For the oil pan to fit nicely, you need the crossbar to be at 18½ inches.
When you have several of these engines, and shop space is at a premium, this cart can be indispensable.
Bellhousing Disassembly
The only way to separate the bellhousing from the engine is to remove the transmission, clutch assembly, and then the flywheel (if not already removed). You need to remove two bolts on the outside of the bellhousing, then four more on the inside, two of which you can’t access until the flywheel is removed. You can get to all of this via the bellhousing access cover that has four screws directly under the bellhousing. Be sure to save the three tin lock-down plates that hold the flywheel bolts secure. They are necessary and difficult to find if you lose yours. Try not to bend off the tabs.
If needed, you can consult the shop manual for reference. It is easiest to remove the transmission, clutch assembly, and flywheel when the engine is still on the vehicle.
Oil Pan
The oil pan is probably the most neglected piece of tin on the vehicle. Rocks dent it, stress warps it, and often you find an over-torqued drain plug. Water condensation causes major rust pits and even rust-through. I spent an entire day blasting this oil pan and inspecting it.
Once your pan is blasted, use 400-grit sandpaper to sand the entire pan inside and out. This makes it easy to see cracks, bumps, and abnormalities in the surface.
In this example, the previous owner didn’t want to address the small hole made by a sharp rock and used Bondo to cover it. In all, there were three holes. One was from rock damage, another was rusted through, and another was an actual crack, about an inch long. These are not surprising because the pan is more than 60 years old.
Being organized takes very little time and could help prevent a catastrophic failure. For example, use resealable bags to keep small items together. Mark one with “oil pan bolts.” Mark the others similarly. You get the idea. Also, take pictures of each assembly prior to the teardown. The images will help with reassembly. ■
It is important to get every crevice completely clean inside the pan so you can assess its condition. This pan has suffered a lot of abuse.
It’s down to the bare metal, so I can add some weld to seal these holes and cracks. First a little body work, smoothing and light hammer and dolly work to make things straight again. Once all the bumps and bruises are smooth, I weld the holes and cracks shut, redress the metal, and then it’s time for another decision: How far I want to go with dressing up this oil pan. There are rust pits and various imperfections. My answer is always; no shortcuts!
If you perform metal working the same as if it were part of the vehicle, it becomes time consuming. I draw the line with putting Bondo on the oil pan because of rocks kicking up and making it look much worse than if you would have used an epoxy primer. Having the least amount of substrate the better.
This pan has lots of dents and damage due to the engine being set on the floor with the pan facing downward. It is difficult to seal these pans even without oil leaks, let alone trying to do it with a deformed pan.
When welding cracks, start about 1/4 inch before the crack on each end. This ensures the unseen start and finish of it is addressed too. Here, the rust-through was minor, and the welding went smoothly.
In this case, I had to address a stripped-out oil drain plug. Someone had already installed an oversize plug, and it stripped out. After redrilling out the oil pan’s drain plug hole to 37/64 inch, I use a 5/8 x 18-inch tap.
As it turns out, this plug is available as a Dorman product (65313). It comes with the nylon gasket as well. This oil pan has a metal reinforcement at the drain plug that is plenty large enough to handle the size of the Dorman plug. Now the pan is like new.
This venerable old engine deserves the very best, and you don’t want to get in the habit of cutting corners. I found many rust pits, dents, dings, deep scratches, cracked metal in the oil pan, side cover, and valve cover. They needed much hammer and dolly work to get them into shape.
Once they are sandblasted, you can use 400-grit sandpaper on a long board to check most of the surfaces of these parts. I recommend using a short Dura-Block to access other areas. You sand by hand if neither of those methods reach the spot.
You are checking for degree of flatness and smoothness. Once the metal is 95 percent there, apply a few thick coats of DPLF epoxy primer to the surface and then finish sand with 400-grit sandpaper. PPG’s DPLF came highly recommended for engine tin because it is safe for up to 500°F. Once it’s dry, you can apply rattle-can engine paint right over it.
Engine sheet metal often requires many hours of work but preserves the tin and makes additional rust virtually impossible. The oil pan, side cover, timing cover, and valve cover receive no paint on the inside. This avoids introducing possible contaminants into the engine internals, which is important. Once the outside is painted and dry, apply engine oil to the inside surfaces, letting the oil soak into the metal.
If needed, retap the pan plug, making sure there is an available plug to go with the size you choose. It’s important to not over-torque the plug. Snug is fine because the plug’s washer does most of the work. Replace the washer if it looks worn or out of shape.
Valve Cover
The valve cover on the 1953–1955 engine has open slits on the top. General Motors wanted the engine to breathe but didn’t take into account the severe damage that underhood dirt and grime getting into the valve cover could initiate. If your valve cover has open slits, a couple of ideas to remedy the situation come to mind. To preserve the look, close the slits from the inside using J-B Weld. It’s even gray. If you clean the area thoroughly before application, it will stay there forever. Or, you can weld the slits closed. It is very important for a new engine rebuild to maintain a clean environment on the inside of the engine where sand and grit cannot ruin it.
If there are no slits, inspect for damage. The bottom of the cover should maintain its indentions that aid in sealing. The holes should be flat and not warped. It’s a good idea to find some reinforcements for the cover screws so the pressure of the screw head is spread out.
Side Cover
Check the corners of the side cover and inspect for any leakage. Improperly installed side covers often cause leaks all over the garage floor! Flatten the screw hole areas, but maintain the natural indentions. A little tin work goes a long way.
Thread damage, holes in the pan; everything takes time but time well spent if it prevents an oil leak.
After blasting and sanding, a crack is revealed that goes all the way through. I could have replaced this pan, but I didn’t want to take another vintage oil pan out of circulation.