How To: Mild Port on 4G63 Head (w/ results)

[sleepyvr4]

A friend of mine recently went to Wyotec for chassis fab, and while there he got the chance to port a 4g63 head and flowbench it. His results are here:

http://dsmtuners.com/forums/showthread.php?t=170275

Well, I was having my head freshened up at the machine shop, so he decided he wanted to do some port work on it for me while the valves and everything were out.

The tools required are simple, and the time involved was minimal (4-5 hours total).

I was curious what he was going to port, and when I brought him my head he showed me a couple of things.

First, he showed me casting flaws. He was impressed with how they were less pronounced on my gvr4 head than the TEL heads he had seen and worked on.

Here's some parts of the head if you didn't know:

Then he showed me how there was a lip in the bowls, which hurts airflow on the intake side.

With valves/springs/retainers back in, exhaust polished w/ a 60 grit cartridge:

And finally, the finished product: /ubbthreads/images/graemlins/applause.gif

/ubbthreads/images/graemlins/uhh.gif

 

[Ian M]

I did basically the same thing to my head. The valve bowl areas were ROUGH.

Reading flow bench articles in some of the V8 magazines showing improvements gained by mild changes such as valve bowl work,nice performance valves,and a multi-angle valve job,I was inspired. I wanted to keep what I did mild,seeing cases (Nate Pharr back in the day for one) how ported and supposed better flowing heads have actually made a 4g63 SLOWER.

I had to replace valves,and Si valves were very affordable ($10 ea) so I also tried their competition SS valves seeing how low-lift flow was improved with good valves (undercut stems,more streamlined shape under valve) on some of the V8 heads I have seen tested. I had a machinist friend do a 5-angle valve job. A old budget v8 trick is to put a big (I dont remember what the degree) backcut on the bottom side of the stock valve to mimic the better flowing shape of a performance valve,I might have tried that if mine were good.

Yes,I know guys have gone 9's on totally stock heads. Whether or not what I did actually helped Ill never know,but my car runs pretty damn good for what it is,so I figure it didn't hurt. And it didn't cost much more than putting it back together stock.. /ubbthreads/images/graemlins/wink.gif

 

[sleepyvr4]

was your top end improved much? my friend never got to run any of the heads he ported on any of his cars, so we are eager to see it perform.

 

[14bCrazy]

I did the same thing that both of you guys did. Then I toke the head to a local guy to do a valve job and hot tank it. I'm sure it helps some. I didn't take off alot of metal just enough the make things right. When I saw this post that said with results. I thought it ment flow numbers or Dyno numbers. /ubbthreads/images/graemlins/bawling.gif

 

[sleepyvr4]

go to the top of the page and you can see step by step flow results - click on the link.