Re: So... this was in my oil drain pan...
 

Yeah I'm still debating messing with the other plugs. I've often shot myself in the foot with preemptive maintenance attempts lol. I'll take a look once I get there I guess. This is the first I've heard of a screw in plug coming out like that.

Re: So... this was in my oil drain pan...
 

First time for me to


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Re: So... this was in my oil drain pan...
 

Didn't Yun have a plug come out of his new engine build too? Seems like he drove it around for a bit too with low oil pressure but no harm. Just goes to show how robust the oil pump is.

Re: So... this was in my oil drain pan...
 

Well the mystery continues... Marc tells me that the crankshaft oil plugs are too big to make it past the oil pan windage tray. So not sure what to make of the plug I found. Did it come from somewhere else on the engine? Was it already laying in the oil drain pan from some other project and I didn't notice it? Do I need to put down the crack pipe? I guess before I start tearing things apart I should drive the car a bit with its fresh oil and new filter and see what my oil pressure looks like.

Re: So... this was in my oil drain pan...
 

Could be a plug from one fo the cylinder heads located in the cam chain space that seals off the end of the lifter oil gallery drilling Attachment 13974


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Re: So... this was in my oil drain pan...
 

Good memory! Yes, I lost one plug (can?t remember exactly which one) after the first rebuild. My motor barely maintained 15 psi at idle and about 25 at higher rpm. Drove about a year and, I think, about 3-4000 miles. And then, my head gasket went again. We found the cause when Dempsey pulled the motor and disassembled.
Jagdpanzer said something about divine intervention by Corvette God. Or, something like that.:D

Re: So... this was in my oil drain pan...
 

Hard for me see to it, does the plug have drill hole in it? Not from the rod journal if it does.

Re: So... this was in my oil drain pan...
 

I was thinking it could have been a cam plug from the rear of the cams, but I just measured one from a 1991 and it seems to be .5 inch. that is weird? I just looked a bare block and can't find anything like that....

John

Re: So... this was in my oil drain pan...
 

No drill hole in the plug. The plug measures .525 across the threads, and Mark Haibeck is telling me that nothing bigger than about .25 can get through the oil pan windage tray to the bottom of the oil pan where the drain hole is. I haven't checked to see if it fits through the drain plug hole but it should just barely as the drain plug bolt specs as a 5/8's
So that leaves the following possibilities:
The plug is unrelated and was sitting in the drain pan already and I failed to notice it.
The plug fell into the drain pan from somewhere else on the engine
My oil pan windage tray is either bent or modified in such a manner that the plug made it through to the bottom.

I took it out for about a 15 minute drive. On start up and for about the first 5 minutes I'm getting really strong oil pressure, like 65-70psi. Once its good and warmed up I'm seeing maybe 25-30psi after idling for a minute but I'm seeing more like 60psi when I get on the gas.
I finally found the FSM oil pressure specs, they list minimum hot idle oil pressure as 12psi... so perhaps I'm worrying way too much about this. But its odd that it's suddenly lower than it used to read, and its odd that it corresponded with finding that plug in the pan.

Re: So... this was in my oil drain pan...
 

Since you are now not sure.......I will add another possibility......

The Dash Gauge Oil Pressure Sensor and I had one that all of a sudden showed lower oil pressure.....
after replacement oil pressure was fine (normal) at all Temperatures and RPMs :cheers:

https://cimg8.ibsrv.net/gimg/www.cor...9b8c61ffd4.jpg

In general the NPT diameter of a plug is 1/4" larger than the NPT size.....

The oil pressure loss depends on where the "open" 1/4 NPT plug is located in the oil path. And depends on which oil path is involved.