DIY Porting and Polishing

If this is in the wrong section feel free to move it.

Just thought I would give some tips to anyone wanting to do their own head work. It's not as hard as some people might think. I am sorry I don't have pictures but I will put them on here soon because I am doing a complete head job on my 4.0 that I am building.


Cleanliness is EVERYTHING. Get a good clean work area to do your head work on.

Get the right tools. A dremel or other similar rotory tool will work sufficiently. I use mostly air powered tools rather than electric because I find I have a greater control over the speed.(two to three prop. valves). You will need at least two carbide bits, and a selection of rotory stones. A flap wheel or two of different grits also. Standard abrasive has a DIY port and polish kit. But most of the stuff they send you you will not use unless you plan on doing this often. Go to NAPA or other jobber and get what you NEED.

Clean your head up really good before you start any work on it. Degrease everything and hit it with a steam pressure washer.

*If you are planning on shaving you head, do this AFTER you port and polish it. Two reasons. The head shaving job will take off any nicks that are on the surface if you happen to slip or if you scar the surface. And the machine shop will definitely be able to clean the head after their work much more better than you can.

Measure the amount of material that you can remove with a micrometer. You don't want to cut into an oil passage or head bolt hole.

These are just a few tips I have found out that work well when doing your own head work. The rest of the job is pretty standard. There is a link below that will help since it shows some good cutaway pictures. But the only way you can be good at this is to do it a lot of times. I started out doing my head work when I was about 13 or so. I began on four-wheeler heads with no previous knowledge of how to do head work and just learned from there. But believe me it took a lot of time to be able to do a quality fast head job. (haha don't read anything into that last part)

http://www.sa-motorsports.com/diyport.shtm

Good advice...which I plan to use once I get started on mine. I had been looking around locally for SA kit and had zero luck finding it. guess I'll buy the stuff individually as I need it.

I'm surprised to read that you feel a Dremel can get the job done. Just about everything I've seen so far says a Dremel isn't to the task.

A Dremel works by speed - an air grinder will produce more torque. Dremels are fine for metal work, where you do not have to remove much metal. If you are removing more material, an air tool is indicated.

However, for just cleaning up the port (without changing the shape, or cleaning up the "short side radius,") a Dremel should be just find.

As far as the abrasives proper go, if you cannot find them at Summit or Jegs, order a Cratex kit from Brownells (www.brownells.com.) They are not as aggressive an abrasive as the SA kit, and therefore would be more forgiving to the novice.

5-90

This is what it will look like when it's done.....



Well, crap.
This is the only picture of my porting and polishing I could find.
The head was done similarly, but with much more gusto and also around the valves.

FYI, this picture is of the manifold after gasket matching it and the head.

Nice job on the intake porting job. I put my I.M. inside a blast cabinet before I started on it. I had the pressure cranked way up and I used a really hard media (large grain sand) to clean up the inside of the manifold. I had taken some mic measurement before and after this and found that after blasting it the media had actually taken a small amount of the aluminum off. It wasnt a large amt but it would be cool if someone could have a high enough pressure and a hard enough media that they could actually hit the insides of aluminum manifolds and port it waayy deeper inside than with a long shank carbide tip. Just a little info and thoughts. Though I don't think the gains would be high enough to justify spending the money on a lot of media cmpd or taking the time to actually do it when larger intake manifold runners wouldnt do much for power. Just gasket matching the tips should be enough.

Try "extrude honing" - an abrasive slurry is forced, under pressure, in the direction of airflow. This results in a streamlining of airflow in the proper direction.

Port-matching the intake can be useful - but port-match the head ports, first. Otherwise, the intake work will be of limited or no benefit. Also, you'll want to go inward about four times the distance you clean up - take 1/16" off to make the port bigger, and go inward 1/4" to blend the new port into the runner. Ditto the cylinder head - abrupt changes are Hell on airflow.

I think SA Abrasives did a nice article on DIY porting as well - might have to Google for it again...

5-90

There's a link to the Standard Abrasives DIY head porting article on this page of my site:

http://www.jeep4.0performance.4mg.com/head.html

That page also has the write-up on my own head porting job.

5-90 said:

I think SA Abrasives did a nice article on DIY porting as well - might have to Google for it again...5-90

Click to expand...

Try clicking the link I put on the first post...

Don't forget the gasket! Will have tubular and sheet metal intake done in a week or so, I'll post pics...then its header time!

Just be careful on the inside radius where the floor of the port turns to the bowl area...blend carefully, do not cut metal out...this is the most critical area in a port, especially on the intake side...streamline the guide boss but don't cut it down except for a competition head...this will help the life of the valves and seats...the most gain is usually in the bowl...where the bottom of the seat blends into the bowl....and check the head carefully befor eyou go cutting...you may have to compromise if there is a lot of core shift...if any of the ports are a good bit off from the intake gasket...you have core shift.

Terd said:

Don't forget the gasket! Will have tubular and sheet metal intake done in a week or so, I'll post pics...then its header time!

Click to expand...

Dude I definitly want to see a sheet metal intake for a 4.0 NEVER have I seen that done. I've used them on big block fords and not only do they function great they look so darn badass. POST SOME PICS as soon as you finish.