Big block oil filter adapter
 

This is probably a stupid question but I'm willing to take some lumps for it. A friend and I are trying to get a 396 up and running for his 81 Camaro. Neither of us has much experience doing anything like this and we're not mechanics. The block had nothing up in the oil filter area, completely bare. I purchased an oil filter adapter but it was missing one part so I have to return it. In the meantime, I checked a couple of other 427 motors I have on some stands. there is a valve in the adapter I think is called the 'oil bypass', I believe it lets the filtered oil escape from the filter and enter the block. The one I purchased has a spring loaded valve, both of the two that I found on the 427's had the valves blocked off.
What would be the purpose of blocking that valve closed? if it is blocked closed, how does the filtered oil reenter the engine?

The valve is there in case the filter plugs to allow oil to bypass the filter when restricted and protect the engine from damage. If the filter is good, then it doesn't need the valve, but if the filter fails it will damage the engine if it's plugged.

big block oil filter adapter
 

Here is some extremely useful information from a highly respected engine builder:

Hey Daniel,
The oil by-pass is blocked off on hi-performance application to make sure everything goes through the filter and not the by-pass. We highly recommend if your running a H.V. oil pump to block the bypass. If your running a stock engine with a stock oil pump the oil by-pass is ok to run.
Hope that answers you questions.
Thanks,
Ashlea

Tom Pinkowsky

Tom's Performance Machine & Repair

Vancouver WA.

360.256.1722

tomsperformancemachine.com

Ask yourself this question; which would you rather have? Some oil bypassing the filter, or no oil at all getting to the engine?
I know a lot of racers pug the bypass so no oil will go around the filter when they use high volume/pressure oil pumps, but if the filter collapses or gets plugged, you wont get any oil to the engine. I guess I'd rather have some oil get past the bypass and filter, than have a filter failure cause a complete engine melt down.