My 70 GS Stg 1 Ragtop has experienced an as yet unexplained oil pressure loss. We have gone through the oil pump, found a sticky pressure relief valve,(filter bypass valve spring in bore) but that didnt fix the problem. We have lots of flow, using primer tool on drill motor, but no resistance inside the motor. Timing cover came off today, We found only more of the same, no resistance to air at the oil return galley, (the one the pump pressurizes and has the tap for pressure senders/gauges) I was hoping to find a blown out lifter galley plug, but, no. Car was cold and had a miss/stumble on part throttle,(suspected carb. problem) when I went to rap the gas, I saw the oil @ 40 psi (1800rpm) and after a 4k blip, I saw 0 psi. I cut the ignition immediately. I never heard any metal/ heavy motor noises and even cranked/ started the motor again, let it idle for 5 seconds, listened, and turned it back off. If any one has any input it would be appreciated. BTW, I have all of TAs oiling parts, except oil filter/pump cover (booster plate, shimmed gaskets to get .0025 end play, Adj. pressure reg., timing cover, grooved cam bearings) and running 10w30 Mobil one after break-in. 2500 miles on fresh motor. Im looking for some internal passage that could have come uncovered. Maybe a main bearing? Thanks for your help. Chuck Jacobi
Any other oiling mods done? The only other suggestion would be to drop the pan and see if the pick up is still attached to the block correctly. o No:
Pumps lots of oil out of motor w/ oil filter removed.... I'll pull the valve covers off tommorrow, but if nothings broke... Stay tuned till the motor comes out (and I can pull that pan off)
I doubt it is a main bearing. I spun 3 main bearings, 2 cam bearings and some rod bearings. It had 0 pressure at idle but did go up with the rpm's. Mechanical gauges do fail. I've seen this happen. I'd check that first. Good luck.
Do the simple things first - like verify the guage /oil line/ sending unit are working correctly. Dont overlook something this easy !! good luck.....
Gulp!! I hope you don't have the same problem a couple others of us have had. A loose oil pump pickup tube. Mike D.
Sorry to take so long...... The rocker shaft broke. It was # 2 cylinder exhaust rocker. This is the first place the oil gets any resistance, and after blowing the lifter out of the bore, hello Old Faithful. The shafts break easily @ the ends, as I've read in previous threads. Now I wish I hadn't used those dual valve springs, If I hadn't already had the heads machined for them, I would've used the new TA heavy duty single that gave me enough lift. It looks as if I caught it in time not to do any other damage Thanks for all your help
