crankshaft to transmission

[robtc]

I am putting back together a 1955 champion engine to an automatic transmission. The bolts to connect the crankshaft to the flexplate have gone missing. (OK. I confess I lost them). Can anyone tell me what size, pitch and grade the bots are?

Also, comparing this engine to a '51 engine I have is puzzling me a bit. on '51 the bolts come from the engine side through the flexplate and then the flexplate is held on by nuts. On the '55 there is no room between the end of the crank and the engine itself for bolt heads and so it looks like the bolts go in through the flexplate side. Are both correct for their respective years?

Thanks.

[StudeRich]

Are you sure the '51 is a SIX? All V-8's are as you describe the '51, with nutted bolts.

[ROADRACELARK]

IMMIC, those bolts come through the crankshaft flange from the front side. They have a special head that locks aganist the crankshaft hub. The nuts and flat washers are on the flex plate side. It will require removal of the rear main bearing cap to insert these bolts. Hope this helps.

Dan Miller
Auburn, GA

[robtc]

in the '55, when I took it apart the bolts went from the transmission side through to the crankshaft. The crankshaft, "hub" I guess it is called, has threaded holes for the bolts. Anyone else have a situation like that?

[ROADRACELARK]

The statement I made above would reference the Flight-0-Matic, first avaible in some '55 models. The '51 models would have used the "Studebaker Automatic Drive" aka, the Detroit Gear Automatic. Depelnding on whether it was a Champion 6, or the Commander V8, there were 2 or 3 different models of the DG trans. The shop manual cut-a-way pictures of both transmissions showed the flex plate bolts to the crankshaft coming through FROM the engine side of the crankshaft flange or hub, then the flex plate, reinforcement plate, flat washers then nuts. Depending on which transmission will determine the type of flex plate attachment to the torque convertor. The DG torque convertor may very well have threaded studs welded to it. The Flight-0-Matic's torque convertor has "threaded nut plates" welded to it, and the short bolts that go through the flex plate into the nut plates. I hope this makes SOME sense. If I'm in error, I apologize. I'm going by the info. and cross section drawings in the '51 and '55 shop manuals and parts manuals. Again, I hope this helps.

Dan Miller
Auburn, GA

[allstateguy]

I have heard of people threading the holes in the crank hub so that the more common method (flywheel bolts on from the trans side) can be used.
Maybe someone in the past did this and while not stock, it can be convenient. I would just try bolts hand-threaded in, until I found the right size and threads, then go buy some Grade 8's of the right length to put in.
I plan on having the machine shop thread my 289 crank this way so I have the option to switch from the current aluminum flywheel to a flexplate sometime in the future without dropping the pan and rear main, IF I ever get tired of shifting (not for a few more years, I hope)

[Dwain G.]

I believe all the 185's use bolts into a threaded crankshaft hub. My manuals not available right now to verify that.

[robtc]

Thanks Guys. Everyone was a big help.