Entry 2Pulled the head off my GTX motor to change a bent rod. (Yep to many dragstrip passed on a bad fuel pump).
So I got to looking at it. Mazda was kind enough to cast in some nice restrictors on the head. I've decided to do a DIY P&P on the head. First step is to hog out the restrictors. Once I clean up one or two of the cylinders I'll run it down to have the head bench flowed. Since I don't have any dyno numbers before to compare a before & after this is the best I can do.
Since I've only read about how to port and polish I'll probably pick the brain of the porter down at the shop when I get the baseline flow. Of course I'll have them flow my initial hogged out ports. I'll then implement his changes and try to make it down for one final session before re-installing the head.
It's hard to get photos of them but here is one of the restrictors I've 1/2 hogged out. I guess I was granny shifting the drill and not double clutching like I should because it died and halted my progress for the evening.
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... -port1.jpg" alt=" - " />
Entry 3Here is another crummy closeup of the port. Damn hard to do these photos with a point & shoot digicam. You can see here I've got a little more hogged out than the previous photo.
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... -port2.jpg" alt=" - " />
Entry 4Here is the 1/2 hogged out restrictor from the other direction...
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... ction1.jpg" alt=" - " />
Entry 5This is what the original looked like from the same angle. You can see two of them on the left sides... Right side doesn't get a restrictor.
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... iction.jpg" alt=" - " />
Entry 6I'll keep trying until I get a good one. I messed with this a little so you could see it better.
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... ction2.jpg" alt=" - " />
RESULTS:Final pic of the night. You can see based on his gasket how poorly the manifold fits. So I'll be port matching this bad boy as part II of the project.
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... nifold.jpg" alt=" - " />
Ok, on kikine's computer again. I picked up my head from D&D performance. I have to say that they're a great bunch. Very easy going and definitely a lot of expertise way out there. I've plotted the flow for exhaust.
On the exhaust ports I spent very little time. I opened up the port to match the gasket, cleaned up the bowl and smoothed the small radius transition. Finally I smoothed up all the casting marks. I assumed the 1/2 hour or so spent would result in a few CFM's increase. Even Ed, their porter seemed surprised at the difference...
<img src="http://www.redliners.ca/iB_html/uploads ... xhaust.gif" alt=" - " />
Long post but a good reference.On the intake port I removed the most material and spent more than an hour doing it. I did the standard tasks of cleaning up the bowl area and removed the casting marks. Also did a little work smoothing out the small radius on the floor of the port. I did a lot more work widening out the port opening and port matching this.
I wasn't 100% happy with the results but I'm not prepared to spend $1000 on learning how to make the last amount of power with my heads. If I were I'd do some more cleanup and try again. Surprising to me I lost some of the flow at lower lifts. On the good side I did gain significant flow on the higher lifts. This is the area that's going to make the most difference. It doesn't have nearly the duration of a pushrod V8 but the valve still does spend a lot of time at high lift.
-Michael
<img src="http://www.redliners.ca/iB_html/uploads ... intake.gif" alt=" - " />
<small>[ December 31, 2003, 03:53 PM: Message edited by: T-Rose ]</small>
