Author Topic: polishing con rods.  (Read 2674 times)

Offline sinbad

  • Uk north west coast
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 73
  • Karma: 0
polishing con rods.
« on: 28.09. 2010 20:20 »
Hi Guys,
           can anybody tell me if there is any advantage polishing the con rods.
  Cheers.
Rod
1960 A10                             1998 Honda Cb 500
1953 sunbeam s7                   1988 Mz 250
1953 Nsu Consul 500 single        Jzr cx 500 Trike

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8101
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: polishing con rods.
« Reply #1 on: 28.09. 2010 20:42 »
G'day Sinbad,
                      besides the fact they look pretty and your the only one that knows. Polishing removes any nicks, scratches and burrs that could turn out to be a fracture. A must in high performance motors.  If yours look like they have been through the whirlpool, it would be a good idea.. File out any imperfections then use wet & dry going down in grit size to 1200 then polish with a mop & wax. Just take the bare min to remove the flaw.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
Australia
Muskys Plunger A7

Offline sinbad

  • Uk north west coast
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 73
  • Karma: 0
Re: polishing con rods.
« Reply #2 on: 29.09. 2010 15:41 »
 Thanks Muskrat,
watched a guy on you tube with highly polished rods just wondered. cheers.
Rod
1960 A10                             1998 Honda Cb 500
1953 sunbeam s7                   1988 Mz 250
1953 Nsu Consul 500 single        Jzr cx 500 Trike

Offline Mark Parker

  • Yea I'll probably get kicked off
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 29
  • Karma: 0
  • Looking for a picture of my old A10 :( :(
Re: polishing con rods.
« Reply #3 on: 30.09. 2010 09:52 »
Even with polishing, if they are old and fatigued, they can still break and take out cases etc. If new rods are expensive or difficult to get Ridgecrestengineering in Melbourne make nice alloy or steel rods to a high spec. I got some years ago to replace norton rods in my motor and had them made a little longer. 

Mark
Had a nice A10 once, :( now only have the power egg child A65 :(

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8101
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: polishing con rods.
« Reply #4 on: 30.09. 2010 11:49 »
Hay Mark, too pretty to be on the inside. *smile*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
Australia
Muskys Plunger A7

Offline Mark Parker

  • Yea I'll probably get kicked off
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 29
  • Karma: 0
  • Looking for a picture of my old A10 :( :(
Re: polishing con rods.
« Reply #5 on: 30.09. 2010 12:43 »
The crank is a std A65 we cut in half and bolted up at 90 deg. It makes quite a difference, (more responsive and smoother at revs). The rods are on my longer stroke altered norton crank which is also 90deg, the reason for the bolts screwing into the cap is the lack of space in the crank case.
I want to make a crank like in the photo only with a ballancemaster ring in the centre flywheel, the short stroke 90 is quite smooth but the ring should smooth it more and maybe get it similar to an engine with a ballance shaft but without the weight and performance loss.
 Yea I had an old pair of Norton rods I polished and fired one through the cases, should have made mounted it for the wall, it chopped all around even into the gear case, the oil pickup tube was in the centre of the road. These rods are rated for 100HP per rod, so should last for a while with a lot less thumping at them than that.
  I met Carey the other day, we were near his place and heard a twin running and so intoduced ourselves. His A10 will be nice when he gets it sorted.
Mark
Had a nice A10 once, :( now only have the power egg child A65 :(

Offline wilko

  • Resident Legend
  • *****
  • Join Date: Mar 2010
  • Posts: 681
  • Karma: 4
Re: polishing con rods.
« Reply #6 on: 30.09. 2010 20:33 »
Do those rod bolts screw straight into the cap material, or are there steel inserts?

Offline sinbad

  • Uk north west coast
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 73
  • Karma: 0
Re: polishing con rods.
« Reply #7 on: 30.09. 2010 20:47 »
I noticed that Wilko,
Thanks for the info Mark I will inspect my rods very carefully.At the moment I am struggling  with the removal of the anti drain valve grub screw,just soaking with Plus gas for a few days after which I will try with a little heat and impact wrench  Cheers
Rod
1960 A10                             1998 Honda Cb 500
1953 sunbeam s7                   1988 Mz 250
1953 Nsu Consul 500 single        Jzr cx 500 Trike

Offline Mark Parker

  • Yea I'll probably get kicked off
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 29
  • Karma: 0
  • Looking for a picture of my old A10 :( :(
Re: polishing con rods.
« Reply #8 on: 01.10. 2010 09:16 »
They screw straight into the alloy, they are ARP bolts and do up to 50-55ftlb, the cap registers in the rod on serations, and the shells are retained by a brass plug in the cap with a hole drilled in the centre of the bearing shell.  Maybe in drag racing it provides a more positive stop against bearings spinning.
Mark
Had a nice A10 once, :( now only have the power egg child A65 :(

Offline bonny

  • Valued Contributor
  • ****
  • Join Date: May 2010
  • Posts: 262
  • Karma: 1
Re: polishing con rods.
« Reply #9 on: 01.10. 2010 22:32 »
hi mark , i was looking into doing this for a triton project i have sitting about , putting a norton crank into the triumph cases , i thought that if i had to make a new flywheel anyway (cast iron flywheels explode) i might as well do a 90 degree conversion too , the snag came when i wanted to get some camshafts , is there anyone doing them for triumph/bsa's ? i heard that dave nourish was making them as he's a fan of the 90 degree crank , but theres a rumour going around that he's retiring soon.  

p.s. what steel did you use for the flywheel ? en19/4140 ? 

Offline Mark Parker

  • Yea I'll probably get kicked off
  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 29
  • Karma: 0
  • Looking for a picture of my old A10 :( :(
Re: polishing con rods.
« Reply #10 on: 02.10. 2010 10:37 »
I had a couple of 90deg cams done in melbourne at wade cams, they found they needed to grind back all lobes and build them up with hardfacing to suit the lobe shift, the lobes on a BSA cam are close together and the heat from welding a couple of lobes upsets the factory hardening of the others, so doing them all is the go. I just went for std spitfire profile, which would be good in a Triumph. With the valve sizes I use 44.5mm and 39mm I really need one with more valve lift to get more out of the motor, probably around .450" and might try that when I ever have another cam done. I put offset rockers in it giving .020" more lift than stock giving it .410" and that gave about 6HP extra, it would be interesting to see what an extra .040" on that might do, other than wear stuff out *conf*.
  I don't know what the steel was. I want to put one of these ballance devices in one sometime, it may be worth while.

http://www.balancemasters.com/flywheels/index.html
Mark
Had a nice A10 once, :( now only have the power egg child A65 :(

Offline trickytree

  • A's Best Friend
  • ***
  • Join Date: Jun 2010
  • Posts: 146
  • Karma: 1
  • Lincolnshire, England
Re: polishing con rods.
« Reply #11 on: 02.10. 2010 11:24 »
bonny, Newman Cams will do one offs, although for a triumph they may even have the dimentions on record.

1965 A65 Bobber
A10 Bitza project

Offline bonny

  • Valued Contributor
  • ****
  • Join Date: May 2010
  • Posts: 262
  • Karma: 1
Re: polishing con rods.
« Reply #12 on: 02.10. 2010 13:06 »
thanks for the help mark and tricky.