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No oil psi I was driving my fresh rebuild and I noticed at idle about 750rpm that I am reading 0psi on my electronic oil sending unit and gauge. I checked to make sure I had oil, and I do. I fired it up and shut off, pulled the stick and made sure that oil was being thrown up the stick, and it is. I drove the 2miles home scared to death. It would only read 15psi at 2000 rpm. Higher if I get on it but I didn't want to hit it too hard. Is this normal? Oh temp was right around 170degrees.... and I'm still trying to do the 500mi breakin |
Re: No oil psi Put a mechanical gauge on the engine to confirm oil pressure. |
Re: No oil psi
Originally Posted by AlkyIROC
(Post 6281406)
Put a mechanical gauge on the engine to confirm oil pressure. |
Re: No oil psi Cant find a mechanical oil pressure gauge that will read pressure under 20psi accurately!!! I'll keep looking |
Re: No oil psi Delete |
Re: No oil psi https://www.ebay.com/itm/ASHCROFT-0-...0AAOSwukZcO5sE To check your existing gauge - run some regulated shop air to it. Was the oil pressure different when the engine was first started? Have you cut open the oil filter to check wear materials? Was the main line done and the cam bearings replaced? GD |
Re: No oil psi Was told the main line was done, align honed, and the cam bearings were done. The OP when cold is about 45# until 170-180 degrees |
Re: No oil psi The numbers you give aren't right. But to Alky's point, you still don't know whether you have a gauge problem, or a pressure problems. You divide the problem in half and determine which half of it you need to solve, by substituting for one or the other. The gauge is obviously eeeeeezier to substitute in a known-good than it would be to substitute in some known-good oil pressure for the existing gauge system to read. But it doesn't need to measure below 20 psi "accurately". What you need in this case is not a "number", like 18.59 or something. What you REALLY need is a good/bad indicator. Yes it's working right, or no it's not. Think about it... you've got an oil system that's probably set up to do around 20 - 25 idle and 45ish @ 2500. (both when hot) if it's NOT doing that, Like if it's sitting on 0 at idle and doesn't even struggle all the way to 20 at 2500, you've got a problem. Go verify the gauge. You could install a 2nd gauge, or just change out the factory gauge's sending unit. (the gauge hardly ever goes bad in such a way as to read wrong, but SUs fail all the time) If it reads right, then you have (had) a gauge problem. If the new setup reads the same as the old, you have a pressure problem. |
Re: No oil psi https://cimg3.ibsrv.net/gimg/www.thi...b7c507d979.jpg First start , cold https://cimg0.ibsrv.net/gimg/www.thi...7a64008ba4.jpg 12min https://cimg5.ibsrv.net/gimg/www.thi...3f6c6f92b5.jpg 17min I'm ordering a oil pressure tester.trim putting it right beside the oil filter. So I can compare the two at normal operating temp at the same time. Will take about 4days for tester to get here. But this has me upset. I'll let u know what kind of breakin oil is in it when I get home |
Re: No oil psi Oh 180 stat and fan switch |
Re: No oil psi In the mean time - cut open the oil filter and check break in materials. Use an oil filter cutter, or tin snips, or pliers, etc that won't produce any filings. Seriously you NEED to be doing this regardless of the oil pressure. We cut filters for the break in and for several oil changes after to visually check wear and break in on new engines. Even without any oil pressure variations you want to check for things like cam lobe failures, etc. Also - those gauge segments make my brain hurt. 4 psi?! Really? That's dumb. GD |
Re: No oil psi https://cimg6.ibsrv.net/gimg/www.thi...7eefacf94c.jpg excuse the quality of the u tube vids. I cut the filter open and did not see nor feel anything in the filter. The filter was ac delco. The engine has literally about 20mi on it. As u can see in the videos the pressure gauge responds instantly to any rpm change.. 1. |
Re: No oil psi To properly check a filter, you take out a chunk of filter material. Squeeze it in a vise to get all the oil out then open it up to check for metal. Personally if you start with good oil pressure then it drops down to almost nothing when the engine is hot, you probably have a bad bearing. Bad rod bearings will make noise. Main bearings will seize up or score the crank in a very short amount of time. A bad or spun cam bearing will easily drop oil pressure when hot. All 3 should show metal in the filter. I know you're not going to want to do it but pull the engine and strip it down. Something isn't done right. Loss of oil pressure when hot won't have a bandaid fix. |
Re: No oil psi Your killing me |
Re: No oil psi I agree. With two independent gauges telling you there's effectively no pressure, you need to tear it down. I've built a lot of engines and monitored a lot of oil pressure and if the clearances are right you get somewhere between 15 and 30 psi of oil pressure at a hot idle. I personally don't like to see any less than 20 psi. The golden rule often stated is 10 psi for every 1000 rpm. And with a cold pressure of 40 you know the pump is plenty capable so it's definitely not that. The pump only generates flow, it is the engine oil clearances that generate a restriction to flow and thus pressure. What you have there is insufficient restriction to flow and thus no pressure. Unfortunately that means stop running it to mitigate further damage and tear it down. GD |
Re: No oil psi U know, when I put together the top end myself 5yrs ago. I didn't have this problem. I did it and it lasted 3.5 years even with me playing with it and acting a fool. unknown/unproven short block, No cam breakin out of round main bearings, no star washers, electrical problems and all. Now I hook up with a guy who said his dad was a hot rod builder. And I've have had my car down a year and a half. $4800 and I drove it over there with the bad cam had to have it towed back, had to set the timing just to get it running and now have to tear it back down!!! Ok, where do I start this weekend???? |
Re: No oil psi Well I would start by just pulling the engine out and putting it on a stand. Tear it down noting clearances and damage as you go. If there's been one constant in all my years of wrenching it's this: "If you want it done right, do it yourself" Every step of the way it's been this way on my 3rd gen. I bought a 9 bolt center from 9bolt.com.... garbage. I got a trans from a "respected" local builder.... garbage. Had my vortec heads built by a respected local head guy.... garbage. Always have to do it myself. GD |
Re: No oil psi Man dang if I told u my story, u would be pissed with me Would it be better just to put my recently purchased 6.0 in? Just heads and cam stock bottom end and do the turbo later? |
Re: No oil psi
Originally Posted by budget builder
(Post 6281684)
U know, when I put together the top end myself 5yrs ago. I didn't have this problem. I did it and it lasted 3.5 years even with me playing with it and acting a fool. unknown/unproven short block, No cam breakin out of round main bearings, no star washers, electrical problems and all. Now I hook up with a guy who said his dad was a hot rod builder. And I've have had my car down a year and a half. $4800 and I drove it over there with the bad cam had to have it towed back, had to set the timing just to get it running and now have to tear it back down!!! Ok, where do I start this weekend???? As far as where to start going forward, that depends on your level of skill/knowledge. |
Re: No oil psi
Originally Posted by GeneralDisorder
(Post 6281673)
I agree. With two independent gauges telling you there's effectively no pressure, you need to tear it down. I've built a lot of engines and monitored a lot of oil pressure and if the clearances are right you get somewhere between 15 and 30 psi of oil pressure at a hot idle. I personally don't like to see any less than 20 psi. The golden rule often stated is 10 psi for every 1000 rpm. And with a cold pressure of 40 you know the pump is plenty capable so it's definitely not that. The pump only generates flow, it is the engine oil clearances that generate a restriction to flow and thus pressure. What you have there is insufficient restriction to flow and thus no pressure. Unfortunately that means stop running it to mitigate further damage and tear it down. GD |
Re: No oil psi I have learned a lot but I don't know everything one beautiful thing is I'm always willing to learn more and I think that going forward I am about to take what I can learn off of thirdgen.org and ls1tech build this stock engine to the best of its capability give me a car manifold and run it at least it's something happens to eat 5 years down the road the engine only cost me less than $1,500 |
Re: No oil psi I haven't been around the site very long. I bought my IROC last spring. Good bunch of guys here that know thier stuff. Yet to get my first bad advice here. |
Re: No oil psi Gr8 site |
Re: No oil psi
Originally Posted by butchc
(Post 6281706)
Kudos for providing quality factual information Sir. You are among the rare that understand flow and pressure. One of my mentors told me that restriction to flow is the only thing that causes pressure period, cement that in your mind and any pressure issue become easy to diagnose. If you get really deep into the science of pressurized journal bearings you find that a lot of it is based on about 100 years of trial and error and real world experience. The problem is that you want sufficient clearance so the journals don't touch, but not so much that oil runs out too quickly. And of course the film strength and thickness depends on lots of oil properties - not least of which is viscosity. An engine is essentially a big controlled oil leak. You control the leak rate with clearances. If the leak rate is too high for the pump volume then you need to find out why. Because if you can't build pressure you will have insufficient oil retention in the bearing to produce hydro-dynamic film strength to support the journal. This will result in contact between the journal and the bearing resulting in rapid failure. And if you pump too much oil volume to generate the required pressure you end up pumping the pan dry and that's a whole different problem leading down a path of ultra-heavy oils, dry sumps, and so forth. There is a sweet spot and that is what GM built the engines around. You don't want to stray very far from that sweet spot or the whole carefully balanced system collapses. Factory pump volume and pressure is entirely adequate for normal street engines. GD |
Re: No oil psi I didn't see where he put a mech gauge on it. Did I miss that? You really need to confirm with a mechanical gauge before tearing open an engine. Next before tearing it open maybe check for some obvious stuff. Like a blocked oil pickup or a sheared pickup O-ring. Or some kinda clog in a line (if it has lines with oil). I wouldnt just go "oh well the electric gauges say it needs to be torn open" |
Re: No oil psi What kind of oil filter are you running? |
Re: No oil psi
Originally Posted by Kingtal0n
(Post 6281775)
I didn't see where he put a mech gauge on it. Did I miss that? You really need to confirm with a mechanical gauge before tearing open an engine. Next before tearing it open maybe check for some obvious stuff. Like a blocked oil pickup or a sheared pickup O-ring. Or some kinda clog in a line (if it has lines with oil). I wouldnt just go "oh well the electric gauges say it needs to be torn open" There's no oil pickup o-ring on a Vortec 350 block. Could be plugged I guess but with what on a "new" engine? And how would that explain the 40 psi cold? It would be zero all the time.... GD |
Re: No oil psi
Originally Posted by Kingtal0n
(Post 6281775)
I didn't see where he put a mech gauge on it. Did I miss that? You really need to confirm with a mechanical gauge before tearing open an engine. Next before tearing it open maybe check for some obvious stuff. Like a blocked oil pickup or a sheared pickup O-ring. Or some kinda clog in a line (if it has lines with oil). I wouldnt just go "oh well the electric gauges say it needs to be torn open" |
Re: No oil psi
Originally Posted by midias
(Post 6281777)
What kind of oil filter are you running? Rebuilt 010 block with vortec top end |
Re: No oil psi damn man. 40 cold and drops down to 0 when hot... that does sound like its pissing oil away somewhere inside. maybe a plug was left out or something. I dont know that block but maybe someone can think of a place where oil can bypass easily (oil bypass spring failure maybe?) something like that. The cold pressure being 40 also seems low, shouldn't it be like 80 on that motor? I know the LS engine doesn't have a very high cold pressure (mine doesn't) but I think the old engines would show like 60-70psi cold starts. |
Re: No oil psi
Originally Posted by Kingtal0n
(Post 6281823)
I dont know that block but maybe someone can think of a place where oil can bypass easily (oil bypass spring failure maybe?) something like that. |
Re: No oil psi Sometimes something as simple as installing the cam bearings wrong will cause OP problems. In my experience they should be put in so that the oil holes are somewhat toward the driver's side of straight down; something around 4:30 to 5:00 as viewed from the front of the block. This delivers oil to the journal just as it is about to arrive at the point where there is max load on it. The gap between the journal and bearing is small at that point, to avoid excessive oil flow; but large enough to deliver a reasonably thick film. The front one, with the 2 holes, should be at around 3:00 and 6:00, for chain oiling. Worst case is to install them with the holes up around 11:00 to 12:00; the clearance at that point can be quite a few thousandths. If a cam bearing spins in a block, something really terrible is going on... it would have to weld to the cam pretty solidly to get yanked out of the block bore. Or, the block, or the bearing, would have to be the wrong size. SBC cam bearings are 3 diameters: #3 is smallest, then #2 & #4 are larger, then #1 & #5 are larger still. #1 of course has 2 holes while all the others have 1. Some old 70s core like 010 with the pitiful quality control in those days, wouldn't surprise me if the block has been damaged over the course of its life, or even was just poorly machined originally. Always seemed to happen, back when I was building lots of motors, when people would come up with a block, or a whole engine, from somewhere, and it came with some kind of fish story about how this "good" block or "strong running" engine was up for sale impossibly cheeeeep. I can recall one guy telling me the PO "wanted something for his wife that got better gas mileage", another that "wanted to drop back to a less expensive class to run"; another that "exhaust was too loud and didn't want to change the cam"; all basically LIES. The REAL PROBLEM was, there was something unrepairably wrong with the block; the Starter Bolt Hole Problem, the Bell Housing Dowel Pin Problem, the Oil Passage Doesn't Line Up Problem, the Lifter Bore Alignment Problem, and so forth. Cam bearing tunnel defects fall into the same class of things. People talk about "just get it drilled for roller cam bearings, which sounds GREAT; but, why put $500 worth of machine work into fixing a block you can REPLACE for $100? Doesn't make sense. Only makes sense if you're starting out with a pristine and near-perfect block; not just repairing some defective old ragged POS. |
Re: No oil psi I replaced a Dart Big M block. I cracked the webbing under the #1 main bearing. Showed up under a magnaflux. |
Re: No oil psi With how cheap used Vortec blocks are, I don't see much use in starting with anything older unless it's really something special. I bought my fully dressed 98 Vortec (running) pull-out for $200 and the guy loaded it in my truck for me. Had an intake gasket failure which is not uncommon. Upon tear down it was virtually perfect inside even with 177k on it. From my research they got things pretty straightened out on the production floor by the time the L31 was introduced so they are a pretty safe bet. GD |
Re: No oil psi I hesitate to show my ignorance by asking, but are there plugs around the cam (behind the timing chain cover) like earlier blocks. Similar pressure readings when those are not installed. |
Re: No oil psi
Originally Posted by dlinger
(Post 6281888)
I hesitate to show my ignorance by asking, but are there plugs around the cam (behind the timing chain cover) like earlier blocks. Similar pressure readings when those are not installed. GD |
Re: No oil psi Yes there are plugs around the front cam bearing. They plug the passages the factory drilled from end to end of the block (well, … to the point of the Oil Passage Doesn't Line Up Problem mentioned above, they drilled em halfway through from the front, and halfway through from the back, but sometimes they end up kinda like this... Hey you think THAT'S paranoid???? I'M the paranoid. I ALWAYS ALWAYS ALWAYS ALWAYS ALWAYS ALWAYS on EVERY SBC I build, tap em out to ¼" pipe, and put in screw-in ones. EFFFF a bunch of weenie-a$$ "thread locker" and epoxy and other ORGANIC crap. :devil: I like METAL. Never forget: just because you are NOT paranoid, does NOT mean that they are NOT all out to get you. |
Re: No oil psi OK, so it's messed up, and now I can't edit it. Go here for a nice factory oil passage in a 010 block. I actually had (and scrapped) a really otherwise nice 509 block (go look it up) because it had this problem SO BAD, that a ¼" diameter piece of wire couldn't be slid through the MAIN oil passages. :eek: I couldn't knock the welch plugs in the front out from behind by sliding in the rod and bonking them out. Woulda had to use a dent puller type arrangement and pull em. But then my unsuspecting customer woulda had a motor that spun the #1 & #2 mains, and/or the #1, 2, or 3 rod bearings, NO MATTER WHAT s/he did to try to repair em. Which is probably why I picked it up for TOOOOOO CHEEEEEEEEEEEEP in the first place. Oh well, ya lives and ya learns, or ya doesn't live long. |
Re: No oil psi Well, that one is messed up too, and I can't edit it either. Let's try this for a visual of The Oil Passage Doesn't Line Up Problem: https://camo.githubusercontent.com/f...61696c2e6a7067 |
Re: No oil psi Oh BTW, I should also mention, I usually drill about a #75 hole in the 2 side passage plugs (lifter feeds) but NOT in the top one (main, rod, & cam bearing feed), to piss oil on the cam sprocket, so that the chain is UNCONDITIONALLY oiled adequately. You might be surprised how much less they "stretch" when they get some lube. |
Re: No oil psi My dad told me to buy a gm goodwrench/Chevy performance short block slap my heads,intake, ac's, oil pan, decent cam and carb on and drive the friggin car. If I pull the motor which has been out the car a 3rd time: junk it and get a warranty block and bottom end... I am hesitant about blueprint and atk although I found a 383 short block for less than 2200. I'd rather stick with the gm 350 block... smh |
Re: No oil psi Sofa I have learned trust no one but yourself, learn , take your time, get a warranty!!!!! I should have listened to you months ago when u first told me about the 70s blocks and not to drop my money into this project. But i was thinking i had a top notch mechanic on my side and it would be soooooo fun . Now I'm in $4800 in just the engine. This doesn't include money paid for work performed or misc parts and time spent spinning our wheels accomplishing nothing some days. And this was a 40yr engine builder. I drove my car over there with a wiped lobe. And had to have it towed back. They couldn't get it to run under 1500rpm idle. And wanted to keep it there. I towed it back only to find out they drained my gas tank and the timing tdc was off by 9degrees. Never again... then the son ,my boss, asked me what was the bottom dollar price I would sell it to him.... God help me I want to tear somebody head off.... but I wont. Never again!!!! Sorry fEllas I'm venting ... I've had this car 5yrs and so far have 10g in it and cant even drive it. And honestly if it wasn't for thirdgen.org and my wife I've basically had 0 help. Thx fellas I think I'm going to follow my dad's advice.... |
Re: No oil psi Please figure the problem out before you just trash the engine. It could be something very simple. Let me add some info to this subject. My engine had a problem where I had to troubleshoot the entire oiling system to find the problem. I used diesel fuel and spun the oil pump with a cut-off distributor shaft to make a preluber. You will see the diesel fuel streams that shoot out from the parting lines of the front main bearing. This lubes the timing set, but I also have a small hole drilled in the block where the back of the timing gear is. These pics should hopefully shed some light on your problem. https://cimg1.ibsrv.net/gimg/www.thi...695acff7a5.jpg https://cimg3.ibsrv.net/gimg/www.thi...b2b568df0c.jpg https://cimg7.ibsrv.net/gimg/www.thi...c24900e4b1.jpg https://cimg8.ibsrv.net/gimg/www.thi...1e852c19e5.jpg https://cimg9.ibsrv.net/gimg/www.thi...965f693c4c.jpg https://cimg4.ibsrv.net/gimg/www.thi...7da3e9b95c.jpg |
Re: No oil psi
Originally Posted by NoEmissions84TA
(Post 6282043)
Let me add some info to this subject. My engine had a problem where I had to troubleshoot the entire oiling system to find the problem. I used diesel fuel and spun the oil pump with a cut-off distributor shaft to make a preluber. GD |
Re: No oil psi
Originally Posted by sofakingdom
(Post 6281981)
Hey you think THAT'S paranoid???? I'M the paranoid. I ALWAYS ALWAYS ALWAYS ALWAYS ALWAYS ALWAYS on EVERY SBC I build, tap em out to ¼" pipe, and put in screw-in ones. EFFFF a bunch of weenie-a$$ "thread locker" and epoxy and other ORGANIC crap. :devil: I like METAL. Never forget: just because you are NOT paranoid, does NOT mean that they are NOT all out to get you. GD |
Re: No oil psi
Originally Posted by GeneralDisorder
(Post 6282044)
Interesting. What were you looking for and what did you find? GD I got my engine back together after a resurrection due to chowed cam lobes because of improper valve seals installed by RHS (insufficient retainer-to-seal clearance). I did the break-in on my test stand. Pre-lubed it, cam lube on lobes, break-in oil, every measurement checked and double-checked.......... everything done to ensure a successful BI. I even grooved the lifter bores. Ran 20+ minutes varying the RPMs above 2000 and backing down the engine speed towards the end of the break-in. Everything seemed fine. That is until I added the extra mufflers and idled it down and heard the dreaded light ticking.:eek: Oil getting everywhere like it is supposed to be. Lifters and pushrods rotating as they should. More running to troubleshoot only causing more damage. I eventually pulled the lifters and found very strange wear patterns on the bases. I began testing the entire oiling system of the block as described above. Then I substituted different known good hydraulic and solid lifters to compare the amount of oil being sent to the pushrod/rockers. The SKIP WHITE Guaranteed Made IN USA Delphi lifters that come in a white box were not delivering nearly the amount of oil as the known good lifters. I bought these because these had the spun-welded on chilled hardened bases like the good GM lifters have. I have never seen this type of lifter collapse or even show wear, so I thought I was doing a good thing by using them. WRONG! The last cam ended up with a few chewed lobes and that shrapnel got circulated throughout the entire engine, damaging nearly everything. So this was the last thing I wanted to happen this time around. But it did. 1 lobe on the cam was already missing .038". So that I don't completely hijack this thread, and the pictures are not getting attached right now, I will stop here and continue this in a post of my own just as soon as I can. The pictures show it all. |
Re: No oil psi Okay here is the game plan when I get home tonight I will take loose the belts that run the alternator and the power steering pump I will leave on the one that runs the water pump to keep the engine cool as I understand it and I hate to do it this way but when the oil pressure gets low if I hear a squeaking 9 out of 10 that will be a cam bearing I do appear to be having a squeaking noise when the engine is running so now I'm curious whether I find anything or not I will be prepared to take off the timing cover the heads pushrods intake / the motor out and I will post my results as to what I find thank you |
Re: No oil psi I just found out they are calling for rain this weekend... crap We'll see |
Re: No oil psi Hate to do it this way but 40min of running with and without accessories no change but no weird noises. Will teardown when not rainingif I rev engine to 800 and let off pressure maintain 2psi . Will teardown |
Re: No oil psi It could be due to a few things, but let's talk just about the cam bearings. If any of the front 4 walked, that would cut off the oil supply to their respective main bearings, and also the rod bearings fed from that journal. If so, then I think the engine would have seized by now. If the rear cam bearing walked forward far enough, then you would have a huge oil leak there and virtually no oil would be getting anywhere else. The 2 lifter galleries are fed from the annulus around the back of that bearing. The rear cam bearing really can't walk rearward because the rear cam plug would stop it. https://cimg5.ibsrv.net/gimg/www.thi...d40cf0ba18.jpg https://cimg7.ibsrv.net/gimg/www.thi...69442b1555.jpg https://cimg8.ibsrv.net/gimg/www.thi...1f5a2f7735.png |
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