Mystery by-pass valve.....what's the application?

[Michael G.]

Last week while swap meeting bought a 141 oil canister and inside it was a unique by-pass valve.....very similar to the one used on early Chevrolet V8 engines. The valve 3915164 uses slightly larger mounting bolts and bolt pattern is nominally wider than that of the 141 by-pass. I've posted a PF 141 by-pass valve 5573842 next to for comparison. Winner, winner chicken dinner......whats the application?

[Joe L.]

Re: Mystery by-pass valve.....what's the application?

Last week while swap meeting bought a 141 oil canister and inside it was a unique by-pass valve.....very similar to the one used on early Chevrolet V8 engines. The valve 3915164 uses slightly larger mounting bolts and bolt pattern is nominally wider than that of the 141 by-pass. I've posted a PF 141 by-pass valve 5573842 next to for comparison. Winner, winner chicken dinner......whats the application?

Michael------


In 1968 Chevrolet V-8 engines were converted to a spin-on type filter and all block castings were redesigned for the new adapter and filter. However, not all applications from 1968 onward used the spin-on filter. Chevrolet series 10-30 trucks, taxis, and police cars continued to use the canister-type filter for awhile. However, these applications also used the 68+ style blocks designed for the spin-on filter. So, there was an adapter released which allowed the use of a canister-style filter on a block designed for a spin-on filter. That adapter was GM PART #3915163 with CASTING #3915164.

Now, we all know that there were and continue to be a variety of adapters available to convert a canister-style block to a spin-on filter. However, as far as I know, the GM adapter referenced above is the only adapter ever available to convert a spin-on style block to a canister style filter. Why would anyone want to do that, including GM for the 68+ truck, taxi, and police car application? That, I have no idea.

[Stuart F.]

Re: Mystery by-pass valve.....what's the application?

The canister style filter lends itself better to heavy duty service applications where the underside of the engine (without a skid plate) may be exposed or vulnerable to ground debris. The original GM manufactured canister is made from a very heavy gauge material (not the reproduction units due to the special tooling required to draw this gauge). It can not be easily pierced/punctured. I have witnessed the severe damage to an engine when the vehicle ran over some road debris that damaged a spin on filter on the side of the engine and it lost all of its' oil. This is the reason I rejected the idea of changing to a spin on conversion, even though I had the adapter kit and a case of Wix spin on filters ready to go. I also have both my original canister and a reproduction canister. I used to trade off at each oil change, which gave me more time to clean the one that I removed and cut down on the "on ramp" time to do the service. I no longer do that, rather I take the time to clean the original canister for the same safety concern. I also feel that I am getting a better prep of start-up oil by filling the canister before installation than I would with a spin on filter.

Stu Fox