flywheel, would help? Then perhaps OEM size mains would be enough?

bushmechanic · Aug 28, 2014

I like the idea of a thicker drive side crank web, there is a picture somewhere on ben ballards site of one

he also made some with a champher between the 30mm diam section and the crank web

i reckon you could like the engine more without the counterbalancer, mine are smoother in the upper RPMs without it.

Dr_C · Aug 29, 2014

spanner said:
If I was making a pin I would consider increasing the internal bore diameter ( to save weight ) and offsetting it to the outside of the flywheel, like some car cranks have.

We put in a model in Ansys of a pin with centered hole, and with 3mm offset hole. With an offset, the flex increased by 5%! Thinking about it, it makes sense. Youngs modulus is the same regardless of the direction of the tension(press vs pull). So there is nothing to gain in stiffness with an offset hole. The tensile strength however, is a different matter!

So I will have some pins made of the same design as OEM. As there is a 0,8mm orifice for the oil in the pin, I do not think large axial play for the rod will dramatically reduce oil pressure in the system. Maybe the oil in the big end bearing washes off faster with a large axial play though...

Right now a thicker web on the transmission side and an extra main bearing outside the casing on the flywheel side, looks as the better way to increase life of the mains and life of the press fit of the crank pin. But still the big end bearing will surrender equally fast as now... NO, I will NOT produce a whole ******* engine! I think...

Dr_C · Aug 29, 2014

Water cooler cores are in da house (Pace Products rocks!) and the cams are welded and grinded. The weekend is salvaged! [emoji1]

bushmechanic · Aug 29, 2014

dr_c said:
we put in a model in ansys of a pin with centered hole, and with 3mm offset hole. With an offset, the flex increased by 5%! Thinking about it, it makes sense. Youngs modulus is the same regardless of the direction of the tension(press vs pull). So there is nothing to gain in stiffness with an offset hole. The tensile strength however, is a different matter!

So i will have some pins made of the same design as oem. As there is a 0,8mm orifice for the oil in the pin, i do not think large axial play for the rod will dramatically reduce oil pressure in the system. Maybe the oil in the big end bearing washes off faster with a large axial play though...

Right now a thicker web on the transmission side and an extra main bearing outside the casing on the flywheel side, looks as the better way to increase life of the mains and life of the press fit of the crank pin. But still the big end bearing will surrender equally fast as now...

no, i will not produce a whole ******* engine! I think...

never! LOL

Dr_C · Aug 30, 2014

As I have had to plug a couple of cells in my coolers, I ordered new cores to make sure capacity is intact. As several times before http://www.paceproducts.co.uk/ was given the task. They allways deliver custom cores within 2 weeks, with super quality and with a careful package. This is without a doubt a supplier I highly recommend!

spanner · Sep 1, 2014

Originally Posted by dr_c View Post
we put in a model in ansys of a pin with centered hole, and with 3mm offset hole. With an offset, the flex increased by 5%! Thinking about it, it makes sense. Youngs modulus is the same regardless of the direction of the tension(press vs pull). So there is nothing to gain in stiffness with an offset hole. The tensile strength however, is a different matter!

Hi Dr C
Did you analyses cover differing hole sizes, such as the Husabergs 18mm id
vs the heaver prox ktm pin 14mm, what size are you considering?

Dr_C · Sep 1, 2014

spanner said:
Hi Dr C
Did you analyses cover differing hole sizes, such as the Husabergs 18mm id
vs the heaver prox ktm pin 14mm, what size are you considering?

We didn't run so many variations. Only 18mm hole as is and with an offset. I do not think a smaller hole will help much on stiffness, as the added mtrl is around the center of the bolt. I'm staying with the 18mm for now.

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