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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I've recently noticed some weirdness with the oil pressure on my fairly fresh 350 (~2000 miles on it). I think it might be the oil climbing up the back of the pan and getting whipped up by the crankshaft? I've been doing research on what happens when there's a windage problem but I'm not sure because I haven't experienced this before.
Hot @ 625 RPM ~30 PSI
Hot @ 2000 RPM cruise ~50 PSI
Hot revving (not accelerating) @ 4000 RPM ~60PSI
If I do a rolling start at, say, 2000 RPM in 2nd and accelerate to 5000 RPM, the pressure will climb to with the RPMs until it gets to 60 PSI by around 3200 RPM, but once it gets around 4000 RPM, it dips to around 45-50 PSI and hangs there until I up shift and bring the RPMs down. I've yet to see it dip below 45 PSI when doing this.
I've done 3 or 4 oil changes already, all with new filters, to flush out the engine and to make sure I didn't have a bum filter (hoping it was an easy fix). I have also replaced the oil pressure sending unit and tried a different brand with no effect.
The initial fill for break in was Lunati 10w30 break in oil. From there, I've been using Pennzoil Platinum 5w30. I also tried Mobil 1 0w40 to see if maybe the Pennzoil was on the thin side. I have tried Wix and STP oil filters. No appreciable changes between any of them. I'm currently running Pennzoil Ultra Platinum 5w30 and a K&N HP-3002 (found out Amazon had both pretty cheap).
Does this sound like an oil control/windage problem, or something wrong with the oil pump/pickup? And more importantly, does it sound like a situation where the engine needs to come out and the issue resolved ASAP? I have mixed feelings since the pressure stays high, but the fact that it dips when it should be riding the pressure regulator bothers me.
Engine specs:
ATK SP03 - 350 short block (.040 over, 12cc dish pistons, looked like LT1 rods)
Lunati Voodoo 20080720 (211/219 @ .050, .507"/.515") w/recommended springs
Chevrolet Performance "LS7" lifters
EngineQuest CH350G "Vortec hybrid" heads
Melling M55 standard pressure/volume oil pump
Melling pickup for that pump and pan depth, tack welded
Stock TPI intake
Stock replacement oil pan
No windage tray (same way it was stock)
You could very well be experiencing foaming since you have no windage or baffling. The fact that it behaves normally when still points to that. If that is the issue, your 45 psi is a 45psi of an oil/air mixture and air doesn’t lube very well. I don’t trust factory gauges for accuracy so I always verify by using a quality mechanical gauge. In this case I believe you will see the same thing though. Taking that one step further, you can’t go wrong with a quality oil pan with oil control, it’s cheap insurance and often overlooked in a home performance build. So my vote is pull it and get that stocker off and give it a good pan with oil control. You can also check for any suction leaks in the pickup tube, make sure it is fully seated in the pump body and your pickup to pan clearance is correct.
Yeah that's what I'm thinking I need to do. The reason I stayed stock is because realistically, I'm just driving this car on the street and it's not anything wild. I thought stock would be 100% adequate for my needs and that ~$500 of oil pan upgrade was genuinely overkill unless it was going to the track or drag strip.
When I was building the engine, I was looking at a Canton 15-244T road race pan along with the appropriate pump, pickup, dipstick, etc. And now, a Moroso rear main cap baffle as well. Guess I should have done it. If only the engine/trans didn't have to come out yet again to swap the pan. Makes me miss the auto trans, don't have to completely remove it to get the engine loose.
Another thing that’s a bit easier to try is to make sure your oil level is correct. Too high of a level you could see a similar result. I’ve dropped the oil level in a very similar situation and it made a slight improvement but ended up having to go in for surgery. Worth a look anyhow.
That's not a bad idea. I can dump out a quart (while staying within the OK range on the dipstick) and see if that does anything. It's usually at the very top, if not a hair over, the full mark after an oil change with 5 quarts.
I noticed that the pan I have is advertised as a 4 quart pan, maybe it needs more like 4-4.5 quarts in the system. Not sure that the filter can actually hold an entire quart.
I drained a quart which put it right at the "add 1 quart" mark and drove around a bit. The pressure now seems stable under acceleration all the way up to 4500. But right as it hits/passes 4500, it drops from 55-60 to 45. Definitely only while accelerating, if I go slow and/or hold the RPMs in that area, it doesn't drop. Sounds like I need to get a better pan/pump/pickup setup.
Thanks for the link to your thread! The videos looks pretty similar to what I experience except that I have to try a lot harder to get it to happen, probably because your 383 pulls a lot harder than my TPI strangled 357.
Are you happy with the Canton pan and pickup and all that? I was looking at a Canton 15-244T because it seems like one of the few that'll fit no problem with a stock routed y-pipe (Hooker 2055 header and y-pipe). Kicking around the idea of going with a Melling 10552 as well. The bolt-on gasketed pickup is pretty nice. Pricey though.
I'm OK with the oil pan, but I'm bothered by not being able to run what the pan was listed for without windage being an issue. The crank scraper had to be notched for my crank, this was fairly easy to do, but leaves a lot of metal debris to be cleaned out. Having the windage screen and oil control door in there made it difficult to wash out. I like the pump and pickup.I did have to modify the pickup slightly to get it to bolt to the bottom of the pump, so they aren't a perfect fit. I intended to use the pump with stock pressure spring. The part description says it comes with stock and high pressure control springs... it didn't. However, Melling quickly sent me the missing spring when I asked about it.
Hmm, yeah I've read that oil pan mounted windage trays and scrapers are pretty mediocre. Better than nothing, but could be a lot better.
Maybe I'll look into just adding a louvered windage tray along with a Moroso rear baffle and new pump and pickup. I can't help but to think that it's kind of ridiculous/overkill to spend $500+ on an oil pan setup on a street car that can't even rev to 5500.
Hmm, yeah I've read that oil pan mounted windage trays and scrapers are pretty mediocre. Better than nothing, but could be a lot better.
Maybe I'll look into just adding a louvered windage tray along with a Moroso rear baffle and new pump and pickup. I can't help but to think that it's kind of ridiculous/overkill to spend $500+ on an oil pan setup on a street car that can't even rev to 5500.
I agree, my goal was larger capacity and exhaust clearance at the time. Oil pans seem way overpriced for what the are.
And actually, I forgot that I have a Corvette L98 short block carcass which has the OE version that tray and the main studs. That would put it on par with an f-body LT1 since it uses a similar windage tray. Wish I remembered that it was just sitting there when I was building this engine...
Originally Posted by Lurbie
I agree, my goal was larger capacity and exhaust clearance at the time. Oil pans seem way overpriced for what the are.
They really do seem overpriced. At least the ones that should fit the car perfectly considering how little the differences are between them.
This is the pan I'm using. Seems like it should work pretty well, although I haven't put my car to task yet. I can say that it clears my long tubes fine and there's no ground clearance issues. It doesn't hang lower than the K-Member or the header collectors.
Unfortunately I'm stuck with a stock routed y-pipe exhaust due to California emissions laws or I'd totally go with a setup like that. Good to know an 8" deep pan doesn't hang noticeably lower, stock is only 7-1/2".
Just a little update after driving more with the oil at the add level and no windage tray or anything... so far I haven't experienced any oil pressure dips unless I rev up to and over 4500. Which is fine since I have a stock TPI intake. I'm not too concerned about it for now. Definitely going to pull the engine and add some oil control at some point in the next few months, but for now I just want to enjoy the car after all the disassembly and reassembly over the last few months fighting various vibrations. Plus I just blew a good chunk of change on a driveshaft to hopefully finally nail down the last major vibration.
I had a similar issue in the Express van turned out to be a combination of having the wrong windage tray (4qt factory tray for a 5qt pan) as well as valve float causing the lifters to bleed way too much oil. Nearly caused #1 rod bearing to spin from oil starvation. I was dropping from 70 to 30 psi above 4,000 even stationary. While I had it apart I put a standard volume/high pressure big block pump and a milodon full length tray.
I ended up pulling this engine out of the 3rd gen to put it in my 2nd gen. While it was out, I installed a Canton 15-242T (could've gone bigger -- didn't realize how much room there actually was) along with their pickup and a Melling Shark Tooth 10553ST standard volume oil pump. I didn't bother swapping the preinstalled 70lb pressure spring in the pump for the standard 60lb one that came with it. Doesn't really seem like a big deal to have extra pressure capacity and I didn't think it'd go over 60 except at higher RPM after warming up anyways.
Canton says it's a 6 quart system capacity pan, so I filled it with 6 quarts, primed it well on the engine stand (didn't disassemble the engine, only changed the oil pan and intake manifold), and then adjusted the dipstick so that it would show full after draining back. The full level is now a good 1" lower than stock and the oil pressure is nice and steady in the RPMs and conditions that were problematic before.
I'm wondering if something was up with the old oil pump because the oil pressure is better everywhere now. But I'm also running an oil I haven't tried before, Motul X-cess 5w40, so maybe it has higher viscosity than other 5w/10w40s, or the Shark Tooth pump moves more oil even though it says it's standard volume. Will probably drop to 5w30 since it's a waste having the pressure so high at these lower RPMs. 650 RPM hot idle is 45-50 PSI and above 2000 RPM hot runs 65-70 PSI.
Also thinking the new pump has an issue with the pressure relief valve because I've seen it at 85+ PSI @ 2500+ RPM when it's cool/cold. It comes down to something more reasonable after a few minutes of that, and after it's fully heat soaked and warmed up it seems to start regulating again so it doesn't exceed 70-ish even if I wring it out. Like the valve is stuck or lacking full travel when cold and is fine when hot. I verified that the pressure is going high with a second analog gauge, so it's not my sending unit/gauges.
This engine is sure a lot more fun with full length headers, Weiand Speed Warrior, and a Holley Sniper compared to the stock TPI intake and shorty headers it had in the 3rd gen. And it still only has 2.56 gears with a TH350/2400 stall. Can't wait to see how it is after re-gearing and swapping the T56 over.
I ended up pulling this engine out of the 3rd gen to put it in my 2nd gen. While it was out, I installed a Canton 15-242T (could've gone bigger -- didn't realize how much room there actually was) along with their pickup and a Melling Shark Tooth 10553ST standard volume oil pump. I didn't bother swapping the preinstalled 70lb pressure spring in the pump for the standard 60lb one that came with it. Doesn't really seem like a big deal to have extra pressure capacity and I didn't think it'd go over 60 except at higher RPM after warming up anyways.
Canton says it's a 6 quart system capacity pan, so I filled it with 6 quarts, primed it well on the engine stand (didn't disassemble the engine, only changed the oil pan and intake manifold), and then adjusted the dipstick so that it would show full after draining back. The full level is now a good 1" lower than stock and the oil pressure is nice and steady in the RPMs and conditions that were problematic before.
I'm wondering if something was up with the old oil pump because the oil pressure is better everywhere now. But I'm also running an oil I haven't tried before, Motul X-cess 5w40, so maybe it has higher viscosity than other 5w/10w40s, or the Shark Tooth pump moves more oil even though it says it's standard volume. Will probably drop to 5w30 since it's a waste having the pressure so high at these lower RPMs. 650 RPM hot idle is 45-50 PSI and above 2000 RPM hot runs 65-70 PSI.
Also thinking the new pump has an issue with the pressure relief valve because I've seen it at 85+ PSI @ 2500+ RPM when it's cool/cold. It comes down to something more reasonable after a few minutes of that, and after it's fully heat soaked and warmed up it seems to start regulating again so it doesn't exceed 70-ish even if I wring it out. Like the valve is stuck or lacking full travel when cold and is fine when hot. I verified that the pressure is going high with a second analog gauge, so it's not my sending unit/gauges.
This engine is sure a lot more fun with full length headers, Weiand Speed Warrior, and a Holley Sniper compared to the stock TPI intake and shorty headers it had in the 3rd gen. And it still only has 2.56 gears with a TH350/2400 stall. Can't wait to see how it is after re-gearing and swapping the T56 over.
Its probably just not able to bypass enough oil when it is cold. I had almost 100 psi in the Express van cold at 2,500 rpm and 70 psi at cold idle.
Its probably just not able to bypass enough oil when it is cold. I had almost 100 psi in the Express van cold at 2,500 rpm and 70 psi at cold idle.
Crazy. I was thinking that too, but it seems like they'd make it so it can handle bypassing any typical weight oil under typical conditions. But I guess it doesn't really matter as long as it can keep up once it's up to temp. Mine will hit the same pressures when cold too. Saw that it was in the low 90's at 2600 when it was still cold (for here at least, 50f) this morning.
I've never had an oil pressure dash gauge that went over 60 PSI -- liking this Intellitronix digital dash setup. Never would have noticed otherwise because I only use the 0-140 PSI test gauge when priming the oil system with a drill.
I remember the old mod for the SBC oil pumps. There is a very small pressed-in plug for the bypass passage. You are supposed to remove that plug and drill the passage larger, and then tap for a 1/8" NPT pipe plug to go where the pressed-in plug was.
Edit: wrong picture. The plug is in the cover. I will replace image when I find the correct one.
Last edited by NoEmissions84TA; 11-29-2019 at 07:24 PM.
I remember the old mod for the SBC oil pumps. There is a very small pressed-in plug for the bypass passage. You are supposed to remove that plug and drill the passage larger, and then tap for a 1/8" NPT pipe plug to go where the pressed-in plug was.
Edit: wrong picture. The plug is in the cover. I will replace image when I find the correct one.
Never seen or heard of that modification. I run standard volume, high pressure big block pumps in my small blocks anyway. The latest 383 has a Moroso 7qt pan with kickouts on both sides and a milodon rh dipstick windage tray. With the correct pickup it holds steady oil pressure as high as I dare rev it. Shift it at ~6,000 rpm.
I changed to Pennzoil Platinum 5w30 which is supposedly at the thin end of the 5w30s and it's more reasonable now. The highest I saw was 85 PSI while accelerating onto the freeway and still cold. After a few miles it settled from 80 PSI down to 65-70 PSI cruising between 2400 and 2700. Getting off the freeway after 25 minutes, it now drops to 35-40 PSI at idle and still comes up and over 60 PSI quickly off idle. Could probably even run a good 5w20 without issue during the "cold" months here on the street.
I'm running a K&N HP-3002 filter since they're really not expensive if you have time to order and wait for it, and they claim to have a 550+ PSI burst pressure. Plus the 1" hex is handy for loosening/tightening from awkward positions -- I usually only raise the car up enough to slip the drain pan under and reach in from the side to do an oil change.
I wonder what the burst pressures are on some of the commonly available filters. I don't doubt that the super cheap ones could pop. A friend of mine briefly worked at a quick lube chain and they used some seriously flimsy filters. Could probably crush it by hand. The cheap Fram filters felt like beef in comparison.
The Subaru engines I build regularly with high volume pumps they run in the 100 psi neighborhood at cold start running 15w50 Dominator. Never had a filter failure with WIX or Amsoil filters we run. Also the high pressure has never caused any issues.
The Subaru engines I build regularly with high volume pumps they run in the 100 psi neighborhood at cold start running 15w50 Dominator. Never had a filter failure with WIX or Amsoil filters we run. Also the high pressure has never caused any issues.
GD
I think the lesson is stay away from cheap filters.
Mobil One for example claims their burst strength was 9x the maximum operating pressure for that engine. If you assume even 50 psi max, that is 450 psi.
05-31-2018, 11:57 PM
