IDRIVEAG8GT

So, I fired my fresh 364 setup a few days ago with 5-30 conventional motor oil just for break in. Since then I put 204 miles on the car and have been having an oil pressure problem. I built it slightly loose but nothing insane. I figured that idle oil pressure would be low like 20-25 psi when warm after everything was said and done but when I first fired it I had 41 psi cold, and 26 psi warm with no miles on it. With miles it has been slowly dwindling. Now when warm on my way back from a party it dropped to 7 psi and something in the motor started rattling. I figured the oil was just terrible for my application so I changed it, and just for extra measure I went with Valvoline 20/50W VR1 full synthetic and ran a Mobil 1 M1-113 filter. Fired it, my VCM Scanner showed 55psi cold (Which is the mechanical limit due to the oil Pans bypass), and then when the oil temp hit 175 it dipped all the way down to 12 or so psi. So I killed it, and now it sits out in my garage. You guys have any idea where I should start looking for problems at?

Thanks,
-Robbie.

IDRIVEAG8GT

Forgot to mention that with this oil and oil pressure it quit rattling. I was thinking about the O-Ring down below on the pickup tube. Does it exhibit symptoms like that?

Could I have messed up and knocked one of the rubber O-rings off on my top plate for the DOD-Delete?

I'm just grabbing at straws here.

realsquash

iTrader: (1)

You built it loose? What does that mean exactly? If you didn't get the o-ring in the right spot on the pickup tube that could be your problem.

Andy

BattleSausage

iTrader: (3)

I'm sure he meant clearance wise but I'm wondering what loose translated too clearance wise in the build. However, to me that doesn't account for the drastic drop in pressure from temp changes if all the info we have is correct.

litle88

iTrader: (20)

What went wrong is, you built it.
You dont break in a forged motor on 5-30 synthetic, you should of gone with some breakin oil like Joe Gibbs , or comp cams or Valvoline vr1, something with lots of zinc and phosphorous to help the rings seat.

How "loose" did you build it?

Sales4@Texas-Speed

iTrader: (4)

Whenever we are breaking in a motor we always use a specific break in oil because they have some extra additives that really help the rings seal. That is the most important part of an engine break in, IMO. With the problems you are seeing, the first thing I would look at is the oil pump o-ring. The o-rings are very sensitive and the smallest nick or pinch in the ring can cause it to not seal typically. When the motor and oil is cold it is thick so you won't see the oil pressure drop until the oil warms up and thins out. I would also check the oil itself for any shavings or residue, it is common to see some shavings from a fresh built motor but I would be more looking for a gold/bronzish color to make sure there is no issue with the bearings.

crainholio

iTrader: (2)

Define "insane" as most of us think in 0.00xx" terms. What clearance did you measure at the main and rod bearings?

Is the block aluminum or iron? Aluminum block main bearing clearance specs are in the 0.0012" range cold if I recall right...the clearance grows considerably as the block is heated.

Sales2@Texas-speed

iTrader: (5)

Curious as to bearing clearance as well. Particularly on aluminum engines, the bearing clearance loosens up when it reaches operating temp. It is not as profound of an increase on the iron blocks though.

IDRIVEAG8GT

5-30 conventional SAE by PRC. It's a good break in oil. Not synthetic. Rings seated fine too by the way.

This is an aluminum block. Main bearing clearance was .0018 via my pwk gauge.

IDRIVEAG8GT

Oh and rods were all .0020 by the way, except for number 8 which measured out .0021-.0023 in different spots everytime. (ACL coated and rod bearings apparently have a little variance.)

IDRIVEAG8GT

Thanks John for all that insight. There was a wee bit of metal shavings in the oil I dumped but it was a real bright silver, not even close to bronze.

Old Geezer

iTrader: (3)

When you cut the filter open, what was in it??? You DID cut it, right??

DAVESS02

iTrader: (30)

My LS2 stroker Has between .0015-.0018 for main clearances and holds over 40PSI warmed up on Torco brand 10W-40 with a melling HV oil pump so I'd have to guess oil tube o-ring as well. My rods have .002 on all except one thats .0019.

IDRIVEAG8GT

Yessiree! I did cut it. If I could figure out how to post pics here I'd show you that it looked pretty good.

IDRIVEAG8GT

Thanks Dave that makes me feel better, I just have to figure out if there is any possible way to get the oil pan off while it is in the car.

IDRIVEAG8GT

Remember though guys, I just put brand spanking new oil in it and brand new filter. I don't have an oil cooler so no blockage can be there. If I spun a main it would be evident correct? What about a rod bearing? What would that exhibit? I'm hesitant to Pull the motor if I have to again. It's really ******* hard to do.

67RSCamaroVette

iTrader: (63)

You will hear a spun bearing, it'll sound like a leprechaun in your motor trying to get out with a hammer. Have you checked your o-ring yet? If it's sucking air, it will explain the low pressure. How close is your pickup to your pan? What oil pump are you using, and is it healthy? If you leave a motor "loose," you'll want higher volume from the pump.

IDRIVEAG8GT

Nope I haven't got to it yet. It's in my G8 and I'm not sure yet how I will be able to get to it without pulling the engine. If I have to I will I'm just a little apprehensive. Thanks for the insight on bearings

67RSCamaroVette

iTrader: (63)

Remove your motor mount bolts to the motor. Jack the engine up by the transmission bellhousing, or lift it with a picker, until the engine is 1-2" higher than on the stand. Now you can lower the oil pan enough to get to the bolt on the pickup tube. Use a magnet stick in case you drop it. Most of us do it anyways during a cam swap; pros don't drop the bolts, though .

IDRIVEAG8GT

^^ Your awesome, I'm gonna give it a whack, I just have to be careful not to crush the SCM module that's almost directly on top of the transmission if I do that. Thanks once again. You're an asset to the LS1Tech community.