deadmemoryy

UPDATE: Put the stock OPS in and the light cut off after 2 seconds. False reading from a blown oil sending unit, thanks!!


have a 400+ HP GSR motor that had been running on 17psi for 3 years. After 3 years of running, and after a mis-shift, it spun a rod bearing and started knocking 60 miles later. My good and trusting friend and engine builder Chris helped me to rebuild. We re-built the motor with the existing CP pistons and Eagle rods. I had the one rod with the spun bearing resurfaced. I bought a NEW GSR crank, due to scarring. So in a nutshell, CP Pistons, Eagle rods, ARP Headstuds, ACL race rod bearings. All NEW parts other then the pistons and rods that were in there. I broke in the motor perfectly for about 1000 miles and one oil change, and installed an autometer Oil Pressure gauge to prevent future failure. I took my girlfriend out to dinner one night last week and was merging on the interstate, and got on it a bit. Didn't take it past 6k in third gear and threw it back from 2-3-2. Novice mistake which I have never made, but wasn't used to throwing gears or weighted knob in a while. saw the tack clock past 8 and way into red and hit the clutch. My Gauge lost all pressure right after the shift. Went straight to 0 PSI. I blipped the gas and there was NO MOVEMENT at all. I shut the car off, towed home, and let it sit a week. Started it back up today cold and the gauge didn't move one bit, nor with any gas. No knocking, good connections, and the motor sounds perfect as it always is while running...it was running about 20-25 PSI at idle, and was at at 90ish PSI by 5k RPM, before the miss...now 0PSI across the board

---Could I have blown the sending unit due to too much pressure at over rev? Wouldn't there be SOME pressure especially at a cold start and a little throttle if it were a bearing? my pressure is below 0. (on an electronic AUTOMETER gauge)

--Could I have cracked the oil pump and caused a leak in pressure?

--Or could I have spun another bearing and it just hasn't started knocking? I feel like I would still have a bit of pressure even with a spun bearing, but i have NONE NONE NONE....the needle didn't move a bit.

Please give me some ideas before I begin stripping it down. I was going to put the dummy light back on and see what happened, but i don't want to keep starting the motor. Thanks in advance.

Fabrik8

The sending unit should be a fairly standard thread type usually, so get yourself to Lowes and cobble together some parts to test out the sending unit using (regulated) air pressure from an air compressor. That will give you a sanity check, and you can start exploring the other possibilities if the sending unit turns out to be fine. I actually test all of my pressure gauges like that to make sure that they're accurate. It's easy enough to do, so why not..?


And thank you for making a thread under your own user name.

laserspeeddemon

I'm confused, you test your gauges by throwing your car into +8000 rpms?

To OP, it sounds like you just blew the sensor unit (This is assuming you have a digital/electric type sensor). Your cars oil pressure relief isn't designed to take 8000+ rpms worth of oil pressure all of a sudden. Most oil relief systems (at least imports) are on piston/spring design. Which means the spring couldn't compress fast enough to allow the oil into the bypass so you probably exceeded 100psi for a brief moment. Sense the sensor is connected to the same housing it took the brunt of the pressure spike. Likely blowing the sending unit. Start with replacing the sending unit.

You should also be concerned about your turbo. Oil seals don't like high pressure either; especially ball-bearings.

deadmemoryy

No problem, sorry, didn't want to remake and cause a congestion of threads. Thats a good idea, I could at least see the gauge move potentially.

I called autometer, they said basically the same thing. The unit is meant to see no more than 100 PSI, which it did for sure past 8k. I am trouble shooting today, thanks for the good help, I'll report back.

laserspeeddemon

No problem. If you were closer, you could hook up mine to your car to see if you got any pressure. I am willing to bet your oil pressure is fine. To be safe check to see if you have any leaks around the oil pump or filter housing.

**edit** Nevermind, forgot that the OFG is cast into the B-series blocks.

Fabrik8

Why yes, I talked all about oil pressure at 8000+RPM in my post. That's a great conclusion to draw.

Acrytet70

Whats up Blake. Get a mechanical oil pressure guage from Harbor Freight for $12. You know I had a mess of oil pressure problems and the mechanical is the most accurate!

deadmemoryy

I am really hoping man. Tomorrow morning before work I am going to put the dummy light in and see what happens. I called autometer and the pro tech said those sending units can blow after seeing +100 PSI.
Yo!! I'll go pick one up tomorrow, good looks, didn't want to spend 30$..after its fixed, (crossing my ringers that I don't need another rebuild) I will finally make my way out to your shop.