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-   -   Pin a crankshaft (https://www.rcuniverse.com/forum/engine-conversions-92/7647574-pin-crankshaft.html)

motorhd 06-22-2008 11:33 AM

Pin a crankshaft
 
Can someone discribe how to pin a built up crankshaft

captinjohn 06-22-2008 01:28 PM

RE: Pin a crankshaft
 
I am just guessing...if the flyweight or flyweighs have the shaft pressed in ...a pin is placed 90 degrees to shaft. The pin will keep any slipage from happening. May I ask what you are going to do with the crank? What engine is it for? thanks Capt,n;)

motorhd 06-23-2008 02:02 AM

RE: Pin a crankshaft
 
Hi Captain, I am assembling an Echo -BME twin useing 2 - 23.6 cc cylinders.
motorhd

captinjohn 06-23-2008 11:05 PM

RE: Pin a crankshaft
 
It would seem lke some kind of pining of the parts could be done...instead of welding. The parts may have to be machined a little differant! Best If luck.....Capt,n;)

av8tor1977 06-24-2008 11:27 AM

RE: Pin a crankshaft
 
No, the two crankshafts have to be welded together. Then Keith from BME also recommended that the original, factory pressed together joints of the crankshaft be pinned as well. They had problems with the crankshafts sometimes twisting at the pressed together joints and getting out of whack. I think one of the people that built one of the twins had the same problem.

What you have to do is drill a hole through the crank throws and rod journals where the crank is pressed together, and drive in a drift pin. Be sure that the holes and their pins are 90 degrees to the direction of rotation so that centrifugal force does not try to throw the pins out. I would also use some stud lock, or perhaps Loctite on the pins when installing them.

You might browse through the thread on the twin, as I vaguely remember that someone posted some pics of doing the process.

AV8TOR

Ralphbf 06-24-2008 12:27 PM

RE: Pin a crankshaft
 
The winning combo for me was pin and weld.
Simply tack weld one end of the pin while your welding the crank.

av8tor1977 06-24-2008 12:36 PM

RE: Pin a crankshaft
 
What kind of pin did you use? A split roll pin?

AV8TOR

flyguyeddy 06-24-2008 08:06 PM

RE: Pin a crankshaft
 
can someone weld up my crankshaft? ill pay to have it done. i can handle the pinning.

buck1856 06-24-2008 09:23 PM

RE: Pin a crankshaft
 
Billzair replied to your last post,did ya get hold of him yet.

Ralphbf 06-25-2008 02:25 AM

RE: Pin a crankshaft
 


ORIGINAL: av8tor1977

What kind of pin did you use? A split roll pin?

AV8TOR

Yep !

captinjohn 11-02-2008 11:49 AM

RE: Pin a crankshaft
 

ORIGINAL: Ralphbf

The winning combo for me was pin and weld.
Simply tack weld one end of the pin while your welding the crank.
It seems like pinning would help in keeping the posistion of both cranks for welding! Capt,n


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