Re: Brian's 1956 Packard Clipper

Posted by HH56 On 2019/5/27 11:04:46

The Olds pump mod was not developed until about 10 years ago. Packards International Club developed their pump "fix" back in the 70s which was fairly heavily promoted in the US. PI had a rather large international following at the time so their pump could have been the go to cure in Australia too.

The PI mod consisted of a reworked stock pump that had the vacuum pump section removed and replaced with a thick machined steel bottom plate. Theory was the original pot metal bottom plate separating the two pumps was swelling and allowing air from the vacuum pump to enter the oil path. The heavy steel plate was promoted as providing a better support for the oil pump gears and being thick, the plate couldn't swell plus no vacuum pump meant no air.

As far as I know, the possibility of the shaft being an issue was never in consideration at PI and other than the plate adding more support for the gears I don't believe any direct work was done on that end. I have read there was one fellow that might have addressed the shaft by adding a bushing but his reworked pumps didn't have any of publicity PI's did. I don't recall them ever being mentioned at any meets I attended. As a result, probably not installed in very many cars. Conversely, the PI mod was a topic at tech discussions for years and many cars had them installed -- including mine. If your car had a pump change 35 years ago it could well be in your car too.

Not all who installed the PI pump went to the trouble of completely removing and plugging the old vacuum setup, some wanting to keep a stock look. With your electric wiper I expect the balance valve and intake manifold source is gone but for grins you could check on the right side of the engine block between the oil pan and head for a 1/4" steel tube. There is a port about midway on the engine where the tube connects to an elbow and goes inside the crankcase. A check valve in the tube a few inches rear of the port remained so if the port was not blocked off internally and the manifold vacuum source was still connected the check valve was all there was to provide a means so vacuum didn't leak. If you still have the original pump setup and the pump is working there would be vacuum at the tube when the engine is running.