Fairbanks Morse Z 1.5 hp piston advice

Reddog15

New member
Hello,
While running my engine at a recent show and before that I noticed a knock coming from the piston area. There's a bit of play in the wrist pin. In anticipation of having someone make new bushings for me I removed the piston and found that the slop is between the wrist pin and piston and not the bushings. Is this sort of the nature of the beast with the pin not being a press fit? From what I can see the pin and piston don't look beat up. Thanks for any advice.
 

ScooterBob

Subscriber
I'm not sure about your particular engine, but a lot of these old engines used set screws to hold the wrist pin tight in the piston. Is there any evidence of tapped holes on either side of the connecting rod area on the back of the piston?
 

Reddog15

New member
I'm not sure about your particular engine, but a lot of these old engines used set screws to hold the wrist pin tight in the piston. Is there any evidence of tapped holes on either side of the connecting rod area on the back of the piston?
There's a square headed bolt on one side with a pin on the end that protrudes into the wrist pin. It seems tight but is rather hard to reach with a wrench.
 

ScooterBob

Subscriber
There's usually a lock nut around the set screw also, have you dug out all the crud to confirm that a lock nut is what's holding it tight?
 

Reddog15

New member
It's actually a different arrangement on mine; there's the square headed bolt and it had a kotter pin through it. No lock nut.
 
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