help, no oil pressure at startup!

[bgjohnson]

hey guys, I did the search thing and found nobody with similar problems as me. well heres the thing i just got done doing an H/C/i combo and am very happy with it, while I was in there I did a melling highvolume pump as well and here is my problem. when I start up from it sitting for a couple of hours or overnight, there is no oil pressure for like 3-6 seconds. and this is coming from the stock gauge( i'm testing it this saturday) and just to make sure the picktube would clear the pan I pounded out another 1/2-3/4 of an inch to make sure the pickup wouldn't be starving for oil. so I'm not quite sure what to do at this point, once the pressure goes up it stays up and stays there for high RPM use also. right now I'm running 10W-30 mobil 1 synthetic oil, and 1 quart of it is lucas oil additive( I added this after seeing no oil pressure after startup but it didn't help). should I go with a thinner oil maybe? or do I have to get a different pan? or is my stock gauge just crap?

p.s. it didn't do this before I took it apart


oh and I forgot to add that when I start it up after it's been sitting for only 10 minutes or so the oil pressure comes up faster(within 1-3 seconds)

 

[jrichker]

Put a tee in the gauge line and use a cheap Home Depot mechanical gauge. I did this, and have one installed at the end of 2 ft of high pressure fuel hose. It will tell the truth about when you have pressure.

 

[bgjohnson]

any other ideas why it has no oil pressure at startup?

 

[SlowGT]

I don't recall for certain, but I believe there's a check valve somewhere in the oil pump. When the pump stops, it should keep the oil from draining back through the pump into the pan. I've been trying to remember where I heard that but I'm drawing a blank. It may not be true at all. Just something to think about.

What kind of pan & pickup did you use that required you to beat out the bottom of the pan? I think that 1/4-1/2" of clearance between the pickup and pan should be more than adequate.

 

[twizted91gt]

This may be a longshot but when I had my oil pan/pump and pickup replaced they forgot to put the seal between the pickup and pump so it would draw air in and all the oil would drain back out of the pickup and pump. (I guess even after you turn the car off oil stays all up inside the pump and pickup)So when you started the car I would have no oil pressure for like 3-6 secs. Just a shot in the dark for you but after i had the mechanic put a new seal back in it was fine again.

 

[bgjohnson]

the thing with the pickup tube to pump gasket is what I'm thinking happened, I just can't remember if I tightented it up or not, so first I'm trying putting a different oil filter on to see if the other one drained back, I'm also ordering a autometer oil pressure gauge so i can get a more accurate reading, I might have to rip the pan back off