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Engine basics => Engine set up tips => Topic started by: John KruziK on January 18, 2011, 05:31:21 PM

Title: fox 59
Post by: John KruziK on January 18, 2011, 05:31:21 PM: How much clearance should there be between crankpin and rod? This is a ringed engine. Thanks John
Title: Re: fox 59
Post by: Chris Wilson on January 18, 2011, 06:54:44 PM: Quote from: John KruziK on January 18, 2011, 05:31:21 PM
How much clearance should there be between crankpin and rod? This is a ringed engine. Thanks John

Between the crankpin and the rod? (As in the big end?)

Zero or a freely sliding fit that really can't be measured.

Being ringed or not should have no bearing (pun intended) on this one.
But perhaps you mean the crankshaft counter weight and the rod?
Title: Re: fox 59
Post by: John KruziK on January 18, 2011, 06:58:47 PM: I do mean between crank pin and rod. It seems that there is a few thousandths, it has a little wiggle room.
Title: Re: fox 59
Post by: Chris Wilson on January 18, 2011, 08:10:04 PM: The clearance between the conrod and the crankpin should be so small as to be immeasurable but I have seen poor fits last along time due to the fact that rod only really acts in compression and needs little in the way of a tight fit.
Title: Re: fox 59
Post by: Ward Van Duzer on January 19, 2011, 08:37:46 AM: Most folks taking apart engines don't realize that connecting rods are made to fit one way on the crank pin. Note that the pin has a rounded surface where it meets the crank shaft. Sort of like a small filet. The hole in the connecting rod is chamferred on one side, and drilled straight on the other. The chamferred end goes on the filet! Otherwise...MISFIT!

W.
Title: Re: fox 59
Post by: M Spencer on January 19, 2011, 08:13:18 PM: Angular rock is normalish , maybe 4 degrees . any more is a bit much .