Big end shell bearing

[JonE]

that's why I'm intrigued about other engines currently being stripped. Are the characteristics of the 3 bearing shelled rod such that the any measurement there is irrelevant, i.e. entirely subservient to the piston location?

[Bob Culver]

Conrod side movement should not be limited by gudgeon side clearance. It is quite inmportant little ends are central in piston. Otherwise there is a bending action on con rod.

[JonE]

but the gudgeon is not free floating... it's secured by pinch bolt?

[Colin Reed]

HI 
THINK ABOUT IT THE GUDGEON MOVES IN THE PISTON

[Bob Culver]

Side clearance at gudgeon.

[Dave Mann]

It always intrigued me that on the 16" bore engines we built at work the rods had a good 1/2" side play but never any sign of contact on the side faces even on the vee engines with two rods on one pin. It was a normal test after assembly that the rod could be easily moved sideways.

[Steve kay]

Am I misunderstanding something, or is this about three bearing engines being very different. Thursday in the workshop involved using pinch bolts to attach conrods to gudgeon pins, and then circlips for lateral location of the pin in the piston.

Does anyone know how to install a techno spellcheck, that prevents having to spend longer correcting a comment than writing it? Goujons, combats, cyclists, punch bolts........

[Bob Culver]

The exact operation of the con rod drillings is obscure. The oil jet must be very dispersed and oil is also flicked/blown down from the cyls. So on part of the upstroke oil must enter at the conrod drilling.

[Howard Wright]

Am I misunderstanding something, or is this about  three bearing engines being very different. Thursday in the workshop involved using pinch bolts to attach conrods to gudgeon pins, and then circlips for lateral location of the pin in the piston.

Does anyone know how to install a techno spellcheck, that prevents having to spend longer correcting a comment than writing it? Goujons, combats, cyclists, punch bolts........

Hi Steve

I’m not sure you need both pinch bolts and circlips. Circlips are for fully floating gudgeon pins when the top of the con rod does not have a pinch bolt (Nippy rods are like this).

Cheers

Howard

[Colin Reed]

HI Howard,
You Are right if the Gudgeon is for a pinch Bolt You dont use the circlips,
If the gudgeon has no provision for a pinch bolt then it is for a fully floating Bush and you use the circlips
 
Colin 
NZ