Low oil pressure, found problem but what next

[Witt51]

I've made other threads before about having low oil pressure on a new rebuild I did.

Everything is new inside and had a machine shop recommended to me that I wish never touched my car.

Oil pressure at start up was 30 psi and dropping to about 10 when warm. This was checked with a manual pressure gauge.

Changed valley cover orings with no success.
Pulled off the water pump and front cover to get to the melling high pressure /volume pump and cam retainer plate. Spun the starter got no pressure and no oil leaks. Now I pulled off the pump and hooked a oil primer to the oil filter housing. This time had fluctuating pressure and found that the oil is being pushed out at the crank and front main bearings.

I know this is going to require me pulling the engine back out and checking the main bearings. Could this be from not putting sealant on the mains bolts? Or am I in for something worse?

I can't remember the bolts used. I'm almost positive they are all ARP hardware on the bottom end.


The red mark shows where the oil was coming out of.



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[Greenhornet2]

I am not an engine builder I've done some for myself and I've never built one of these. I don't know if there are any pitfalls or findings to watch for on the particular engines. I would likely reach out to an engine builder that knows the ls3. I would likely plastigage the bearings, thinking they weren't sized just right. I've never used sealant on a main bolt only oil, but if the call for it, maybe. Sorry i can't be more helpful on this one.

[Witt51]

Originally Posted by Greenhornet2

I am not an engine builder I've done some for myself and I've never built one of these. I don't know if there are any pitfalls or findings to watch for on the particular engines. I would likely reach out to an engine builder that knows the ls3. I would likely plastigage the bearings, thinking they weren't sized just right. I've never used sealant on a main bolt only oil, but if the call for it, maybe. Sorry i can't be more helpful on this one.

Not sure if I can put links on here from ls1tech.

Here is thread talking about it. I believe they are ARP bolts. I've seen some they have issues and some don't. I'm not even sure if it's the bolts causing the leak but other than than I'm not sure what else it could be. Is there a seal on that front mains to seal it up? I tore it all down myself and I don't remember a seal. I figure someone on here would have have seen this issue.

I will check the clearences. It's a stock crank and was installed with king racing bearings that are the stock size. I have a plastigauge but never used one before.

Check this out. If it's against rules can you remove the link

https://ls1tech.com/forums/generatio...lt-sealer.html

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[Witt51]

Originally Posted by Greenhornet2

I am not an engine builder I've done some for myself and I've never built one of these. I don't know if there are any pitfalls or findings to watch for on the particular engines. I would likely reach out to an engine builder that knows the ls3. I would likely plastigage the bearings, thinking they weren't sized just right. I've never used sealant on a main bolt only oil, but if the call for it, maybe. Sorry i can't be more helpful on this one.

I used this book along with a couple other books "how to rebuild gm ls series engines" by Chris werner

Only snug these bolts for now, then install the side cap bolts loosely. If you are re-using your old side bolts, apply some RTV sealant under the heads to prevent oil leakage.

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[Witt51]

No one has seen this or have an idea what it could be

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[xc_SS/RS]

If you haven’t I’d post this on LS1Tech. Way more traffic on that site and there are a lot of engine builders who frequent it

[Witt51]

That's where I was going to go next and ask. I've noticed people are usually friendlier over here. I will go there. Thanks

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[blue-bayou]

This problem is a little hard to diagnose remotely. First things first-I would not pursue the sealant on the main bolts as it isn't required and wouldn't play a role with oil pressure (unless there is a hole/crack in your oiling circuit that extends to the main threads).
30/10 PSI seems quite low for HVHP pump.
Are you getting sufficient flow to the valvetrain?
Where did you tie the manual gage to the system? There may be something blocking the oil passage to the pressure tap.
Oil coming out at the location identified: this may be normal but can't confirm without seeing the condition and method of producing the condition.

Personally it seems to me that either your oil pump isn't functioning correctly or the engine isn't built to handle an HVHP oil pump. On initial startup was the oil system primed. Oil pump cavities should have been full/submerged in oil. If not immediate damage can result in oil pump and/or engine.
Why HVHP? Were bearing clearances, seals, etc.modified to handle HVHP? If not, pressures can easily be over 100psi which can blow out seals and cause bearing damage.

[Greenhornet2]

From the other threads, i was under the impression the pump currently in the vehicle was a stock pump. The other thread was asking if the hvhp pump could help with oil pressure if i remember correctly.

[Witt51]

Originally Posted by blue-bayou

This problem is a little hard to diagnose remotely. First things first-I would not pursue the sealant on the main bolts as it isn't required and wouldn't play a role with oil pressure (unless there is a hole/crack in your oiling circuit that extends to the main threads).
30/10 PSI seems quite low for HVHP pump.
Are you getting sufficient flow to the valvetrain?
Where did you tie the manual gage to the system? There may be something blocking the oil passage to the pressure tap.
Oil coming out at the location identified: this may be normal but can't confirm without seeing the condition and method of producing the condition.

Personally it seems to me that either your oil pump isn't functioning correctly or the engine isn't built to handle an HVHP oil pump. On initial startup was the oil system primed. Oil pump cavities should have been full/submerged in oil. If not immediate damage can result in oil pump and/or engine.
Why HVHP? Were bearing clearances, seals, etc.modified to handle HVHP? If not, pressures can easily be over 100psi which can blow out seals and cause bearing damage.

I understand that it's tough to give an answer without seeing. I was wondering if others have seen it or if someone would know off the top of their head. Was looking for direction where to look next. I've read about if the side bolts on the mains weren't sealed they lead but not sure about losing pressure and I didn't have any oil leaks.

When the engine was running it got oil up to the rockers but when I used the oil primer i didn't see the oil get to the top. Another thing I'm trying to figure out exactly the path the oil runs. I have the illustration but couldn't figure out exactly the correct oil paths.

I tapped the oil gage to the valley cover. At start up the oil pressure hit 30 and then dropped to 10 but seems d to keep dropping and then I turned it off. Also when I raise rpm the oil pressure wouldn't go up with rpm. I changed the valley cover orings going for the easiest first. That didn't help so I stuck it in the garage and pulled the front cover to check for anything obvious. I pulled the oil pump and hooked the oil primer to filter housing to see if there is pressure from there and try to rule out if the pump was good or bad. I got about 7 psi on the gauge and never built up and kept bleeding off. That's when the oil seeping out of the crank/mains area. The oil was coming out the 12 o'clock to the 3 o'clock position but never leaked out on the lower main caps. (I'm guessing I'm going to need to check the main bearings for damage).

Oil pump was submerged and I filled the pump the way melling says. I talked to melling and they said to check the oring and if that was good then it was probably a bearing clearance issue. I asked about the oil relief getting stuck because when I tried to raise the rpm and increase oil pressure the pressure never raised with rpm. He said they haven't had oil relief valve issues (not according to the internet, I've seen plenty of relief valve failures)

I went with the hphv pump because I've had it installed when the motor was cammed and shaved heads installed and when the motor was rebuilt recently. Both speed shops recommended that pump.

The motor is cammed, heads done, headers and all other bolt-ons. I have upgraded bearings and all arp hardware.

I hope this doesn't make things more confusing. I wanted to lay out my steps also that I have completed.

How do you see if the relief valve is stuck? Is there a way to check that? I would think the oil pressure not increasing with rpm would be a symptom of that and maybe that's why I never got a rise in oil pressure when just spinning the crank with the starter.

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[Witt51]

Originally Posted by Greenhornet2

From the other threads, i was under the impression the pump currently in the vehicle was a stock pump. The other thread was asking if the hvhp pump could help with oil pressure if i remember correctly.

No it was melling hphv. I've had it installed 2 other times. Once when modified the first time and then after it was rebuilt. I should of put my mods in my original post.

Btr stage 2 cam, shaved. 030 heads with prc dual springs, Texas speed headers, melling hphv pump, custom jre pistons for valve clearance, rxt dual clutch, bmr suspension.

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[Greenhornet2]

Usually if the relief sticks there's 0 pressure from what I've read. I don't have first hand experience with it.

[Witt51]

Why can't anything be easy. It's all a big pain in the butt everytime I try to do something

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[Witt51]

I got off the phone with Texas speed and they said that is a bearing clearance issue that no oil should be coming out of there. So it looks I'm going to be pulling the motor and check the bearings. I think that's probably the best bet. This is the second time I've had engine issues after using this machine shop.

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