7.3 Cold cranking blow by?

[AcIdBuRn02ZTS]

Hey guys...

Just bought a '90 f350 5spd 4x4. Didnt get to hear it run as the "starter was bad" so the guy delivered it. Its a 5 speed crew cab with a king pin dana60 up front and the price I gave was an ok price for parts alone...

Anyways.. so after fixing some loose connections at the batteries, it cranks over. Glow plug system is dead and no starting fluid on hand so I couldn't get it to fire...

Cranking over stone cold, with the oil cap off, there was a pretty good puff with each rotation of the crank. Also, the intake manifold is coated inside with oil.

I was told the engine had been "rebuilt"

Now, I think the oil in the intake could be CDR related... the oil leak looks to have been coming from the top/front of the engine (possibly the oil fill cap).

Anyways... I ran out of light tonight so tomorrow I'm going to get a fresh can of diesel and a couple cans of starting fluid and see if I can get it to fire but wasnt sure how much "puff" I should be getting out of the oil fill cap when cranking over.

I'm taking a wild guess and saying the engine is toast but I could just be over thinking it.

On the plus side, Ive got another complete front clip from a 91 sitting in my driveway with a complete 7.3 that has ~130k on the clock... clean coolant and full of oil so if worse comes to worse, I'll swap this one in.

Thanks for any insight.
-Chris

 

[crash-harris]

Not sure about cranking, but a normal engine will expel white vapor from the oil neck until warm.

 

[AcIdBuRn02ZTS]

This is pressure more so then vapor... an actual "huff" as the engine turns over. I can hold my hand 6" from the fill hole and feel a puff of air against my hand as the engine turns over...

 

[79jasper]

I would like to say that's abnormal.

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[Hydro-idi]

These engines have plenty of blow by when they rack on the miles. I would say this is normal. If the blow by disappears when you rev it up to around 2k rpm, I think you don't have anything to worry about.
I was pleased to see that my reman engine has absolutely zero blow by from filler neck & CDR. It will appear one of these days tho.

 

[79jasper]

Actually thinking about it more, I believe a cold engine will more than a fully warm engine. So it could be fine.

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[AcIdBuRn02ZTS]

Well... perhaps I'm just jumping to conclusions.

There is a lot of hack going on with this truck... I drained the tap water out of the cooling system... wiring is a mess... I'd at minimum say the engine certainly isnt "fresh"... but perhaps it will still be driveable.

I'll know more tomorrow I suppose. REALLY looking forward to getting this truck going... would prefer not to have to pull the engine to get it there.

 

[Kevin 007]

Probably purrs like a kitten still

 

[turbo elk]

First off... Don't use starting fluid on your IDI you can blow a head gasket or worse.
I hope you read this before you use starting fluid on it...

 

[AcIdBuRn02ZTS]

Hope so.

 

[AcIdBuRn02ZTS]

First off... Don't use starting fluid on your IDI you can blow a head gasket or worse.
I hope you read this before you use starting fluid on it...

...I suppose if the glow plug system was hooked up and working, there would be a potential to blow the prechambers out of the heads or to blow a headgasket... but the glowplug system is not functioning.

We started a 7.3 idi with starting fluid and unhooked glowplug controller for nearly a year every day without any ill effects... just used it sparingly.

Keep in mind, there are quite a few diesel engines that came with factory installed ether injection system (detroit being one of them). With glow plugs out of the equation, compression temps, etc. are the same. When used correctly/sparingly, there isn't much risk involved.

You can also use a gasoline soaked rag or wd-40 or just about anything that is flammable... just cant go overboard with it.

Anyways, without some form of starting aid, this engine isnt going to fire and Im not going to spend money on a questionable engine to correct the issues with the glow plug system, just to find out its clapped out and needs to be pulled.

Also keep in mind I say sparingly.. by that I mean just enough to get more then one cylinder to hit. A very light tap is all it ever took. I would strongly advise against hosing one down with the stuff. Lol

 

[turbo elk]

WD40 doesn't seem to work for me for some reason.... But you are right, starting fluid is ok IF its used sparingly... problem is some people don't know what sparingly means, I've had people give my truck a heavy dose of SF when I've had problems starting... it's aggravating to have to sit and wait for the stuff to evaporate.

 

[79jasper]

On the idi wd40 will hardly ever work. It's not made like it was 10 years ago.

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[IDIoit]

On the idi wd40 will hardly ever work. It's not made like it was 10 years ago.

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so its actually WD-41????

when your engine is cold, your rings are not sealing.
you need to assess the engine while its warm.
dont write it off yet, it may still be a decent runner after you fix the "hacks"

 

[icanfixall]

Any money or parts you put into this glow plug system can be used on the other engine too. So its not wasted money spent on a fubared engine. You seem to know how to use starting fluid from what you posted. After all. This is your truck. Several years ago I was attempting to help a member get his wrecked 6.9 with a turbo to start. Dead batteries. No air filter and the front end wreck had moved the front clip over enough that the fan had worn off much of the fan schroud... We gor no cranking smoke out the tail pipe. After a light spray directly into the intake hat still nothing. As it was cranking I wetted the intake but still not a puff out the exhaust. Nothing was getting in the intake. We never figured this out. With a completely wet from starter fluid this engine acted like it had a completely blocked intake. After leaving on my drive home I recalled the no turbo air filter and remembered a large piece of the hood insulation missing.. I wonder...