harley engine rebuild snap ring issues

[poortrey]

OK to start with I got this 1970 3 wheel harley cart and it was having an issue with the clutch as it was not properly set with the shims and set too tight and holding the belt while it was trying to start. After getting the clutch set right the cart started running well until a friend decided to take it on a 3 mile drive. after driving it that far upon trying to start it the next day it had no compression as it had melted the rings so I went into doing an upper rebuild. I went and had the engine bored 50 over and replaced the piston, rings, wrist pin bearing and reassembled. Then engine ran good for about a week doing short runs and then it quit and so I pulled it back apart to find the snap ring for the wrist pin on one side was gone and had gotten into the cylinder and he rings so it was time to rebuild the upper end again. took the cylinder to be bored and found a crack that could not be repaired so had to get a new cylinder and went back to a stock piston. I thought I may have made a mistake in reassembly on where I put the snap ring so I reassembled the motor. Ran great for about a week and it did the exact same thing snap ring on one side of the wrist pin is gone and rings are trashed and head needs to be bored. I have since bored the cylinder and got another new piston ready for rebuild but wanted to know if anyone had any idea what I could have been doing wrong to keep loosing the snap ring and trashing my rebuilt motor.

[jonr3]

As long as the snap ring fully seats into the groove, I don't see how it could come out. I had to take mine apart and it was pretty tough getting the snap ring out even with a good set of snap ring pliers.

[Shepard]

I'm not sure what type snap ring your using. If its the traditional 2 hole snap ring -- they are directional. Here's a picture of proper snap ring installation.

[Lochlin]

Get a manual and check it. I don't know the earlier carts but on the later 80s carts some of those snap rings are tapered and have to be installed in a certain direction.

[jonr3]

I couldn't find anything in my manual about installing snap rings a certain way. On my dirt bike engines, they are supposed to be rotated with the opening at a certain angle. Also, my replacement snap rings didn't have a flat side and beveled side that I noticed - looked the same from both side.

[Shepard]

99% of all snap rings are die cut or punched. If you look at them there's a rounded side and a sharp side. Also the opening should be at either 6 or 12 o'clock according to the stroke.

[poortrey]

thank you for the information. Just for clarification the beveled side of the snap ring should be towards the wrist pin? I will also make sure the opening of the snap ring is at 6 or 12. great information guys.

[Shepard]

Yes