I'm in the process of assembling my 1961 390 for a series 62 convertible, and I'm discovering some missing bolts. I have the service manual so I have the size and thread pitch, but I'm missing the length and style. I would greatly appreciate anyone that can provide the missing info for the following bolts.
Oil filter mount to block
Starter
Flex plate to Crank Shaft
Hydromatic bell housing to block
Motor mount to Block
On the topic of motor mount, I thought the tabs on the block both slide either inside or outside the mount, but having made some measurements I realize it must sit with the block tabs shifted so the front block tab is either in the frame mount or in front of the frame mount. I would appreciate clarification on that alignment. One of the joys of putting together a car you didn't take apart. Thanks in advance for the info.
I think I solved the mount position question. Thanks to
@Clewisiii for doing such a great job of documenting his restore with photos. I found a pic of his motor with mounts attached and they are behind the engine tabs. This also makes me think I need to pull the mounts off my frame, and install the engine with mounts attached.
For the motor mounts the driver side mount goes behind the casting ears.
The passenger side mounts goes in front.
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Motor mount bolts are fine thread 3/8 x 1 1/4.
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Starter are 7/16 course x 2 1/2
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I beleive Flywheel to crank is 7/16 x1/2 20tpi.
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Bell housing is 7/16 x 1 1/8 14tpi
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The oil filter has three bolts, two sizes. All course thread. I do not remember the size.
The grid paper these are on is metric. So 10mm each.
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Carl, you're the best!
Thanks!
Quote from: dbzsjones on January 26, 2025, 01:09:26 PMOn the topic of motor mount, I thought the tabs on the block both slide either inside or outside the mount, but having made some measurements I realize it must sit with the block tabs shifted so the front block tab is either in the frame mount or in front of the frame mount.
This is a question which is coming back on a regular basis!
Del, do you have the spacer/washer that goes in the end of the crank shaft between crank and trans fluid coupling.
I don't remember there being a spacer there when I tore things down. I have the flex plate, but no spacer. I was going to bolt the flex plate directly to the crank. Did every car have the spacer?
Thanks,
Del
This is the spacer. A thick disc really. It goes in the cavity on the back of the crank shaft. Often lost if you send out the engine or crank for rebuild. It gets stuck in the back of the crank and falls out during cleaning.
I am not sure its purpose. I think it acts as a thrust washer between the crank and fluid coupling.
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I believe it is there to place the fluid drive in its correct location when pressure is being applied during acceleration.
Possible that the Unit could try to expand as internal pressures build up creating an internal fluid leak within the Fluid Coupler, thereby limiting the amount of oil pressure being created.
Bruce. >:D
I tried to check the back of my crank, but it's still on the stand so access is really limited. Feeling inside the back of the crank there is a hard shoulder about 3/8" inside and then a dimple inside of that. It definitely did not feel flat like that spacer looks in the photo. When I look at the center of the fluid coupling it looks like it's designed to fit into what I felt in the crank, but I wasn't able to get depth measurements to determine how tight the fit would be.
I think I can officially declare my spacer missing, if it's required does anyone know where to find a replacement?
I have a spare.
PM Sent
So happy to hear that! I searched the internet and I'm not sure many people know this part exists, or I didn't know what to search for. I found 1, that was long sold.
Quote from: dbzsjones on January 29, 2025, 10:36:50 AMPM Sent
So happy to hear that! I searched the internet and I'm not sure many people know this part exists, or I didn't know what to search for. I found 1, that was long sold.
Chips Caddies (spelling?) on Ebay, sells a lot of repro Caddy bolts and related hardware, for several years of Cadillac. He might have something. I bought his new exact repro exhaust manifold bolts for my '56 and they worked out really well. They even had the built-in flange around the head, just like the originals. As he explained, I did have to cut one of them down in length and clean up the threads prior to use. I guess this set was made to fit several years of Caddies where bolt length might have changed. But they were exact reproductions. Can look for his site info if you wish. Clay/Lexi
It is Chips Caddys. Attached is the link below. Have a look or contact him as he may have items available that are not listed. I have purchased from him a couple of times or more, and have not had any issues in dealing with him. A good resource to have. Clay/Lexi
https://www.ebay.com/str/chipscaddys
Found it.
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Quote from: Clewisiii on January 26, 2025, 02:31:18 PMI beleive Flywheel to crank is 7/16 x1/2 20tpi.
20250126_143006.jpg
It always surprises me that there are no lock washers on these bolts.
Quote from: dbzsjones on January 30, 2025, 06:53:21 PMIt always surprises me that there are no lock washers on these bolts.
Other GM brands use lock washers on these bolts. Not the single turn ones, but the star type. With the external tangs.
Bruce. >:D
Most torque calculation testing finds lock washers do not really work.
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Quote from: The Tassie Devil(le) on January 30, 2025, 07:17:01 PMOther GM brands use lock washers on these bolts. Not the single turn ones, but the star type. With the external tangs.
Bruce. >:D
It seems that even a small thin flat washer would be a good idea to keep the flex plate from getting gouged out as it normally does.
The new bolt set did come with star washers. Not sure it hurts anything to use them, but it they didn't use them originally, I'm not sure I should add them.