Ok I finished my complete restoration, while I had the motor out I changed oil pans to a milodon street strip oil pan that I found out is about a inch deeper than my stock pickup tube. (I didnt realize it at the time, I thought it was just wider and got more capacity that way)

So heres the problem. had 5W-30 oil in it got real low oil pressure the hotter it got. changed to 20W-50 oil and now I have a good 50 psi at idle and it moves up with the revs of the engine, however after it warms up, and out on the highway and higher rpms, the oil pressure drops and has almost zero at idle.

My Plan was to change to a stock depth pan, but I talked to a mechanic today who said that one inch shouldnt make a difference, I have other problems like bearings being hurt.

Any advice??? Please Help!!!!!!

If the problem wasn't there before the pan swap and you changed nothing else, I'd blame the pan swap. The thicker oil may even contribute to the problem as it will return through the engine to the pan slower than the thinner oil leading to starvation.
Keep the pan and get the correct pickup!!!!

Thanks, Thats what I keep saying the only change was the oil pan.

The thicker oil definitely seemed to help.

I was was going to buy the new pickup but I was scared to mess with the pump or pick up, so i ordered a new milodon stock replacement pan. I am going to try to swap pans in the car. Its a small block so I think I can do it. Hopefully the low oil pressure didnt cause another problem though.

Dan. The only problem with a "incar" pan swap, Is insuring no leaks. Take your time and make triple sure that you get all the surfaces clean and you don't bump the gasket as you install it. Good luck!!

The going from like 5 or 10-30 to 20-50 (thicker oil ) increasing the oil pressure as much as it dd for you shows an issue with bottom end clearances.

There is no way the new pan install should make the oilpressure be ower unless maybe your dipstick isnt accurate and when at cruise the motor is pumping enough oil out of the pan to be an issue at times wit oil pick up suking air. Try adding another qt of oil to see if that stops the oil pressure issues,if not you have bottoend issues of some sort.

Maybe if the new pan/dipstick combo wasnt accurtae and the oil lvl wad in fact lowlike i stated then maybe that hurt the bottom end when it was sucking air at times so now there is a bottom end issue when there wasnt prior to the pan change.

But as long as there is ample oil for the pickup the there is nothing in the simple pan & gasket change that could cause the oil pressure to all the sudden do what it did in your case,somthing fishy is going on .

Buy this is a longshot but maybe the new pan is actually shorter then you think in depth then the stock pan by just enough that the oil pickup in touching the bottom /inside of the pan casuing oil starvation issues. This new pan may be picking up the increase in capcity in width only and not in pan depth.

This aftermarket stuff can really mess you up at times.

Ror ex,if you buy a Stewart satge 2 perf water pump for bbc they really dont tell you that the stock gm puley wont work with it and the power sterring ,alt etc wont line up either,but the their stage 1 pump all ois fine.

So it would not surprise me at all if you new perf pan wa shorter in depth by just enough then the stocker resulting in the pickup being on the bottom even though you thought it wasnt unless you checked the clearance with clay so you knowf or sure the pickup was not on the bottom of the pan.

And as you stated if the pickup was 1"-2" further from the bottome of the new pan then is should be it should not affect the oil pressure at all as long as there was ample amont of oul surrounding the pickp at all times and thats why isuggested tryin to add another qt or maybe 1/2 qt additional oil to ensure there is enough oil arround the pickup and go for a test run.

If that helps you know what the issue is.

Good luck.

Scott

Thanks for all the input guys.
The 5W-30 had good oil pressure cold as well. but as soon as it got hot it went low. The thicker oil just seemed to take longer to thin out and cause the lower oil pressure. I drove around over 400 miles back in may and never seemed to have a problem. It would get low idling but go right up with the RPMs

I spoke with a guy from Milodon awhile back and he said the pickup being an inch short is a definite problem.

It is totally possible something got hurt while driving around with low pressure. I am very scared something could be wrong.
I think I am going to drop the pan , try to check out the main bearings while I have it apart. and see what happens, hopefully nothing is hurt.
I ordered a one peice gasket which should help reinstallation. If it was winter, I had a little more room and hadnt just put it back in Id pull the motor completely out and check it out, but I really want to do some cruising.

Also the guy from Milodon said that while running more than 75% of the oil capacity is circulating throughout the engine and leaving only the last 25% in the pan and with the short pickup now its starving of oil.

Dan the oil pickup being an 1" higher in the pan is only an issue if you dont have enough oil in the sump.other then that it shold not be an issue at all.

And i dont think there is 75%/3.5qts of oil circiltaing in the at any one time under normal driving cond,maybe 2.5-2.75 qt's (with std shorter pf35 oil fileter)and 3.5qts-4qts when your on it at full top end rpms which would make more sence.

Think about it,if a motor is uing 3.5 qts oil just for circulation in the motor under slower engine cruise speeds with a stock pan then what hapnes when you hit it and run up to 5k-6krpm for a 1/4 mile run when considerably more oil will be pumped and pushed out of the lifters/pushrods/thrown off the crank? If that was the case wouldnt you think a lot of motors would blow up due to lack of oil at high rpms which isnt the case?

Also,if you were a qt low leaving only 4 qts left in sump and hit the gas the motor would almost surely blow up if 3.5 qts of 5 qt total sump capacity was required just for circulation and you only had 1/2 qt left over to supply the motor at higher rpms,a lot more motors would be blowing upif that was the case.

Not all techs on the tech lines are correct or know what they are doing,i just read a post where the guy called the comp cams tech line 3x and got 3 totally different cam suggestions for same exact setup and type driving he described to them. I had similar exp with crane a few yrs back,they told me a 210 deg @.05 hyd flat tappet caqm on a 114 lsa was way too lrg for my 88 monte ss 305 HO and it would idle rough and such and i was like what the heck are you talking about,thats a farily mild cam for a 305. And BTW way that cam ran great in the L69 305ho,it idled with an authoritative note but still smooth (with auto trans in gear too)and had it a lot more umph then the stock cam had (esp on top end) and & he was way off base . Think about it,do these companies want to pay an experienced person what they would deserve to man the tech lines ,heck no so you get what these mfg's are paying for when it comes to the tech help in most cases which is likely $10-$15 per hr max .

I also went thru heck when i updated to wirless at home last yr,the tech help totally sucked,i litterally spent 7-8 hrs on the phone with mult lvls of tech help over 2 days that could not get me squared away,i knew more then most of them did (which inst saying much LOL!!!),was really frustraing. But i bit the bullet and dug totally into it myself and found out how to hack into my routers base settings by seraching it on good old GOOGLE and i was able to figure it out from there. Took me approx 1 hr to fix after spending 7-8 hrs with mult teck lvl's looking all over my laptop remotely from where they were based,most tech help sucks IMHO wheather its for our car stuff or computers too.

Scott

When motor is hot and oil pressure is almost zero at idle what is the idle rpm and what is the hot idle pressure at like 2k-2500 rpm?

If the idle is low like 600-700rpm increase it to to 800-900 rpm if possible,all you need is 10-15 lbs oil pressure at 900rpm idle to be ok and 20-25lbs at 2k-2500 rpm with motor & oil hot.

If you have these minimum oil pressures,motor is quiet with no knocks or valve lifter noise if hyd and dont beat on the motor and just want to cuise you can likley get away with it untill off season IMHO. But i would add an additional .75-1qt oil at all times to ensure the oil pickup always has enough oil so you there is no more oil startvation utill you geta chance to tear it down.

Aslo,is this a mech or elec oil pressure gauge?

Before you pull the motor try another oil pressure gauge just to be safe and verify its not an issue with the current oil gauge where it wont read acurately when the oil/motor is hot for some odd reason.

But from what your descibing the oil psi is good cold and goes to crap when hot,thats usually an oil pump/bearing clearance issue if the oil gauge is reading properly and there is ample oil for the pickup to pull from.

Scott

I usually agree and learn from Scott. On this item i am thinking more like the guy at Milodon. Counting on oil sitting a few inches deep in the bottom of an extra deep pan to get up to a too high pickup is not a good deal! Windage off the crank has oil going everywhere! I know there are different issues but several years ago working on an alcohol dragster we found a huge amouunt of oil is and stays up in the top of the engine once reved up those cars stage with RPM "up", 5,500 in our case and what we found was you litterally had to have all the oil the pump was going to pump in the pan when the RPM was brought up, very little can drain down when reved.
I would keep the big pan, it is a much better deal than the stock replacement pan (I have the Milodon 7 qt on mine but its a big block). Return or resell the standard pan and get the correct pick up.
All that said I agree with Scott, your engine has too much clearence or an internal leak. I would pull the engine, strip it and check everything! Start with galley plugs, (the internal leak option) rod & main clearences both side and diameters.

it idles around 8-900 rpm, its hard to tell exactly where is it on the gauge, its an autometer electric gauge and its short sweep. I thought all along the gauge just reads weird being that is electric and short sweep.
The oil pressure seems fine from 1000 to about 3000 rpm then it starts to fall off when the motor revs past 3 approx. Thats why I think the pickup being short is the problem. The mech at work I was talking to told me to pull a main cap off and check the clearance with a gauge while I had the oil pan off. if it smashes the ;little peice of plastic then I am good. I think I am going to drop the pain use that gauge he gave me on a main cap and if its good put the shorter pan back on and see what happens.

I dont have the time or money for expensive engine work right now.

Dan just for HA HA's just prior tp pulling the motor dump in an additional qt of oil to raise the oil lvl further above the oil pickup just to see if that helps the above 3k oil pressure drop .

If thats the case the oil pickup being too far off the bottom of the pan is definately the problem and i would not be surprised if the pickup is further from the bottom of the pan then you think it is.

It wont hurt to do that test and doing it would give you more info before pulling the motor so let us know the result if you try the additional qt of oil test.

Scott

Thats not a bad idea scott. before I go through the hassle of the pan change. Thanks for all the help everyone.
I see your in eldersburg, where do you usually go cruisin at?

I agree with Scott, ad a quart and see what it does. If my theory is correct the crank windage is blowing the oil away from the pick up and having another qt there will reduce the pressure drop to higher RPM.

ist't the standard pickup to pan tolerance .25 min to .375 max ??.......a whole xtra inch or more is really wrong.......why not start there......as previously stated add another quart or so if its fixed then there ya go.......its a pickup clearence prob not bearing clearence prob

Thats not a bad idea scott. before I go through the hassle of the pan change. Thanks for all the help everyone.
I see your in eldersburg, where do you usually go cruisin at?


I agree its a good test, I don't see it as a fix! Crank windage will have much of the oil moved around, result will be you will rev it up one day, it will starve for oil and sling a rod out the side

a test was all it was ever meant to be.

scott

Ok I finally got a chance to do the test, I added an extra quart of oil and went for a ride. While the engine is cold everything is fine, once the engine warms. it was still doing a similar thing.

1 At idle it would go real low and I could even hear a valve tapping (I think) put it in neutral it jumps right back up to 10-20 PSI

2 If I accelerate it goes up at first then goes back down to zero after I let off the gas it jumps right back up to 25-30.

I am still confused. what it could be. I am thinking about going ahead and pulling the engine and have the bearing checked out by a machine shop.

My biggest fear is I dont get to do anymore driving till next spring. Money and time are both pretty tight till end of september. I am half tempted to go ahead and try to swap the pan and see what happens, just dont want to do the work and then have to go ahead and pull the motor anyway

With the additonal qt of oil and its still acting up,either the oil pickup came off or you have some bearing/oil pump issues going on that may have been caused by prior oil starvation that was due to too much pan to oil pickup clearance when you 1st installed the new hi perf pan.

You should definately pull the pan because you had more then enough oil in it to reach the oil pickup and you stated it even has idle oil pressue issues too ,pull the motorsand do it right by checking main & rod bearing along with oilpup and oil pickup to pan clearance .

Scott

Well I went ahead and did the pan swap. What a pain the ass!!!!
Almost the same as just pulling the motor.
So far so good. 2 long rides and oil pressure is very consistent never goes to zero, the lowest it has gotten is at idle it drops to about 10 psi but all the way around especially at speed it stays up well over 50.

Dan,glad to hear you got it fixed,man a pan swap is esp hard with motor in car.

Just curious,did you re-install a stock type pan or a different type aftermarket pan?

Scott

I stuck with milodon but went with their stock replacement pan.
I have the old one listed on ebay.

Unless your running a wild setup which i dont think you are you should be fine with the stock pan.

But "always make sure to keep the oil lvl full "so when you decide to hammer every so often you will have an adequate amount of oil in the pan to handle the higher rpm blast.

But its when your running a stock pan thats maybe a qt low on oil that you could possibly get into trouble when you hammer it sucking up considerably more oil from the pan in that case so to be safe always keep the oil full to avoid that sitaution and you should be fine.

Scott

Its a 400 HP 350 small block, not too wild. So far drove around all weekend and oil pressure has stayed up over 50 almost all the time. At idle whe n hot it dips down to around 10 but has neevr touched the zero like it did before. I bought the larger capacity mainly for longer trips, but with a turbo 350 and 4.11 and I am not going to be making any long trips anytime soon. I think one of my next moves will be some typ or overdrive Id really like to swap in a tremec tko but money is alittle tight right now. I am just happy to cruise arond town for now.

As always thanks for all the advice.