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6.5 carnage

I push this motor hard, but water temps and egt were kept in the "safe" zone. Full crosshatch and no scuffing in the bores.
 
It doesn’t need to be pushed real hard for this to happen. This is a super common issue. Exactly the reason @Twisted Steel Performance did his ‘steam port coolant flow manifold’ thing in the valley- instead of no coolant flow at all there, hence the term steam port- he tapped all the plugs where the brass insert tube would go in. Chris- did you add the tubes in yours just as precaution or just replace the push in freeze plugs by fittings after tapping the holes?

Either way is an improvement imo.
Now coolant can flow through them regardless of how fast or slow - from factory it just gets some coolant there and has no where to go.
I was taking about adding brass tubes to mine even if it didn’t have any cracking yet because I know eventually they almost all get it. I seriously can’t remember a 6.2/6.5 with 150k or more pulled apart that didn’t have it. But I was just thinking of 8 tiny ball valves or a small pipe sticking out- then bleeding off coolant in each to ensure no trapped air. But Chris told me he was a step ahead (as usual I have learned) and was planning a hose from all 8 to a manifold where one exit hose would cause circulation.
But since all 9 hoses are same size, only a tiny amount could ever flow through them all. So it eliminates the possibility of being a “steam pocket” which is how they most likely crack.

Those steam pocket is the reason I bought that mightyvac 4525- instead of filling the coolant the normal way, you pull the coolant system into a vacuum- then the vacuum draws coolant into the system and SHOULD fill all the voids. This is the only way to do some exotic cars along with a couple odd ball mass production engines. Otherwise they overheat immediately.
When War Wagon was trying to get 1 good set of take off heads from all the dismantled 6.5s from Boyce motors- they said they had pallets of heads and went through all of them- every single military take out head was cracked. I thought they were just shafting him- called a cousin who lived within 100 miles from there in Utah and had him swing by. Seriously hundreds of heads- every single one had at least one crack.

Chris’ steam pocket manifold is experimental and therefore unproven- so can’t be fairly recommended, but I am 100% doing it to my heads wether I stick to the current optimizer heads or if I can figure a way to finance a set of p400 heads. Even if a person decides they don’t want to introduce flow all the time- you can have the fitting there and bleed away the air every time you refill the coolant system.

I’m gonna add some links in a following post
 
Here is the cut apart head - and who did this work? @Twisted Steel Performance did it- Chris- maybe add your steam pocket manifold pics to that post showing future readers what your solution is on that other thread? And maybe a cooler name than whatever I keep rambling off? Haha


Whoever “villy m.” Is that made this video- they are awesome. Shows exactly what to do to add the brass tube. Read the comments below video- villy says dimensions required, and another person gives a kit number for it. Somewhere on this forum I posted a different kit for sale from a different company. But sourcing the tube, drill bit and tap yourself would be far less expensive. Because the brass is far softer and will deform way before it does the iron head.

milling a perfect set of heads shouldn’t be required from just inserting tubes, however check for straightness always and mill whenever required is engine building 101. Even when a guy is flat broke- doing the sandpaper on glass thing is an option when a head isn’t straight- they must be milled somehow.

 
I push this motor hard, but water temps and egt were kept in the "safe" zone. Full crosshatch and no scuffing in the bores.

Contrary to popular belief, "seeing crosshatch" means nothing, the cylinders are still wore smooth and the bite the rings need is gone, at least ball hone them with 400gt.
 
Because there is a coolant passage between the valve openings in the head to help keep the seat area between the valves cool. When the head cracks between the valves, it cracks into that coolant passage. Thus when running, the compression leaks into the cooling system because compression presure is well past 400psi while cooling system pressure is 15psi. After shutdown, the hot, pressurized coolant seeps through the cracks and into those depressurized cylinders and gives you the white, billowing, acrid-sweet smelling clouds out the tailpipe at cold start up that screams "blown head gasket or cracked heads".
Ohh ok, thanks!
 
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