piston pin fit?

[Powerhouse]

Hello,

In a 47 P15 Engine...should the piston pin move easily side to side in the rod? Specs in the book say a thumb fit??? The pin in the piston is a snug fit. I have no numbers to go by....

[martybose]

Hello,

In a 47 P15 Engine...should the piston pin move easily side to side in the rod? Specs in the book say a thumb fit??? The pin in the piston is a snug fit. I have no numbers to go by....

Yes, the pin should move easily since it is a bronze bushing in the pin end of the rod. That's why there is a set of pin locks in the piston, as they are what locates the pin.

Marty

[Powerhouse]

OK...thanks.

[LuckyDevil]

While we are on the topic, is there any way to tell if the wrist pin has gone bad or worn out? I don't want to tear my engine apart if I don't have to, but I hear a weird noise every now and again, and with this being my first really old car I am not used to the different kind of noises it makes.

[james curl]

It can be done but it takes a lot of time and effort. First you have to get the car high enough to remove the oil pan after draining out all of the oil. With the transmission in neutral, turn first one cylinder to TDC and with a strong flashlight check for any movement in the wrist pin bushing by rocking each cylinder back and fourth several times while watching for movement of the rod without the piston also moving the same amount. You can observe the bushing in the gap between the bosses in the piston and the relationship of one to the other while rocking the crank about three degrees before and after TDC., if the bushing is bad you can detect the movement up and down in the bushing area at the bottom of the pin. The noise that a loose piston pin bushing makes is much like a loose lifter to valve noise only harder to isolate. Good luck in your quest.