383 oil pressure issues

low idle oil pressure on the 383 i cant find the issue

[@TheSouthdownband]

ive built 3 383s with the 1 piece rear main and all of them cold start runs around 50-55 and as soon as its up to temp drops down to around 25-30ish with high volume pumps and under revs jumps right up no problems, i did some digging on it and found out that the stock 5.7l drops down to like 10-12 psi warm and they said that that is normal for those motors, i have ran the balls off my engines and not had any issues at all, it def sketched me out for the longest time also, so i feel you on the lower pressure. glad to see you made a video on this issue tho!

[@oldmanintheshopbuiltnotbou8726]

vox that definately makes me feel better still dont like it

[@TheSouthdownband]

@@oldmanintheshopbuiltnotbou8726 same i havn't liked it myself but havnt really found a way around it yet either lol

[@user-zu2ed6ye5w]

Old blocks will tap that hole with, i think its pipe tap, nub. 27 by 18 thread,be careful to get it right between both gallerys, and you can install a allen plug, one piece seal blocks, you have to driill with a 9..16ths drill, because the hole in the block is smaller, then you can tap it. Hope this helps !

[@user-zu2ed6ye5w]

Get a 51061 wix filter, i run them on all the hot rod engines that i build, it can stand alot of pressure ! Napa num. Is ..1061 hope this helps ! I also push out the oil filter bypass in the aluminum adapter and tap it for an allen plug .

[@oldmanintheshopbuiltnotbou8726]

i will give it a try thanks the motor is in a s10 im building now

[@waynepatilla8763]

Double up distributor gasket to let pressure of oil pump rod. You should have checked oil pump bottom plate for gear wear. Also change oil filter adapter to non bypass

[@cfmechanic]

Well I know u know alot more than me, I am curious where the pressure bleed down is happening. My first thought is lifters or possibly cam bearings. I know alot of people rarely change them, I have also heard of certain distributors having seal issue effecting oil pressure. Interesting to see how it all plays out. I'm with you I don't like oil pressure that low. I had a tired 350 that only made 7 psi for every 100 rpm but it ran good for a long time like that before it wiped a came lobe due to a rocker stud backing out

[@oldmanintheshopbuiltnotbou8726]

CF it has new cam bearings in it and the cam and lifters is the hyd roller i had in the 327 so all that stuff is new i wish i knew where the bleed down is at

[@AR_420]

Start with the easy option 1st. Thicker oil. Its not cold weather for startup and you're dang close to a decent average idle pressure. 2nd guess, stuck relief spring or bypass but you got another pump so bypass maybe? I plugged mine and will be using thick wall "Baldwin" filters to help with ballooning. Also, i have a Melling HV but its HV155, and has the 3/4" inlet, that Vortecs used. I believe it was done to solve cavitation but please don't quote me..lol. And I believe that's a higher than idle RPM issue. Worth looking into maybe? But i like the idea of 1 step up in thicker oil. 2.5-3 thou is what 5w30 should like. 3-3.5 10w30 and 3.5-4.5 thick molasses King syrup kinda oil 😆. Sorry for the rant and lenghy reply but i care...lol. We have very similar builds going on and you're just a decent good ol boy👍✌️

[@oldmanintheshopbuiltnotbou8726]

AR I looked back in my notes and my clearances ran from 2.5 to 3.5 thou on the rods and mains I'm leaning towards the way you're thinking about the bypass

[@oldmanintheshopbuiltnotbou8726]

AR I just thought about it my block is a 87 and I bought the pump for a 87 but both pumps are the same so maybe I should look into a pump for a vortec motor or maybe a big block pump I'm sure the oil pressure on the motor is acceptable to some but not to me I'm really liking the ideas that we are tossing around

[@AR_420]

@@oldmanintheshopbuiltnotbou8726 Absolutely I agree 100% That the oil pressure at idle is probably acceptable by the book but it'll drive me nuts till i get what i want. Within reason of course 😆. Bypass modification has it's negative aspects also, but id rather have 100% of my oil going through the filter at ALL TIMES. If I blow up an oil filter, A low oil pressure switch can be wired to your Ignition and fuel pump to shut the engine off, if a catastrophic pressure loss happens, fairly quick. This is just on the drawing board I have not put it into practice yet

[@oldmanintheshopbuiltnotbou8726]

@@AR_420 in my drag car i always used a low oil pressure light for just in case

[@AR_420]

@@oldmanintheshopbuiltnotbou8726Right on. Preaching to the choir...lol. 😊👍

[@Supanova70]

My 2cents. Change oil filter had one bypassing inside causing issues. HV pump tends to push real hard. Get a WIX or Napa gold same thing.

[@oldmanintheshopbuiltnotbou8726]

John the bypass spring was bad I replaced the oil filter bracket and put a wix racing filter on it with Rotella 15/40 in it and now it's at 60 psi cold idling and 40 psi hot idling thanks for checking us out

[@MrBReal-xc7qm]

my 400 Dart block is a 1 piece seal. I run Penn Grade 15w40 with a high pressure pump and a 7 qt pan. the pressure is 60 psi all day hot

[@oldmanintheshopbuiltnotbou8726]

im running 10/30 maybe i should step it up and see

[@Willie-t5409]

Seeing a lot of good comments and seeing that gauge dance around reminded me of the oil gauge in the MX-5. At idle it sits low and when you rev she does the same as what you're seeing. Again that a 4cyl engine. Thinking JB is on to something - high vol and high press are two different ways of oil delivery. If the same pump delivered higher pressure in the 327, I am thinking it points to something Chevy did with the oil delivery in the later motors. Maybe they enlarged the oil channels to keep the flow happening? Also the discussion has hovered around two-piece versus one piece seal. Is there data to support that one delivers more consistent oil pressure than the other? Just some random thoughts on what could be the culprit.

[@ScottandTera]

hey we share the last name .. Howdy

[@chevyfan82]

Could always be one of the front oil Gallery plugs is leaking a little but also a lot depends on the clearances if they're towards the limit oil pressure will naturally be lower at idle. The only other thing I could think of is maybe the lifters are bleeding off some pressure at idle that is if you're running hydraulic. You said that you had the oil pump on the 327 and all was good then probably not a pressure relief issue. Seeing you have instant oil pressure as you rev it I would say all is good. I myself don't like lower oil pressure but there's the old rule 10 psi for every 1,000 RPM and a added benefit is it gives more time for the oil to carry the heat away from the bearings. If you're staying at 25 at idle it is okay I wouldn't worry about it unless you're getting down under 15-18psi at idle fully warmed up. It's always nerve-racking when you first get them fired up a lot of time and a lot of money and too many things that can go wrong but if your bearings and oil look good then you should be just fine.

[@oldmanintheshopbuiltnotbou8726]

chevy the oil looked like it hasnt been in a motor no glitter in the pan i did let it get up to 190 degrees and it stayed at 20 psi

[@chevyfan82]

@@oldmanintheshopbuiltnotbou8726 never thought to ask what weight oil

[@jjsonsspeedshop4962]

I’ve seen the oil filter bypasses stick before, you might want to check that. I hope you figure it out, that’s got me stumped.

[@oldmanintheshopbuiltnotbou8726]

JJ im going to replace the filter holder and the distributor tomorrow

[@jbslittleshop2897]

I’m offended. I didn’t get a phone call. 😂😂😂. I thought you were letting me borrow that thing. Geez 👍👊

[@oldmanintheshopbuiltnotbou8726]

i am weve got to get it lined out first

[@joe-hp4nk]

With the valve covers removed, the oil should be seen coming up through the push rods. If it is, you're fine. Also check your oil clearance in the main caps, to much will lower oil pressure.

[@oldmanintheshopbuiltnotbou8726]

good oil flow at the pushrods

[@2old2rodeo]

You are a lot more experienced than I am but here are my thoughts for what it is worth. The 383 I built with a high volume oil pump is carrying 80 lbs pressure on start up and drops to 65 once the oil is warmed up. It is a two piece rear main seal. I still have 15w-50 break-in oil in it. Could it be your sending unit or gauge? I could not get the oil pressure or water temp gauges that came with my run stand to work at all. On first start I was a little panicked seeing no oil pressure but I knew it couldn't be correct because I had primed it with a drill until I got oil through the rockers. I plumbed a mechanical gauge in up front where the plug is between the passenger side head and the water pump. Like I said, the mechanical shows 80lbs. One last thought, Could it be the distributor not being the correct height? Maybe engaging the cam to run the distributor but not fully engaging the oil pump? I don't know if there is a difference in distributors and oil pump drive shafts between a one piece and two piece main seal? Good luck, I'm pulling for you.

[@oldmanintheshopbuiltnotbou8726]

rodeo i replaced the gauge and they both are mechanical no real change in the 2 gauges like i said ive built a bunch of motors never had a 1 pc. seal before all the 2 pc motors have been like what you were saying so i really am lost on this

[@2old2rodeo]

@@oldmanintheshopbuiltnotbou8726 Good Luck! Let us know what you find.

[@nicklehman3984]

Did you keep track of all your clearances during assembly? Maybe try a standard pump to see if it makes a difference? Im not a professional, but measuring everything before assembly is critical. For what it's worth, I have a 97 vortec motor (1pc seal) that has 270k miles on it and still maintains 60 psi of oil pressure even when warmed up.

[@oldmanintheshopbuiltnotbou8726]

nick i did keep up with tolerances they were running 3-5 thou on mains and rods

[@nicklehman3984]

@@oldmanintheshopbuiltnotbou8726 Okay that shouldn't be the culprit then....wish you luck in figuring it out. I wouldn't like seeing that low of pressure on a fresh built 383 either......even though TECHNICALLY they say it's enough.

[@oldmanintheshopbuiltnotbou8726]

@@nicklehman3984 im going to do something just not sure what yet

[@TonysHotRodGarage]

@@oldmanintheshopbuiltnotbou8726 sorry, commented before I read this one... .005 is way too loose for a SBC unless you're making really wild power. In my experienced opinion this is where your problem lies. It's doubtful that it will hurt the engine, but definitely looser than I like to see.

[@nicklehman3984]

@@TonysHotRodGarage you're probably right. Spec says around .002" clearances for rods n mains, I didn't catch that the other day when he replied.

[@TonysHotRodGarage]

It's not a relief spring problem because the pressure rises with RPM. This is a classic example of excessive clearance somewhere... and that clearance grows as the engine warms up. I know this is a pain in the butt but you need to recheck your rod, main and cam bearing clearancees. .001 per inch of journal diameter is how I like to set up my engines. No one piece rear main SBC I've ever built this way has ever behaved like yours is. Hope this helps.

[@Marksracingengines]

on the one piece blocks I've had issues with the cam tunnel not being right and opening up the cam bearing clearance AND the front main being to big. also I always run the mains no more than .0025 on those blocks and no more than .003 on the rods. if its standard main journal (not turned) you can try getting a set of .001 main bearings of the same brand you put in it and use half the shells in the caps to tighten it up a half a thou. and see if that brings the pressure up. I almost bet it will. just out of curiosity what weight oil are you running? you probably already know full synthetic runs low pressure but just had to throw that out there. it is weird the way the pressure jumps up to almost 70psi and falls back to 25...kinda acts like a hung bypass but you ruled that out with a new pump. Ive seen trash in the oil pressure line cause weird readings as well...have you tried another gauge? one more thing to check if you haven't already is the oil filter. I've had so much trouble with oil filters collapsing with high volume pumps in the past few years that I only run Wix filters now. Anyway I hope this maybe gives you a place to look. it'll be something simple when you find it. oh yeah one more thing to check...the front plugs. any chance one blew out or is leaking?

[@oldmanintheshopbuiltnotbou8726]

the rotating assembly is a eagle kit all balanced 10/30 oil but today i put a wix racing filter and 15/40 conventional oil and actually replaced the filter bypass just because it was simple after that i fired it up and 35 psi and it didnt vary so much with rpm peaked around 60 psi the bearings are all std king bearings so i should be able to get .001thou bearings and tighten it up a little

[@lefty207]

10 psi per 1000 rpm is not a bad thing. When it comes to oil pressure, more isn't always better. Too much oil pressure is a bad thing.

[@oldmanintheshopbuiltnotbou8726]

I'm with you lefty it just makes you feel better when the gadgets up a Lil higher

[@oldmanintheshopbuiltnotbou8726]

Guage

[@20havenfun08]

I had a bad gauge. I stalled a different gauge got the pressures I needed. Good luck

[@oldmanintheshopbuiltnotbou8726]

thanks mike im thinking about pulling the pan off again and really checking clearances again

[@MountaineerGarage]

Do you remember what the rod and main clearances are? I know it seems really low but about 15 psi per 1000 rpm is probably safe. Looks good at upper rpm

[@oldmanintheshopbuiltnotbou8726]

2 to 4 thou

[@MountaineerGarage]

3-4 is on the high side so I would say that might be most of the issue but it’s better to have a little more clearance then not enough. Some one told me, too much clearance and only you will know, but not enough and everyone will know.

[@oldmanintheshopbuiltnotbou8726]

@@MountaineerGarage that is a cool saying if i remember correctly they were right at 3 thou its in my papers i did write it all down just funny to me how the pressure jumps at the crack of the throttle

[@MountaineerGarage]

I had a 355 and a 318 that did the same thing it did seem strange but they alway ran ok and lasted a long time.

[@jbslittleshop2897]

I have no idea. But maybe check the oil bypass valve. Then maybe the mains aren’t right? I can sit and say a lot. But not a high volume. Maybe a high pressure pump. But 20-25 seems low. Should be around 30 at idle. That’s just my opinion!? 👍

[@oldmanintheshopbuiltnotbou8726]

jb id be ok with anything over 30 psi idling but not under 25 maybe i need to go with a hi pressure pump

[@jbslittleshop2897]

@@oldmanintheshopbuiltnotbou8726 that’s the next thing I would do. High volume just moving a lot of oil. High pressure is a different critter!! Again just my opinion.

[@AR_420]

@@oldmanintheshopbuiltnotbou8726 look into that high pressure pump and clearance. Trouble can start with too much pressure. I don't want to sound dramatic but it's possible to literally blow the oil off the bearings with a large bearing clearance. High pressure pumps are fine but they have to be matched to the correct bearing setup, or its arguably as bad or worse than low pressure. Im worried for almost as much i think. Stressful times😔

[@oldmanintheshopbuiltnotbou8726]

@@AR_420 you're exactly right to much pressure is as bad if not worse than low pressure think I will try 15 40 oil instead of 10 30 and see what happens

[@patknight-zb4nt]

If you're pushing 10 pounds of oil pressure through a 1/2 inch hole and you still maintain 10 pounds of pressure going through a 5/ 6:10 6:10 8 hole, you're definitely getting😅 more oil. Don't confuse pressure and volume. Never built an engine, but my background is setting. Valves for power plants, volume pressure capacities, so hope this helps.

[@3madeamps]

plug the bypass

[@ScottandTera]

where are you pulling off the pressure reading close to the pump or at the front of the block?

[@oldmanintheshopbuiltnotbou8726]

Above the oil pump

[@ScottandTera]

@@oldmanintheshopbuiltnotbou8726 are the clearances larger on a stroker and if they are would it not allow more oil to flow past the crank and dump strait back in the oil pan

[@oldmanintheshopbuiltnotbou8726]

@@ScottandTera no the clearances are the same as a stock motor would be im thinking my distributor is letting pressure bleed off im going out in the shop and replace the dist. and see if that helps

[@FUELFIREGARAGE]

Do you have oil restricts for the cam in the back of block. I always use Moroso big block oil pump with the moroso shift #22090

[@oldmanintheshopbuiltnotbou8726]

no comp cams told me not to use the restrictors i have a big block pump i could try

[@oldmanintheshopbuiltnotbou8726]

i didnt say but the cam is a hyd roller

[@FUELFIREGARAGE]

@@oldmanintheshopbuiltnotbou8726 i always use them the blue one i think are .060 i drill them to .090 for soild lift .its just one way to control your oil flow .

[@mikedenson1589]

Always run my idles higher.

[@user-mi7su3lr7k]

Starting with the easiest I would change the oil filter

[@oldmanintheshopbuiltnotbou8726]

after some research the one peice seal 5.7s dont hold as much oil pressure once warm as the older blocks do

[@ScottandTera]

is this crank cross drilled?

[@oldmanintheshopbuiltnotbou8726]

Yes it is

[@ScottandTera]

@@oldmanintheshopbuiltnotbou8726 im a novice engine builder but it made me think twice the oil flowing through the crack

[@oldmanintheshopbuiltnotbou8726]

@@ScottandTera thats a thought

[@reesehooperr8906]

I say bearings sorry I had this happen but if it's not please let me no

[@oldmanintheshopbuiltnotbou8726]

the bearings are at .002 to .003 thou

[@reesehooperr8906]

@@oldmanintheshopbuiltnotbou8726 so did you figure out what was wrong with it

[@oldmanintheshopbuiltnotbou8726]

@@reesehooperr8906 the one peice seal motors hold lower oil pressure at idle than older style blocks so it is what it is i did go to 15/40 oil in it and it holds around 40 psi at hot idle and around 70 at 6500

[@TheRoguelement]

Every SBC I ever built had between 30 and 50 LBS cold at idle that's using the MV-55 oil pump with large tube dia pick up welded and trap door 7QT pan I've NEVER seen any SBC idle new with 20LBS oil cold .. NOT EVER...

[@oldmanintheshopbuiltnotbou8726]

man ive also built many sbc engines and this was a first for me also from what ive learned the 1 peice seal motors have larger oil galleys so they dont hold the oil pressure at idle as the older blocks do

[@patknight-zb4nt]

One thing I thought of you could be losing pressure because of cavitation.