OK help!

[Moosebob]

Finally finished my 7.3 rebuild, managed to get it back under the hood, got the air out of my injector lines and it fired it up..... but almost no oil pressure! Mechanical gauge is hooked up at the new turbo, which won't spin freely anymore. Revving it up doesn't help the pressure any and it struggles to rev, due to the turbo not turning I suppose. Before the rebuild I had almost 40psi at a cold start, now I get like 2psi. I pulled the oil supply line to the turbo off and found no oil there, line was clear. Truck starts right up, runs fine, no knocking or ticking..... so oil is at least making it as far as the lifters. When I shut off the engine I can hear the oil dripping back down to the pan. Any ideas what's going on???? Anyone have an oil flow diagram?

 

[racer30]

Did you have new cam bearings installed? Did you do anything to the oil cooler?

 

[OLDBULL8]

I've got an oil flow diagram, see if I can upload it, it's a bit map file, don't know how to change it to a jpeg file. Yup it did it. Here is the coolant flow also. Click on either pic and it will expand it.

Edit: Your gonna ruin the turbo bearings without oil too them, maybe trash the whole turbo.

 

[theguruat12]

The oil feed line is clear as in you took it off and blew compressed air through it clear? That would be my suspicion, was that the line was plugged....

 

[Moosebob]

Did you have new cam bearings installed? Did you do anything to the oil cooler?

Yes new cam bearings were put in. All the holes appeared to be lined up correctly. I took the oil cooler apart, cleaned it, and put new O rings on it.

 

[Moosebob]

The oil feed line is clear as in you took it off and blew compressed air through it clear? That would be my suspicion, was that the line was plugged....

Yes I took it off and air blows through it just fine. That was my first suspicion also. I thought maybe one of the brass compression sleeves had turned sideways and blocked it off, but they were all good when I checked.

 

[icanfixall]

I'm betting the oil pressure regulater valve in the rear oil cooler header is stuck open. Somewhere on this forum is a pic of the valve in the stuck position. You need to remove the oil filter to see the stuck valve. Can be messy. Sometimes its a simple fix with a small screwdriver or pick. Other times is completer replacement of the rear header.

 

[OLDBULL8]

I'm betting the oil pressure regulater valve in the rear oil cooler header is stuck open. Somewhere on this forum is a pic of the valve in the stuck position. You need to remove the oil filter to see the stuck valve. Can be messy. Sometimes its a simple fix with a small screwdriver or pick. Other times is completer replacement of the rear header.

I agree with that. To confirm oil pressure out of the filter, remove the plug on the drivers side trans. mounting flange, attach a gauge to it. That may be where you have the oil line to the turbo, if so, you know you don't have any oil pressure there now.

 

[crewchief219]

The link below has just about everything you need to know about the oil pressure regulating valve. I had an oil pressure problem a few months ago and changing the oil cooler was my fix, bought one from someone on the forum. Hope it helps.

http://diezelcrazeesidipage.homestead.com/oilregulatingvalve1.html

 

[crewchief219]

Let's try that again..

http://diezelcrazeesidipage.homestead.com/oilregulatingvalve1.html

 

[Moosebob]

As far as I can tell with a mirror and flashlight the valve is closed. Even if it was stuck partially open I would think at 12 gallons a minute that I would get some pressure. The oil filter was full of oil, so the pump is pumping something. If there was no oil to the hydraulic lifters wouldn't they just collapse and make the engine not even run???

Was cranking it over today hoping to get a pressure reading at the back of the block and got a funky smell followed by slower cranking......... really hope my starter just went rather than my engine starting to seize up!!!

 

[racer30]

The engine would run with collapsed lifters, The cam lift is .380 and the lifter has about .350 of movement and is at about 85*pumped up during operation. pulling the oil cooler is easy compared to the Engine...Although running it to much with low pressure will damage the bearings....Starter's hate cranking engines, They will complain if asked to do it to much....

 

[Moosebob]

My starter was almost brand new, probably only 20 starts from it before the rebuild. I really hope the bearings didn't get damaged, I just replaced them and turned the crank and don't have the money to do it again. My current theory is I have a very large clog in an oil passage and its close to or at the oil cooler header. I mentioned before I didn't think the pressure relief valve could allow 12gpm of oil flow through it even if it was stuck open and that it looks closed anyways. Well I'm guessing that it can't flow that much oil, which is causing a very high pressure to build up and nearly stopping the oil pump thus making it a real ***** for the starter to crank it over.

My question now is where is this clog , where did it come from, and what the hell could clog it well enough to stop that much oil pressure from pushing it through???

 

[diezelcrazee]

As far as I can tell with a mirror and flashlight the valve is closed. Even if it was stuck partially open I would think at 12 gallons a minute that I would get some pressure. The oil filter was full of oil, so the pump is pumping something. If there was no oil to the hydraulic lifters wouldn't they just collapse and make the engine not even run???

Was cranking it over today hoping to get a pressure reading at the back of the block and got a funky smell followed by slower cranking......... really hope my starter just went rather than my engine starting to seize up!!!

You can only see about 1/2 or so of the relief port when looking at it from the oil filter side. When mine was stuck open the only way I could tell was by feeling with an oring pick. See if you can "hook" the edge of the plunger inside the relief port.

 

[Moosebob]

I did try with a very pointy pick and could not catch anything. The relief valve is meant to relieve excess pressure not all of it. I'm not getting any pressure now. I can see oil and air pockets in the line to the gauge and they don't move at all.

So far I am blaming the machine shop, they said they would clean the oil galleries after the sleeve job.