Cracked injection cup???

[zmck150]

In the middle of pulling apart my project engine I came across some cracks in the heads, not sure what this is from but I assume that the heads are junk.

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Any input?

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[FarmerFrank]

As long as those cracks do not go into the fire ring you are good. Little cracks are fine but if they go apast that headgasket ring you need new cups

 

[zmck150]

Sorry forgot to include background info. It's a 7.3 idi, unknown miles or anything I picked it up with low compression for dirt cheap. Inside the engine is cleaner than most gas jobs I've seen.

My phone won't let me upload anymore pics but once it lets me there will be more

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[ToughOldFord]

Yeah, those small cracks in the pre-chambers aren't a concern and even if they were bad, like FF said you could just replace the chambers. If that's the worse you have then don't worry about it.

 

[zmck150]

That piece is replaceable? And the crack is in the fireing ring if you can see it in the picture.. I don't know if the phone uploaded it or not?

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[ToughOldFord]

They do come out, they're just lightly pressed in there. Not sure who has replacements though.

I see two pics, I'm not seeing any cracks near the head gasket ring.

 

[icanfixall]

Those are the precups and they are replaceable but very expensive. I believe they are made from a material called inconel steel. As posted, they can be reused if the cracks are not out of the fire ring seal area.

 

[ToughOldFord]

Here's a couple of pics:

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[zmck150]

Thanks guys I appreciate the great info. What causes this to happen? And if I don't replace them what's the chance of running into a problem later on down the line

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[rhkcommander]

Most have run cracked cups safely, cant recall any horror stories of it.

Extreme heat and pressure causes it. Injectors spray relatively cold diesel agaist them, they are meant to be hot, compression can be upwards of mid 400-500psi going thru that hole. And then combustion coming back out violently

 

[icanfixall]

I recall those pics. Russ aka typ4 cut down a head and shipped it to Mel aka agnem. then Mel painted the insides to show intake, exhaust, coolant and what else that flows thru the heads. Each section showed a different port flow path. I'm sure Mel still has them for show & tell at the rallys. The precups have a depth recession set in the heads. They can be up or down 2 1/2 thousands from the head deck and be ok to run fine.

 

[typ4]

Those are very nice precups in our world, run them. Mine had much bigger cracks in them 100k ago, about 5/16 long. If you do replace those, Ill take the old ones