Cracked Block

jdgleason · Feb 4, 2013

mike@haller's said:
On the block that cracked the holes were clean and dry. Were gonna try cryoing but I dont think it will stop this kind of failure.

I've always been told cryo is more for wear really than anything else. Either way, I think it's still a real good idea for these motors.

mike@haller's · Feb 4, 2013

It is more for surfaces that wear. Regardless we are still cryoing the block.

punkrockford · Feb 4, 2013

I have never heard of this being an issue before. what year were the trucks, could this be a early weak point that was worked out in later years?

gman1 · Feb 4, 2013

punkrockford said:
I have never heard of this being an issue before. what year were the trucks, could this be a early weak point that was worked out in later years?

Build dates or miles has nothing to do with it.

Dzchey21 · Feb 4, 2013

I was thinking we need to start a thread to see what block castings are ones that failed and year of truck with stud brand number so we can keep track.

Im sure mines cracked too I just got lucky and fixed it with paste

tensixniner · Feb 4, 2013

Dzchey21 said:
I was thinking we need to start a thread to see what block castings are ones that failed and year of truck with stud brand number so we can keep track.

Im sure mines cracked too I just got lucky and fixed it with paste

It would also be nice to know to what value people are torquing their studs to.

.

gman1 · Feb 4, 2013

Dzchey21 said:
I was thinking we need to start a thread to see what block castings are ones that failed and year of truck with stud brand number so we can keep track.

Im sure mines cracked too I just got lucky and fixed it with paste

Great idea. Its amazing how many people never heard of this.

Rmartin-97 · Feb 4, 2013

What are symptoms of this?

Dzchey21 · Feb 4, 2013

Usually starts with loss of coolant in the crankcase. Mine traveled up the stud. I put sealant on it and that fixed it for now

AllanB · Feb 4, 2013

jdgleason said:
Not in the couple cases that I know of.

I have only heard of two cases. How many do we know about that have had this problem?

Dzchey21 said:
I was thinking we need to start a thread to see what block castings are ones that failed and year of truck with stud brand number so we can keep track.

Im sure mines cracked too I just got lucky and fixed it with paste

I fully agree with this. It would be good to keep every ounce of information on those trucks that we can get. How much torque was on them, what type of lubricant was used, amount of boost and hp they were running, how many miles had it run after major upgrades such as more air and fuel, etc, ect. The best way to narrow this down is to have all the info you can get, and see what the common denominators are.

SEABEE08FX4 · Feb 4, 2013

Who did the stud job? The proper way of installing the studs is to bottom them out and then back off half a turn. The put the washer and nut on and bottom the nut down hand tight without letting the stud turn, because when you go to torque the nuts the stud will turn. And if it doesn't have that buffer room to keep going deeper in the stud hole it will bottom out and crack the block.

gman1 · Feb 4, 2013

Rmartin-97 said:
What are symptoms of this?

Loosing coolant, lots of vapor out the ccv and the same greenish snot (pic) coming out the ccv.
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Dzchey21 · Feb 4, 2013

The stud will just turn until it's bottomed out if you do it like that. I thought about doing that and then using loctite on the studs so they can't turn.

All the instructions say to bottom the stud out finger tight. I do agree with you that this could be the issue

AllanB · Feb 4, 2013

SEABEE08FX4 said:
Who did the stud job? The proper way of installing the studs is to bottom them out and then back off half a turn. The put the washer and nut on and bottom the nut down hand tight without letting the stud turn, because when you go to torque the nuts the stud will turn. And if it doesn't have that buffer room to keep going deeper in the stud hole it will bottom out and crack the block.

I don't know who installed them. I didn't ask. But from the questions I did ask. It is to my understanding that a very qualified shop that has been doing these for a long time done at least one of them. I guess everyone can make a mistake. But if they are as qualified as I was told, I doubt it was installment error. Could be, just going off the info that I got. I believe this is the reason for the concern is a few people are sure that it was not a mistake on installment.

SEABEE08FX4 · Feb 5, 2013

I'm just saying thats how I do them, never had this issue. If the stud is already bottomed out then it has no where to go when you keep torquing the nut so thats where the stud hole cracks come from.

jdgleason · Feb 5, 2013

SEABEE08FX4 said:
I'm just saying thats how I do them, never had this issue. If the stud is already bottomed out then it has no where to go when you keep torquing the nut so thats where the stud hole cracks come from.

Of the thousands of studded 6.4s, a very very small handful have ever had this issue.

Dzchey21 · Feb 5, 2013

SEABEE08FX4 said:
I'm just saying thats how I do them, never had this issue. If the stud is already bottomed out then it has no where to go when you keep torquing the nut so thats where the stud hole cracks come from.

That doesn't make any sense tho.

If you bottom the stud out and torque it and your saying it keeps turning and pushing the stud in causing the block to crack, then how can you back the stud off half of a turn and keep it from moving?

Like I said I tried it this way and I marked the stud, it will just turn until it's bottomed out.

AllanB · Feb 5, 2013

jdgleason said:
Of the thousands of studded 6.4s, a very very small handful have ever had this issue.

I feel the same way, and I don't know who did the stud job. Just heard it was from a reputable shop. But like I said before everyone can make a mistake. It only takes one time with one stud to screw up a block. I believe what left a question in some minds about the block was that there have not been a lot, if any 6.4's out there running high hp for a lot of miles. But with the amount of hp these blocks have seen, I would be really surprised if it were related to the block, and not human error, or something with the studs themselves. Not saying it is. But it can only be one or the other. :shrug:

SEABEE08FX4 · Feb 5, 2013

Dzchey21 said:
That doesn't make any sense tho.

If you bottom the stud out and torque it and your saying it keeps turning and pushing the stud in causing the block to crack, then how can you back the stud off half of a turn and keep it from moving?

Like I said I tried it this way and I marked the stud, it will just turn until it's bottomed out.

By applying force on the stud with the nut and using an allen head wrench to hold the stud still and a open top socket or open end wrench to put a preload on it before torquing. I do it on every stud job and it works. Just saying thats all, and even if it does turn it wont turn that half a turn you backed off to were its bottomed back out. The studs are already harder than the block, your exerting more force than the black can take by torquing it with the stud already bottomed out. A hair line crack is all it takes for a leak.

gman1 · Feb 5, 2013

AllanB said:
I feel the same way, and I don't know who did the stud job. Just heard it was from a reputable shop. But like I said before everyone can make a mistake. It only takes one time with one stud to screw up a block. I believe what left a question in some minds about the block was that there have not been a lot, if any 6.4's out there running high hp for a lot of miles. But with the amount of hp these blocks have seen, I would be really surprised if it were related to the block, and not human error, or something with the studs themselves. Not saying it is. But it can only be one or the other. :shrug:

I know of 1 truck that has a fractured block using 1722s and 2 using CA 625s. So I dont think its the studs.