Oil pressure relief valve. Options

[Keith914]

To the "brain trust". Two experienced engineer/mechanics have described the following:
When our Type IV engines are at operating temperature and rpm's exceed about 3,000 the pressure relief valve (ball bearing valve seen in the oil filter bracket) opens up and prevents or reduces oil flow through the filter. Thus, this reduces oil flow through external oil coolers attached via a "pancake" to the engine, greatly reducing there cooling effect when needed most, e.g. at the track. They have altered this valve so that it cannot open, and advised to keep rpm's low until the engine is warmed up -- particularly in cold climates. there are various ways to "plug" this valve, easy when removed from the engine, -- drill and thread a bolt with lock nut to hold the ball bearing closed, press in an aluminum plug, etc.
Two questions: 1) are there other (than too high an oil pressure with cold engine with higher rpm's) unintended consequences, and 2) can this valve be "plugged" and how, without removing the engine to get at it?

[GregAmy]

Just picked up on this topic (was away racing last time this came up).

I have a vexing oil temperature problem on my street car. Just basic driving around during the summer and my oil temperatures hit the red zone on the center console gauge, dipstick thermometer reads 260+ and oil pressure goes below 5 psi at idle. Chris installed his oil pressure relief valve and it didn't seem to make a difference. I've checked as best I can (short of pulling the engine covers) that the oil cooler is free of debris. The thermo bellows is working fine and I can hear the doors moving and whacking their stops when I actuate it manually.

In reading through this and looking at that diagram above...I'm now wondering if that filter bypass valve is either soft or mis-located? If I read that correctly, if that ball is not properly seated then it would allow oil to not only bypass the filter, but the cooler as well.

Chris mentions above that oil flow would stop if if that bypass were disable and the filter becomes plugged. However, don't all modern oil filters come with an internal bypass valve? If the filter spec'd for the T4/914 does not have an internal valve, I have to imagine you could find one with the same physical specs but with an internal bypass?

Why would we not want to take this legacy bypass valve completely out of the system and go with a modern bypass oil filter? Is this something that can be disabled while the engine is still in the car?

Greg

Edit: Just looked at Post #15 diagram again...what caught my eye was the EXTERNAL oil cooler, not the stock cooler. So then this valve doesn't appear to have an effect on stock oil cooling flow.

However, same query applies: why not replace with a filter with a bypass and disable that internal valve?