Seized 7.3 engine...kinda long...

[zigg]

Well, I had a longwinded question about my siezed 7.3 engine, but then I decided to go to Mels FAQ and "cavitation" article, and lo and behold, the answer jumped out at me...

While I've got some work to do.....,

yet again, a great big "ATTABOY" to Mel for all his work...

zigg

 

[icanfixall]

Sorry to hear of this Zigg. I hope for you its just a headgasket or either head but we will see later on I'm guessing. Best of luck anyway. Cavitation has bitten me twice on my motor. Thats why its been parked for way too many months.

 

[yARIC008]

So how are you sure it's cavitation?

 

[EvergreenRanch]

hydrolocked?

 

[zigg]

Well, I'm not sure yet, but I picked this truck up last fall, and we got it running just long enough to get it up onto the flatbed so I could pull it home. Once home(my sisters place about 60 miles from me here) we got it started again to get it off the trailer, and it was bangin' and fartin' and smoking something awful, and then it quit, and wouldn't start again, and then it just seized up.
Sat over the winter, and today I went and decided to start lookin' it over. I thought, well, I'll drain the oil and have a look.

I pulled the plug, and about 2 gallons of nice bright green coolant drained out of the oilpan!!

So, then I put the 15/16ths socket on it, and lo and behold, it bars over just fine. Compresssion and everything.

There's a big puddle of oil in the intake that came from the CDR on the drivers' valve cover through the turbo(I'm talking LOTS) but no oil in the Rad, but I could hear compression gasses gurgling up into the rad as I turned it over.

so, the question was, is it cavitation or maybe head gasket, or cracked head etc. Well, I suspect cavitation, but whatever, doesn't matter, the engine has to come out anyway...

I've got a "built" 6.9 to go in it's place, I just want to get the flexplate and bellhousing adapter to make the 6.9 bolt onto the E4OD off the 7.3.

I imagine I'll eventually tear the thing apart and find out what killed it, but for now, this jury is voting cavitation...

182,000km(110,000mi on this engine)

Zigg

 

[EvergreenRanch]

no expert on the topic, but any chance the oil cooler is leaking? would account for all the coolant in oil. might explain few other of the symptoms, but ill let someone more experienced chime in if im correct in my thinking

 

[dsblack]

Zigg,
I believe that the plate off of the 7.3 will fit the 6.9 and allow the trans to bolt up.
Good luck! Sounds like a sweet truck.

Doug

 

[Freight_Train]

actually,I just had a 6.9 put in the Enterprise and all they had to do was swap the flywheel.The 6.9 was from a 84 with 4 speed and the Enterprise is a 91 with E4OD.Only thing changed on the 6.9 was I installed the Enterprise 7.3 pump,G code injectors(Had 4 new ones laying around so I just bought 4 more and threw them in),ZD9 glow plug and glow plug system,Put the 7.3L rocker arm assemblies since the 6.9 sucks with the aluminum bridge hicky(One broke while reinstalling.YOUCH they were gaulled up),dumped those stupid phillips head valve cover screws.

 

[bikepilot]

A leaking oil cooler wouldn't allow coolant into the combustion chamber.

 

[Rawpower]

There's a big puddle of oil in the intake that came from the CDR on the drivers' valve cover through the turbo(I'm talking LOTS) but no oil in the Rad, but I could hear compression gasses gurgling up into the rad as I turned it over.

Zigg

You sure it wasnt forced up and out the CDR by the rad fluid? I mean, 2 additional gallons in the pan is a lot... maybe not enough though.

Maybe thats what you are saying, and it ended up going through the turbo...

 

[EvergreenRanch]

A leaking oil cooler wouldn't allow coolant into the combustion chamber.

did i miss that somewhere? all i see is coolant in the oilpan mentioned....

 

[zigg]

A leaking oil cooler wouldn't allow coolant into the combustion chamber.

Well, it would allow coolant into the oil, but I'd think if there was any connection at all, the higher oil pressure would tend to push oil into the rad. Since there's no oil in the rad, I'm not inclined to suspect the cooler.

Rawpower:

Yep, I think you might be right. the tube from the CDR to the turbo was full of oil, and so was the intake, and exhaust pipes too. I'm inclined to think it got pushed up via the filled up oilpan.

There are other places where coolant and oil could easily mix, and could be in large amounts. Between each of the intake passages on the heads are 1/2dia. holes that are connected to coolant passages(originally there during the casting of the heads), but are supposed to be sealed by the valley pan when it's applied. If these leak, coolant can run down(under pressure) into the valley and down around the lifters. Also, the front plate on the engine is held in place partially by the bolts on the water pump. If the pump is ever changed, then the gaskets behind the front plate could be compromised, and again coolant under pressure could be forced down the front of the engine via the timing gears and into the oilpan. Wouldn't take much. End result would be the same. The only fly in the ointment, though is that none of these places, front plate, valley pan, oil cooler are connected directly to the compression in the cylinders, so why do I hear compression gasses leaking via the rad when turning it over.

This makes me suspicious more and more of the big "C" or at least a major cracked head or head gasket

I think what I'm gonna try to do next weekend if I get a chance is I'll try to pressurize the cylinders one at a time and try to figure out which one is making the noises via the rad. Then once I figure out which one, I'll try to pressurize it with the piston at TDC, and if the pressure to the rad is stopped, then there must be a crack somewhere down the wall of the cylinder...

I guess I could try to start it up without coolant too, see if it runs. Couldn't hurt much at this point.

Here's a pic of the rig if anyone's interested:
..Pic 1..
..Pic 2..


Zigg

 

[Rawpower]

...the higher oil pressure would tend to push oil into the rad...


...the tube from the CDR to the turbo was full of oil, and so was the intake, and exhaust pipes too...

Zigg

cracked block perhaps? or cracked head?


The cavitation would draw in radiator fluid on the intake stroke, but I dont see how oil would be getting into the exhaust if it is a lot. If it is a small amount then I guess it is possible through the intake, but it seems like the oil would be burned. There is soooo little clearance at TDC, that I dont see how it could pass a significant amount of oil through a cylinder and not burn it, or crack a piston from a significant increase in pressure.

OR what if the sleeve cracked along the lower portion of it, low enough so that oil could get in towards the bottom of the intake stroke. That way it would be able to suck oil and rad fluid in. Never mind. That doesnt work out because of the dry sleeve thing...

Another unlikely scenario is that it was passing oil into the cylinders via intake, until it became too much oil in the cylinder during compression at one time, and the piston failed. That is highly doubtful though, I'd think something else would go, like a rod or something...

I guess is the oil in both sides of the exhaust? that would help

edit: i like the truck its going in though

 

[zigg]

Well, since the pipe from the valve cover to the turbo was full of oil, and the turbo had oil in it, and the intake is full of oil, then I suspect that the oil was getting into the engine via the intake.
I originally suspected the turbo was shot, but then realized all the oil was in the pipe from the CDR, so that's where I think it was coming from.

Since the oilpan is full of coolant, I suspect it filled till there was no more room, and the oil got pushed up through the valve covers. As you said, the fact that it was in the exhaust is just testimony to it being pushed through the engine.

Either way, I'll be pulling the thing out. I was thinking it might be nice to be able to get it to run(not put coolant into it) just to be able to get it up on a flatbed again to tow it to my house(about 60 miles south) but it might just not be worth the hassle.

We'll see eventually.

zigg

 

[Agnem]

yet again, a great big "ATTABOY" to Mel for all his work...

zigg

Zigg, just to keep me honest, I can't take credit for Eric's (Yaric008) masterful article. I'm just the editor. Glad it is helping you, and I think everyone here knows the value of your contributions as well. The strenght of Oilburners is in the strong reference material we have here, none of which would be possible without the dedicated efforts of people who take the time to grab a camera with the wrench, and a keystroke with the brewsky.