Cowboys Head Porting Endeavor

[Cowboy]

I blew my head gasket on my 12V'er over a month ago, and have been shaving away at the head since.  I'm not going to pretend like I know what I'm doing, I just want to document what I've done.  Some of these pictures arn't up to date, I'll update them as I get new ones.  Taking pictures of this stuff have proved to be challenging.

 

First things first.

 

Now, here's a look at the factories handy work.  Notice the difference between these two cylinders.  I can't do any worse than that!  Also note the horrendous lip around the inside of the valve seat blocking much needed air flow.  Plus there is an excess of material around the valve guide.

 

 

And a stock exhaust port.  In stock form they really arn't that bad, a slight lip around the inside of the valve seat, and the large area around the valve guide.

 

Here you can see the floor of the stock intake runner.

 

And then after some massaging.

 

And then for the actual port work, of which I'm not completely done..

Intake:

Exhaust:

I also did a number on the valves, including giving them some shine and grinding the seat width back to spec (1.5-2mm) mine were 2.5-3mm.

 

 

Edited December 3, 2015 by Cowboy

[The_Hammer]

Looks good man. Are you going to have the head resurfaced while it's off? 

[Cowboy]

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.  

[The_Hammer]

How many miles on the engine? 

 

[Cowboy]

228k

[Mopar1973Man]

Your still going to lap the valves right?

[The_Hammer]

28 minutes ago, Cowboy said:

228k

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

Edited December 3, 2015 by The_Hammer

[Cowboy]

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.

[CTcummins24V]

This is awesome!

[Cowboy]

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

Exhaust.

 

Intake

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

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

 

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

 

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 December 4, 2015 by Cowboy

[CSM]

What angles or techniques are you using for the valve job?

[Cowboy]

Nothing fancy, just the stock 30* intake, 45* exhaust.

[CSM]

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 December 4, 2015 by CSM

[Cowboy]

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.

 

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 December 5, 2015 by Cowboy

[CSM]

Very interesting info!  Do you have a lathe?

[Cowboy]

A vertical one yes, some people also refer to it as a drill press.  

[Vais01]

Personally I'd send it to a machine shop to inspect things like the head for cracks, the valve guides and clean the coolant galleries in the head etc. 

Nice work on the smoothing of the casting. 

[Cowboy]

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.

[TFaoro]

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?

[Vais01]

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 December 5, 2015 by Vais01