An Amateurs Guide to Porting a 12 Valve Cummins Cylinder Head: Tips, Tricks, Cutaway's, and Examples

Heres an older video that I had made up but never fully got around to finishing up until now :) I'd like to revisit this another time with a more methodical and step by step process, at the time of filming I was just tackling the port job head first and seeing where I could go! I hope that some of the things I show in the video give you insight into what you can do when porting your 12 valve cylinder head
Feel free to ask any questions in the comments below, or if you're more experienced in cylinder head porting i'd love to hear your take on what could be done to improve things!
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[@V8Lenny]

Swirl is not for streetability, it is for power. Take that swirl ramp out and you get more smoke and less power.

[@FatBoy7.3Powerstroke]

I subscribed to your channel for the sheer fact you present confidence in something that doesn’t offer much information on many youtube channels. That’s awesome and I can appreciate your efforts and patience. I’m porting a set of 7.3 Powerstroke heads, mostly on the exhaust side I’m gasket matching them and with the particular design, I’ve been able to pick up 3/16” from the stock 1.5” port. In a 7.3 Powerstroke cylinder hear the intake and exhaust valves are the same size which is 1.675”. I’m looking mostly to lower EGTs for durability and possibly improving efficiency by a slight amount. After opening the 1.5” exhaust port another 3/16” it is very close to 1.675-1.680, very relative to the valve size. I’m still in the painstakingly time consuming part of this process, but I do anticipate seeing a significant reduction in back pressure and a faster transfer of heat out of the combustion chamber. I’ll try to have some more information on the intake side once I get to that section of the head. Operating off Boost, I believe opening up some of the restrictions in the intake ports and upsizing the valves to the 1.80 - 1.90” area along with 45 degree cut valve and valve seats will allow more CFM. It will be a very tight fit but for this particular application on a 7.3 Powerstroke I see quite a bit of room for improvement. I’m Definitely going to have my clearances checked before taking major steps away from original engineering, but if my calculations are correct, I’ll increase airflow quite a bit. I’ll know more in the future. Keep up the good work man, there’s not much out here about diesel head and port work, So I know I sure appreciate videos like this one.

[@MrAVA700]

Awesome job, waiting for om606 project

[@Hazardous-Hotrod-Knowledge]

I’ve been thinking about adding a S366 to my Om606 daily, would be a cool fabrication video to show!

[@MrAVA700]

@@Hazardous-Hotrod-Knowledge please do that

[@dbfabworks5320]

Very Nice!!! Love the How To tech, not much info out on what material can be removed. Keep it up!!!!

[@Hazardous-Hotrod-Knowledge]

Thanks! I wish I had more info on advanced porting and what to do, maybe I’ll revisit this in the future but at least it gives a guy a little guideline on what he can do!

[@jordanmotz3235]

Good to know. I remember I bought a jetta off of you a few years back and it promptly blew up on me. Either way, nice to find a familiar face

[@Hazardous-Hotrod-Knowledge]

Was that the rat rod MK2? I sold that car with a broken timing belt and needing a engine, was it you that put the new one in and then it blew up again? Haha! Cancel Reply

[@elroyelblander6277]

👍👍...Ive got a couple extra head's lying around here, 6B and Isb...like most do, im sure... time permitting, might have to try something like this myself someday, just to see what happens 😂.... thanks for all your time and videos 👍👊🤘

[@Hazardous-Hotrod-Knowledge]

Go for it! It’s time consuming… and messy!

[@willrb1997]

I got a bit carried away a couple times from this job taking me so long that i cut too much of the valve seat away in a couple spots 😅😅

[@buckshot927tx]

I’d like to see the before and after flow difference of doing this. Just wondering if it’s worth it or not. Same question applies to my OM602 and 603 projects!

[@Hazardous-Hotrod-Knowledge]

So I’ve been watching more videos on porting (from Eric Weingarter and David Vizard) and how I opened up around the valve opening was wrong to do, it’s better to have a radius, so I may have actually hurt flow. I’ll have to make another video revisiting head porting and use the new knowledge!

[@Hazardous-Hotrod-Knowledge]

I think with the 602 and 603 they’re more limited by the connecting rods than the cylinder head flow, but more flow is always worth it! I don’t know what the stock valve size is but if you can fit a bigger valve that would be my first thing to look at

[@palmersperformance7117]

Unshrouding the chamber side helps flow at all lifts, think about it, air runs into a wall for the first couple hundred thousands of lift.

[@ChaosViper67]

Hey sorry about the disappearing messages. I don't know what's going on with my Instagram, I've never messed with the settings and I didn't see any to change anything. I was just wondering how much timing in that rev video.

[@Hazardous-Hotrod-Knowledge]

Hey there, I updated my IG and it fixed things! If the rev video is my p pumped 6.7, I honestly have zero idea where timing is at, if it’s the p pump 24v, then that truck was set at 30

[@jamesbaker429]

Shows how appallingly bad the standard head is ,small , shrouded and jagged cast and flash it works inspite of factory ,great care with a diesel head for substantial power gain.

[@Hazardous-Hotrod-Knowledge]

Totally! They’re like 140cfm max from the factory… on a 5.9L engine! Needs to be like 230cfm. Granted, these engines only were “designed” to make 160hp new and peak torque was meant to be at 1800rpm or so so the port is “correctly sized”. They left a lot of room for improvements

[@jamesbaker429]

Its your time or big bucks paying someone else to do the same ,they may be better then you but may not on more unusual porting with a squashed half port from factory any increase in flow very desirable.

[@Hazardous-Hotrod-Knowledge]

Yeah it’s definitely a little different style of a port with having the swirl ramp and the intake plenum, some people like to retain the swirl ramp while others get rid of it for max flow. There’s a good bit of meat you can remove to help stuff out, but the overall design to begin with isn’t the greatest