Oil Pressure Puzzler
This Oil Pressure Puzzler was created while attempting to solve the Pulsating Oil Pressure problem at Pulsating Oil Pressure.
In this puzzler, two different oil pump covers were installed on a 231 cubic inch V-6 engine from a 1979 Chevrolet Monza Spyder that is now powering a 1984 Buick Regal.
The first oil pump cover was installed without a gasket using gasket sealer only. The engine started but there was no oil pressure. There was no oil pressure because the oil pump was not primed before installing the oil pump cover.
A second oil pump cover was installed without a gasket using gasket sealer only after priming the oil pump. The engine made a snap/thump noise when the starter engaged and the engine rotated but did not start.
This second oil pump cover was removed, oil pump reprimed, and the oil pump cover reinstalled without a gasket using gasket sealer only. Once again, the engine made a snap/thump noise when the starter engaged and the engine rotated but did not start.
It was eventually discovered that the engine would not start after the second oil pump cover had been installed because the distributor gear was broken in two places, once for each time the second oil pump cover was installed. This is what was causing the snap/thump noise. The photos below show the two places where the distributor gear was broken:
The distributor gear was replaced and the second oil pump cover was again removed, oil pump reprimed, and the oil pump cover reinstalled but this time with a gasket and no gasket sealer. The engine started and ran with normal oil pressure.
Puzzler Questions:
- Why did the engine run after installing the first oil pump cover with no gasket?
- Why did the engine distributor gear break each time the second oil pump cover was installed with no gasket?
- Why did the engine run properly after the second oil pump cover was installed with a gasket?
The answers for question #2 and #3 may be obvious. But what about question #1?
The answers to the Puzzler Questions reside on an Internet Web Page. To acquire the address of the Internet Web Page, email your answers to Tim026300@aol.com