Engine/Transmission (1994 - 1998) Low oil pressure at Idle

[Cody Gamble]

Hey Guys,
After rebuilding I am getting 25 psi at start up but then as it approaches 140 F oil temp, the pressure gradually drops down to around 6 psi. At that point, I shut it off. Otherwise I wouldn’t be surprised if it went down to zero. When I rev the throttle, there is a corresponding increase back into normal range ie 10 psi per 1000 rpm. I already replaced the pressure regulating spring and no change. Next, I’m gonna replace the oil filter head and the bypass valve. If that doesn’t work, I’m going to replace the oil pump. If that still doesn’t get it, taken care of, I think I’m going to have to tear down completely and rebuild again . All I know about the history of the vehicle is that it is a 97 p pump outta a F600 and was a KDP kill (p pump gear, cam gear, and crank gear had broken teeth; I reused the oil pump and torqued in sequence per the manual). Question 2: is it normal to get a little bit of oil blowing out the back of the turbo at high RPMs? It’s like 1-2 cc’s in 20 seconds…I am still running the engine in on the stand. Thanks!

Cody

 

[Ozymandias]

9-10psi idle hot is normal.

Second, get another gauge for this low level measure.
Your Amazon gauge isn't really precise at such low pressures, I know because I used the same.

Don't rip your engine apart without verifying the gauges reading.

 

[Ozymandias]

Blowing oil is nowhere normal around the Turbo.

 

[Tuesdak]

Question 2: is it normal to get a little bit of oil blowing out the back of the turbo at high RPMs? It’s like 1-2 cc’s in 20 seconds…

This is the critical thing to find. DO NOT RUN THE ENGINE AGAIN UNTIL YOU FIND THE OIL LEAK! It could runaway on it's own oil. Start by inspecting the turbo to see if the oil may be coming from the compressor side or the exhaust side. Inspect the intake and exhaust manifold for wetness to help pin the source down.

The re-used the oil pump on my 2003 rebuild. They had to warranty the engine for low oil pressure in 500 miles.

 

[BigPapa]

I think he's saying it's blowing oil out the hot side into the exhaust, not the cool side into the intake.

Still, no, it's not normal. You said you were running it on a stand. Do you have the intake running through the CAC into the intake? I don't see any CAC tubing from the turbo in your pic. Is the the crankcase vent operational? Is the vacuum pump hooked up and functioning properly?

 

[Cody Gamble]

I think he's saying it's blowing oil out the hot side into the exhaust, not the cool side into the intake.

Still, no, it's not normal. You said you were running it on a stand. Do you have the intake running through the CAC into the intake? I don't see any CAC tubing from the turbo in your pic. Is the the crankcase vent operational? Is the vacuum pump hooked up and functioning properly?

Thx for all the help! BigPapa is correct. The engine is getting swapped into a 4x4 ford van bc the 6.0 died. It’s on a stand I made to test before install. The oil is blowing out the exhaust side of the Hx35w only, side to side movement is minimal, no end play. The turbo is not feeding anything as this engine is on a pallet stand with a radiator straped to it. No CAC tubing and no exhaust piping fabbed yet. The CCV tube on the tappet cover is clear of obstructions. The turbo drain tube has some S curves on the way to the block drain hole but I routed it so as to not back up. Maybe it’s still too curvey. Vac Pump / Power Steering pump is installed but w/o the lines. It has its own oil feed though. The vac pump does produce suction. My diagnostic plan for the low warm idle oil pressure: replace filter housing and bypass, inspect housing gaskets. Retest. If it is still low—replace oil pump. Retest. If it is still low, rebuild again… With specific attention to main and cam bearing clearances (was good but I dunno maybe I misread the plastigauge). Regarding the turbo issue: straighten the drain tubing. Restest. If still leaking out the back, remove turbo and exhaust manifold and check for wetness at head ports. Go from there…Ozy— I used 2 diff brands of manual gauges and both showed 6ish PSI hot idle.

 

[Mikey-KE7LBB]

It would be easy to just remove the turbo and see what kind of oil pressure you're getting. Since it's leaking, it needs to come off anyway.

 

[Cody Gamble]

Yeah I might do that too Mikey. Last night I removed the turbo and manifold and found wetness in ALL 6 of the exhaust ports—so it’s not likely the turbo. It’s either oil or diesel coming from each of the combustion chambers OR oil leak down from the new McBee valve seats. I’m going to swap a new set of MAHLE ones in and see if that fixes it. Hopefully I don’t have to buy new valves. For the hot idle oil pressure is I am also getting a 0-20 psi pressure gauge to definitively see what hot idle pressure is like Ozymandias recommended. I’ll let you guys know what I find when all the parts come in. Interestingly upon inspection of the oil passages and items—everything seems to be getting adequate supply, no fluids are mixing, and it idles clean (no smoke/steam). This motor only has about 30 minutes of total operating time after rebuild. Originally had 80k. Am I missing anything?

 

[BigPapa]

You need to determine if it's oil or fuel.

 

[Tuesdak]

Maybe a massive leak dumped enough diesel in the oil to cause low oil pressure?

 

[Cody Gamble]

Maybe a massive leak dumped enough diesel in the oil to cause low oil pressure?

Doubtful. Oil level, as measured by the dipstick, has been constant this whole time.

 

[Ozymandias]

That's definitely to much oil there, sure it takes some time to seat the rings and all that, but this is beyond acceptable even for the break in period.

Have a close eye on the oil rings that they are installed the right way around.

 

[BigPapa]

I can't help but have a gut feeling this is somehow due to the turbo and/or the vacuum pump not being connected/fully operational, and possibly as Ozy mentioned, possibly not fully broke in.

 

[Tuesdak]

Why was this engine rebuilt? Details on what all was done?

 

[Cody Gamble]

Why was this engine rebuilt? Details on what all was done?

It was a KDP kill outta a 97 Ford F700 dump truck w/ 80k miles (broke teeth on whole gear train except the oil pump, scuffed the side wall of the timing cover, and fell into the oil pan)…guy I bought it from had already torn it down and ordered an Interstate-Mcbee rebuild kit .P pump had been rebuilt by Cummins Recon after the KDP issue… He wanted to rebuild for “reliability” and bought a bunch of stuff for it to that end. He then got tired of it as it was his 15th swap and got tired of operating out of his garage etc. He tested the head for leaks (as did I) and flatness w/i spec and everything passed. I bought it from him. I honed the cylinders, put ARP head studs n main studs in, re sealed everything, checked all the clearances etc (everything passed), put 3k springs in, and reman Bosch body stock injectors in. I used an Army technical manual on the 6BTA for reference on all this.

In other news today I determined it IS oil (not diesel) and it’s most likely coming from all 6 combustion chambers as all the head exhaust ports are wet with oil. I bought a few new (non-Amazon 10$) gauges and the hot idle oil pressure is 9-12 psi depending on which gauge you believe. Everything is getting lubed properly and no fluids are mixing. So I don’t think oil pressure is an issue. Now I’m concerned about the spackling of oil blowing out of the exhaust. Maybe the rings have not seated yet? On install I oriented all of the rings properly. My next step is to build a manometer per the manual and test the blow by to see if it’s w/i limits. I can’t simulate a load like the manual calls for though. No dyno. I’ll just have to do it by rpm.

One mistake I DID make PRIOR TO FIRST START was filling it with 12 GALLONS and not QUARTS. I realized my boneheaded mistake around the 10th gallon and suctioned it all out then carefully measured in 12 qts. Maybe residual is still blowing out? Or maybe windage issues?

 

[Cody Gamble]

BigPapa…I was actually starting to think today that the turbo not being hooked up might be causing this issue too bc of the lack of extra pressure in the cylinders. After all, ALL 6 are uniformly spackling. How does the vac/ps pump not being hooked up factor in to this at all?

 

[BigPapa]

How does the vac/ps pump not being hooked up factor in to this at all?

It’s just something rattling around in my head. Forget about the vacuum pump.

If you put 10 gallons of oil in it, I imagine that’s your issue. That much oil would have pretty much filled the block up. There’s probably oil still in places it’s not supposed to be.

 

[GAmes]

Speaking of rings not seating, that is what happened to the engine I had that was rebuilt with Interstate McBee parts. Their head gasket failed with less than 5000 miles on the engine as well. Your engine doesn't have enough time on it to know, but don't be surprised.

 

[NIsaacs]

BigPapa…I was actually starting to think today that the turbo not being hooked up might be causing this issue too bc of the lack of extra pressure in the cylinders. After all, ALL 6 are uniformly spackling.

Low oil pressure:

Not likely, the B series was built without turbos, naturally aspirated, in some applications. Possibly missing oil galley soft plugs or piston cooling nozzles?

Oil consumption:

If there is a bad internal oil leak from something missing, that might create enough oil turbulence/violence for the pistons/rings to not be able to shed the excess oil?

 

[Cody Gamble]

Low oil pressure:

Not likely, the B series was built without turbos, naturally aspirated, in some applications. Possibly missing oil galley soft plugs or piston cooling nozzles?

Oil consumption:

If there is a bad internal oil leak from something missing, that might create enough oil turbulence/violence for the pistons/rings to not be able to shed the excess oil?

I was pretty careful to make sure the PCNs were installed and I didn’t mess with the internal soft plugs but maybe...how many internal freeze plugs are there? I am only tracking the one behind the timing cover. Do you guys think I should just start taking it apart and do it all again?