What is the proper way to determine if your connecting rod has too much play on the crank pin? I have a new Dynamite engine and it seems to have a significant amount of play at TDC. When at TDC with the glow plug out the flywheel can turn about 3/4 of an hour without moving the piston. It has visible play with the back cover off and kind of ticks back and forth. Is this normal or is there a way to measure this without special machinist tools?

3/4 of an hour without moving the piston? That's it?

I think most of my engines rotate at least 2 - 3 hours without moving the piston.

I don't have any hi-tech way to measure rod slop. I kinda just try to hold the rod in there and then turn the crank and see if I can feel anything.

In my Beat 5, my main bearing was really sloppy so when I changed the bearings, I changed the rod knowing that it took a little beating from a sloppy bearing.

I hope somebody comes on here with a good idea or tool or something for measuring that cause I've wondered about that myself.

Interesting subject!

When the crank pin is more than 0.04mm out of round, it's considered worn as far as I know. Perhaps the same applies to the connecting rod also?

That's normal

Thank you for your responses...
I guess I didn't realize that nitro engines had a huge amount of dwell time.....

I'm surprised none of the engine guys commented on this. I know they know the tolerances for an out of spec crank or connecting rod.

For the crank pin I'm quite sure the following applies:

When the crank pin is more than 0.04mm out of round, it's considered worn as far as I know.

Would be nice to get the answers from the engine guru's