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Sun Oct 18, 2015 3:08 pm

What are some good resources for polishing and porting VW heads? Can you give me some good examples for how to polish and port at home? Thank you in advance.

Sun Oct 18, 2015 3:43 pm

I don't think anyone polishes anymore. That's an old-school term nowadays... IMO, the only home port job that anyone could do succesfully is a very light smoothing-out of the intake tract. You could blend the seats into the port, and remove the rough casting finish from top to bottom. I doubt you could do harm by performing that light modest port job. Also, consider it a waste to do any porting besides blending the seats, if you don't remove the guides. There are no shortcuts. All porters do their heads bare, and then install the guides.

Sun Oct 18, 2015 4:41 pm

yes some still polish, yes you can do a lot with the guides still in. as far as what to do. if you have all the stuff to do it you can do a full race port work at home...... the location of the heads has little to do with it....if any. I seen many heads that had a mild port job but a "diy exspert" and the heads were now junk. so..... as far as books...non of the vw books for sure. but you can get some od david vizzards books(he has many, not just on heads) just remember the head dosent know wtf it is. and farther more the head dosent know it isant a vett head, or mustang head. so...... if it works on a chevy or ford or mopar head....toyota too yes it will work on a vw head.

Sun Oct 18, 2015 10:13 pm

Polishing is a way of seeing every mm of combustion chamber get even.

Your in Sacramento too! Gerolomy Engines in Fair oaks has a flow bench fyi.

This is my Mofoco 050 after I smoothed and polished the chambers. Some will say it doesn't make a difference, but I had these flowed before my polishing work and there at Gerolomy's now being flowed again after I completed them just to see.

Jeff

Mon Oct 19, 2015 12:47 am

I not only polish the combustion chambers but I also polish the valves and piston tops. It will reduce the amount of heat picked up by the pistons, cylinder heads, and valves and makes it more difficult for the carbon to build up. Just how much? Not sure. But after 25,000 miles there wasn't much carbon in the chambers or on the piston tops. Figure it this way, polishing the combustion chambers and piston tops won't hurt anything and might help it. Plus it looks cool.

The book How to Hot Rod VW Engines had some basic porting how to information.

But unless you have a flow bench and air velocity probes you could do more harm than good with anything but the mildest of porting. Generally you want to maintain the same cross-sectional area inside the ports. Blending the area underneath the seats may be the most productive thing to do. Polishing inside the ports is probably not worth the effort as it isn't likely to in increase the airflow very much.

Match porting the intake manifolds to the cylinder heads is also a good idea and worth the effort.

If you need to reduce your compression ratio, opening the combustion chambers and making sure the chamber volumes are all equal is probably the best way to do it.

Increasing the deck clearance to lower the compression ratio is generally considered poor idea.

Use the smallest deck clearance that your crankshaft and rods will allow. A stiffer counterweighted crankshaft will allow a smaller deck clearance.

Scott Novak

Mon Oct 19, 2015 4:31 am

Dont take it wrong guys but what a waste of time , i would rather put effort where its needed , 1 week of running and your polish job looks like crap . im all for spending time on something thats gonna help but not there .. no way ..

Mon Oct 19, 2015 10:10 am

raul arrese wrote: Dont take it wrong guys but what a waste of time , i would rather put effort where its needed , 1 week of running and your polish job looks like crap . im all for spending time on something thats gonna help but not there .. no way ..

Actually, 25,000 miles later and it still looks smoother than the typical head with less carbon buildup. A small improvement perhaps. But every little bit helps.

Not to mention that the process of polishing the valves rounds off the sharp edges.

Scott Novak

Mon Oct 19, 2015 10:17 am

well im all for removing sharp edges but polishing to that degree , not me ...

Mon Oct 19, 2015 1:30 pm

Scott Novak wrote: raul arrese wrote: Dont take it wrong guys but what a waste of time , i would rather put effort where its needed , 1 week of running and your polish job looks like crap . im all for spending time on something thats gonna help but not there .. no way ..

Actually, 25,000 miles later and it still looks smoother than the typical head with less carbon buildup. A small improvement perhaps. But every little bit helps.

Not to mention that the process of polishing the valves rounds off the sharp edges.

Scott Novak so you want all the shap edges off all the valves??

Mon Oct 19, 2015 1:46 pm

What I am about to tell you is the best info you will ever get if your new to porting heads. If you are not an experienced head machinist, absolutely stay away from carbide cutting bits to begin with! Get yourself a port and polish kit with sandpaper rolls from Summit or Jegs or Grainger. It will come in a little plastic box with several augers and a bunch of rolls. You can destroy a head in seconds with a carbide or metal cutting bit. I am not trying to be a smart butt at all so please don't take what I said the wrong way. I started years ago with dull sandpaper rolls as the old man who trained me instructed. Once you get the feel for it and learn what you can and can't do you can get comfortable with a carbide or cobalt cutting bit. As far as tips on how to do it. I recommend using the stock gasket, (get yourself some machinist die, it comes in a little can that looks like a pipe cement can) use some machinist die and trace it out on the head and then on the intake your using. Scribe around the outside edges with a sharp metal scribe or sharpened small punch. Then take your time just getting the entry matched to the scribe marks. Do not go any deeper than a 1/2" into the port here. When your matched up and everything looks good, you slowly start blending it into the rest of the port, this doesn't take much area to do but you do not want a sharp step either. Also keep your roll slanted to where you take most of the material out on the edge, you do not want to dig a ridge into the port at the end of your paper roll. Then just make everything in the intake port nice and smooth but not polished. Leave the intake side the grit of the sandpaper rolls. You can however polish the exhaust side out with some rouge if you want. Just take super small steps and watch how just small movements change the port. Make good sweeping smooth movements, never stay in one spot long unless removing an imperfection or casting knot. I hope I have helped a little.

Mon Oct 19, 2015 2:12 pm

mark tucker wrote: Scott Novak wrote: raul arrese wrote: Dont take it wrong guys but what a waste of time , i would rather put effort where its needed , 1 week of running and your polish job looks like crap . im all for spending time on something thats gonna help but not there .. no way ..

Actually, 25,000 miles later and it still looks smoother than the typical head with less carbon buildup. A small improvement perhaps. But every little bit helps.

Not to mention that the process of polishing the valves rounds off the sharp edges.

Scott Novak so you want all the shap edges off all the valves??

Yes , right where it seats ......

Mon Oct 19, 2015 4:33 pm

Plus polishing the chambers helps eliminate detonation. Sharp edges and rises are key areas prone to detonation.

Mon Oct 19, 2015 6:15 pm

Bodacious wrote: Plus polishing the chambers helps eliminate detonation. Sharp edges and rises are key areas prone to detonation.

Yes very true!
The cartridge roll kit that you mentioned is also great recommendation. I use this with a High speed electric rotary grinder but I put the rotary grinder on a variable speed drive(harbor freight $15).

Jeff

Mon Oct 19, 2015 7:38 pm

keep a sharp edge on the intake valve margin/face in the chamber. rounded on the ex margin

Tue Oct 20, 2015 2:34 pm

This is a pic of what Marc is telling you. This shows the area on the valve where it makes contact with the head and it's seat. https://images.search.yahoo.com/search/images?p=in...r2=piv-web

Tue Oct 20, 2015 3:19 pm

I really depends what you want from the motor and what Cam/Carbs/CC you are running.

For a stock 1600 in a daily runner or bus, I do the following.

Intake matching (inlet manifold to head) as described by a poster above. Clean up any casting marks in the ports and smooth entry to the back of the seat. Back cut the inlet valve and get a decent 3 angle seat cut on both inlet and exhaust (60/45/30). Leave the exhaust port as is, just clean off any carbon build up.

Going beyond this will mean taking out the guides.

DO NOT GRIND THE NUB IN THE INLET, THIS IS THE BASE OF THE SPRING SEAT.

Tue Oct 20, 2015 4:58 pm

Bodacious wrote: If you are not an experienced head machinist, absolutely stay away from carbide cutting bits to begin with!

All you need is a steady hand. I can cut opal and tigereye. Using a flexible shaft grinder is no big deal.

But to insure that I don't damage the seating surface for the cylinders I bent 1/4" square copper into rounds that fit into the cylinder heads.

I'm not about to do much more than a bit of cleanup on the heads without a flowbench. I will match port intake manifolds.

Scott Novak

Tue Oct 20, 2015 6:13 pm

Since discovering 1/8 shank carbide wood carving burrs I can port stock valve heads without removing the guides! And that should also help illustrate how little metal actually needs to be removed.
Many heads the ports would benefit from being filled in.

"Port and polish" is an old term and I think it's fine to call it that, but today the only thing that gets polished is the exhaust port.

Tue Oct 20, 2015 6:39 pm

I once knew a guy that made a good living by specializing in port/polish jobs for 5.0 ford motors. People would wait months and pay over $2k (not including the actual heads) to have him do them. Moral? Done right is worth the money because someone that knows what they are doing and does it right will make more HP without sacrificing longevity.

Wed Oct 21, 2015 5:00 pm

Scott Novak wrote: Bodacious wrote: If you are not an experienced head machinist, absolutely stay away from carbide cutting bits to begin with!

All you need is a steady hand. I can cut opal and tigereye. Using a flexible shaft grinder is no big deal.

But to insure that I don't damage the seating surface for the cylinders I bent 1/4" square copper into rounds that fit into the cylinder heads.

I'm not about to do much more than a bit of cleanup on the heads without a flowbench. I will match port intake manifolds.

Scott Novak
I agree Scott, but you take a 17 year old young man who has never used any power tools and a mix of good old YouTube "hold my bear". You could possibly have bought yourself a ticket to the head shop to have them fixed or at the very least an unbalanced port. I meant no offense to the people out there that know how to run a grinder. I was just iterating how much material a carbide will take if your new to the game. And it's a heck of a lot harder to put the aluminum back in right than it is to take it out. Cast iron is a whole other story lol.