The Stovebolt Site Forums The Shop Area Engine Shop Those three dowel pins- - - -

The ones in a stovebolt crankshaft flange- - - - -They just happen to be exactly aligned with the three pairs of connecting rod journals. If a crankshaft has been indexed incorrectly during a previous regrinding job, a machinist who knows that little tidbit of information can get the journals back into the proper 120 degree separation by using the dowels to index the crank as it's ground to a smaller undersize. That's also how I'm planning to get the stroker shafts I'm making as accurate as possible when I increase the stroke and grind the journals to a smaller diameter. Just a heads-up for anyone who is going to get a crank reground anytime soon.
Jerry

Jerry, have you ever tried welding up the crankshaft journals and turning them back down to standard. I have 2 crankshafts that are worn so bad they won't clean up even for 60 under. Just wondering if they are rebuildable or just scrap.

I bought a spray welding rig recently, but I haven't tried to use it yet. Metalspray was an alternative to welding crankshafts when my father was building race engines back in the early 1950s, and some pretty hot engines got that treatment. The shaft is turned undersize until it's round, and V grooves are cut into the surface. Then the shaft is heated with a special acetylene torch and powdered metal alloy with a binder is sprayed onto the grooved shaft. Then the shaft is reground back to standard size. The process is used when rebuilding jet turbine engines, so if it's done properly it's safe and reliable.

Another method of building up a shaft is by "submerged arc welding". In that process, powdered flux is poured over the shaft as it rotates and a specialized MIG welder is used to build up the diameter. Then the shaft is reground to the desired size. Both of the above procedures are fairly complicated and somewhat expensive, but they're cost-effective when scarce or high value parts are involved. Here's a video of the submerged artc process. The machine shop in Nashville where I ran the connecting rod reconditioning department did a lot of crankshaft welding.

www.youtube.com/watch?v=UYGzVzpWrw4

Jerry

Sounds way too expensive for a 235. Thanks for the info.

I modify the block to take smaller diameter main bearings (Small block Chevy 400 V8) and grind the crankshaft main bearing journals undersize to fit the bearings. All the mains end up the same diameter, and they're about 1/8" or more under the original diameter. That also solves the problem of scarce, ridiculously expensive main bearings. The stroker shafts I build end up with rod bearings way undersize from original, and a 4 5/16" stroke. That makes a 216 end up at 258 cubic inches, a 235 at 270, and a 261 almost 300, all running the same 235 pressure lubed crankshaft. The smaller diameter bearings reduce rotating friction dramatically.
Jerry

Too bad you're so far from Tennessee- - - -those "scrap" shafts would be ideal for the kind of modifications I do. Is there a Fastenal facility near you? Their "Blue Lane Freight" trucking facility ships palletized items pretty inexpensively.
Jerry

The rod journals have the wear I'm guessing won't clean up. I've talked to couple of machine shops in the area about grinding them to see where they would clean up. Then possibly order special rod bearings for them. The machine shops are so busy and under staffed that it will take months to even get them in the door. I was told by one they don't do cash and carry any more, just their commercial customers and their own built engines. One quit doing auto engines all together, he's just doing ag engines. It's getting so the guy that works on his own stuff is SOL.
If I hit a dead end I will see about sending them to you through Fastenal.>

I'm glad I invested in my own machine tools over the span of several years. Now the only "machinist" i can blame for not getting the job done is myself! Now, if I can just figure out how to purchase another 20 years or so of time somewhere! I've got crankshafts, cylinder heads, and connecting rods covered so far. The guy who grinds my camshafts is in his 90s, and he's on chemotherapy! I hope his cam grinding machinery will be for sale eventually! There's a rod bearing for a Perkins 3 cylinder Diesel engine (Federal Mogul 2015CPA) that can be adapted to the stovebolt 216 Babbit connecting rod by boring out the Babbit metal and a little of the rod material, and "standard" diameter is 60 thousands under the stovebolt crankshaft journal size. The other dimensions of that rod are close enough to use in a late model 235 with a little massaging. It requires the big ends of the stovebolt rods to be resized, and the crank ground to fit the ID of the bearing.

On my stroker 235 crankshafts, I'll be using Chevy small block 400 main bearings, and Chrysler 4 cylinder (3845CP) rod bearings. The smaller diameter rod bearings allow me to offset-grind the crankshaft for a 3/8 in longer stroke and LOTS more torque.
Jerry