[dilligaf]

Pulling the engine apart because of a noise that sounds like a wrist pin knocking. Come to find out that the wrist pin is frozen in the rod and rotating in the piston with some difficulty. This does not sound right to me. It seems to me that I remember from years ago while working on engines that the rod always moved back and forth freely on the wrist pin while the pin was pressed into the piston. Please correct me if I am wrong.

[CNC-Dude]

The majority of the time, the wrist pin is a press fit into the connecting rod and doesn't move or rotate in it, only the piston has the pin moving freely in it.

[oldbogie]

Originally Posted by dilligaf

Pulling the engine apart because of a noise that sounds like a wrist pin knocking. Come to find out that the wrist pin is frozen in the rod and rotating in the piston with some difficulty. This does not sound right to me. It seems to me that I remember from years ago while working on engines that the rod always moved back and forth freely on the wrist pin while the pin was pressed into the piston. Please correct me if I am wrong.

Other way, if it's a pressed pin, and most are, the pin will be pressed into the rod and floating in the piston. Reason for this way is that the wearing surface is doubled reducing loading where the movement is.

Bogie

[cobalt327]

Originally Posted by dilligaf

Pulling the engine apart because of a noise that sounds like a wrist pin knocking. Come to find out that the wrist pin is frozen in the rod and rotating in the piston with some difficulty. This does not sound right to me. It seems to me that I remember from years ago while working on engines that the rod always moved back and forth freely on the wrist pin while the pin was pressed into the piston. Please correct me if I am wrong.

Detonation will tighten up wrist pins. I'd be looking closely at the ring lands to see that the rings weren't tight, as well as the rod bearings to see if there's any more indication of detonation.

Pay close attention to the timing, plug heat range, fuel quality, any hot spots in the chambers along w/anything else that might cause detonation as well.

This engine ever see any nitrous or boost? If it's a SBC there were three different timing tab/damper lines that can be mixed up causing the timing as indicated by a timing light to be off. THIS page describes them.

DETERMINING TDC will allow you to be sure the timing tab and damper are correctly indicating TDC.

MAKE A TIMING TAPE to see what the total timing is, w/o needing to use a dial back timing light. You can also buy a timing tape, get one that matches the diameter of your damper.