Panhead External oil filter check ball valve

[TGoode60]

My external oil filter housing (# 63805-48) is missing the check ball valve located in the housing next to where filter element seats. My question is this:

When does this check valve operate? When oil is cold, when filter is clogged? I assume it is a bypass, but can't find any manuals stating how or when it works...

Also, can I run it without, or will the oil just go around filter element without it?

Any help greatly appreciated!

[Schorsch]

Hi, this is a bypass to safe oil circulation when the filter is clogged. If you run the motor without that bypass vent-ball,
so you have no filter function...
George
AMCA 2781

[TGoode60]

Thanks for the info George...a filter bypass is what I suspected, even though I couldn't find any documentation to back that theory. I'm still looking for a replacement check ball valve and have plugged the hole with a homemade threaded stud to make sure the oil goes through filter (for the short term).

[Magic]

I wouldn't plug that bypass if you think about it when Oil is thick when cold only so much can pass through most filters under pressure. Until Oil thins out pressure stays high and needs to bypass some. It's the only place in the system to relieve its self. You may develop leaks you don't want by plugging the bypass. JMO

[TGoode60]

JMO,
I agree, cold oil under higher pressure probably utilizes that bypass until it gets hot...I'm not having good luck finding a replacement check ball (no one sells that part alone). In the interim I plugged it and am keeping a close eye on leaks etc. It has developed a small leak at top of housing until oil gets hot, but since I'm in the "break in" period of this engine I want the oil filtered to catch any bigger metal flakes that may be floating through oil.
Thanks for the advice/help.
TG