broken world heads

[RL]

A couple holes with a drill, or better yet snap the piece off - a bit of cuttimg on the face may be required -.

[340king]

No matter what the cause is outside of a gasket thickness or torque issue, the weak part of the head has been found. Now the question might better be addressed as was this an isolated incident or is this just an early occurance due to the stress level? If you could cast in some fillets or gussets that run up the head face from the area outside of the bolt spot facing it might help. The W2 heads were changed in this manner some years ago to prevent the same thing from happening. The sharp angle formed by the bolt area to the head face is the stress riser that influenced this break. Any method to increase the material available to take the stress from the bolt boss up to the head face would be better. Even raised flat surfaced areas that run from the face to the deck bolt area would help, if this is a running stress related issue. By that I mean not a severe impact issue due to a tuning problem.

[LTD351T]

No matter what the cause is outside of a gasket thickness or torque issue, the weak part of the head has been found. Now the question might better be addressed as was this an isolated incident or is this just an early occurance due to the stress level? If you could cast in some fillets or gussets that run up the head face from the area outside of the bolt spot facing it might help. The W2 heads were changed in this manner some years ago to prevent the same thing from happening. The sharp angle formed by the bolt area to the head face is the stress riser that influenced this break. Any method to increase the material available to take the stress from the bolt boss up to the head face would be better. Even raised flat surfaced areas that run from the face to the deck bolt area would help, if this is a running stress related issue. By that I mean not a severe impact issue due to a tuning problem.

The water jacket area under the flat plate portions that join the bolt boss to the rest of the head are very spacious, extra material could easily be added with the outside of the casting remaining the same while still retaining more than ample coolant 'room'.

I wonder what a basic analysis using FEA would show, if a simple cross section profile was modeled, well I'm pretty sure what it would show, but it would be interesting none the less. It would also be interesting to know what level of analysis world products perform while developing a 'power adder' head like this one.

[john@bmp]

Look, guys...

This isn't the first set of these heads we sold.

This isn't the first time we've had people running boost.

This isn't the the first time someone made this kind of power with these heads.

However, this is the ONLY case where we had this kind of failure.

I just don't want this to turn into another urban legend of wide spread problems and faulty castings.

I'll be sitting down tomorrow to address this specifically. I don't know what the result is, and as I said earlier, I don't care. I just want to know next time this customer bolts up heads, it's the last time. That is my concern.

Maybe there was a casting issue, since the dates on the heads are 2 different production runs, and the earlier runs are the ones that broke, maybe not.

I just don't know yet.

In all sincerity I sincerely appreciate you guy's input as to what the problem was. I'm hoping it will trigger something or come up directly with a root cause. The biggest issue is I wasn't there, and none of us were, so we have to work with what we have. If we were all involved in the build, maybe we could have caught something.

This is an isolated case, a one time problem, and if we simply throw a need head at it, we'll never know. If that head breaks again, the rumor mill will start.

I promise, we are working on this. At this moment it has us stumped. We all know how hard it is to isolate a one time problem over something that is wide spread. Just give us a little time, I don't want this to get away from us.

[raynorshine]

Look, guys...

This isn't the first set of these heads we sold.

This isn't the first time we've had people running boost.

This isn't the the first time someone made this kind of power with these heads.

However, this is the ONLY case where we had this kind of failure.

I just don't want this to turn into another urban legend of wide spread problems and faulty castings.

I'll be sitting down tomorrow to address this specifically. I don't know what the result is, and as I said earlier, I don't care. I just want to know next time this customer bolts up heads, it's the last time. That is my concern.

Maybe there was a casting issue, since the dates on the heads are 2 different production runs, and the earlier runs are the ones that broke, maybe not.

I just don't know yet.

In all sincerity I sincerely appreciate you guy's input as to what the problem was. I'm hoping it will trigger something or come up directly with a root cause. The biggest issue is I wasn't there, and none of us were, so we have to work with what we have. If we were all involved in the build, maybe we could have caught something.

This is an isolated case, a one time problem, and if we simply throw a need head at it, we'll never know. If that head breaks again, the rumor mill will start.

I promise, we are working on this. At this moment it has us stumped. We all know how hard it is to isolate a one time problem over something that is wide spread. Just give us a little time, I don't want this to get away from us.

I was there!

[john@bmp]

I was there!

COOL! What happened?

[af2]

Ok I give!!!!!!!! I bought and ran a set of 220 Mowtown heads and they broke in the exact same place! The heads were from a JR Fuel rail and were pristine! Excellent porting but to get the weight down they ground the entire outer side of the heads. Well after the first year with water in it and a sub 22* night and or 2 the EXACT same thing happened. I now have a 100 watt bulb directly under the radiator/ engine and has been good for the last 5 years.

[340king]

Hey John I am cool with this process. I am a Mechanical Engineer and I was assessing the failure mode and offering some ideas for increasing the stiffness/stress capability in that area. No big deal. Like you said none of us, except raynorshine and the owner, were there. I was just looking at the material offered for examination and offered some critical evaluation. I was attempting to offer some help is all.

Sometimes all it takes is a little different perspective to catch a problem. I did just that for a factory snowmobile racer that was breaking jack shafts all the time. They were making them out of titanium when I got involved and they were still breaking. They were machining the step down from the bearing to the splined section with a nearly zero radius on the cut. I informed them to make the same shaft with a larger radius and see what happened. Problem solved. This was a factory team with technical support from the manufacturer, so it too was being "worked on."

[raynorshine]

I was there!

COOL! What happened?

Not much to report, blew up in waterbox doing burnout, no pass....apparently this was the 2nd time, the other head had also split during burnout

[john@bmp]

I was there!

COOL! What happened?

Not much to report, blew up in waterbox doing burnout, no pass....apparently this was the 2nd time, the other head had also split during burnout

Now we just have to figure out why. If I were convinced this were a defective head I'd have one out tomorrow. This is the only engine that ever did this. Something's missing something I need to figure out, we're overlooking something. To just throw parts at it isn't going to solve the problem.

FWIW, the samples we took from the head are on the way to the foundry for evaluation as we speak.

[john@bmp]

Hey John I am cool with this process. I am a Mechanical Engineer and I was assessing the failure mode and offering some ideas for increasing the stiffness/stress capability in that area. No big deal. Like you said none of us, except raynorshine and the owner, were there. I was just looking at the material offered for examination and offered some critical evaluation. I was attempting to offer some help is all.

Sometimes all it takes is a little different perspective to catch a problem. I did just that for a factory snowmobile racer that was breaking jack shafts all the time. They were making them out of titanium when I got involved and they were still breaking. They were machining the step down from the bearing to the splined section with a nearly zero radius on the cut. I informed them to make the same shaft with a larger radius and see what happened. Problem solved. This was a factory team with technical support from the manufacturer, so it too was being "worked on."

I appreciate everyone's input. Hope I didn't give you the impression otherwise.

[revolutionary]

I still haven't heard any response about how much of the oring was protruding. Obviously there was no receiver groove in the heads. Torquing the heads on both sides of something sticking up in the middle is gonna put some big stress on there. Add in a tuning issue/detonation and there's your breaking point.

[LTD351T]

I still haven't heard any response about how much of the oring was protruding. Obviously there was no receiver groove in the heads. Torquing the heads on both sides of something sticking up in the middle is gonna put some big stress on there. Add in a tuning issue/detonation and there's your breaking point.

He may have been using SCE copper gaskets that do not require o ring or receiver groove??

I believe SCE used to make gaskets for these heads but I no longer see the part listed.

[Kevin Johnson]

The straight witness mark on the outer border of the block side of the head has been mentioned and I agree that it is important and needs to be explained.

Some possibilities include:

At some point a standard gasket (versus Man O War) was run and weakened the castings which subsequently failed even with the correct gasket in place. The additional outer bolts would use the normal gasket border as a fulcrum.

Angle milling was employed that on a standard Windsor head would be of sufficient depth but in this case was incrementally too shallow because of the effectively wider Man O War head. The angle generated would need to be very shallow in order to also allow a witness mark (present) around the outer bolt holes. If a solid copper head gasket was not used in this situation the gasket might have yielded sufficiently.

It might be (?) that the correct gasket normally leaves this witness mark.

DSCF1377Medium.jpg

[avengerengines]

The straight witness mark on the outer border of the block side of the head has been mentioned and I agree that it is important and needs to be explained.

Some possibilities include:

At some point a standard gasket (versus Man O War) was run and weakened the castings which subsequently failed even with the correct gasket in place. The additional outer bolts would use the normal gasket border as a fulcrum.

Angle milling was employed that on a standard Windsor head would be of sufficient depth but in this case was incrementally too shallow because of the effectively wider Man O War head. The angle generated would need to be very shallow in order to also allow a witness mark (present) around the outer bolt holes. If a solid copper head gasket was not used in this situation the gasket might have yielded sufficiently.

It might be (?) that the correct gasket normally leaves this witness mark.

DSCF1377Medium.jpg

We're all just guessing on this, My guess is in agreement with you. I still think it looks like the crack started with tightening the studs and possibly with the wrong gaskets.