The 230 Headerfold project

[monkeymissile]

Well, I guess this is more or less the "official" start of my project to build a better performing exhaust system for my M43's 230.
My hope is to design and build a substantially improved, and possibly "tuned" headerfold that I can offer in limited quantities to interested people. I'll use stainless if I can, steel otherwise.

First of all a huge thanks to everyone who has taken the time to contribute all sorts of great information in the previous posts. Now it's time to put it all into motion and see where it leads. When I removed my cracked manifold a few weeks ago, I could plainly see the economy of it's design, but also it's shortcomings and fragility. I knew I could do better and after being relatively unimpressed with the aftermarket offerings, I started researching. With a tremendous amount of support (you know who you are!) I think I finally have a design worked out.

The first step was to get an accurate and precise drawing of the intake/exhaust ports and mounting studs. I carefully measured (and remeasured) my recently manifold-less engine with calipers and got a CAD drawing started. I posted it here and when complete, will be available to anyone who wants a copy.
The challenging part comes when I start a 3D model to figure out how to snake all those pipes together.
So let the fun begin and have a great holiday everyone.

Justin

[monkeymissile]

Headerfold configuration question #1

so my design up until recently was to take pipes 1+2+3 and 4+5+6 down into (2) 3:1 merge collectors, then into a 2:1 merge collector and finally into the primary pipe. However it was suggested I try to pair pipes 1+6, 5+2 and 3+4 pipes so the configuration would be (3) 2:1 collectors into a 3:1 collector and into the primary. This design should, theoretically, provide much better flow like a true Tri-Y.
My issue is that I don't know how I'd keep those 3 pairs of pipes the same approximate length, seems like the 1+6 pair would be really long, 5+2 a bit shorter and 3+4 the shortest.
I was under the impression that you should try to keep all these pipes the same lengths, within reason, so that all pulses are traveling the same distances to the primary.
Is this true or not so important?
Thoughts on these two possible configurations?
Thanks and hope everyone has a safe holiday.

Justin

[Cheyenne Dave]

so my design up until recently was to take pipes 1+2+3 and 4+5+6 down into (2) 3:1 merge collectors, then into a 2:1 merge collector and finally into the primary pipe. However it was suggested I try to pair pipes 1+6, 5+2 and 3+4 pipes so the configuration would be (3) 2:1 collectors into a 3:1 collector and into the primary. This design should, theoretically, provide much better flow like a true Tri-Y.
My issue is that I don't know how I'd keep those 3 pairs of pipes the same approximate length, seems like the 1+6 pair would be really long, 5+2 a bit shorter and 3+4 the shortest.
I was under the impression that you should try to keep all these pipes the same lengths, within reason, so that all pulses are traveling the same distances to the primary.
Is this true or not so important?
Thoughts on these two possible configurations?
Thanks and hope everyone has a safe holiday.

Justin

Equal length pipes have always been the goal with high performance bike exhaust systems, so it seems you are on the right track. Quite an undertaking you've taken on...

C.D.

[maineSS]

The "split" design could be constructed to have 3 consecutive pulses 120 deg apart from the other 3 cylinders by running 1,5,3 into one tube and 2,4,6 into the other, then joining the two tubes into a collector. If it were set up similar to the Jeep header, it wouldn't be so difficult to fabricate as a true Tri-Y. I'll ask my friend whether it would work as well.

[Sickcall]

MonkeyMissile,

I printed your cad drawing of the intake/exhaust ports but I can not make out all the dimensions. Can you increase the font size for the dimensions? Also what is the dimension for "x", the verticle dimension from the center of the port to the center of the stud. I wanted to start the fab of the flange plate. Thanks

[monkeymissile]

MonkeyMissile,

I printed your cad drawing of the intake/exhaust ports but I can not make out all the dimensions. Can you increase the font size for the dimensions? Also what is the dimension for "x", the verticle dimension from the center of the port to the center of the stud. I wanted to start the fab of the flange plate. Thanks

I still need to get that X dimension, will do so tomorrow since I'm still in NH with truck. I'll repost the drawing with larger dimensions too. I can also email you a copy if you want. Thanks.

[monkeymissile]

updated CAD file

for all interested folks, I have attached the updated CAD file of the port/stud layout. I am 99% sure it's all correct, but I plan to make a paper template to test it out first. Thanks.

[maineSS]

MM:
Here are some URL's for for 6 Cyl jeep header images:
http://www.quadratec.com/Assets/Imag...9/36419-lg.jpg
http://www.quadratec.com/Assets/Imag...1/52221-lg.jpg
http://www.quadratec.com/Assets/Photos/p36410c.jpg
http://www.rocky-road.com/xjthorley.html

All of these are primarily aimed at restriction reduction rather than wave tuning as evidenced by the pairing and length of the primary pipes. I asked my friend about these layouts, and his opinion was that the lengths required for wave tuning at low RPM would be a royal pain to fit-especially pair 3&4. His recommendation was along the lines of the Thorley header (bottom of page)- keep the bends gradual and pair the pipes ASAP with as few collectors as possible. The stock Jeep header apparently had cracking problems, and was meant to be more of a tubular exhaust manifold than a header. It looks like you could pair up the pipes in the right order into a couple of triple collectors, but whether that would make a big difference is doubtful. The biggest fab problem will be the collectors, so designing something that can use manufactured units will save a lot of time.

[JimmieD]

No doubt life is a series of choices. It would be much easier if objectives didn't get in the way! We know that in planning a war a man must first determine the cost, and then only if practical, get on with the objective.

There are several possibilities:

1] design and build something that offers little improvement but creates personal monentary gain

2] design and build something that works better and offers some improvement over stock and is saleable at some profit

3] design and build something that is as good as the best available, and offer at a lower cost hoping to beat the market

4] design and build the most efficent device for the purpose and be prepared to absorb the cost regardless

#4 relates to the fact that sometimes a man has something to say that is hard to express in simple words. I don't much care for the company and some of its ideals, but for more info see the link, and look closely at the 'bundle of snakes'....

http://gpma.org/Archive/gt40s.html

[monkeymissile]

I think my goal is somewhere between 2 and 3. I am pretty sure my design will be more efficient than stock and since I plan to build it, it won't be too complicated that it can't easily be reproduced.
I think I now fully understand the Tri-Y concept with pairing the 180 degree cylinders, but that likely means pipe pairs of greatly different lengths unless I make some pairs longer than they need to be. This may start to complicate fabrication. Therefore I have just started a 3D CAD model of both the Tri-Y design and the more traditional 3-2-1 (Langdon style) design to see which one is easier to build. It looks like S&S, SPD and some other header shops have an assortment of collectors that could work with either design.
I'll post images of the two designs as they develop.
Thanks for all the continued input and support. The Thorley page was very informative.

Justin

[maineSS]

One thing to keep in mind is that headers can get hotter than the hinges of **** - those orange-red pics you see in car mags aren't just seen on turbo setups. Thermal coating inside and out would be a very good idea. Don't want any oil/ gas leaks either- your truck will burn to the ground faster than you can say "French Toast". Coolant is flammable after the water boils off- vehicles have been lost to fires due to coolant leaks also. The Jeep 4.0 motor figures out to ~ 244 cu in, so dimensions for it should be close for the 230/251 engines. The Thorley uses 1 5/8" for primaries, 2 1/4" for the two branches, and 2 1/2" into the last collector. Your dimension for the ports was 1 1/4", so we might want to do 1 1/2" on the primaries.

[monkeymissile]

primary diameter

One thing to keep in mind is that headers can get hotter than the hinges of **** - those orange-red pics you see in car mags aren't just seen on turbo setups. Thermal coating inside and out would be a very good idea. Don't want any oil/ gas leaks either- your truck will burn to the ground faster than you can say "French Toast". Coolant is flammable after the water boils off- vehicles have been lost to fires due to coolant leaks also. The Jeep 4.0 motor figures out to ~ 244 cu in, so dimensions for it should be close for the 230/251 engines. The Thorley uses 1 5/8" for primaries, 2 1/4" for the two branches, and 2 1/2" into the last collector. Your dimension for the ports was 1 1/4", so we might want to do 1 1/2" on the primaries.

yes, ports are only 1.25". I suppose there wouldn't be a problem if the primaries were a larger 1.5" as you suggest. It does make finding OTS merge collectors easier since it's a more common size.
Ceramic coating would be sweet, but pricey. Maybe that header heat-wrap tape I've seen? I realize I'm going to need to make some custom heat shields for fuel pump, etc.

[JimmieD]

In general the header wrap tape has a reputation for doing some pretty bad nasties. The header gets screamin hot in use, then the engine cools down until next use. We all know about condensation when a hot substance cools. Guess where are those lovely little water droplets end up? Yep, between the header wrap tape and header tubes: rust city!

In some circumstances that's just the price you have to pay in a difficult insulation problem. If possible I'd look into a more durable and less damaging answer, like maybe powder coating? Seems to me there's a similar process that actually deposits metallic dust on a surface under high heat to coat it, rather than just paint.

[monkeymissile]

coatings

In general the header wrap tape has a reputation for doing some pretty bad nasties. The header gets screamin hot in use, then the engine cools down until next use. We all know about condensation when a hot substance cools. Guess where are those lovely little water droplets end up? Yep, between the header wrap tape and header tubes: rust city!

In some circumstances that's just the price you have to pay in a difficult insulation problem. If possible I'd look into a more durable and less damaging answer, like maybe powder coating? Seems to me there's a similar process that actually deposits metallic dust on a surface under high heat to coat it, rather than just paint.

I have a contact at a local powder coater. Not sure if it's good for high temps though, I'll find out. I think I've seen some DIY ceramic paints that you then cure in an oven or outdoor grill. Something like that might be more cost effective than a professional ceramic coating.
This all may be a moot point if I can fab it all from stainless.

[JimmieD]

Don't remember where I saw it but was looking at 'spray powder metal' units that fit to your home acety-torch & compressor. Seems that some were close to reasonable price, especially if you would be selling these sets or do a lot of fab stuff. It must have been cheap 'cause I was thinking of buying a setup hah!

Every imaginable type of powdered metal substrate is available for heat/spray application, very similar to straight up powder coating. Please, please, please thoroughly check out the MSDS for any metal spray! Some can kill ya quick!

Might try Eastwoods for a start to get some industry nomenclature on process terms then do a web search. Very practical answer to complex oxidation/rust issues.