Re: 1989 Force 85 - new piston/rings installed, but NEED HELP
Re: 1989 Force 85 - new piston/rings installed, but NEED HELP
You can take a hardwood dowel or a block of wood and through the reed opening either tap the end of the rod or if you can actually get it back into the piston, tap the piston. May take a bit of persuasion and the wood may split but it will go--after all, you got it in, didn't you?
I don't like to use a ring compressor. Sometimes I will compress the rings with a nylon zip tie and other times I just use a flat blade screwdriver. With both rings installed on the pistom, slide it into the bore until the first ring touches the top of the block. Now, put one end of the ring at the pin and while pressing in on the piston with one hand, work around the ring with the flat screwdriver pushing it in. Takes a knack, and a little more time than a compressor, but you will quickly learn how much pressure to put on the piston to hold the ring and how to work around it with the screwdriver. Once the ring pops into the bore, do the same for the top ring. ---And before you ask, no, it doesn't damage or scratch the ring. A bit messy on the hands, but DAWN gets the oil off nicely.
I can do this with flat rings, 2 deg. semi tapered like supplied with WISECO and semi keystone rings. Each type takes a little different feel but the beauty is that you are absolutely certain that the rings are properly positioned on the locating pins.
NOW once you have the piston out, look at the big end of the rod. On each side you will see a ground and polished flat. If you look closely you will also see at the split a VEE shaped notch.
These rods are the outer bearing of the crankpin/roller/rod assembly. They are called "Cracked Cap Technology." They are manufactured as one piece. Then the flats are ground on the outside for reference points. After fully hardening the rod, (which makes it a bit brittle) the VEE is "Staked" and the rod splits relatively cleanly. However, each side splits a little differently. Thus, the rod cap only fits one way.
When you reassemble the rod, logic says that if the reference flats are smoothly mated at the crack, then the inside of the rod where the rollers ride must also be smooth at the crack. Thus the rollers will ride over the crack without bouncing. You check for smoothness by running a pencil point, scribe, piece of wire, or welding rod over the joint. And as I have said in the past--This is one case where good enough is not good enough. You must be fussy, critical, and perfect. Even though the crack is on the side where there is not much load, if the rollers bounce, they will hammer it and they will begin to spall and eventually (rather quickly) fail, ruining both the rod and the crank.---Very expensive.
NOW: If you have assembled the rod with incorrect alignment and then torqued the cap bolts, the mated ends will be messed up and may not properly align. This ruins the rod. That is why I always tell people to only hand tighten the cap bolts until the rod cap is perfectly aligned.
SO: While you have the piston out, examine both sides of the rod big end and try to mate the cap to it. If it does, you are OK. However, if it will not mate properly, then you need to buy a good rod.
And that, is the lesson on engine rebuilding for today!
