Oil pressure dropped quite low

Ok had to pull motor cuz rain it 8 inches means might as well just pull it its 2wd but still u cant lower pan without raising it at least 8 inchs more like 10 but that wouldn matter anyways cuz whoever had it b4 me was an idiot and instead of using a gasket he literally epoxied the pan to the engine so I had to pull it torque converter and all since I couldn't get the pan off at all until it was pulled.

. Pump screen clean a few pieces of plastic from the timing chain tensioner that got ate up about a month ago on that fix but that was it and lil gunk og old oil but ive seen alot worse. Pump gears seem tight and show no wear impeller that meets with cam shaft shows no wear either but the damn felpro head gasket that I had put on obviously is a piece of shit because even tho my mating surfaces were spotless and not warped or anything it showed signs of oil leakage ( very slight hardly any but still could see the signs of it)in 3 out of four cylinders and a lil in the coolant( and I torque them to specs and in the proper chiltons order 43 for short bolts 46 for long then plus 90 degrees for all of them) so wtf guess perma seal shit aint all that great and maybe next time il have to over torque a tad or was it just a faulty gasket. Idk. My question now is could that slight leakage cause that loss of oil pressure?

Because the head gasket that was in there b4 was in pretty bad shape nut no pressure drop I only changed it cuz I noticed a tiny tiny bit of oil in the coolant and I love working on cars and trucks and like my equipment to be perfect. Are there any specs for the oil pump so I could check it out other than the 56 psi at 3000 rpm thing cuz since its pulled I cant exactly check things out. Oh the sender was fine its #'s matched the mechanical gauge within about 2-5 psi. But I have to get a new one now anyway since I cracked the damn thing while pulling the motor I accidentally grabbed it while jiggling the motor forward to get the damn thing out with the freaking torque converter still attached.

. I mean epoxy are you kidding me? Good news I found where a oil leak was coming from. Not the rear main seal but the lil 3 bolt on plate at the back of the came shaft the three bolts were barley even finger tight so that explains the oil all over the starter etc. Oh the bearings didn't look worn really either maybe a little but since its pulled im going change them. Anything else I should do while its pulled any advice would be greatly appreciated this is my first engine pull for myself iv helped people before but never all by myself so hank you in advance for any advice or insight :)

Wait so if that presure switch was clogged it would not let the pump run all the time? But how would you explain high presure at start up. Wouldnt that mean its running at start up but then somehow stopping once it gets warm? That doesnt quite make sense to me?

No the head was off when o cleaned the gunk out. Im not an ase mechanic but im not an idiot either I wouldn't just let it fall down in there. But there was left over bits of the timing chain tension that got ate up from when the timing chain broke but no pieces made it past the screen that I can tell and even if they did they are plastic its a 2 metal gears type pump so it would chew out of any thing that's not steel or not to big. Is there anything on the pump that fails that I should be checking or is it probably the gasket that was causing that pressure loss. That seems like a lot of pressure loss for just a slight leak in a gasket to me?

My oil pump is mechanical driven by the cam shaft so its pumping all the time the only faster or slower it gets is with rpms presure switch is actually just a presure sensor I dont think it caauses any thing to "switch" pleas correct me if im wrong?

Ok that pressure relief valve spring loaded thing was stuck took sum working around a bit but got it back moving freely i'm curious if my bearings are in need of replacing for the 60 bucks I should probably just do them but im a lil broke right now. Good news is they honored the head gasket warranty and gave me a free new one. The bearing dont look that bad to me the only wear they show is a slight bit on the bottom obviously from cold starts but its minimal when u look at what would be the sides of the bearings there is absolutely no wear at all but il take some close up pics of them and post and get your opinion but I think that or something else was done recently cuz the rear main seal is so new I was able to get it out and its still perfect where I can reuse it which is something I would normally never even consider doing(reusing a gasket). Oh when I bought it I new it needed a head gasket and the timing chain was making noise thats why I paid 1900.00 and book is 3800.00 cuz to me my labor is cheap and parts for these thing are abundant and cheap so figured wtf I just fix anything wrong with it but the guy def slacked on the reg maintenance which sucks cuz reg maintenance prevents all this ya know. Pics to come soon ty again :)

Ok pretty sure I found the problem the 3rd main bearing from the front is f'd wore down 2 almost nothing no oil channel left at all but whats weird is every other damn bearing in the engine is almost like new and they only sell the mains in a set so even tho I only need 1 I have to buy the whole set about $65 checking now to see "why" it failed going to make sure the oil passage way to that bearing isnt logged or something but from what it looks like the "hole" in the bearing got sealed by the melted (silver maybe)idk what it is the outer part looks like copper though so pretty sure this was the problem. Another question what can I use to very gentle polish the crankshaft this on has some very slight scoring but measures within factory specs so high #ed sand paper or what?

Well it doesnt seem that bad from what I read online if your finger nail doesnt "catch" or drag it can be slightly polished and mine doesnt catch but I have to get a measuring device regardless to make sure its within factory specs or its time to have it ground and and oversize bearings but really hoping its all good with my buddys c clamp looking measuring device it wa within specs but with that its hard to tell if your centered I measuredin a few spots though and seems good but I would like to find a more acurate way to measure maybe somekind of digital laser deal or something whats the most acurate way to measure the journals?

Ok got it rebuilt with all new bearings and installed had some problems do tue my cuzin kickn over my nice lil row of rod caps so I could get them back in the exact order they came out and when trying to turn it over by hand b4 installing it it was tight so did some movn around thought I found where they went but after running it fir about 45 seconds it seemed to be having trouble turning over so I cut it off guess i'l have to pull it back out now is there any way to find out the order those rod caps where in stock they have casting letters on them a, b, g, e some one told me there might be marks on the piston stems to correspond with those castings. What do you think? If not can someone get me the the oe specs for the rods that way I can make sure im within specs. That way I figure I should be fine. Another thing someone said I should do is use engine assembly lube this time which I dint the first time ( I used a lil heavier weight oil to pre lube the bearings? So hope I dint mess them from that 30 or seconds?

Ok got it all pulled back out that was a pain un the rear 4 hrs found out how to tell what bearings and what caps went where the lil serial #'s for each bearing left a oil stain of the exact 3 of that particular bearing that was in there so woo hoo luck me but think il still plasy gauge them as well just to be safe :)

Yeah just got it put all back together ready to drop in it turns over noticably easier now but im not dropn it till morning cuz I need to get some of that shiny heat proof tape I want to redo the wires that go near the exhaust since I can tell they are a bit worn through the heat tape and its much easier to do with the engine out. Also used engine assembly lube this time but the oil I used lasat time must have worked cuz the bearings still looked brand new. So I guess that means that crank is all good aswell that 1000 grit wet sand paper on the center bearing spot on the crank didnt seem to affect it at all so ill let you know tommorow how it all goes :) ty for all the help :)

Ok finished it new rod bearings and new main bearings and now im feeling like a dummy for not changing the pump bcuz the presure is still low at idle but goes up with higher rpms there was nothing visibly wrong with the oil pump and it seemed just as tight as the new on I compared it to at advance so what else could be causing this. Oh it has a new oil pressure sender already bcuz I cracked the old one while pulling the motor the first time. Is there anything else that could be causing this other than the pump b4 I go get a new one. And if im going to get one whats the best pump I can get with a forever warranty so im not doing this again?

It was never that low b4 tho and I havent checked it manually since this all started but I have three dif presure sender things and they cant all be bad( when I was at the junkyard I grabed a few just 2 be sure). Well looks like the third time pulln this motor will be the charm :(. And if a center main can be as bad as mine was and not be the cause of low oil presure than bearings clearences aint as important to oil presure as everyone makes it out to be thats fosho?

Ok just thought id post this so everyone would know how it ended after taking the motor in and out 3 times I came to the conclusion it was either a cracked block or worn cam bearings well I got a motor from the junkyard for 200 bucks it was out of a crashed 2001 sunfire with 87,000 on it so just a lil more than half the miles then my trucks motor looking at my old motor block I couldn't visibley see any cracks but the cam bearings were wore into and past the copperish brass layer so they were def bad but it could also have been a cracked block and I couldn't see the crack with my eye cuz it only widened when it got hot enough. Cuz that's when the oil pressure dropped well either way I needed a new block. So about 300.00 dollars later and more hours of my labor than I can remember its all fixed but now it does seem a bit weaker than my old engine? SO NEW? CAN USING COPPER GASKET SEALER ON THE HEAD GASKET CAUSE LESS POWER? I put a healthy coat on each side of the gasket since I cheeped out and reused the head gasket from my old mote(it was only a month old) and came out with no problems at all and still looked totally new but figured the perma seal might need some refreshing so coated it with that copper gasket spray can that make a difference or is it just cuz its been hot as hell lately and im running the ac more and these 2.2s are just weak to begin with? Might just be me but my last motor seemed more powerful?