Re: Connecting Rod Alignment?

Posted by Scott726 On 2008/4/8 22:09:24

OK, I think I have it figured out. I don't think whoever rebuilt my engine (20 years ago) figured out the whole two different rod part numbers thing. There seems to be no rhyme or reason which face of the connecting rods has the most babbitt. I pulled the #6 rod/piston which had the rod that was riding the farthest forward on it's wrist pin. The top of that rod looks like it is right up against the inside of the skirt. I see that the front of that piston has some scuffing. To be precise, the scuffing is directly over the wrist pin hole that faces forward. The scuffing is even, top of the piston to bottom of the skirt.

I think that what must be happening is this: I push on the clutch it pushes the whole crankshaft assembly forward the .005" of available play (the spec is .002"). That pushes the connecting forward which is making the piston knock.... I can't figure out why else the thing would be knocking when I push in the clutch and then only when it's cold, before everything has expanded. Once it's warmed up you can't make it knock.

Short of rebuilding this engine I am thinking of pulling all the off kilter rods, measuring the journals and having the babbitt re cast and machined on those rods so they will be centered or at least not too off centered. I will probably have to de-glaze the cylinders and put in new rings too. A complete rebuild just isn't in the cards at the moment...

Comments are welcome.

Scott

PS Packard V8, The slots are all on the passenger side of the car, all the pistons are the same.