Clutch / Torque Converter: crankshaft/flywheel bolts

[bosshoss61]

Thank you, I have looked through all three shop manuals for my crankshaft to flywheel bolt sizes. The 1950 Studebaker Champion with the 170 in./flat 6 shop manual says 3/8-24, but not how long. The flywheel is slotted (similar to the holes in the vibration damper)---- is this for washers? And how do I get the nuts for the flywheel between the block and flywheel? Any tricks, any pictures or knowledge on bolt length. thanks

[Tom Bredehoft]

The flywheel bolts are not your common everyday hardware store bolts. They are inserted in the crank before the rear main bearing cap is in place and the six heads interlock. The nuts go on the rear side of the flywheel. You'll have to get them from one of our many exellent vendors.

[altair]

flywheel bolts

Thank you, I have looked through all three shop manuals for my crankshaft to flywheel bolt sizes. The 1950 Studebaker Champion with the 170 in./flat 6 shop manual says 3/8-24, but not how long. The flywheel is slotted (similar to the holes in the vibration damper)---- is this for washers? And how do I get the nuts for the flywheel between the block and flywheel? Any tricks, any pictures or knowledge on bolt length. thanks

I am just a little unclear you mention "the nuts for the flywheel between the block and the flywheel". The bolts are inserted through the crankshaft then the flywheel is attached to the protruding bolts with the nuts on the outside. The bolts have to be inserted with the pan and rear main removed. The overall length of the bolts are 1-5/8", bolt shaft 1-1/4" thread length 1/2". The catalog wouldn't spec the bolt just a part number. They are a special design bolt for that purpose. It is very possible that there are other engines that use the same bolt and if they were longer it would be ok to cut them to length. I have a curious question is this engine assembled with out the bolts in the crank shaft? Dave British Columbia

[candbstudebakers]

I have lots of them.

[StudeRich]

Aren't the 6 Cylinder Engine flywheels just fastened to the crank with "screws" (bolts without Nuts) into threaded holes in the Crankshaft from the flywheel backside?

I am like most here, almost never working on 6's so it is hard to remember.

[altair]

crankshaft bolts

Aren't the 6 Cylinder Engine flywheels just fastened to the crank with "screws" (bolts without Nuts) into threaded holes in the Crankshaft from the flywheel backside?

I am like most here, almost never working on 6's so it is hard to remember.

I have a spare 6 and it has 1 5/8" bolts inserted through the crankshaft flange and the flywheel is then attached with nuts Dave

[bosshoss61]

thank you, you've answered a lot of my concerns. The holes in the crankshaft and the flywheel are smooth bore, requiring a bolt and nut assembly. It appears, I really screwed up and did not put the bolts in before I set the crankshaft in place. Now the motor is about ready to go back in the car. I hate it when I do stupid stuff, but that's how I learn. My tool chest has 18" open end wrenches standard size. Trick I use (put tape on one side of the open end wrench where the bolt goes, then stick the bolt to the tape) I've put some bolts on in pretty strange places that way. Thanks for all the help..........Looks like my options are to tear the bottom end apart or put the bolt and nut in reverse order. I'll order the better grade bolts. Do you gents or ladies see anything wrong with the bolts going in backward? Thanks

[starliner62]

I never tried backwards nuts and bolts. The flat of the nuts will have to be against the crankshaft and a lock washer would be impossible. I guess red Locktite would work. You would also have to make sure the bolt is not too long when tightened so it won't hit the back of the block while the engine turns.

[bosshoss61]

I believe I have found the bolts and nuts. (3/8 diameter by 1-1/2 long and about 24 tooth thread) Do they have a round head with about 25%of the head flat? Hate to admit defeat, but the motor is all done. OOPS --was all done. It's on the stand now so I can take the pan off---darn thing is top heavy. Is there some kind of plate missing that held these bolts in place with a flat sided head like that?

[bosshoss61]

Thanks to those that helped me. I pulled the pan off and the rear main bearing. the 6 bolts with the round head that has about 90 degrees on the side of that head--flat---fit right in. Actually I found out that the flat part of the bolt was up against a raised part of the crankshaft itself. That was what kept the bolt from spinning. Man, did I learn something. The shop manual has a cutaway of the champion motor for a 1950, but it sure looks to me like the 6 bolts are threaded in from the flywheel side. But, I'm done