Good day bolters, anyone know the size bolts and how many needed for mounting starter to clutch housing. There is a stud on one side, it has a fine thread. Engine and housing are in storage but in know I put a nut on the stud at one point. 1953 216. Thanks for help.
Stud uses a 1/2" fine threaded nut. Bolt is 1/2" coarse threads.
~~ Jethro 1954 3100 Back to Life In the Dity Gallery 1951 3100 (gone) / 1956 4400 (still in the neighborhood) / 1957 6400 with dump body (retired) / 1959 3100 panel (in the woods junked) / 1978 Custom Deluxe K10 / 1993 S-10 4.3 / 2004 Chevy Crew Cab / 1945 John Deere H / 1952 John Deere B / 1966 John Deere 2510 / 1967 John Deere 1020
so the stud is the fine and the other bolt which i found in bucket of bolts looks to be the one, with star washer. any reason they had one fine on stud and other course going into bell? i ran into top of threaded trans mount to bell, thinking it was for that.
We can only guess what the engineers were thinking back 70 odd years ago. The stress on the top stud would be much higher than the stress on the lower bolt. When you hit a pot hole, the weight of that heavy starter would tend to pull out the top stud; it needs to be strong. So not only NF threads but maybe stronger grade steel.
A similar situation situation exists with firewall mounted brake power booster and master cylinder. Hitting a pot hole tends to pull the top bolts out from the firewall. In the early 1980's GM recalled some pickup trucks; they added a strut from the master cylinder to the firewall. There had been some accidents where the brake assembly had pulled away from the firewall.
My take on why there's a stud instead of a bolt on the top mount is that it's easier to stick the starter over the stud than to hold the starter in position and start a bolt. Anything that makes assembly quicker at the factory is usually done. The starter lines up in the hole for the nose, but can be out of rotation to find the hole for the bolt (instead of stud situation.) The stud is coarse thread on the end that screws into the bell housing, so strength at that point is basically the same as using a bolt. Why a fine thread is used on the stud/nut is still a question in my mind.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Holding up the starter is certainly a bonus. However, the real reason for a stud is that it is impossible to use a bolt in that position. You cannot get a bolt with the same amount of threads as the stud into the hole. Access is blocked by the switch.
1950 Chevrolet 3100 (Ol' Roy) 1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1956 Cadillac Sixty Special Fleetwood (The Godfather) | 1966 Oldsmobile Toronado (The Purple Knif) | 1966 Ford Mustang (Little Red) | 1964 Ford Galaxie 500 coupe | 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
Good point Otto. It's been a day or two since I messed with my starter.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
My take on why there's a stud instead of a bolt on the top mount is that it's easier to stick the starter over the stud than to hold the starter in position and start a bolt. Anything that makes assembly quicker at the factory is usually done. The starter lines up in the hole for the nose, but can be out of rotation to find the hole for the bolt (instead of stud situation.) The stud is coarse thread on the end that screws into the bell housing, so strength at that point is basically the same as using a bolt. Why a fine thread is used on the stud/nut is still a question in my mind.
I believe that fine thread nuts do a better job of staying in place than course threads. Maybe has to do with more friction imparted by the additional number of threads.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Holding up the starter is certainly a bonus. However, the real reason for a stud is that it is impossible to use a bolt in that position. You cannot get a bolt with the same amount of threads as the stud into the hole. Access is blocked by the switch.
Yepp. Even on the later ones with the big solenoid on the starter, that stud & nut assembly are snug up against the nosecone. Im glad I can get mine loose, then take the nut off by hand.
1962 C10 with a 235 6cyl -- all of the drive train seems to be original. Some of this story is in the Side Lot Some people like a new truck. I liked the old ones.
We can only guess what the engineers were thinking back 70 odd years ago. The stress on the top stud would be much higher than the stress on the lower bolt. When you hit a pot hole, the weight of that heavy starter would tend to pull out the top stud; it needs to be strong. So not only NF threads but maybe stronger grade steel. 
It's been a day or two since I messed with my starter.