Just got my Street Dominator back.

[Nightmist66]

Don't forget the regulator on the air compressor.

[Yellow Truck]

An air die grinder can be had much cheaper, but you have to have the compressor. Sadly I just started up the electric one and it vibrates like mad - clearly not working correctly. May need to go use the shop air and buy an air grinder.

[TomP]

I have several die grinders but old trusty Makita electric is the one I always use. I put up with it's vibration, I don't like the noisy air ones with cold wind blowing aluminum chips in my face.
 I use the carbide burrs with really coarse teeth and they need a real gentle touch and will sometimes grab. The less aggressive burrs for steel work like BB says. I use the sanding rolls once the major material is removed.

[Qikbbstang]

I can't understand the going to fast as a problem. Re: (...Electric is just a switch and in my opinion is usually far to fast for anything..)
          High speed gives a very precise easy to control cut.  Just the lightest touch on aluminum and it cuts like and as smooth as butter.  Where as low rpm to me is made worse by the lack of power that makes the rpm's fluctuate badly with load. Varied RPM makes for jerking loads on the grinder.  You want to feel and see a mess use a 3,000rpm drill with a carbide burr.

                       Plenty of times I used the motor out of my 40 year old Black & Decker router to die grind (all use 1/4" collets) they are about 20,000 rpm and discharge vent air at the shaft. You just slide off the base.  I recently scored a like new Dewalt laminate trimmer from a pawn shop for $12. that also can be used for a die grinder and it also can be run w & w/o base.  The no Rolls Royce electric 1/4 Die Grinder from Harbor Freight is about $20.
 
http://www.ebay.com/sch/i.html?_odkw=laminate+trimmer&_osacat=0&_from=R40&_trksid=m570.l1313&_nkw=laminate+trimmer&_sacat=0

                   
       

[57 lima bean]

This stuff worked great....

http://www.eastwood.com/ew-grinders-grease-8-oz.html

[GJCAT427]

Being in the welding business I own a ton of grinders and sanders for fab and repair work. One of the best tools I have is a Dyna File belt sander. I use it in porting and polishing on alum, SST and good ole cast iron and steel. Smokey Yunik used the same tool in his shop. It has different ends and the belts come in a variety of grits so you can blend and polish to your hearts content.

[jayb]

As I mentioned everyone I know uses the air die grinders these days, but the electric grinders that I saw in use back in the 1980s were variable speed.  I remember talking to some people about those back then, and one of the attractions was that the grinders had a fairly large rotating mass, giving them a lot of inertia.  So you could slow the speed down, and if the bit caught in the work it wouldn't tend to stop like it does with an air grinder, it would just keep going because of the inertia of the electric motor.  So that made them easier to control at low speeds, which some of the guys doing the porting found to be useful.  I also remember seeing the electric motors hung up over the bench, with a flexible shaft on them down to the tool holder.  One of the issues with the electric grinders was that they were very heavy, so this was an attempt to make the grinder easier to handle at the point where the operator held it.

Also back then almost everyone was porting cast iron heads; very few aluminum heads were around.  It might be that as aluminum heads became more prevalent, the air grinders became easier to use and most people eventually made the switch.  Just guessing on that one...

[Yellow Truck]

Well, not having $800 lying around to buy a Dynafile (very nice tool), and not having an air compressor that will drive that kind of air (ruling out an air grinder as well), I sorted out the vibration on my old Makita and got a coarse carbide tip to cut back the aluminium. Since I'm not working the ports, just inside the plenum, I decided I could risk the more aggressive cutting head even though I am a complete novice. Here are two pictures of the work in progress. I have a question - is there any other material that should be removed from this area? I have not smoothed it yet.

[jayb]

That's exactly how you should do it.  Smooth out the grinding marks and radius the entry from the plenum into the runners, and you've got it - Jay

[Yellow Truck]

Thanks Jay, you guys are good teachers. I need to go pick up a porting kit to do the smoothing.

[plovett]

Thanks Jay, you guys are good teachers. I need to go pick up a porting kit to do the smoothing.

You can do the smoothing with your hand and sandpaper, too.  Aluminum is soft stuff.

JMO,

paulie

edit:  various files, or screwdrivers wrapped in sandpaper work, too.  Low tech and tedious?  Sure, but it works.  I find it relaxing.

[Qikbbstang]

Here's a Street Master I did after paying a lot of attention to intakes I looked at in PRI and elsewhere. You are kind of limited in how much you can remove from the top of the runners by the outside of the manifold

http://i807.photobucket.com/albums/yy359/qikbbstang/FESM1.jpg
I believe this is from an older engines masters winning Ford by Jon Kasse
http://i807.photobucket.com/albums/yy359/qikbbstang/engine%20masters%20BBF%20IntakeMan.jpg

[Yellow Truck]

I assume there is nothing to be gained by taking the dividers between the runners back. After reading your reply Jay, I took the roof of the runner where it meets the plenum back a bit to create a radius, there had been a bit of a hard corner there. I can take the top of the entry into the runners back a bit more if there is HP or torque to be gained. I am hoping to keep as much low end torque as I can. Not sure how much more makes for an improvement.

[jayb]

Taking the dividers back will shorten the runners and hurt low end torque, so I would leave them as is.  If you put a 1/2" or so radius from the plenum into the top of the runners, that should be sufficient to ease transition of the air/fuel mixture into the runners; probably don't need to go any further than that.

[Yellow Truck]

Thanks Jay. I'll get right on it.