Polish and port try 1

[SilverXJ]

I used my old 0331 head to try my hand at polish and porting before I hit my 0630 that will be going on the engine. Basically I wanted to get a feel for the different bits and try it before I go mucking up the 0630. Lets take a look at the pics (click to make larger).

Intake:






Exhaust:




Combustion chamber close up:


A few comparing before and after:






I started at 5 and finished around 8. I went from a carbide burr, to the grinding stone, then to the 40 grit rolls, then to the 80 grit rolls, then finally to the cross buffs. I didn't really care that much about hitting the valve seats and I did a few times, but I will be careful on the real deal. I found that the carbide bits cut really fast... i made the mistake of attempting to unshroud the exhaust valve with one, that is why it is so lumpy looking. I didn't have my manifold gasket with me so I just went off of the marks form the original gasket. Not sure if I will open up the intake that much or not on the final one. Neither of the ports are actually polished, only the combustion chamber, which I know requires a bit more work. Also, there are a few bits in the runners that I would like to make a bit smoother. I will also be putting dowel in the valve guides to protect them and using old valves on the combustion chamber polishing. I did encounter a problem with the cross buffs... they won't fit in the exhaust port.. its just too big.. suggestion on that?

So, whats the verdict? Am I on the right track? Where do I need to put more effort in?

Oh yeah.. any one have a pair of valves that I could use to protect the valve seats?

-Chris

[Flash]

Looks good to me, for a first time attempt. A couple of suggestions.......

Don't try to do your porting, when your in a hurry, you could remove too much metal in the Wrong Spot

You should be trying to round and smooth the ports(Note enlarging the port) nothing works better then you finger........Which you have probably already figured out

OK, one more, When your trying to smooth the radius or rounding from the seat down.........light, carful pressure. And after you have made a sweep across, wipe the suffice with you finger. Removes the shine off from the suffice so the next swipe, you can see how close you got next to that "dangerous" valve seat area, you can see which angle you need to get closer too, or farther away, to make it round off


Flash

[SilverXJ]

This wasn't 100% effort and i didn't take my time 100%.. but I didn't rush through it either. I'm really glad that DC was thoughtful enough to give me this POS 0331 head to practice with. Now I know where i can improve and that the carbide cutter will not be used on the combustion chamber... it cuts a bit quick.


Looking over it again one problem I encountered was on the exhaust port right under the valve.. there is a fairly deep ridge that I thought I would have to cut too much and create a rather deep surface.

[Flash]

Sound like you got you mind rapped around it!

Flash

[John]

Concentrate on smoothing the surface, not grinding material away, the biggest gains are in the pocket under the valve. Flash commented on the use of your finger as a guide and to wipe the shine as you go. If you haven't seen this link, it might be worth a read, http://www.chevyhiperformance.com/techa ... index.html What are you using to run your cutters and abrasives, Air, electric , most try to run too darn fast and make the bits prone to chatter.
John

[SilverXJ]

I have seen that site and read it several times.. along with the SA link. I'm using an air grinder cut down to around 10,000-12,000 RPM via a regulator set at iirc 50 psi.

[John]

The air powered die grinder set 40-50 psi works well, and tends to chatter less than the electric ones, they are more apt to slow or stall when being crowded where the electric will bounce. I use both kinds depending where and on what I am working. Sounds like you are on the path.
John