On my 74 2.0L, I still feel that I am experiencing engine oil temps that get too high. For example, in San Ramon, CA yesterday it was in the 70's I believe.

On a short 15 minute drive on the highway, my oil temps got up to just under 220 on a VDO gauge. Yes, these gauges are not perfect, but the only measuring stick I have at the moment. In the past, the things I have done:

1. Adjusted valves
2. Adjusted timing to 27 degrees at 3500 RPM
3. Complete oil change
4. Sprayed some brake cleaner up into the oil cooler from below and blew out with compressed air.
5. Thermostat and flaps operating correctly (new thermostat cable installed last weekend).
6. Plastic flaps are there hanging under the body at the firewall.

In the 914 oil flow diagram, there is an oil pressure relief valve that is supposed to close as the engine oil warms up. Do these ever fail? Or sort of fail such that they never get to position "c" in the diagram below?

It can. In fact, it can stick to the point where it dumps oil back into the sump rather than sending it to the bearings, resulting in low oil pressure.

You can remove the bug slot-head screw thing that goes up into the case near the oil filter flange and check the bore and piston for smooth operation.

BTW, 220F is not a bad temperature. As long as you're below 240F I think you're fine.

--DD

I had a similar problem with my 2056. While I did later add an external oil cooler, I was instructed to go back through the basics. Timing was my problem because I had used the 27 mark as TDC and then advanced.

So verify the timing mark you are using it should be the "0" that is visible on the back side of the impeller. Not suggesting you did the same but I swore I had not done it either!

Also check your cooling flaps for correct operation and visually confirm that the oil cooler is not blocked. I know you did blow it out but I had a portion of a plastic bag stuck to mine once. A cheap USB camera can do this easily.

Check your valve clearances. I know! But I have done them wrong even after setting them correctly numerous times before.

Check your plugs to see if you are running lean.

Then verify the temperature with an external method.

I was able to get my temps back to normal after correcting the timing. Because I anticipate some hot weather driving I added the cooler after fixing the problem. If you just add the cooler you could mask the problem and eventually cause damage.

Yes, they can also leak even if closed. What was the oil pressure like? If that was OK I think you are OK. I would expect if the valve is the problem you should have had low pressure. I ended up resurfacing mine and it improved oil pressure, but had little effect on temp. I run an external cooler on my 2056. Good luck.

Most of them fail to close.

What's the remedy? New spring? And make sure it is clean in there and generally feels like it can slide in and out of there freely?

I don't have an oil pressure gauge, but my idiot light comes on and goes off as "normal" during startup. Idiot light never comes on during operation of the car. Of course, that doesn't mean the oil pressure is correct (or within accepted ranges) during operation.

I'm going to have to invest in an oil pressure gauge setup someday....

I had it get stuck in my 2270. I believe I rented a ream from Aircooled.net to clean up the bore and I haven't had a problem since.

I'm definitely going to pull it out this weekend. If that doesn't help lower the temps a bit then I will have to get myself an A/F gauge setup and look and see what I have for mixture going on. When I changed my plugs a couple months back, they looked fine however.

What's the best tool to remove the oil pressure relief valve plug near the oil filter? Is there such a thing as a flat blade screwdriver that wide?

I think they call it a drag link tool. I had mine EDM out to a hex.
http://www.sears.com/stanley-proto-stanley...mp;blockType=G6

you can "tap" on it with a chisel.
Or most flaps carry a socket that looks like a huge flat blade screwdriver