Cutting off exhaust ports?...

[machoneman]

Now that Rod is a great idea. Maybe JDC could 'do' a scrap head and check the flow.

[cjshaker]

Rod, that is an interesting idea. I'll look into it a little more when I get the head back, but I think there will be more to gain by going back to the valve cover rail. I AM thinking that not near as much of the port will need cut off as I originally was thinking. Basically just take the top off and raise the angle. No need to cut the sides, and the bottom can be filled. That would help maintain as much port wall strength as is possible. I stopped to get the head today, but he didn't have it done. He said to stop back Monday.

And Bob, I have thought about seeing if Joe would be willing to port the heads, but I'm not sure if he would be willing to get involved in this. And since the whole engine/car combo will cost me enough, I'll be trying to do as much work as I'm able to on my own. With some help from a couple old friends in the machining and TIG welding though.

[cammerfe]

On my Tunnel Ports that were cracked between the valves and had sunk exhaust seats it was just adding to the welding that was done. Otherwise i'm sure the $600 i paid then (late 80's) would still apply to just the exhaust port stuff. What they did was weld the floors of the exhaust in about and inch and around 1/2" deep. The tops of the outsides of the ports were welded up with about 1/4" extra material. The little ribs was gone, the whole port top was that level.  I raised the ports around 1/2" at the exit which is pretty much where the Blue Thunder ports are already and i'm going to raise those higher.
 You can't do much about the depth of the valve bowl.

 The Doves are a better solution i'd say. They can be bought with a variety of chambers and ports , it'd be worth any issues that might occur.

What Dove refers to as his 'Second Design' exhaust ports are raised, they're spread laterally to straighten out the runners, and reshaped. At the flange face the openings are an almost-oval with one lower corner somewhat filled-in.

The heads look so different on the exhaust side that they're not instantly recognizable as FE pieces. They require custom headers. A rolled-up piece of paper inserted in the  runner on such a head---mounted on a block in the chassis---will point UP---at an angle of course.

KS

[Joe-JDC]

I will flow that for you, no charge, you ship.  However, unless someone comes up with a regular intake port that will flow over 300-310cfm for the iron heads, then increasing the exhaust flow by extra-ordinary means is kind of a waste of money.  Most street/strip engines work best with ~70-72% intake/exhaust port flow bias, and you can port most iron heads to achieve this percentage.  Headers pull most heads up to above that flow bias, and with camshafts that have more exhaust duration than the intake, then they compensate for the poorer flow bias by holding the valve open slightly longer with the duration increase.  So an intake port that flows 280cfm at valve lift, only needs the exhaust to flow 196cfm which most FE heads can be made to flow.  What the FE world needs is a small  port 2.150" valve that flows 360cfm, and the exhaust 1.600" that flows 252cfm.  That would be a neat street/strip head for the masses.  Joe-JDC

[TomP]

With 8mm stems. Sort of like a smallblock AFR185 but for FE's. I think Barry's heads are as close as we get.

[TomP]

Of course no matter what heads you'd have to offer them as a whole package, intake, cam, pistons, etc...  with no substitutions to keep somebody from screwing up the combo because they want to leave their 75 truck pistons in there or use grandads old 3 Stromberg setup.

[cjshaker]

I will flow that for you, no charge, you ship.  However, unless someone comes up with a regular intake port that will flow over 300-310cfm for the iron heads, then increasing the exhaust flow by extra-ordinary means is kind of a waste of money. Joe-JDC

Somehow I missed these last posts. Thank you for the offer, Joe. I was contemplating doing this on an aluminum set of heads with very good intake flow numbers on a big inch build using my Genesis block and a stroker crank. So the improvement in the exhaust would have been worthwhile I believe. I just had the iron head cut to get an idea of what I would be looking at port-wise. I know there would be differences between the iron and aluminum, but it would at least give me an idea of what to expect without experimenting on a new set of aluminum heads.

I finally got the head back. I just had him cut one exhaust top off, and from what I can see there would be a LOT to gain if the port were continued in an upward travel with custom headers. Here's some pictures of the cut head.





These angles show how the port is really still in a near vertical angle as it exits the head. If the angle were continued with a gentle slope outward, it would make for a nice smooth flowing exhaust port.





This shot shows how the height is essentially the same as it exits the head, as it is when it exits the exhaust port. But given the vertical angle of the port at the head exit, it really shows how sharply the port bends in that short area in between.



Unfortunately I ran into a major snag. After speaking with my friend who is a retired welder, I found out that his only welder is an air cooled TIG unit, and according to him he can not build enough heat to weld thick stuff. You need a water cooled TIG unit for that. I have lots of MIG experience, but no TIG experience, so that was new to me. I just assumed that the water cooled units were the professional high duty cycle set-ups and didn't realize it had anything to do with heat output and penetration on thick parts.

This is a major bummer for me because this was only going to happen if I could do it cheaply (but still professionally). If I had to send this out or pay somebody professional rates to weld up 8 ports, then it would be an investment more than I could readily afford. I had considered getting my own TIG unit before (just an air cooled unit), but the water cooled jobs are NOT cheap, and I can't justify the costs for one project. I still believe though, that if JUST the tops of the ports were cut off so that the bottom of the port could be welded up to maintain cross section, then weld up the top with layers of weld so that the port could be ground out with a much more favorable angle, that it would be a nice and worthwhile improvement in a non-shocktowered car.

So I guess I'm back to looking at the raised port BT heads and just port the exhausts up as much as is acceptable for flow.
Anybody need a head with 3 exhaust ports?...LOL

[jayb]

Doug, I think you should consider going outside to have the welding done.  You would only need to weld the floors of the port to raise it up where you have made the cut; a machined plate with ports cut it in could do the rest.  I'll bet just adding weld material in that area wouldn't be real expensive, maybe $200-$300 for a pair of heads.  I like the general idea, and have been thinking about that for FE heads since the '80s, when the raised port Clevelands and 429-460 engines were being done.  It would be great to find out just how much flow you could gain doing that...

[cjshaker]

Doug, I think you should consider going outside to have the welding done.  You would only need to weld the floors of the port to raise it up where you have made the cut; a machined plate with ports cut it in could do the rest.  I'll bet just adding weld material in that area wouldn't be real expensive, maybe $200-$300 for a pair of heads.  I like the general idea, and have been thinking about that for FE heads since the '80s, when the raised port Clevelands and 429-460 engines were being done.  It would be great to find out just how much flow you could gain doing that...

Actually, I hadn't given up totally on the idea yet. The guy who cut the head has a full machine shop including 2, 5 axis CNC machines and does some CAD designing. And it just so happens his son is into cars and is learning CAD design, so maybe I can work with him on this. I would however, like to keep the individual ports rather than a plate deal, just to keep some resemblance to the FE head design. So that really pushes me to the welding idea rather than plates.

I'm going to go ahead and get some BT heads and do alot of measuring and talk to some local experienced welders and see what they can tell me. With the General Dynamics/Abrams tank plant nearby, there are plenty of experienced and out of work welders in the area that are more than capable of doing the job. I'll just have to see how things work out.

[cammerfe]

You should look at the Dove 'Type Two' design for exhaust ports. He raised them, re-shaped them into an oval with one bottom corner filled-in and changed the spread---all to increase the flow. With the heads on a block in an engine compartment, a rolled-up sheet of paper shoved into such an exhaust port points UP at about a 60* angle. You have to remove the spring towers in a Mustang to use them. And build custom headers.

KS

(What you see here is an example of 'Old Fart Brain Fade'. I made the first post, above, a whole month ago. You can't expect me to remember things like that, can you?)

KS

[Joe-JDC]

It still is important to remember that you need arount 70-72% exhaust flow bias of whatever intake flow you obtain.  Barry's new aluminum head is capable of 360cfm, and 250+cfm on the exhaust.  The Edelbrock Pro Ports can be ported with a round exhaust port, and I am in the process of porting a set to try to come up with just how much can be had with those heads.  I fully expect the Pro Ports to be topdog for flow if they can be gotten large enough as cast.  Joe-JDC.

[cjshaker]

You should look at the Dove 'Type Two' design for exhaust ports. He raised them, re-shaped them into an oval with one bottom corner filled-in and changed the spread---all to increase the flow. With the heads on a block in an engine compartment, a rolled-up sheet of paper shoved into such an exhaust port points UP at about a 60* angle. You have to remove the spring towers in a Mustang to use them. And build custom headers.

KS

Thanks, Ken. I have not seen those heads before. I'll try to find some info and check them out. I have never been real impressed with the quality of the Dove products I've seen over the years, but occasionally you do see some nice pieces.

It still is important to remember that you need arount 70-72% exhaust flow bias of whatever intake flow you obtain.  Barry's new aluminum head is capable of 360cfm, and 250+cfm on the exhaust.  The Edelbrock Pro Ports can be ported with a round exhaust port, and I am in the process of porting a set to try to come up with just how much can be had with those heads.  I fully expect the Pro Ports to be topdog for flow if they can be gotten large enough as cast.  Joe-JDC.

Thanks again, Joe. Very good info. I was surprised when I saw the exhaust ports of Blairs Pro Port heads. First time I had seen that style of round port on an FE head, and they looked very nice. Since I will be gathering pieces for this build over the next year, hopefully you will find out your results and post them here. It should be interesting. This is why I have been trying to gather some flow numbers from all the aftermarket heads.

I do have a question though, is there a disadvantage to having an exhaust port that would flow over the 70-72% rule? Or is that what is considered a minimum for max power/minimum pumping loss?

[Ford428CJ]

You need a spray metal torch Doug!

http://www.youtube.com/watch?v=NXqVO6hFEUI

[Joe-JDC]

Yes, it will overscavenge the incoming fuel, and get poor gas mileage, not make as much horsepower.  Today's camshafts aren't designed for that effecient of an exhaust port on the FE, and it would be a total relearning curve.  You can get by with close to 80%, but the power starts to fall off, and the mileage goes away in a hurry.  I ported a set of SBF heads once that flowed 83% of the intake flow without a pipe, and that engine ran terrible, got awful mileage, and the exhaust valve, port, header, plugs were always fouled, black mess.  I have since studied many engine theories, and read everything I can find on that particular subject, and it seems to be that the pumping efficiencies always perform well at or near the 70% bias.  That is why many ford cams have more exhaust duration than the intake, and for Nitrous, or blower engines, they spread the exhaust bias with even more duration to allow more time for the exhaust to escape.  Those cams on a regular engine will not perform well in a non-nitrous engine all else being the same.  Anyway, sometimes we try to re-invent the wheel, only to find it was already figured out fairly well, and it becomes a waste of time, energy, and money to just satisfy a curiosity.  BTDT too many times when working on these older engines.   ;)Joe-JDC.

[FEDER]

Having done a lot of aluminum tig welding on many different things I'll throw in a few thoughts. First thing is You will need to bolt the head to a block  on an engine stand for  two reasons. One being the head will warp doing that much welding and bolted down will help a lot to hold its straightness. 2nd would be You could set the head at an angle comfortable to weld.
 Using an older tig welder with a water cooled torch and using a helium argon mix will help but still need preheating and will transfer ALOT  of heat to the head. Enough to maybe make the seats fall out. You use a helium mix when welding thinner matl  to thick matl. Also for cast aluminum it takes way less time to melt the metal so You can begin welding.You would want to move around from port to port to help keep warpage down. What You really want is someone who has a new Miller Dynasty tig welder. They have all the newer technology on AC  to do just what your after. No preheat and no helium just set the machine properly and go for it. All the best aluminum weld shops have them. Those pretty Hogan manifolds and super nice looking repairs on aluminum blocks  are now done with these welders. I have a watercooled Miller 300 amp machine thats about 30 yrs old it will weld about anything but not even close to what these new machines do. I do want to buy one but they are 4 k for a 200 amp with not even a footpedal just the bare machine. Make sure the weldor You choose is  good, see some work Hes done dont take His word for it. Iv'e tested hundreds of weldors over the years and few were as good as they said.   FEDER