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ZERO Oil Pressure!
https://www.slantsix.org/forum/viewtopic.php?f=19&t=21641		 Page 1 of 2
Author:  vynn3 [ Sun Jan 28, 2007 1:26 pm ]
Post subject:  ZERO Oil Pressure!
I've been tweaking the new engine for the last day and a half, adjusting the timing, etc. The whole time (that I was inside the car and checked the mechanical gauge, that is), there's been a rock-steady 50 psi of oil pressure.

I've made a few short trips, more tweaking in between. Suddenly, after I return from a 2-mile trip, I look down to see the oil pressure at ZERO. The oil light isn't on, but the sending wire had popped off. I fixed that, cranked her on, and sure enough, oil light and zero oil pressure on the brand-new Autometer gauge. Holy crap!!!!!!

The rebuild included a brand new, stock flow Melling oil pump.

HEEEEEEELP!!!!!!!
Author:  vynn3 [ Sun Jan 28, 2007 1:32 pm ]
Post subject: 
Update: I pulled the coil wire and cranked the engine for several seconds. The gauge pulses to one PSI every few seconds, but that's it.
Author:  sandy in BC [ Sun Jan 28, 2007 2:31 pm ]
Post subject: 
Thats exactly what happened to me a week after rebuilding my engine. I had a stripped oil pump gear. Cost me a crank.
Author:  vynn3 [ Sun Jan 28, 2007 3:09 pm ]
Post subject: 
So, is it likely to be the gear on the pump, or the gear on the cam? What's the possible cause, if that's what it is?
Author:  Pierre [ Sun Jan 28, 2007 4:20 pm ]
Post subject: 
Does oil reach the rockers after its running? I'd try attaching a manual gauge first.
Author:  vynn3 [ Sun Jan 28, 2007 4:34 pm ]
Post subject: 
Well, the Autometer oil pressure gauge is mechanical (I just chose that over electric because it was so much cheaper, but now I'm glad I did - Otherwise, I'd be guessing I had a bad sender right now).

Just looking at the nylon supply line for the gauge, there's a lot less oil in it now than there was before. So, I guess that confirms the problem. Besides, I'm a little hesitant to run it any more until I pull the oil pump and inspect the gear.

I'll tell you what, though. If the gear is fine, I may just strip the Swinger of everything useful and either sell it off or swap it onto my '67 GT convertible. You guys are probably tired of reading my whining, anyway. :oops:

Thanks, guys.
Author:  SlantSixDan [ Sun Jan 28, 2007 6:18 pm ]
Post subject: 
Could be as simple as a stuck-open oil pressure relief valve, which is not hard to unstick. Cleaning the pressure relief valve is actually a scheduled-maintenance item...hands up who remembers ever having done it? :-)
Author:  sandy in BC [ Sun Jan 28, 2007 6:21 pm ]
Post subject: 
The fact that I cant remember having done it doesnt mean I didn t do it last week........oh! ....so that what maintenance records are for?

If his crank didn t go ~"ÖINK""~ it might well be the relief valve.
Author:  vynn3 [ Sun Jan 28, 2007 6:29 pm ]
Post subject: 
SlantSixDan wrote:
Could be as simple as a stuck-open oil pressure relief valve, which is not hard to unstick. Cleaning the pressure relief valve is actually a scheduled-maintenance item...hands up who remembers ever having done it? :-)


Oh, Dan, PLEASE make my day and pass along bit of profound wisdom!!! (I own the FSM, but on CD, so I have to borrow my wife's PC and go sortin'.....)

I'm waiting on pins and needles....
Author:  vynn3 [ Sun Jan 28, 2007 8:24 pm ]
Post subject: 
There's a check valve in the oil filter...

So, is the answer, "Change the oil filter"?
Author:  Doctor Dodge [ Sun Jan 28, 2007 10:14 pm ]
Post subject: 
Look for a large hex or square head plug, it will be facing forward and best accessed from under the car.

Remove the plug, the spring will also come out.
Stick your little finger up the hole and see if you can slide out the relief valve.
Once out, sand it smooth, clean and re-install.
DD
Image
Author:  SlantSixDan [ Mon Jan 29, 2007 7:36 am ]
Post subject: 
vynn3 wrote:
There's a check valve in the oil filter...

So, is the answer, "Change the oil filter"?


Probably not. The check valve you're thinking of is the antidrainback flap valve that keeps oil from draining out of the filter after shutdown.
Author:  SlantSixDan [ Mon Jan 29, 2007 7:38 am ]
Post subject: 
Yep, see Doc's post. The FSM warns to use only crocus cloth, not a sharper/grittier adhesive like emory or regular sandpaper (you don't want to get grit into this area). After spraying carb cleaner up into the relief valve bore to flush out any solid chunks of gunk, I twist up a shop rag into a cylindrical shape, wet it down with spray carb cleaner or denatured alcohol, and twist it into the relief valve bore to wash down the cylinder wall. Remember also to wash the valve shuttle itself similarly before reinstallation.
Author:  Charrlie_S [ Mon Jan 29, 2007 11:14 am ]
Post subject: 
Couple of years ago, I had the opposite problem, too much oil pressure. Fresh engine, NEW oil pump. Started the engine and pegged a 100 psi gauge, at fast idle and 10-30 oil. Pressure bypass valve was stuck closed.
Author:  Bren67Cuda904 [ Mon Jan 29, 2007 3:32 pm ]
Post subject: 
when can we expect a status report on wheather or not the gear failed?
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