Winter Beater Build 2.0- '66 Short/Fleet BBW

[theastronaut]

The NP440 swap.... this was supposed to be a quick swap to make it to Run to the Sun, but when I took it apart "just to add new gaskets" I found that the bores in the case for the countershaft had pounded out oversize and needed to be bored and sleeved.




http://youtube.com/shorts/eAlnyHWEN_...cIkpNI7KQfqRRL


Since the bore was no longer the original size I couldn't just find the center and use that location to bore it. I used the countershaft pulled tightly against a small unworn area and superglued it in place, then used a tenths indicator to sweep around it and find the original center.







I double checked that I had the correct location by setting up the boring head so that it just barely took a cut, which evenly cut only across the unworn area. I took it from (off the top of my head) roughly .945 to 1.350 to make room for a steel sleeve, and added a step around the edge. I machined a sleeve with a ~.003" interference fit and a matching step. I also left the sleeve's bore slightly undersize so I could ream it for an exact fit after it was pressed in.











After both holes were bored and sleeved, I cut one side for the locating keyway, then reamed the sleeves to a slight interference fit so that the countershaft needed to be tapped into place with no clearance. I've read that originally the aluminum case version of the NP440 had .005" clearance between the case and the shaft which caused it to wear oversize, but the iron case version had a slight interference fit and never had this problem, so I replicated the iron case's interference fit.







When we cleaned out my granddad's workshop after he passed, I found an original bellhousing for one of these trucks and tucked it away. I pulled it out of storage to use for the trans swap, thinking I'd use it for mock up. It turned out to be in really nice condition with no rust, no stripped holes, and a really nice coat of the original 230/250 blue that I was able to use to color match new paint.





I chucked the input bearing retainer in the lathe and turned it down to fit the original bellhousing's ID. This cut into the oil return slot so I had to weld that up to prevent it from leaking.







Quick test fit. Notice the difference in tone in the aluminum castings- I used aluminum brightener acid on the tailhousing and it cleaned it to almost looking like new.





The seal area of the input shaft was very pitted, so I chucked it in the lathe and lightly turned it down until it cleaned up. I did keep checking that the seal still fit snugly, I think I had to remove .013" to get it to clean up. The seal still fit snugly so hopefully this won't cause a leak from being undersized.







Reassembly. I used a heated ultrasonic cleaner for all of the internals which saved hours of cleaning by hand.









Completed assembly.





I attempted to DIY shorten the driveshaft after watching a few YT vids. Before cutting it I put it in the lathe to check runout after zeroing the yoke in the four jaw with a tenths indicator. The high spot was /043" directly opposite of the weight added to balance it. I think I took 5 3/8" off and got runout down to .008" via aligning it before welding, then peening the tube/welds after welding with a smoothed chisel I modified for linear stretching sheetmetal. I'll balance it using the two hose clamp method once its back together.









At the moment it's dropped back into the truck to work out the new shift rods, then I'll pull it and go through all of the engine gaskets and repaint the engine. I'll swap in the power steering box and Dellorto carb when it goes back together, and maybe a header or 292 manifold to open up the exhaust. The old exhaust system has been hanging on for dear lift since I originally got it running so I'll redo it with 2.5" tubing and a Vibrant Ultra Quiet resonator.




I repaired the clutch linkage while the engine was out, the joints were worn pretty badly. I drilled the holes in the Z-bar oversize and added oil impregnated bronze bushings. Not sure what the Z bar arms were made from but my HSS drill bit wouldn't touch it and my boring head won't adjust down that small so I used the torch to make them soft enough to drill.