joec
Well-Known Member
maybe its just the picture but that intake port looks pretty clean(as in not much reversion)!
Missed on this combo?
- Thread starter Ironmike
- Start date
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Ironmike
Well-Known Member
Showed him the flow numbers and said throw that away. Yea, they look lousy low and mid lift, but don't live or die on numbers.
So... what he hated that CAN be fixed is how they over-cut the back and sides of the port. Light bulb shaped. My best option is to ditch the heads and buy a pair from Rod Bloomer.
My other option is to epoxy the back, sides and part of the floor to give the air a straight shot into the cylinder. He felt there has to be huge turbulence the way they are now.
Showed me some AFR, Dart, and TrickFlow heads. No lightbulb shaped ports in those
He used modeling clay to give me a sort of "template" as to how to shape them, and gave me the part number for the epoxy they use.
I think I posted 4 pics as they are and 3 of how he wants me to change them. keep in mind, the 3 pics are done with clay and rough but I get the idea.
Also said keep the cam. It is ground correctly and SHOULD make more power. Just changing cams "will not fix this".
so.....at this point, I'm going to goop 'em all up, get them even and smoothed and give it a shot. If that doesn't help, i guess I'm selling some guns and buying a pair of BPE's.
What does the short turn look like? I believe that's where the shelf was at. They look better.
nm9stheham
Well-Known Member
Very interesting, IM. Reminds of the troubles with 351C exhaust posts.... narrowed down over a huge shortside hump then opened way up and formed a low velocity area before the exhaust flange. Guys did all sorts of things to fill that low flow area to keep the velocity more uniform throughout the ex. port, which helped the whole exhaust system work quite a bit better; epoxy was one of them. It'll be good to see what you end up with; I'll hand it to you for being determined to make this work
What kind of guns?
What kind of guns?
moper
Well-Known Member
A mentor of mine was one of those messing (and winning) with the 351C heads. Iron inserts welded in and the port was reshaped.
Iron - For what it's worth I agree with your guy.
Iron - For what it's worth I agree with your guy.
If the epoxy he told you to get is a 2 part that when mix up look like a military green, then let me help you out.
altho this stuff sands nicely your finger tip will be wasted before you ever get one head done.
Get a black nitrile glove(thin rubber gloves)
Get some 36 grit sand paper that a body man would us on a longboard(the ones that have sticky on the back of them.
Get some super glue.
Install one glove on hand, tare of small pieces of that 36 grit sandpaper and super glue them on all 5 finger tips(the glove not your finger.)
Now it real tough to get in there with a glove full of sandpaper with out messing ups things like seat angles.
Remove sandpapered glove and pull the pointer finger off of the glove and then reinstall on you finger.
Now you have great control over the sand paper and it don't fold up.
Now you can get into the nooks and crannies and make a great shape. The good thing is that if you go to far......you just mix up some more.
The stuff i us is called Z-Spar and was originally used to patch up boat. It will set up under water.
takes about 12 hours to set up when it's cold outside.
It mixes up like putty and acetone or lacquer thinner work good to thin it out so you can flow and shape it better. I prefer Lacquer Thinner.
Clean the port out with Lacquer Thinner, scuff the port area and then clean it again. Clean Clean surface is a MUST!!!!
A real Thick putty knife or gasket scraper work best to mix it up. It's like mixing up TAR!
Back in the day, the one and only on i saw hand half of the exh port cut off then a alu piece was bolted on to fix the exh problem.
Was told that it work GREAT! but was a ***** to keep coolant leak out of the equation.
Ironmike
Well-Known Member
Epoxy is called Goodson 2 part cylinder head epoxy. Mixes to consistency of soft clay. He told me a wet finger will do perfect. Might not even need sandpaper (I will). You have 15 minutes to work the stuff. Ordered it today.
You can't tell, but that unmachined black area is a good .175 taller than the surrounding port. In his words, just a mess....
Geez, if only I knew.
You can't tell, but that unmachined black area is a good .175 taller than the surrounding port. In his words, just a mess....
Geez, if only I knew.
Pretty sure that's the same stuff.
15 minutes to get it where you want but can buy some time with a little lacquer thinner.
EDIT a wooden dowel is a good idea to keep sanding dust out of them brass valve guides.
15 minutes to get it where you want but can buy some time with a little lacquer thinner.
EDIT a wooden dowel is a good idea to keep sanding dust out of them brass valve guides.
Mike, is there any venturi under the seat? If its there I can't see it.
Hey Mike, Where can you get this material?
Link?
o1heavy
1974 dart sport
The consensus is
The large port eddy heads aka big mouth heads
Are not awesome ???
The large port eddy heads aka big mouth heads
Are not awesome ???
stixx
Well-Known Member
Seems people selling them had a big mouth calling them Big Mouth.
stixx
Well-Known Member
Very cool that you are taking the challenge to try improving the heads yourself!
nm9stheham
Well-Known Member
I can remember that fix.. that short side exh. hump was the water jacket! Then there were the steel flanges that bolted between the head and the exhaust flange that had 'tongues' that stuck into the exh. ports to 'fill' this area.
Let's hope this is the key for IM. People have been working on these port problems for a long time, it takes a lot of work and some special knowledge and ability to understand and visualize the flow to figure these things out.
nm9stheham
Well-Known Member
I am guessing that they use just one bit to do all that milling in that area, and that they can't get it any closer to the guide in that area. A different, smaller bit would be needed, runnig slowly in that area, and that is a tool change (if it is not a multi-bit head) and costs time and $$.
MOPAROFFICIAL
Oogliboogli
I got the pinch real thin on a few ports, to where you could flex it with your finger, used this and still holding, cast iron on the street.
Simply google goodson, they sell machine shop supplies, fairly quick turn-around.................
RAMM
Well-Known Member
I don't know why they don't just drive the guide just below the surface in order to get in and be able to profile the guide boss completely? J.Rob
RAMM
Well-Known Member
Their milling machine does not have a toolchanger --the solution here is to push or remove the guides prior to running the program. J.Rob
RAMM
Well-Known Member
Here's a link to study and a crude hand drawn picture I whipped up (it is exaggerated for illustration but not much). Just going to leave this here and I'm out. J.Rob
How Kaase created a cylinder head for modern street-strip use | Moore Good Ink
How Kaase created a cylinder head for modern street-strip use | Moore Good Ink
It's like the "prostock" theory that I heard go around about 1990, basically the floor was a ramp down the backside of the valve at whatever max lift was accomplished. I don't
think anybody is still clinging to that. Well, almost anybody....................
There are stock ports that have almost no SSR, & work best by maximizing whats there w/a clean break at the floor, so the transition from utilizing the SSR to bypassing
it is as narrow as possible.
yellow rose
Overnight Sensation
Hughes is doing the SSR like that because it's cheaper. It takes less time in the CNC and it's easier to machine.
The only other option is the guy who developed the port is an idiot.
This is a CLASSIC example of how CNC does NOT equal great. Or even good. RAMM is correct, you can't fix that head without welding. But you can probably make it workable. It will never be optimal without welding. That includes the bowl. The bowl is what happens when you use a big valve and you have to have area to feed the valve. If you fill in the back side like you are going to do, you will bring up the low lifts, help a bit in the mid lift and lose at higher lifts. And average port speed will go up, probably to the point of being turbulent.
Ironmike
Well-Known Member
I just called them. 1 800 533 8010. 37 bucks for a can. Called late yesterday, UPS says it'll be here tomorrow.
I'm off Thursday, too. God help me, I'm goin' at it.
Ya know.....I thought about selling them to a guy who's just looking to build a nice 450-500 horse motor, but really, I mean really, where could I find some good CNC'd heads right now?
Nowhere.
I decided if it could happen, I'd just buy a good pair and call it a lesson learned. Far as I know, nobody has them "on the shelf" and ready to go. I don't have time to order up a pair from someone.
yellow rose
Overnight Sensation
It's a learning process. Glad you ain't quitting. Make the best of it.
I still say you need a cam change to pick up the middle.
Keep us posted with how it goes.
BTW, I'd like to ask you a question, and you don't have to answer it if you don't want to, but it may help someone along down the road.
Question: Before all this happened, would have considered heads that were not CNC ported if someone told you they aren't as good as advertised and hand ported heads could make more power? What would you have said?
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