Chainsaw Repair

Alright, Al, here goes:

The easiest way to weld two rod halves together that I've found is to use an old disc brake rotor with the center cut out. I turn down a piece of round stock to the big end diameter(1.995 for a SB Chevy) and drill a hole through it and the rotor, mount the rod half to it, and using my mill to digitally measure, bolt it directly to the rotor, then use an old wrist pin for the the small end and fasten it where it needs to be to get the correct length. Then I am able to weld both sides, as well as box it in for extra strength. Very simple to do. You use two rods cut strategically and welded together to make one longer one.

Before welding a crank, we weld in boat loads of bracing anywhere we think it could possibly move. And remember, we are only welding one side of the journal, not all the way around, and for every 1 inch of weld applied, you gain 2" of stroke, and as far as I know and have seen, all old IHC and Allis cranks are steel, not cast iron. And as far as internal stresses added after welding goes, well, they are there for sure. I've never worried about them, and not one of my cranks has ever broke. I have had one rod failure, but thankfully it was on my own tractor. Most of the guys who build antique pulling motors for a living send their welded components in to either have them normalized or cryogenically(don't have spell check for that one) treated. 

Remember what those old pistons looked like? The CD(compression Distance) on some of them were more than 3". We use either custom pistons or find automotive ones that have the CD we want. When you add 2" of stroke, the piston is going up 1" higher and down 1" lower.

Getting that extra mass to swing sometimes means grinding big pockets out of the inside of the crankcase. On the WC blocks the inside measures a little narrower than the 17's, so much over 5.5" stroke and 2" rods requires cuts all the way through on the manifold side of the block. The hardest item to clear in an antique stroker is usually the cam. We end up with two flat spots where all 4 rods swing, and sometimes the cam gets ground pretty thin.

And back to the crank, we weld a short piece of thick walled 1/4"ductile iron pipe right on top of the oil hole, which also acts as a guide when applying the build up of weld. Remember Al, one inch of weld translates into 2" of stroke. And obviously, we use a wire feed. I use Spool Arc 83 wire.

As a rule, all stock reciprocating items are usually not used in antique stroker applications. You gotta wrap your head around that one first. Forget what the old pistons looked like and picture what the newer, modern ones look like.

Any more questions feel free to shoot away. Better yet, the next time you're going to be in central Mi, pm me,pop over, and I'll be happy to pull the access panel off from the side of my MM 335 and show you what an old school stroked motor looks like. That one is 4.125 bore and 6.5 stroke and 110 hp @ 540. It was around 30 hp in it's stock form.