Author Topic: 67 327 oil filter bypass valve  (Read 2067 times)

mikefam

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67 327 oil filter bypass valve
« on: January 06, 2013, 02:32:21 PM »
I searched the forums and around the net and can't find what I'm looking for anywhere and CRG has been my favorite source of info for years now so I'm turning to you guys first.

Is anyone familiar with the oil filter bypass valve plate that GM used in the early small block chevy canister type oil filters?  I have the original valve plate and am considering replacing it for new in my new engine but sometimes a new aftermarket part isn't as good as the original.

So my question is:  Does the bypass valve ever need replacing? Does it have any moving parts inside that can stick of does it just divert some oil around the filter? Has anyone ever taken one apart to see what's inside?

TIA, Mike.
68 Convertible w/327 275hp donor engine from a 67 Impala and TH350

67 RS Ragtop

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Re: 67 327 oil filter bypass valve
« Reply #1 on: January 06, 2013, 08:49:15 PM »
  It simply allows the oil to bypass the filter if it becomes restricted / plugged, in an effort to minimize catastrophic engine damages. There is only a single spring loaded disc that becomes dislodged from excess pressure, allowing the oil to bypass the filter cartridge. I've never seen one go bad, as it's a very simple design, with one moving part. The spin on oil filter adapters usually do not have this valve, as the filter has the bypass incorporated in it, while the old style paper cartridge does not have this provision. Many people use the spin on filter adapters, and plug the port for a check valve, when using a high pressure / high volume oil pump. Hope this helps to explain the function of the check valve.

mikefam

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Re: 67 327 oil filter bypass valve
« Reply #2 on: January 07, 2013, 01:57:19 AM »
Thanks for the help.

I took a better look at the check valve today and see how it works now. I had my engine rebuilt professionally and got it back with the spin-on filter adapter attached to the engine block without the bypass plate installed. I spun a filter onto it and started the engine yesterday and the thing leaked like a sieve so I put it away for the night. I saw the engine run on the dyno at the shop so I don't understand what happened between then and now.

I'm just going to put the stock valve plate back as soon as I get back to work on it.

Mike.


68 Convertible w/327 275hp donor engine from a 67 Impala and TH350