'94 IDIT runs rough, low power, nearly overheating after Moose IP

03wr250f

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holy crap those compression numbers are something i would be concerned with!
240 being the low and 100 psi between high and low is huge.
Heck i would consider 320 psi across all of them low , but dropping down to 240 is extremely low. something is seriously out of wack. I would almost wonder about blown head gasket because that is super low.
could try pressure testing the cooling system with all glow plugs out and then hand barring the engine over to see if coolant comes out any glow plug holes if you can pump up the cooling system but it drops psi and no external leaks
 

Kevin 007

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Yup. Something is out there. Either extreme engine wear, broken rings or combustion gasses leaking somewhere is what I can think of. My most "worn" functioning idi has between 370-390 across the board and its had a rough life and hi mileage
 

SLC97SR5

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I pulled the PS valve cover...that sucks to remove.

It looks very similar to the DS, perhaps not quite as clean. Everything moves nicely and the pushrods are able to rotate. No loose rocker bolts.

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After that we removed the oil psi sender for the turbo and placed a hose in a jug, oil is definitely pumping whilst cranking. I was not seeing much or any oil fill the valve covers while cranking and that is something I expected to see.
 

SLC97SR5

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We then drained 6 ounces of oil from the pan and swept it with a magnet.

The drain pan magnet was covered in fuzz, 4 times the amount that has ever been present.

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The end of this magnet showed this from a single pass in the 6 ounce sample.

Obviously this oil is cold and has not been moving for several days other than cranking while troubleshooting.

I don't see any large pieces of carbon or yellow metals. It looks silvery and ferrous.
 

Thewespaul

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Bearing material. I would flush out the pan with some diesel and drain it through a paint filter and see what else is in there, that’s sure a bummer.
 

Kevin 007

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From what I am seeing, it sure seems like the IDIT engines are generally wearing much faster then N/A engines in comparable applications. Just a side note.
 

SLC97SR5

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Bearing material. I would flush out the pan with some diesel and drain it through a paint filter and see what else is in there, that’s sure a bummer.

What does this tell me?

-Lost a main bearing?
-Rod bearings?
-What would cause the low compression in every cylinder?

Any idea what would cause this to suddenly fail?

Clogged oil pickup? My oil changes have always taken nearly 3 gallons of oil so it's not like the pan has been "growing" sludge displacing room for new oil.

What are the chances this engine will be rebuildable? Approximate cost?

Ugh, lots of questions...
 

Selahdoor

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What does this tell me?

-Lost a main bearing?
-Rod bearings?
-What would cause the low compression in every cylinder?

Any idea what would cause this to suddenly fail?

Clogged oil pickup? My oil changes have always taken nearly 3 gallons of oil so it's not like the pan has been "growing" sludge displacing room for new oil.

What are the chances this engine will be rebuildable? Approximate cost?

Ugh, lots of questions...
Worn, stuck, sunken lifters?
 

IDIBRONCO

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What are the chances this engine will be rebuildable?
It's hard to tell without looking at it, but it would most likely be rebuildable. These are tough old birds and, short of running low/out of oil, are generally rebuildable. Rebuild costs? you won't know that until you see what it looks like on the inside. A simple rering and bearing job will cost far less than needing to have the block bored or sleeved. How is your crank? If it needs to be turned, that will cost you more money. Are you going to stud the block? More $$$. unless you can go without your truck for a long time, it may be best to find a used, running engine and swap it in temporarily while you rebuild this one. A 6.9 will work fine for this and will probably save you some money over buying a 7.3. A N/A 7.3 would work fine too and it would probably be cheaper than buying a Turbo engine.
 

ocnorb

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Dang. Sorry to hear about this.

I've got a few parts stashed in the shop if you come up against something hard to find shoot me a pm. No spare 7.3s unfortunately.
 

saburai

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Wow! That really stinks, I feel your pain. OTOH, when all is said and done you'll have a better and stronger engine in a really nice truck. Do you have anything else that is capable of pulling the toy trailer whilst the idit is down for upgrading?
 

Thewespaul

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What does this tell me?

-Lost a main bearing?
-Rod bearings?
-What would cause the low compression in every cylinder?

Any idea what would cause this to suddenly fail?

Clogged oil pickup? My oil changes have always taken nearly 3 gallons of oil so it's not like the pan has been "growing" sludge displacing room for new oil.

What are the chances this engine will be rebuildable? Approximate cost?

Ugh, lots of questions...

Most likely a rod bearing on the big end, since bearing wear opens up the oil tolerance, the piston can travel down and up further in the bore, but since traveling up is always under pressure the piston stays on the bottom for the most part. With the piston rising less in the cylinder it effectively decreases your stroke, which drops your compression ratio, which gives you lower compression numbers. There's probably a handful of factors giving you lower numbers, but thats how I have seen bearings affect compression numbers in the past. As far as what would cause this, wont know until we see whats hiding in the bottom end. Same with whats reusable, wont know until everything is torn down and inspected, see my previous pm for cost ideas.
 

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