Piston pins and rings

[pett3227b]

I have purchased new pistons for my 47' cub and as well as new rings. I have a video that I have been using to understand how to do this. The rings however were described differently in the video than in my old manual. According to the video the top ring it doesn't matter which way it goes in up or down. The manual says the top ring has an inner grove that goes up. I don't see any inner groove. The lower ring the video says that there is a dot and it goes up. I found the dot. the manual says that the lower ring has an outer ring that goes down. I don't see an outer groove. both the video and the manual are in agreement with oil control ring. Also I was sent new piston pins with the pistons. Can I just put the new pins into the old connecting rod or should I take them to a machine shop and have the clearance checked out? I am reading in my manual there is a diameter of 0.6875-0.6876 inches a piston pin clearance in piston of 0.0001-0.0005 inches. The manual also says that there is a piston pin clearance in rod bushing that is important. Is says it should be between 0.0003 and 0.0007 inches. The only part of the piston pins and connecting rods that aren't new at this point are the part where I will have the clearance in the rod bushing. Thank -you for the advice.

[Jim Becker]

Youtube videos are a wealth of misinformation. Unless confirmed by a reliable source, trust the manual over the video.

Several companies make piston rings. They all have their own ideas about ring design. The rings should have come with a set of instructions. Those instructions were intended to go with those rings. So follow them if they differ from the manual.

You should have a machine shop check any clearance you are unable to check yourself or are not confident abouut on your own. You are deep enough in with what you are doing that you don't want to overlook anything that is easy (and inexpensive) to verify.

[SamsFarm]

I think Jim nailed it.

Follow the instructions that came with the rings!

[tst]

the bore should be measured 1st before you buy any parts, it may be to worn just to put rings in and needs to be bored over size

[inairam]

I use videos to get an idea of what the job involves but the details from the manuals and of course from here.