Oversize crankcase alignment bolt source

[Buster]

I will be aligning a set of mismatched 45" flathead cases (1941 sprocket side to 1948 pinion side). I understand that someone (possibly S&S) manufactures an oversized case alignment bolt to use when aligning mismatched cases. Can anyone give me a source of these alignment bolts and what they are called by the manufacturer? Thanks!

[Rubone]

Why do you need oversized? If the holes in the cases are not oversized all the bigger bolts will do is crack the cases.

[Jerry Wieland]

I will be aligning a set of mismatched 45" flathead cases (1941 sprocket side to 1948 pinion side). I understand that someone (possibly S&S) manufactures an oversized case alignment bolt to use when aligning mismatched cases. Can anyone give me a source of these alignment bolts and what they are called by the manufacturer? Thanks!

I usually end up making them myself. I do not know of a source. I used drill rod. Jerry

[Buster]

Thanks Jerry.

[exeric]

You can get drill rod in oversize from McMaster Carr. But, it seems the prime objective is to get the crank bores in-line and I assumed that had a lot to do with the crank-case spigot feature which always seemed like a tight fit on H-Ds. I'm just throwing this out there and not making a judgement. Would like to hear what knowledgeable engine builders think. I don't have this problem so my interest is just basic motor case alignment.

[Rubone]

The factory lower bolts are press fit. They align the cases as well as they will to each other when mismatched. If any deck changes or motor mount changes are needed it isn't because of the factory bolts.

[Jerry Wieland]

The factory lower bolts are press fit. They align the cases as well as they will to each other when mismatched. If any deck changes or motor mount changes are needed it isn't because of the factory bolts.

Robbie That is not what we have found. Seldom do the alignment bolts even go thru mismatched cases. We have had it happen but usually we have to over size the hole and subsequently use an over size case bolt. Usually +.010 will do it.

[Buster]

With the cylinders bolted to the cases, my top alignment bolt will barely go thru both cases and neither of the bottom two alignment bolts will go thru. All other non-alignment bolts will work. I read somewhere that Harley changed tooling after the war and a pre 1944 case is more likely to mate easier with another pre 1944 case, as opposed to a post 1944 case.

[chuckthebeatertruck]

I ran into this different alignment bolt sizing when mating a 46 left case to a 39 right case on a UL. I recall the change had to do with semi blind vs open left side main bores and the machining process. Anyways, the bolts were different diameters, but shared common centerline. It meant I had zero hope of alignment using a factory bolt as I’d have to go with the smaller diameter.

So, I machined a waisted bolt at the center seam, with each end the diameter of the respective hole. That done, everything snapped into alignment, with a light lapping bringing bores into full alignment. Harleys machinists were surprisingly good.

I used 4140, tough as nails, relatively easy to machine, threads nicely, polishes to size well. Had to use a follow rest to ensure consistent diameter on such thin section rods.

[T. Cotten]

The handful of times I needed oversize studs, Folks,..

Were because the cases were broken and re-welded, and only re-locating the holes oversize would allow correction of the mains.

Somebody should have produced them by now.

....Cotten