Porting heads

Tarnx · Post by **Tarnx** » Wed Feb 13, 2002 11:30 pm

Started porting my heads today and already I have run into problems. One the air die grinder using coarse sanding drums is too agressive, so I turned down the air pressure. It works better now. How do you get in deep? I can't extend the mandrel far enough. Also the areas where you have to go in staight and grind from the point of the grinder are a problem as the sanding disks only grind on the side not the end.
Any help would be appreciated! Control is everything and it is harder than it looks.

Stripped66 · Post by **Stripped66** » Thu Feb 14, 2002 12:38 am

Some people have success with those long sanding rolls (they look like a thick piece of sandpaper than was been rolled into a tight role), they fit on a fairly long mandrel...about 3 inches? The diameter of the roll is also nice for cleaning up around the valve-guide bosses.

Tarnx · Post by **Tarnx** » Sat Feb 16, 2002 9:39 pm

Well the porting is going well. I couldn't get into some of the deeper parts of the head so I made a grinder extension. I took a 3/8x4 inch grade 5 bolt and turned one end to 1/4 inch and center drilled the other end with a 1/8 inch drill bit 1 inch deep. I then drilled and tapped two set screw holes at a right angle to the center of the shaft. Using a dremel tool 1/8 inch mandrel with 1/4 inch sanding drums, I can get way deep into the head. It works really well. The speed of the air die grinder is slowed down alot using a air pressure regulator. 40 to 60 lbs gives me the speed which is the most controllable. Full speed just eats the aluminum away too fast. Once I get done I will replace the valve guides and seats. Using your finger is the best way to see how things are going as every thing looks the same once the metal is scratched up.

Post by **sparkmaster1** » Sat Feb 16, 2002 10:05 pm

Since you have the guides out. Run a bead hone down the intakes for a nice swirl polish. Check you local Tool town or auto parts store for the right size. Tim

Marty · Post by **Marty** » Sat Feb 16, 2002 10:13 pm

I fully support anyone doing their own work and commend you all.
I feel a need to offer a little guidance here however. I see a LOT of people trying to do their own head work lately. There is a difference between a clean-up and porting. I have seen people post pictures of the "work" they have done. Some have been very nice, others have been butchered. Please take the time to study a little and read about heads and how they work and even practice on some junk heads before you all go hog wild. Get the right tools to do the job. Many people have been making their heads WORSE than they were when stock. I have been doing this stuff for 20 years and know just a little here. It is not as easy as it looks and bigger is NOT always better. Sometimes it is just better to go and pay someone who does this for a living and get something back that helps and not hurts you cars performance. I would like to see many fast VW's with happy owners and not frustrated people that use to own VW's.

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Marty Staggs

www.staggsracing.com

JD · Post by JD » Sat Feb 16, 2002 10:44 pm

Hey guys heres a link for 2 home built flow benchs. www.spiritone.com/~eoa/Cars/Flow_Bench/Flow_Bench.htm With a flow bench you can tell if your port and polish job is increaseing air flow or doin more harm than good.

Marty · Post by **Marty** » Sat Feb 16, 2002 11:19 pm

You also have to think about port velocity.
As I said - Bigger is not always better. Thats why they came out with Superflow 2's.

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Marty Staggs

www.staggsracing.com

Tarnx · Post by **Tarnx** » Sun Feb 17, 2002 10:53 pm

I believe blueprinting my heads is a more descriptive term. There is alot of casting marks and sand die bumps. Mostly I am just smoothing every thing out. I don't know where the thin parts in the castings are so I am being very conservative. There is major sharp ledge comming out of the exhaust valve port into the exhaust manifold opening. It has been rounded off. There is also a bump right before the exhaust valve guide on the inside which I have smoothed. The intake and exhaust ports will be matched to the manifolds. Today I tried using three abrasive cut offwheels on the mandrel at one time. Using only 40 lbs air pressure they were very controlable and didn't clog up. I could get in and under things I couldn't before. One head is done being ported. It will be polished with 150 grit on the intakes and 320 on the exhaust. The other head has a crack across the exhaust valve guide which means another head. It would probably be ok in a stock engine, but this engine will be tweaked.
With the springs, valves, guides, rocker arms etc, it is surprising how expensive a stock set of heads can be.
For those of you who port heads for a living I have developed a great deal of respect. It is a slow process requireing constant checking.

944vw · Post by **944vw** » Mon Feb 18, 2002 9:01 am

do yourself a favor and have an expert work on them it will save you in the long run,perfomance isn't cheap you already spent for the heads if your still not convinced at least get the right tools for the job.

JohnConnolly · Post by **JohnConnolly** » Mon Feb 18, 2002 1:40 pm

I ported one set of welded heads, and in that process learned enough about the job to make sure to PAY someone else to do it from then on!

John
Aircooled.net Inc.

tarnx · Post by **tarnx** » Mon Feb 18, 2002 11:55 pm

Since I am doing this as a learning experence and to save money so I can buy the engine of my dreams, I am just trying to share my experiences. This is just a little clean up porting. No critical diamensions are being adjusted. Basically the knife edges are being blended, the ports are being matched, and all the little blemishes are being smoothed. The heads are being smoothed out, not hogged out. This is for a small displacement low compression motor. You blue print your rods, crank, and block, why not the heads? As far as cost get someone else to do it as I have about four hours in each hole and they aren't even polished yet. A set of bonified ported and polished heads are cheap, compared to the time to do it your self, and you may not get any improvements.

delbert · Post by **delbert** » Tue Feb 19, 2002 12:50 pm

GOD guys give the guy some credit and tell him not to take out the bump in the inttake port. hes just smoothing them out a little(for the fith time)- I m porting my 3rd set of heads now and my first set on my little 1776 blew my friends 1914 away-w/his 40x35 vavles

Ed Brewer · Post by **Ed Brewer** » Tue Feb 19, 2002 2:37 pm

I'll have to say delbert is right. Nothing wrong with a little home brewed port cleanup. I have also done that to a set of stock heads with excellent results. Like he said, don't take out the bump on the intake port or you risk cutting a hole in the spring pocket. Take your time and have fun!

Marty · Post by **Marty** » Tue Feb 19, 2002 4:16 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by delbert:
GOD guys give the guy some credit and tell him not to take out the bump in the inttake port. hes just smoothing them out a little(for the fith time)- I m porting my 3rd set of heads now and my first set on my little 1776 blew my friends 1914 away-w/his 40x35 vavles<HR></BLOCKQUOTE>

Nobodys flaming here Delbert.
Simmer down.

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Marty Staggs

www.staggsracing.com

Tarnx · Post by **Tarnx** » Fri Feb 22, 2002 6:47 am

Since I found a crack in one head I had to get another. Making sure not to hit any critical edges I shot the ported head and the new head with a media blaster. All those lines in the ported head made it look like I was done. NOT. The uniform texture revealed some additional work was necessary. The guides and seats are still in the heads to protect things while I am porting. The bead blaster eats things uniformly so it is not a good choice to use to port with. One quick pass gave a uniform color which easily shows where to continue. You have to be very careful to miss any machined surfaces because the air will blow the media where you don't want it.