Story by Phil
You know when it happens, a loud bang then the oil light is on…”
Here is some technical information that some owners of older Buicks might find helpful. Being in a Buick only dealership you get to see common problems related to only one car manufacture. The items below are things we saw a lot of and sometimes could be prevented with proper maintenance. Again this is done from memory and I am sure I have forgot some things.
The “Nailhead engine” 1953-1966
The rocker arms would cut there way into the rocker arm shaft. This changes lifter piston position and creates excessive clearance between camshaft and valve causing the noise. Shaft replacement is necessary along with a few rockers. This was caused by lack of oil changes. About 1965 we did at least one a day.
Water Pump Failure
Early failure is caused by drive belt tension being too tight. A V-belt grips on the sides and as it wears it get narrow and drops down into pulley. It then becomes necessary to over tighten to eliminate slippage. This puts too much pressure on the water pump bearing and causes failure. The belt should be flush with the top of pulley. A/C cars use a dual drive on the compressor. This was done because the A5 and A6 compressor uses 15 horsepower to drive it. With two belts less tension was needed. It is important to purchase these belts as a matched set and always replace in pairs. For the correct tension a belt tension gauge is nice but a good mechanic can do it by the finger test. We saw a lot of pumps fail around 35000 miles because the belts were just too tight.
Broken Piston Skirt
This is caused by over revving. Don’t wind a nail head up too high, they don’t like it. They are a high torque, low rpm engine. I pulled the head off a 63 Riviera (401) and one piston was missing. I was looking at a connecting rod and wrist pin but the entire piston was in pieces laying in the oil pan.
Broken Oil Pump
This happens in real high mileage engines only. The shafts the oil pump gears both the drive and idler wear down. This causes the gears to bind up and explode the housing. You know when it happens, a loud bang then the oil light is on. If the engine is shut down right away a new oil pump is all that is needed.
The main reason we saw was a plugged up radiator. The main cause was over age coolant. Radiators plug up from the bottom to the top. Looking thru the fill hole is not a good indication of condition. Of course old hoses and water pump failure caused a lot of it too.
Coolant In Motor Oil
From lack of coolant changes a small hole will develop in timing chain cover behind water pump. These can be welded up if a new cover cannot be found. Change coolant every 2 years.
Blown head gasket from being driven in an overheated condition.
The temp light goes off at 280 degrees. There is no safety zone at that temperature. Shut off engine immediately and you will save the head gasket. Other than 1962-63 215 cu. in. aluminum V-8 and the 1964 300 cu.in. V-8 I have never seen a head gasket go bad for any other reason than an overheat.
Throttle won’t return after being floored
Broken left (driver) engine mount. Rod type throttle linkage binds under air cleaner housing when engine rolls up due to broken left mount. This was the first federally mandated recall I can remember. We installed a cable around the upper suspension control arm and attached it to two head bolts with brackets. Starting in 1968 cable throttle controls solved this problem. Later models have hooks built into engine mounts. I have had this happen to me several times. It’s most unpleasant. Remember go for the ignition switch not the shift lever if you want to save the engine.
Binding Throttle With AFB Carburetor
Metal plate under carburetor has holes in it where it covers exhaust passage. This has allowed wet exhaust to eat thru the aluminum casting of carburetor binding primary throttle shaft. If not too bad the carburetor can be repaired. A stiff throttle spring is not the fix.
High Oil Consumption
Other then the usual worn piston rings common to all engines the nail head likes to wear down the valve guides. This allows oil to be sucked in around the intake valve. Also the 1959 thru 1965 used a stem seal that did a poor job. In 1966 the top of the guide was cut down to accept a positive seal. The nail head is the only GM engine I know of that has replaceable guides. They merely drive in and out with a hammer. The 1966 guides and seals will work with the earlier models. Valve grinding was common with the older engines because of poor gas additives, conservative driving and low spark voltage. It all but disappeared in 1967 and returned in 1975 and left permanently in 1977.
Crankcase Full Of Gasoline
The internal seal would fail in the fuel pump. This allows gas to be pumped into crankcase via the pump actuator arm. Yes the engine will still run when this happens.
Constance velocity universal joint 1962 thru 1970
Because of the long wheelbase of most Buicks and the desire for a smooth vibration free car the CV joint was used in the long drive shafts. The Rivera uses two. It is a ball and socket between two u-joints tensioned by a very stiff spring. Lubrication is done thru a small hole in the part between the u-joints. This requires a needle type grease gun. Also high-pressure grease is necessary. We were replacing three to four of these a week in the old days. The problem was one of two, they weren’t getting lubed or regular chassis grease was being used. When they go bad you will feel a shutter on take off. I had one customer ask for a tune up because he thought it was an engine miss.
Excessive brake pedal effort or brake pull. During the drum brake era thru 1970 we had a lot of this. Mostly the cars had a brake job done elsewhere before coming to us. GM used only new riveted brake shoes. The aftermarket brands were generally bonded rebuilt shoes. Bonded lining is hard and rebuilt shoes won’t re-arch themselves to the contour of the drum. Simply replacing the shoes solved the problem 90% of the time. Bendix still makes new riveted shoes for older models.
The 1956 models with power brakes left the assembly line with what was called a displacement master cylinder. Instead of an internal piston it used simply a large rod going thru a seal that displaced the fluid in the sealed reservoir. The failure rate was high. Most were converted to the piston type master but there still may be a few left out there.
In 1967 and 68 the disc brake system was made by Bendix. It used a 4-piston caliper. One of the pistons would become stiff and cause uneven pad wear. Also the piston seals would leak. This ended in 1969 with the Delco Moraine single piston floating caliper.
Front Suspension 1957 & 1958
The 1957 models came out with A-arm front suspension unlike the king pin used in 1956. The arms were made from cast iron. Iron is a brittle metal and when exposed to a lot of pressure it will snap like a pretzel. At the same time power steering was becoming popular. If you curbed the wheels and turned them into the curb the upper A-arm would snap. This could also happen if a large hole was hit in the road. The 1958 model had the same problem. The fix came in 1959 with stamped steel control arms. There was many a Monday morning we came to work and saw a 57 or 58 in the service yard listing like a sinking ship due to a broken A-arm.
Rivera Engine Size
All 1963s had a 401. All 1964s had a 425 and yes dual quads were available in 64. 1965 single 4 barrel was a 401, dual quads were a 425. All 1966s had a 425. In 1966 the 425 was painted red.