AFTRBRNR

I've searched through other posts but none seem close to mine.

New engine, new Melling high PRESSURE oil pump. Mobil 1 5w30, Mobil 1 oil filter. Engine bearings set to looser tolerances than stock but not too wild as told by the builder.

When temps get >180 degrees and the car is <1000 RPM I will see single digit oil pressure. No valve chatter apparent. As soon as I give it throttle it jumps to 20-40+ and clears the oil lamp.

Changed the break in oil and it seemed thinner than I've ever seen the oil. After a week the new oil is doing the same thing.

So.... what now? Go to 10w40 and AC Delco filter?

rabrooks

Yes, go with a thicker oil. To overcome loose bearing tolerances high pressure oil pump wont do it, you need a high volume pump or both.

Just curious, why build the engine with loose bearing tolerances?

AFTRBRNR

I didn't pick the parts but I had this engine built for a supercharger. Perhaps the builder picked something a little looser for more load?

I decided to take a step back on this engine and let the builder do his thing because my last two engines failed.

outhouse

Its more then oil weight problem here.


Get a mechanical gage and actually make sure its an accurate reading.


If so you have real problems, mine idles at 37psi hot cold idle at 65 psi and that is what a fresh engine should read.

CMY SIX

my LS2 with a new Melling standard pressure and volume pump after a cam job, 25 psi at idle 45 psi at rpm HOT 78000 miles

AORoads

IDK but that sounds quite low to me. I'd ck with another engine builder for their opinion if they'll give you the time to discuss it a bit. Time is, after all, money. Of course, then comes the question: what do you do if it's not good to be that low on oil pressure?

extrapilot

Something is not right, oil pressure should be the least of your problems with a freshly rebuilt engine. I wonder how he made the bearing tolerances greater than standard. With the high pressure Melling pump, you should have greater than stock oil pressure.
Hope this is not the same person that built your two failed engines.
I would have a conversation with the builder, as I think he missed something. May need to double check the OP with a mechanical gauge to confirm.

User Omega

Confirming low pressure is step 1. Once confirmed you need to get with the builder. If it is truly low then you have a bigger issue than oil weight. Could be something as dumb as the retainer plate gasket being damaged.

Please return and update the thread with what you find out and how you solve it.

moh97gt

I don't think clearance is the cause.

it could be the oil pump is sucking air ,if the oil pump O-ring was incorrectly installed.

or the O-ring thickness is small

AFTRBRNR

Car just came back from the tune shop. I changed the oil out to Royal Purple 10w40 and put in an AC Delco oil filter. At 232 degrees, my oil temp range from 14 PSI at idle to 32 PSI cruising at 80 mph. So... thoughts from that?

Note: The pressures are about +10 when below 150 degrees.

If this seems out of character I may bring it back to the shop and let them run diagnostics... although it's $105/hr to keep in mind.

Unreal

I would check oil pick up oring, and pump. I wouldn't not run the car as is.

My "supercharged motor" seeins ~75-80psi on cold starts, and drops to 45-50psi when warm, and 100+ cold and 75-90 when on it hot. 25k+ miles with blower at 1000-1200rwhp.

User Omega

I'm not understanding why this engine isn't out of the car yet..

Did you confirm oil pressures displayed to be accurate?

1hander

im going through something similar...it doesnt sound right..i parked mine till i can get the engine torn apart

outhouse

Sounds like the builder screwed up.


Why???

outhouse

No your the opposite, your engine is toasted to some degree, his is new and set with more play then it should have.

CI GS

Assuming that the clearances aren't somehow way off, or your builder didn't do something goofy like leave the "barbell" oil galley plug out, etc., at idle, you should be seeing ~50 psi cold and ~40psi at operating temps with that pump.
I would bet it's the O-ring. As shown in the video above, the Melling pumps come with two O-rings and instructions that tell you which one to use based on the color of your original O-ring.
If it was the pump (other than the bypass spring being collapsed, or broken) it would probably have grenaded and taken out the motor by now.
If it is the O-ring, it means you're sucking air into the pump and aeriating the oil going to the bearings. Not good.
DO NOT run the engine any more.
Get your builder (or better yet, get a new one and send the old one the bill) to pull the front end of the engine down and take the pump out and see what O-Ring is in there and then take the pump off and apart (with the Melling pumps, you have to do that to put it back on anyhow) and inspect it. I personally would also drain the oil again and check the magnet for metal particles and cut the filter open and check that too.
Simple things like this have killed many a good engine.
**** happens. Just don't make it worse by running the engine until you figure it out.

AFTRBRNR

Good advice here. I have not had an opportunity to run a manual pressure gauge yet.. those plug in behind the intake manifold right?? That would probably be my next step to see if maybe my sensor is goofed up (original from 2000 on its 3rd engine).

I have not noticed any metal in the oil changes; this is the 3rd one in less than 100 miles. I still have both filters I pulled off. Would I just be looking for shavings? There has been no audible ques of oil starvation even when the PSI reads low... although I am aware this isn't a good enough reason to keep driving it. Of note, there is certainly a lot of crankcase oil pressure, the dipstick tube kept flying out on the dyno so we put the bypasses back in on the valve covers.

AFTRBRNR

Last time I had my hand on the engine build I regretted the outcome. This time I gave them a fresh block and said to make something ready to bolt on a supercharger down the line.

I did let a different shop tune it though and now the car is acting right for the first time in a decade.

CI GS

I would definitely check the oil pressure with a manual gauge. There's a oil galley plug on the drivers side of the block, right up front where you can tap into. It's the plug the you can see the side of the head of in the attached picture, right above the ground strap. Just screw that out (provided you can get to it) and use the necessary adaptors to screw your manual oil pressure gauge hose into that.
Maybe you haven't hurt the motor, or you would've heard something knocking by now. I would still cut open the filters and pull apart the pleats and run a magnet over it to see if there's any metal particles.

AFTRBRNR

I just cut open both filters and pulled them apart like an accordion. I can see very small flakes in both. Probably <10 per filter. Would that be normal from a new engine mating contact surfaces or no? You guys are being great BTW in helping me out. I just don't want to believe the engine builder put this together wrong when they build engines for a living and even recommended the melling pump. (I let them build this whole thing based on how they recommended it).

But it's really looking like I may take these filters along with an oil sample back to the tune shop that tuned the car to have them run complete diagnostic on it. I have not seen compelling evidence that considerable damage has been done yet so if there is a problem, you all have helped me to catch it early. (maybe the bearings aren't toast yet? that's a $$$$$$$$$ job to replace)