jaeger_bombs

Okay guys, i have searched through tons of oil pressure forums on here and havent found my answer. so i have a 350 that was just rebuilt. i have low to no oil pressure unless its cold and it shows 15-20 psi. but when it warms up some it shows like 2 maybe none pressure. i got a new gauge and its not the gauge. also at higher rpms like before it shifts into 2nd theres a sorta loud rattle. so i was wondering why i dont have much pressure and if the rocker arms wernt tighten properly if they could be the cause of the noise? i did not recheck them after the new break in. and maybe a clogged pickup screen cause low pressure?

everything is new in this engine besides the crank,block and the actuall heads and rocker arms.
New valves, springs pushrods lifters,all bearings new oil pump,new noise geardrive , new lunati cam 284dur.458lift and new valve springs 0.550 in. maximum lift. installed at 1.750 in. and the pushrods are standard length
im using 5w30 and added and extra quart on 20w50 because i didnt think the HV oilpump was not getting enough oil because it was sucking so much and also thought the oil was tooo thin?

let me know if i missed something<!-- google_ad_section_end --> <!-- begin adsense --><!-- end adsense --><!-- google_ad_section_start --><!-- google_ad_section_end -->

MDTAHOE

How much clearance do you have between the pick up screen and the bottom of the oil pan? Who rebuilt the engine? It is possible that bearing clearance is to large. The pressure is created by bearing clearance.

jaeger_bombs

i didnt know the pickup screen had to have a certain clearance so i might drop the pan and fix that and make sure its all cleaned out and the bearing cleance is good cause he checked it and he knows. me and my dad built this engine and he has done many

BW56

I did many rebuilds just fine till a block came back without the 3 plugs in the front under the top timing gear. They are in the end of the lifter oil line. Did exactly like yours and i took to long to find it and got to redo it all over again. Never heard of that happening before or since. But i check it every time any way.

jaeger_bombs

Update: so pulled the pan again and replaced it with a new melling std volume std pressure pump and new pickup tube. No change. Turned the oil filter "bracket" around got like 15 psi then drops to like none. So i pulled one of the valve covers off, started it up, not getting a single ounce of oil up through the heads at all. so what im turning to at this final point is bearing clearances. i swear ive checked like everything else besides plastigaging the bearings.
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old dog

the only thing i can think of is if there were new cam bearing's installed that one of the oil hole's was not lined up or partially covered ,that will eliminate oil distribution . when i build a engine i always prime it first before starting it ,to make sure it is getting pressure and oil to the top end .

pdrayton

Jaeger_bombs,
I've got the same issue as you. I know I've got a bad rod bearing, but my mechanic told me I have to pull the water pump etc off the front of the engine to get to drop the oil pan. Is that true?

Doesn't look like it when I look at the oil pan. It's a 2003 Express 1500 with the vortec 4.3 V6.

Sorry if this is a hijack. But from everything I've learned, yes, sounds like you have a bearing clearance problem.

2wd-K5

was the block hot tanked and had the oil passages blown out? theres a possibility there could be a blockage if not, also if the oil filter ever got wet it would restrict flow, start by replacing things like that

tgervais

My '98 Z71 is having some problems with the oil as well if anyone can help point me in the right dirrection to get this fixxed. when driving my psi is fine and then when I come to a complete or near complete stop then resume to accelerate my oil pressure drops down to zero, it returns to normal after hitting higher RPM's but could this be a pump or a gauge?

old dog

Did you have the oil pan off ?