farmall h connecting rods

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   Stroke 101: 

The stroke of the crankshaft is measured by the distance the piston moves from top dead center to bottom dead center.

To get an additional 1/2" stroke you would have to remove 1/4" of materal from the top of the crankshaft journal at bottom dead center and add 1/4" of material to the top of the crankshaft journal at top dead center. Or off set grind the crankshaft rod journal much smaller. This would cause the piston to move 1/4" higher and 1/4" lower in the sleeve adding 1/2" to the stroke.

 A longer rod will only mean you will need a shorter piston wheather you  do or don't  stroke the crankshaft. 

If you install a one inch longer rod without changing your crankshaft or piston the piston will be one inch higher in the sleeve or in most cases above the deck. (deck being the top of the block where the head bolts fast)
 The piston will travel down one inch less in the sleeve.  The stroke is still the same but it is a non workable condition.

Edited by Dick L - 19 Jan 2010 at 7:03am

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Dick L Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Edon Ohio Points: 5087	Post Options Post Reply Quote Dick L Report Post Thanks(0) Quote Reply Posted: 19 Jan 2010 at 7:01am
	Stroke 101: The stroke of the crankshaft is measured by the distance the piston moves from top dead center to bottom dead center. To get an additional 1/2" stroke you would have to remove 1/4" of materal from the top of the crankshaft journal at bottom dead center and add 1/4" of material to the top of the crankshaft journal at top dead center. Or off set grind the crankshaft rod journal much smaller. This would cause the piston to move 1/4" higher and 1/4" lower in the sleeve adding 1/2" to the stroke. A longer rod will only mean you will need a shorter piston wheather you do or don't stroke the crankshaft. If you install a one inch longer rod without changing your crankshaft or piston the piston will be one inch higher in the sleeve or in most cases above the deck. (deck being the top of the block where the head bolts fast) The piston will travel down one inch less in the sleeve. The stroke is still the same but it is a non workable condition. Edited by Dick L - 19 Jan 2010 at 7:03am

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mlpankey Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 13 Sep 2009 Location: Vols country Points: 4580	Post Options Post Reply Quote mlpankey Report Post Thanks(0) Quote Reply Posted: 19 Jan 2010 at 8:47am
	In the most simplistic way of however you do it offset grinding or combination of welding and offset grinding . is you simply move the centerline of the cranks rod journal further out away from the centerline of the crankshafts main journal then multiply it by 2 for the full distances of piston movement as Dick mentioned. If I drawed two circles one above the other and drew a lign straight through the center as to measure the diameter of each circle the distance between the circles would be the center to center or half the cranks stroke .IF I remove material from the bottom of the upper circle then I have increased the center to center distance in affect adding stroke to the crank. Now I have just made eveybody with a tombstone welder and lathe in their shop a crankgrinder . NOT SO! Its A LITTLE MORE COMPLEX THAN JUST THOSE TOOLS IF YOU CHOOSE TO DO IT WITH JUST THOSE TOOLS I HOPE YOU HAVE ENOUGH MAIN JOURNAL MATERIAL TO TURN DOWN TO GET IT BACK STRAIGHT FROM THE WRAPAGE OF WELDING WITHOUT HAVING TO MAKE THE MAIN BEARINGS ALSO.