Cracked Block

[Morgan@Midwest Diesel & Auto]

Is it possible the studs are being made too long for the 6.4 block????

No they are studs. Bolts would be an issue if they were too long though.

 

[Trav-O]

Love the great info put into this thread! All in all I learned a lot, but still cant fathom how fast it can happen.

My truck was no high horsepower truck (600ish), I barely even got to drive it and it went from a good running truck to a sitting duck. I already drained a lot of money in it and maybe got to drive it 300-350 miles since the mild build. Out of words at the moment...

 

[Dzchey21]

I hear what your saying however even if the threads on the stud bottom out before the stud its self bottoms out in the block, applying more force to it is going to make it want dig deeper into the block. And maybe thats where the crack is coming from, by wedging the stud hole in the block open ( or displacing it ) more. The studs are a lot harder than the block, forcing it more when there is no room to give will just find the next weakest link. I've personally never seen a cracked one myself so I'm not saying your wrong, just coming at it from a different angle.

If that were the case tho the crack would want to go up and down the block, not side to side as the hole would be wanting to expand outward, not downward, think of a big screw in a peice of wood without a pre-drilled hole

 

[Dzchey21]

I've been considering this all day...

We have been filling the 7.3L blocks (even for street use, above 550-600hp) using HardBlok for over 6 years. We also coat the dried/cured HardBlok with an epoxy sealer to prevent coolant circulation from picking up any 'cement' and passing it through the pump/cooler.

The 7.3L blocks have a casting line that radiates from the cam journals...which is where most 7.3L block failures occur...leaving the main caps and crank sitting in the oil pan as an assembly.

The only downside has been the added weight. For 5+ years, we wouldn't recommend building a 600+hp 7.3L withOUT filling the block, unless our bedplate were used.

We have engines with over 100k miles on them that are filled to @ 2" below the block deck...used daily..towing, etc.

Looking at the '08 core engine, and the relationship b/w the casting line and the threaded portion of the block...it appears that the fill would have to be pretttty high to get above the casting (parting) line to gain block rigidity, and minimize/eliminate casting breakage.

Unfortunately, a 4130 pre-hardened steel bedplate (like the one we designed for the 7.3L) wouldn't add any rigidity to THAT part of the 6.4L block.

I will probably end up filling my 6.4L block...and as long as there is @ 2" of coolant circulating in the top of the water jackets...I don't anticipate any cooling issues, even for daily use.

same chit..different day (different engine platform )...

I agree, it would be damn near a full fill. Thought about doing a full fill on my race truck and seing how that does, really wouldnt scare me in that since it doesnt get too much street time. I suppose you could save an already cracked block by doing so... bit of a risk however.

 

[AllanB]

brake cleaner + compressed air leaves the threaded hole dry as a bone...so a light coat of engine oil on the coarse side simply aids installation.

just good general practice for any engine fastener.

I understand your theory behind doing it. But in my line of business it is general practice not to put anything in a threaded hole that a stud is going in and it will be torqued to proper spec. If you put it on the stud and run it in, the threads will get lubricated. By putting it on the stud this will push the oil out of the hole while turning it in, not into the hole.

It just gets squeezed out, if you turn the stud slowly you can hear it.

Again I see your theory behind this, and you would think it would squeeze it all out. It is a long story, but I had a bad experience doing this one time. That is why I ask Golfer why he would put oil in the hole. Personally I would not chance it. When it starts to torque up you are not going to pass any fluid through the threads. I personally haven't read the instructions, but there is a reason they say lube the stud and don't mention the bowl. I am not in anyway trying to say you don't know what you are doing. I am sure you know more about these Powerstrokes than I do. Just saying that I had a bad experience with this one time, and just trying to help out with information.

Just thinking out loud but what about if you put a little bit of oil in the thread holes as a cushion for the stud against the block. Yes it wouldn't havent no where to go but could potentially keep the stud from bottoming out and cracking the block.

sent from the stool.

That would be the last thing you would want to do. If you have a cushion, you will not get a proper torque. This can cause a lot of problems.

It's just a thin film on the stud threads. Shouldn't be dripping off making a mess.
Head gaskets go on a clean dry surface.
Pretty sure it's explained in the head gasket write up in the west point section.

I wasn't aware that is what the instructions say, but that is exactly right.

 

[Dzchey21]

When I did mine im sure I put oil on the stud. Most likely I dipped it in a quart jug of engine oil and then let the majority drip then installed it.


Maybe it's how the torque effect the block indirectly that effects the crack I don't know.

I always torque inside out on the studs. Maybe too large of increments makes the block flex?

I know when I did my cab on retorque I went from 190 to 250 then to 300 if I remember right. Maybe not even that gradual because it was such a pain to do.

I'm not sure what to really make all of this other than it might be a simple casting flaw

 

[AllanB]

Could be a casting flaw. First time I can remember thinking, I hope this is from human error.
I guess the only thing we can do at this point, is what we are doing here. Just keep adding info if anymore blocks come up with cracks, and try to find something, if anything that these would have in common.
Unfortunately I believe you are right, the problem is with the block.

 

[HD F250]

Trav-O, I am feeling for you brother. $hit sucks for real!!!

 

[tensixniner]

When I did mine im sure I put oil on the stud. Most likely I dipped it in a quart jug of engine oil and then let the majority drip then installed it.


Maybe it's how the torque effect the block indirectly that effects the crack I don't know.

I always torque inside out on the studs. Maybe too large of increments makes the block flex?

I know when I did my cab on retorque I went from 190 to 250 then to 300 if I remember right. Maybe not even that gradual because it was such a pain to do.

I'm not sure what to really make all of this other than it might be a simple casting flaw

Your torquing (ARP?) studs to 300 ft-lbs?

Elite/A1 torque spec is 195 ft-lbs.
Is the extra 105 ft-lbs needed?

 

[SEABEE08FX4]

If that were the case tho the crack would want to go up and down the block, not side to side as the hole would be wanting to expand outward, not downward, think of a big screw in a peice of wood without a pre-drilled hole

I see what your saying, I just haven't seen the crack so I was assuming it was a vertical crack not a horizontal crack.

 

[Dzchey21]

Your torquing (ARP?) studs to 300 ft-lbs?

Elite/A1 torque spec is 195 ft-lbs.
Is the extra 105 ft-lbs needed?

At 80psi of boost... Yes

Truck was puking did the re torque and that went away.

This time they are torqued to 325 ft lbs so far so good

 

[SEABEE08FX4]

I understand your theory behind doing it. But in my line of business it is general practice not to put anything in a threaded hole that a stud is going in and it will be torqued to proper spec. If you put it on the stud and run it in, the threads will get lubricated. By putting it on the stud this will push the oil out of the hole while turning it in, not into the hole.



Again I see your theory behind this, and you would think it would squeeze it all out. It is a long story, but I had a bad experience doing this one time. That is why I ask Golfer why he would put oil in the hole. Personally I would not chance it. When it starts to torque up you are not going to pass any fluid through the threads. I personally haven't read the instructions, but there is a reason they say lube the stud and don't mention the bowl. I am not in anyway trying to say you don't know what you are doing. I am sure you know more about these Powerstrokes than I do. Just saying that I had a bad experience with this one time, and just trying to help out with information.



That would be the last thing you would want to do. If you have a cushion, you will not get a proper torque. This can cause a lot of problems.



I wasn't aware that is what the instructions say, but that is exactly right.

Personally I would not use motor oil, but I was only commenting on that when I haven't gotten all the oil or coolant out of the stud holes before and when to screw the stud in that I could hear the fluid and air escaping. However I don't leave it in there when this happens, I will remove the stud and reclean the hole again.

 

[SEABEE08FX4]

If its possible casting flaw, I know the blocks were cast in Mexico but does anyone know if there was more than one foundry for them down there or were they all cast at the same foundry?

 

[Fast-6.0]

I've been considering this all day...

We have been filling the 7.3L blocks (even for street use, above 550-600hp) using HardBlok for over 6 years. We also coat the dried/cured HardBlok with an epoxy sealer to prevent coolant circulation from picking up any 'cement' and passing it through the pump/cooler.

The 7.3L blocks have a casting line that radiates from the cam journals...which is where most 7.3L block failures occur...leaving the main caps and crank sitting in the oil pan as an assembly.

The only downside has been the added weight. For 5+ years, we wouldn't recommend building a 600+hp 7.3L withOUT filling the block, unless our bedplate were used.

We have engines with over 100k miles on them that are filled to @ 2" below the block deck...used daily..towing, etc.

Looking at the '08 core engine, and the relationship b/w the casting line and the threaded portion of the block...it appears that the fill would have to be pretttty high to get above the casting (parting) line to gain block rigidity, and minimize/eliminate casting breakage.

Unfortunately, a 4130 pre-hardened steel bedplate (like the one we designed for the 7.3L) wouldn't add any rigidity to THAT part of the 6.4L block.

I will probably end up filling my 6.4L block...and as long as there is @ 2" of coolant circulating in the top of the water jackets...I don't anticipate any cooling issues, even for daily use.

same chit..different day (different engine platform )...

The problem is you will block off the water pump holes.

 

[golfer]

The problem is you will block off the water pump holes.

yep, unless you installed tubing there prior to filling...or drill them out.

same thing we do on the 7.3L.

 

[Fast-6.0]

yep, unless you installed tubing there prior to filling...or drill them out.

same thing we do on the 7.3L.

Good Call.

 

[golfer]

Tadd, if y'all do start doing fills

definitely give me a shout...we found some kind of epoxy chit to coat the dried HardBlok with which prevents chit in the system...clogged coolers, etc.

and a spin on coolant filter is recommended...jussst in case

but with good coolant passage prep, and proper curing (torque plate installed & main caps torques during dry time) ...annnnd the sealant...it's the way to go.

on the 7.3L blocks, we deburr/soften/feather the stress riser so the forces aren't focused on that one 'line'...but we still see quite a lot of inconsistency in the quality of the castings from block to block..some have lots of porosity, some have very little...

I imagine that we'll see something similar (inconsistent quality at the casting line) as we build more and more 6.4L's.

 

[White_monster]

Now you have me interested Dave. May have to send my bottom end out to you.

 

[AirFishAutomotive]

Have there been any block failures on stockish trucks or is it all studded trucks?

 

[gman1]

Have there been any block failures on stockish trucks or is it all studded trucks?

All the ones I know of were studded.