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Cowboys Head Porting Endeavor


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Don't plan on it as everything is well within spec.  Cummins allows for .012" warpage, and it's got .004".

 

Also I recorded the before, so once I get this thing back together we are going to SEE the difference it made. :hyper: 

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1 hour ago, The_Hammer said:

I've got just under 300k on mine, hopefully it will be in spec when I finally replace the head gasket and stud it. 

Who knows, but I'm rooting for ya!  I'll know more once I get this head on.  But even if you don't plan on porting, I would be really tempted to get rid of the lip on the inside of the valve seat.  It takes maybe an hour, should give good results.  The burrs cost $10 a piece and you can use a dremel or an air/electric die grinder.

 

1 hour ago, Mopar1973Man said:

Your still going to lap the valves right?

You bet!  In all that porting, I only nicked one seat and that was in the first 10 minutes and was ever so small it came out with the little lapping I did before grinding the valves.

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Got some more pics.  This is the head as-is, basically finished just needs some small work and a bath.

Exhaust.

screenshot_79.jpg

 

Intake

screenshot_80.jpg

Ground down the big hump in the intake plenum, not sure if the 24V's have the same one?

screenshot_81.jpg

Ground these down some, as the one sticks straight into the flow path coming in the intake horn.

screenshot_82.jpg

 

Also drilled/tapped the inlet to #1 and #6 cylinders to see if they truly are "starving" for air.

screenshot_83.jpg

 

I just wanted to mention.  These 12V's are picky about the amount of swirl in the intake port.  It's well known that hamilton's competition 12 valve head is pretty bad down low, on paper and a flow bench it flows equally or better even at low lift.  The main difference is the swirl.  At low RPM's there is lower velocity through the port and hence lower swirl which makes it smokier down low.

Edited by Cowboy
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I remember reading something about the majority of heat in the valve should go through the seat, not the stem.  Looks good!  Should be interesting to see what happens.  I assume you are doing a gasket match on the exhaust to manifold as well.  

Are you doing anything to the chambers?  Cleaning up anything or modifying anything?  

On another note, from here, it looks like the ports are too highly polished.  At least on my gasser experience, you are looking for a somewhat coarse feel to the ports... Kind of a medium grit cartridge wheel finish.  

Edited by CSM
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You are correct about the valves and heat.  That's why I was surprised to see that Cummins had a maximum spec as well.  As for what I did, I got the idea from Will @ PowerDriveDiesel,  that's  what he did on his junker back in 2013, and he's been running 800hp+ for a while without problems that I know of, and he has an aftermarket cam which likely has a longer duration than stock.

Here's the link to his valve job.  http://www.competitiondiesel.com/forums/showpost.php?p=2181807&postcount=1449

 

As far as chambers, no, I unshrouded the valves some and that's it.

screenshot_84.jpg

 

Again, I'm not going to pretend like I know what I'm doing, but I believe the course finish is a gasser thing to keep the fuel suspended in the air.  On a diesel it's only air so it shouldn't matter in my thinking.

About the gasket matching, I don't plan on doing any.  The smaller the volume between the exhaust valve and the turbo the better.  The exhaust pulses stay stronger and help a lot at low RPM, that's a large reason for divided manifolds/turbine housings.  I am going to make sure the exhaust manifold ports are the same size or bigger in every way.  I don't want it stepping down into the manifold.

Edited by Cowboy
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I know that's what should happen, and I recommend other to do it.  But I have no idea where I would even take it, by the time I drove how many miles and paid them, I'm willing to risk it.  So far I have $29 into a fel-pro improved design head gasket.

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On 12/3/2015, 9:16:43, Cowboy said:

You bet!  In all that porting, I only nicked one seat and that was in the first 10 minutes and was ever so small it came out with the little lapping I did before grinding the valves.

You are lapping after the valve grind, correct?

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2 hours ago, Cowboy said:

I know that's what should happen, and I recommend other to do it.  But I have no idea where I would even take it, by the time I drove how many miles and paid them, I'm willing to risk it.  So far I have $29 into a fel-pro improved design head gasket.

So what's improved on the Fel-pro gasket?

Edited by Vais01
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