Author Topic: Alloy Con Rods.......  (Read 3105 times)

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mx250

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Alloy Con Rods.......
« on: November 04, 2011, 03:30:52 pm »
.........who's heard of such a widget ???.


Offline pancho

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Re: Alloy Con Rods.......
« Reply #1 on: November 04, 2011, 04:35:53 pm »
 Mark 5 Jaguar. they used to stretch and hit the head ,Speedway Jap, they used to break, 500 excelsior Manxman, I think they were reliable. Various 4/ stationary engines, probably lots more. Not seen one in a tooee.
 pancho.
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Offline Colin Jay

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Re: Alloy Con Rods.......
« Reply #2 on: November 04, 2011, 05:02:32 pm »
The 1969 Triumph 650 Trophy that I once owned had alloy conrods, and I think the majority of other British twins also used them. I have alway thought them to be reasonably common.

CJ
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Offline John Orchard

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Re: Alloy Con Rods.......
« Reply #3 on: November 04, 2011, 05:04:07 pm »
I've only seen them top-fuel drag cars; but then they're replaced every 5 seconds  :-)
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Offline LWC82PE

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Re: Alloy Con Rods.......
« Reply #4 on: November 04, 2011, 05:16:37 pm »
A lot of Triumphs and Nortons use them.
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Offline pancho

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Re: Alloy Con Rods.......
« Reply #5 on: November 04, 2011, 05:20:44 pm »
  ??? fancy me forgetting Triumphs, AJAYs Matchos Norton twins!
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Offline tony27

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Re: Alloy Con Rods.......
« Reply #6 on: November 04, 2011, 05:50:23 pm »
First time I've seen 1 in a 2 stroke, what is it?

Offline JC

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Re: Alloy Con Rods.......
« Reply #7 on: November 07, 2011, 01:45:58 pm »
Sachs?

Offline Nathan S

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Re: Alloy Con Rods.......
« Reply #8 on: November 07, 2011, 01:53:08 pm »
As others have said, alloy conrods are generally pooh because they have a short fatigue life.

There's a reason you don't see them often.
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mx250

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Re: Alloy Con Rods.......
« Reply #9 on: November 07, 2011, 02:05:16 pm »

Offline firko

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Re: Alloy Con Rods.......
« Reply #10 on: November 07, 2011, 03:17:59 pm »
I'm replacing the alloy con rods in my Triumph with steel Carillo's just to be on the safe side. I don't know how much action the engine's seen so it's better to spend a quid up front than cry over the big hole in the front of my engine later on. ;)  That engine's a Sachs.

*back in the seventies we bought a Chevy bottom end that'd seen action speedway sprint car for our drag racing altered. It had Howards alloy rods which we thought was a cool mod but my mate worked for the Water Board in the pipe testing section so we got the rods magnafluxed (crack tested) at his work. Lucky we did as three of the rods had hairline cracks and would have only lasted a run or two before letting go bigtime.
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Offline Brian Watson

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Re: Alloy Con Rods.......
« Reply #11 on: November 08, 2011, 12:10:28 am »
When I first rode in Juniors.."14-16 years"..I raced the first KTM (Penton) in OZ..see my avatar...It had a 5 speed Sach engine in it , along with an alloy rod....as in the picture.....then one day at Manjimup after the second turn and heading towards rock & roll hill...over the first jump ..and bang......!@#%$&...there goes the alloy rod...still have what is left of the rod at home in the workshop bench draw...

Offline Marc.com

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Re: Alloy Con Rods.......
« Reply #12 on: November 08, 2011, 02:10:29 pm »
British twins of the days used them, there are a couple of reasons to use alloy rods, lighter reciprocating mass so especially when you have British twin with both pistons traveling top dead center at the same time like a big single, then there is a lot of vibration and lighter rods are one step to reducing reciprocating mass.

The other issue is that the alloy rods offer some dampening effect between the pistons explosive force and the crankshaft and bearings, that you can use steel rods but on engines with white metal bearings they hammer them. Both reasons are probably why the drag racers use them.
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Offline VMX247

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Offline Tossa

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Re: Alloy Con Rods.......
« Reply #14 on: November 08, 2011, 04:23:15 pm »
When I first rode in Juniors.."14-16 years"..I raced the first KTM (Penton) in OZ..see my avatar...It had a 5 speed Sach engine in it , along with an alloy rod....as in the picture.....then one day at Manjimup after the second turn and heading towards rock & roll hill...over the first jump ..and bang......!@#%$&...there goes the alloy rod...still have what is left of the rod at home in the workshop bench draw...

you keeping just in case!!!!
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