INSTALLING A REAR MAIN SEAL
In 1953, Buick celebrated its 50th anniversary and introduced its new vertical head Fireball V-8 in the Roadmaster, Skylark and Super Series, retaining the straight 8 in the Special. The term "Fireball" was not a new term, having been used on the previuos straight 8s. It referred to the "fire ball principle", in which the combustion chambers are designed to impart a high turbulence into each incoming charge of fuel, or, as Buick put it, "shaping the charge into a whistling ball of gas and air particles". Spark plugs were positioned to ignite the heart ofthe charge, transforming it into a fire ball that drove the piston. The valves were positioned vertically in the heads to send the fuel charge into the cylinder on an angle, contributing to the "fire ball" turbulence in the combustion chamber. This resulted in a powerful and smooth-running engine: the new 1953 V8, a 322 cubic inch, which progressed to a 364 in 1957, to 401 in '59 and a 425 in '63.
Our project car this month is a 1963 Riviera with a 401 4 bbl with 325 hp and dual exhaust. When we bought the car, it had only 80,000 miles on it, but it rerquired the usual cleaning and some parts replacement. The drive train was in great shape, but had a few serious oil and water leaks! The worst problem we had was a rear main seal leak. This was difficult to dtermine, because we couldn't tell if the oil was running down the back of the engine from the valve covers, the oil pressure switch, the oil galley plugs in the back of the engine, or from the rear main seal. The first step was to "Gunk" and wash off the engine. Then we put the Riv on the rack and started the engine. At first, there were no drips, then there came a constant, stead drip from the flywheel inspection cover. We took a mechanic's mirror and begand to look at the back side of the valve covers and oil pressure switch, finding everything dry. We had already decided while the car was up in the air, to pull the Dynaflow transmission, clean it and put in new seals, fluid and gaskets. This would also give us an opportunity to check the oil galley plugs.
After the transmission was out, we could see the back side of the engine's oil galley plugs. There was a film of oil around them. One way to test them is to pressurize the oil system. Using our engine primer tool, we put 5 quarts of oil into the engine primer, drained our old oil out of the block, hooked up the primer at the oil pressure gauge fitting, and aired up the unit. This filled the engine with oil and pressurized it up to allow us to see any leaks, especially at the oil galley plugs. There were none. This test will not show a rear main seal leak, because it is a seal and not under oil pressure.
Now feeling that the problem was definitely the rear seal, we put on the torque converter (it has the ring gear on it) to allow us to start the car. We started the engine and could see the oil drip from the rear of it, and as the torque converter turned, it slung oil around the galley plugs on the back side of the engine, mimicking an oil leak at the plugs. Having pinpointed the leak to be the rear main seal, now to solve the problem!
TO REMOVE THE SEAL: We pulled the torque converter back off, disconnected the battery's ground cable, removed the fiberglass fan shroud (this will crack when the engine is jacked up), drained the oil and removed all of the oil pan bolts that were accessible. Then we removed the motor mount bolts and pulled the cotter pins, disconnecting the steering and idler arms. Jacking up the the front of the engine, we removed the last two oil pan bolts that we had not been able to get to, and pulled the p an. We lowered the engine back down onto the mounts and remoed the oil pump (noting the direction of the distributor drive). We loosened all the main cap bolts and removed the rear cap. Then, carefully, pried down the crankshaft, creating a space to install the new seal. It seems that you always find something that you didn't expect, and this time was no exception. We found a worn place on the crankshaft counterweight, where the oil pump had been rubbing it over the years. It is an original oil pump that had a bump on the housing, which had worn to the point where it was smooth and didn't hit the crank any more, but it must have made a heck of a noise the first time the engine was started! Since this wasn't really a problem any longer, we continued our project, pulling out the old seal with a hooked pick, and took all parts to be washed and painted, and laid out our new gaskets.
TO INSTALL THE SEAL: We had a choice of two types of seals: rubber and rope. We choise rope, feeling that it would swell and seal better. (We only wanted to do this once!) We rolled the end of the seal to allow it to go into the goove in the engine smoothly, and slipped the seal installer tool through the groove, between the crank and the block.
We placed the guide on the seal tool (tapered end toward the crank--the guide is a small open cylinder taht the seal slides through to help it squeeze into the block groove). We put a film of oil on the rope seal and pulled the guide sleeve over the seal, pulled the tool handle down until the seal was at the crank, then rotated the engine in the direction the seal was to go in, while pulling on the seal tool as the crank turned, pulling the seal around in the groove until there was about 1/2" sticking out on each side. Now we tightened all of the front main caps and trimmed the seal so that it extended on both sides only about 1/16". We rolled the other half of the seal into the main cap, using a large socket to press it into position and trimmed the bottom seal to protrude 1/16" on each side. We put another film of oil on the seal and loosely replaced the main cap. (If there are side seals, push them in now while the cap is loose, then tighten the cap, installing pressure pins and torquing the cap.)
RE-ASSEMBLY: With the seal in, we were ready to button everything up! We put on the oil pump and torqued it, making sure the distributor drive was in the position to line up properly, raised the engine and installed the newly painted oil pan with gasket, using a little 2-B sealer on the pan side, tightened all of the oil pan bolts and lowered the engine. We installed the motor mount bolts, reconnected the steering and idler arm with new cotter pins, put the transmission back in, re-connected our ground cable and fan shroud and put in new oil and filter. The car started up with no leaks! It is easier to replace the rear main seal with the engine out of the car, but there are times when you don't want to chance ruining that newly-detailed engine compartment. This is a workable alternative that gives excellent results! See you next month. Have a happy Thanksgiving! Keep 'em driving!