Porting heads

T

Tedor

Registered User
I'm going to port my heads myself. Is there anyone out there that have any advice to give? Pictures would be awsome, both of companys porting and if you have ported yourself.

Thanks!
 
most machinests keep this info to themselves, but I do know bigger valves and removing the hump in the exhasut chamber is common
 
Gasket match the the intake ports, and clean up any casting flash and seams. It's ok to smooth down the runners, but don't polish because it needs some roughness to keep fuel from sticking to the walls. And don't go nuts, without a flow bench it is better to just clean up the runners than have them off-balance. For the exhaust, just match the ports and clean up the runners. There have been several discussions here and elsewhere as to why the floor of the exhaust port should be left alone, it helps with air velocity. In the chambers, round/smooth the divider in the middle. And it is ok to polish the chambers.
 
what exactly do you mean with "runners"? Im going to run headers but have seen some people that make the exhaust flat on the bottom where it meets the headers/exhaust manifold. The headers are round.
 
:eek: I think it might be worth while paying a professional to do this for you. This is not a BBF.
 
There is more to porting than just hogging ports out. The short radius, if to much material is removed hurts performance. I ported a set of heads once and ended up letting my engine builder finishthem to get it right because he knew where to port to make it worth while. I second the suggestion to let a pro do it. Somethings are better off being done by an expert

Ken
 
I agree with the above statement. I think the way I ported the heads on my 95 is accounting for the lower hp numbers than expected after the work I did. I got all the information I could to make them the best they could be, but unless you make/buy a flow bench and do a lot of practicing with it, you wont ever fully understand or be able to do a precise port job.

The biggest thing you can do is bigger valves, best bang along with porting.

chris
 
I understand why you guys say so, but here in sweden where I live nobody have the experience of these heads and to let someone else do it is very expensive. In the future the plan is to just break the 300 rwhp mark so I just want the heads capable of that. When I'm done porting I will test them in a flow bench. Have also heard from a experienced pro porter over here that sometimes he don't see a improvment in flow but on the dyno it's giving more HP.

I know it's hard to do it good, that's why I'm asking you guys. Thanks for the answers so far. How nasty is the short radius on the exhaust?

/Fredrik
 
Tedor said:
I understand why you guys say so, but here in sweden where I live nobody have the experience of these heads and to let someone else do it is very expensive. In the future the plan is to just break the 300 rwhp mark so I just want the heads capable of that. When I'm done porting I will test them in a flow bench. Have also heard from a experienced pro porter over here that sometimes he don't see a improvment in flow but on the dyno it's giving more HP.

I know it's hard to do it good, that's why I'm asking you guys. Thanks for the answers so far. How nasty is the short radius on the exhaust?

/Fredrik
Click to expand...

Don't touch the short radius is the word given to me. Short of that you can do anything you want. My heads after I ported them showed about a 5% max improvement on a flow bench. I had Dave Dalke install larger valves and reflow them and saw a 15 to 17% improvement over stock. These were not super high end performance heads but I ran 300 rwhp with them. The pictures are of the heads I now run. According to Dave there room for improvement on them as well.

Ken
 

Attachments

  • Ports.jpg
    Ports.jpg
    222.4 KB · Views: 176
  • Port 2.jpg
    Port 2.jpg
    169 KB · Views: 177
Thanks Ken!

I have actually smoothed the short radius on both exhaust and intake, on the intake I removed the big hump alittle bit on th short radius, cleaned up and port matched(Im going to run headers). On the exhaust ports I have seen some diffrent ports, some makes the bottom of the exit flat and some don't. Don't really know what to belive, the headers are not flat at the bottom which the stock manifold is
 
BTW do anyone have the stock flow numbers on exhaust and intake? I know there has been a thread but can't seem to find it. Maybe it will vary between flow benchs?
 
Tedor said:
BTW do anyone have the stock flow numbers on exhaust and intake? I know there has been a thread but can't seem to find it. Maybe it will vary between flow benchs?
Click to expand...

I really think there would be a great variance in numbers from bench to bench. It would be better to put the heads on what ever bench is going to be used for the base line and than run the heads again on the same bench after porting to see a % of gain vs playing a numbers gain. My engine builder told me that and I have no reason to doubt his wisdom;) I looked to see if I had any other pictures of ports but found none. Other than dont remove any material on the short radius I cant really advise you on the rest of your project. I just dont have the knowledge or experence to throw out there on this subject

Ken
 
Last edited:
Tedor said:
BTW do anyone have the stock flow numbers on exhaust and intake? I know there has been a thread but can't seem to find it. Maybe it will vary between flow benchs?
Click to expand...

I think you will find some variances but as a general rule you could probably use 130 for exhaust and 170 for intake.

Paul
 
im not hi horsepower so intake under boost wasnt an issue for me porting the exhaust side helped tremendous the big ridge inside the exhaust valve in the head . it helped so much i almost wanted to tear it back apart and do some more smoothing to the exhaust

ralph
 
Tedor, you can CC the combustion chambers to equal volume, you might want to polish them, as you are going along and be sure to glass bead them with heavy beads as this improves flow over just polishing.
 
You must log in or register to reply here.
Back
Top