Keep cracking heads

[nolaninblaine]

Have you had the heads checked to see if the cracks are actually leaking. Have seen many cracked there that don't leak. Have seen a couple blocks leak, one pinholes, and the other had a slightly loose fitting sleeve that. Was inside the fire ring

Yep. I know they leak because when i start it dead cold the radiator pressurizes instantly. If i have a bleed funnel in place, the bubbles never stop

 

[The_Josh_Bear]

Have you had the heads checked to see if the cracks are actually leaking. Have seen many cracked there that don't leak. Have seen a couple blocks leak, one pinholes, and the other had a slightly loose fitting sleeve that. Was inside the fire ring

Yep. I know they leak because when i start it dead cold the radiator pressurizes instantly. If i have a bleed funnel in place, the bubbles never stop

That could be cavitation too though, unless confirmed it's the cracks. Sounds like you know your way around an engine block though-- I'm not trying to say you're wrong, just throwing it out there. Would suck to pull the engine 3 or 4 times thinking it's cracked heads just to find out it's a pinhole cylinder leak. Now THAT is something much more common to 7.3's.

 

[nolaninblaine]

Well i havent torn it down again yet. But the last 2 times it did this exact same thing. I pulled the heads and found cracks. This is definitely an odd, seldom heard of problem. I already sent another head to the machine shop and will tear it down again this week. I should just order up an inner-cooler right now. Im going to do a water to air set up.

I have 3 weeks to figure this out. We have a trip planned to go over the pass to Idaho for Scarywood. ***** gotta be right!!

Thanks for all the responses. When i do sort this out ill let everyone know. I did start off with a hypermax kit, though the only part of it left are the pedestal and the goofy ass up-pipes. Everything else is in the trash. So this is a bit experimental. Just dont be mad at me when there is a shortage of good used 7.3 heads.

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I would have been pretty cool back in ‘91

 

[IDIBRONCO]

I would have been pretty cool back in ‘91

Huh? What do you mean by "would have been"? With that set up, you still are cool!

 

[Jesus Freak]

Like, whoa cool.

 

[Black dawg]

Yep. I know they leak because when i start it dead cold the radiator pressurizes instantly. If i have a bleed funnel in place, the bubbles never stop

You know there is a leak, but not that it is that crack for sure. Like I said, I have seen many cracked there with no issues. Also very odd that cooling temp stays 180, where is the sending unit?.

If you are in fact cracking heads in a short amount of time, are you sure your exhaust
temps are safe?

 

[nelstomlinson]

Is it possible for the top of the block to be slightly off, somehow not flat, on that side? I've never thought to check the deck on a block with a straightedge.

 

[Rdnck84_03]

It is possible for the block deck to be warped, but that should only cause headgasket failure. I wouldn't think it could be warped badly enough to crack a head, and not have something very noticeable sticking up.

James

 

[FrozenMerc]

This is actually a fairly common failure in the HD diesel world. 4 valve heads are especially prone to cracking between the valves. Hell, I don't think there is a Navistar A26 (13 liter) engine out there that doesn't have a cracked head.

Rather than replacing the head, I would give Tri-State Cylinder Heads a call (shipping from PNW might be cost prohibitive, but worth a shot anyways). Tri-State does puddle weld repair on all of the cracked cylinder heads we can't repair in house, and they do pretty good work. They are a Cummins spin-off. Cummins set up a bunch of cast iron welding shops back in the late 70's, early 80's to support their remanufacturing business, and later spun them off as economic conditions changed.


https://tristateheads.com/

 

[XOLATEM]

s it possible for the top of the block to be slightly off, somehow not flat, on that side? I've never thought to check the deck on a block with a straightedge.

that thought occurred to me as well...if it is not overheating...then something else must be up with it...

If you are going to pull it apart again...I would check the deck with a critical eye...

Also...if you have not chucked your other broken heads...I encourage you to give Tri-State a try on fixing them...that was a good suggestion in my opinion..Frozen Merc...if they have been fixing stuff that long...I am a believer in giving good domestic industry a shot at proving themselves...yet again...

I saw their ad's in a few trade journals over the years and always wanted to give them a shot on getting my business for various things...but it never materialized...

Just my .02$

 

[nolaninblaine]

You know there is a leak, but not that it is that crack for sure. Like I said, I have seen many cracked there with no issues. Also very odd that cooling temp stays 180, where is the sending unit?.

If you are in fact cracking heads in a short amount of time, are you sure your exhaust
temps are safe?

Ill know more when i get it apart.