Oil Pressure Loss, ‘73. 2.0 Options

[trick-e]

All, I’m hoping for some input.

Wanted to fix an oil leak(s) that I couldn’t quite track down. (Either the wind had blown oil all over the place, there were multiple leaks or the overspray of shiny, black undercoating the PO used was playing tricks on me.) I’ve only had the car since 5/2020 and wanted to get to know it a little more so I changed out the pushrod tube, valve cover, cooler, plug, sump (added 914 Werke extension), temp/taco plate and filler seals/gaskets. All is good, no more leaks. Sweet!
I take it to Grattan for my first time. Loved the course and the car was fun. Oldest and slowest one there! I kept on checking the oil pressure and temp throughout each run. Always at 65/70 lbs under load and it never got above 210 degrees. Last run of the day, and as I look at the gauge, the pressure drops to zero, so I immediately shut it down and coast to the shoulder. I didn’t notice if the dummy light lit.

Temp was still around 200. There was no oil leaking and it was at the top mark on the stick. Later on I confirmed that the pickup extension had not dropped.

Reading a few of the threads, I’ve a few Qs:

1. Why would the pressure read about 70#s under load at all RPMS? Seems like I read it should be just under 10#/1000 RPM. It’s been at 70# since I’ve owned the car.
2. The oil pressure line appears to have a little leak, but I’m not finding any pooling. It doesn’t look any dirtier/oily than before. Wouldn’t there have to be a major leak and loss to drop the pressure to zero?
3. Tell-tale sign of a pump failure?

I’ve the 928 brake/pressure line replacement (if I can figure out a way to tighten it. Seems a 9/16 cut socket isn’t common), but I’m just a little apprehensive about starting it up if that little leak wasn’t the issue and it was the pump that had failed. How can I test the pump, just put the end of that new pressure line into a jar, turn it over once, and see if oil squirts out?

-T

[bdstone914]

I would be more suspect of the sender or wires to it. The sender case needs to be grounded to give a reading. Test continuity to gound form the sender case. Then jump the sender ter.inal to ground. With the key on it shou lm d peg the gauge.

[GregAmy]

I'm with Bruce, leaning toward a gauging problem.

A small leak in that line won't cause total loss of oil pressure. If the failure were there you'd have oil all over the freakin place.

Go buy a $45 oil pressure tester from Harbor Freight and test for pressure at the end of that line:

https://www.harborfreight.com/engine-and-tr...-kit-64872.html

Unplug the coil wire and remove the fuel pump relay so it won't start. If you have a fragged oil pump (very unlikely) then cranking it over on the starter without oil pressure won't hurt the engine. Remove the spark plugs to make cranking easier, if you'd like.

Edit: all that said...the Type 4 engine is not the best at managing oil delivery during higher-G loads; in fact, it's quite shitty. Depending on the g-load, tires you're running, and how long the corners are, it's not unheard of that you'll unport the pickup tube of oil due to various factors (flat-bottom "pan" sloshing oil away, oil pooling in the outer valve cover). This is why many will add the "tuna can" or a large oil sump for track days. For my racer on Hoosiers I actually installed a dry sump system; on the other hand, I ran a Track Night in America in my street car on street Firestone A/S all-season tires without a problem.

[trick-e]

Sweet! That’s what I wanted to hear.
I’ll recheck the terminals/grounds.

Thanks friends.

[Jake Raby]

Make sure the sending unit and the gauge match.

[mgphoto]

I’ve had a good bit of success using dye and a uv light to trace oil leaks.