finished product after deburring and copious amounts of glass beading to do minor stress reliving.

Nice work keep the pics coming maybe someone can archive them.

Greg

i'm still digging around trying to get a handle on the different bearings and whatnot. Sonnax sells a repair kit (22556-BRG) that includes three roller thrust bearings (to do three transmissions) for the back of the 727 housing if the sprag race has damaged the case. a preliminary look into this and i "think" this might be the same as the GM N 11 bearing which according to Sonnax has the dimensions of 3.391 x 2.5 x .140. i may email or call Sonnax to confirm.

attached is a PDF file from Sonnax that lists a lot of bearing dimensions and the Sonnax part numbers. for anyone interested in these type mods this file might be a big help.

this stuff would be a lot easier if i knew what i was doing

ok a call to sonnax confirms that their 22556-BRG kit does contain the (three) bearings with the aforementioned dimensions. this kit can be found online for around $22. i did see some vendors that seem to be selling the bearing individually (i assume because it was $7) with the same part number but the sonnax delivered PN contains three bearings

made a little progress on the swift-o-matic transgression being some jewelry showed up today. carving stuff up to install the 6 bolt super sprag. being the dummy i am i "assumed" the other two bolts would fall on the two blank pads well only one of the does so it required a little more work than i thought. the first thing to do was bolt the sprag to the back of the case using allen screws from the inside this located the sprag in the same spot it will be on the inside. then transfer punches were used to center punch the location of the two new holes needed. the holes were drilled then the one pad area machined so a spacer could be used. this way all six bolts will pass through the rear support.

a drill guide and drill bushings were used to make sure the holes were on location and straight. if you do any amount of fabrication these bushings and transfer punches are absolutely indispensable. the (Spellmaco) punches were purchased new the drill bushing kit was a $50 ebay item and i don't know how i ever got along without them.

transfer punches and drill bushing kit, man they make things easier

this shows the sprag and how an 11/16 endmill was used to clearance the pad and spotface the area after the 17/64 hole had been drilled.

a spacer was turned outta 5/8 aluminum bar stock this will support the flange of the rear support when it's thru bolted

Looks good , I used 4 bolt rear supports and just drilled the holes and spot faced for an allen head screw under the support.

Very nice work.
I don't think many people go this far, and they aren't having problems. But I think you did it up right.

Thanks for posting the pictures.
There are a couple ways to locate and machine the holes, yours seems like a standard approach before all the numeric stuff took over. The numeric is great for many repeated jobs, but the setup and engineering to get the numbers may not be worth it for one job.

at first i assumed the holes in the sprag were symmetrical but i'm not sure and never checked it. the DRO on the mill has a bolt hole function but one thing i have to deal with is the mill doesn't have a riser (i been shopping for a 4" don't know if i want more than that) so the height under the quill is limited. i don't have the room to put a case in there then add the length of a chuck plus bit. yea i know it's a little overboard but these things don't cost money so i figured why not. i still haven't decide what i'm gonna do as far as bearings or just thrust washers. at the very least i'd like to put a bearing on the output shaft. i was eyeballing machining a bushing to put in the governor side of the rear support so i can use a longer bearing and take advantage of the machined surface of the shaft but haven't actually measured stuff to see if it's doable and/or worth the trouble.

i never document ANYTHING and besides not being helpful to others it kinda screws me later when it comes to engine dimensions and whatnot. guys like yourself post a lot of info and it's very helpful so i kinda feel guilty. figured if i try to document some of this stuff it might be of use to someone.

I never checked if my Bridgeport has room from the table to the cutter with a case in that orientation, I don't have a riser. I take it you can fit a collet and endmill, but not a drill chuck and bit. So it must be close.

I just dug out this photo of my 1975 case. And it doesn't even have the pads that your's has. And I looked at a 1977 case too, and it doesn't have the blank pads either. Must have been phased out much earlier.

i "think" they were a throwback to the days of the rear pump. i figured it was better to have them thinking the other two sprag bolts would pass through there...well i was half right

The extra bosses are common to all cases before '71 and they're not a rear pump hold-over because pre-'66 rear pump holes don't line up.

I suspect the factory intended to use six bolts in the rear support and then decided to use only four.

OK was dinking around with this some more today. i figured i'd try something different for the rear roller bearing. an aluminum bushing was turned to 2.2515", rough bored to 1.865" then cut off at about .500" length. the rear support was heated and the bushing driven into the governor ring area. then the rear support was chucked and indicated on a non wearing surface to <.0005 TIR. the support and bushing were then bored to 1.8755 (the bearing seemed fat) to a depth of the edge of the oil feed hole. the support was heated again and the B-2412 bearing driven in.

the rest of the bore was left as manufactured my thinking is this. most mods use a longer bearing which requires more material removal (thus weakening the support), oil modifications and a seal but the longer bearing doesn't actually give much if any more actual shaft contact because it bridges the oil band on the shaft. this way you actually have more bearing area because it maintains the factory bearing surface from the oil hole forward and no seal should be required because of this. i can't say this is a good idea but it's what i decided to try.

due to the bushing that supports part of the bearing being in the governor ring area a portion of the parking gear had to be cut off. i could have cut it back to the rear sealing ring but wanted to maintain some of it's length so it would still register on the ground portion of the shaft, this should give the parking gear more stability.

That seems like a good approach for the support bearing.

I never took detailed measurements of where the shaft sits relative to the rear support, but I agree it is about where you put it. See the attached pic, can you supply a location for the shaft (I put it approximately at the top of the pic)?