Steve Briscoe
Lifetime Supporter
You bet. I need to call them next week and get a few questions answered.
Steve
Build your own crossover headers
- Thread starter Mark Worthington
- Start date
You bet. I need to call them next week and get a few questions answered.
Steve
I've used flexible exhaust tubing on couple of occasions to model a particularly tough tube.. Getting the tubes to be equal length adds in a great deal of complexity in the design but it's one of those details that pays great dividends...
How much is that modular system?
How much is that modular system?
Well if you're using stainless in 1-5/8"DIA (the most common small block size), then the only CLR available is 2.5" and 4" so you're hosed because these blocks are only available in 2", 3", and 4", CLR's.
Also note that it's not that hard to build one side at a time so you could buy a 4 cylinder set for $350 less than the V8. .
2D Cardboard patterns work although they are a bit tedious. These plastic blocks would probably speed things up.
The only other problem I see is the lengths while adjustable are fixed to the increments of the segment length. This might cause issues in real tight clearance spots (all GT40's) where you need to measure down to the 1/8" or even 1/16".
Your still going to end up cutting a little long and grinding down to fit, and that's where it takes time.
Also note that it's not that hard to build one side at a time so you could buy a 4 cylinder set for $350 less than the V8. .
2D Cardboard patterns work although they are a bit tedious. These plastic blocks would probably speed things up.
The only other problem I see is the lengths while adjustable are fixed to the increments of the segment length. This might cause issues in real tight clearance spots (all GT40's) where you need to measure down to the 1/8" or even 1/16".
Your still going to end up cutting a little long and grinding down to fit, and that's where it takes time.
This is probably not too bad. Especially if you already tightened the bolts at the head flanges.
It might be easier to assemble one primary at a time and leave all the bolts really loose until all the primaries and collectors are in place and then tighten everything.
I know on my setup you couldn't even get it together like this with all primaries on before the collectors, too much friction. I have a written assembly order on mine.
Was just a write-up on this system (see post #1) in the latest Car Craft (August 2011, page 17). A bit pricey unless you are building a bunch of different headers, but way cool. At $400 for a four-pipe kit (one side of a V-8), certainly not worth buying if an aftermarket header exists for your application, but as most of us are dealing with unique applications (i.e., forced to construct our own headers), it may be worth $400 to make the process easier.
Eric
Eric
Hi guys, Here's a thought that might work, can you buy plastic drain pipe in a variety of sizes to match the steel tube, i have a article salted away somewhere on bending steel pipe filled with sand to make headers, would it be possiable to do the same and fill a plastic tube with sand, that will stop it squashing on the bends, and then just heat it up with a heat gun, anyone tried this method, pvc pipe should bend easy with a little heat.
Graeme
Graeme
Kelly
Lifetime Supporter
I’m in the middle of a header build and saw those a while ago in the mags. Sort of “leggos” for header builders. I really liked the idea but agree with many of the comments posted in this thread.
I think they would be great for the layout work, routing and making equal length segments etc but I have my doubts just how accurate they would be. A small positioning error stacked up on a bunch of segments would still likely mean a fair amount of fitting.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" /><o
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Agreed. The kits are not priced such that an individual could cost justify them for a single or even several builds. The individual plastic pieces themselves are penny parts but I’d imagine the tooling was a substantial investment since they have a number of radii and diameters to accommodate. <o></o>
Professionals who are in the business of building custom headers might be able to justify the price. It’s hard to imagine they are selling very many of these kits because the number of people in the pro category compared to the number that would buy for a one or two time build must be quite small. This really begs for some basic marketing analysis but I suspect they could produce a better return on that tooling investment by dropping the price. This would mean more revenue at lower margin but I would have to think the margin could still be quite good at lower price. Maybe they just don’t want to deal with that volume of customers?<o></o>
Also, for cross over 180s, you need a bunch of it; say enough to layout 12 ft per side or preferably 24 feet for both sides because some of the most significant challenge is laying out the cross over pipes from each bank to the collectors. The “Pro-Kit” does contain 240” of block but what would be the chances it was the pieces you’d need?<o></o>
Scrap cost for a single build, even in stainless, would be very small compared to the acquisition price of the kit and in mild steel, forget it.<o></o>
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I agree with the ripe to be copied part and that is the threat of not doing your pricing homework as suggested above. Even though it’s represented as patent pending, even with such competitive protection, it would still be a solution looking for a problem to solve at that price?<o></o>
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$1850 for stainless 180s ready to go? Not that they would stand a chance of being available for my combo but who is offering stainless 180s ready to go for that price?<o></o>
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I have a nice vertical bandsaw but bought an 80 tooth Ti/Carbide tipped circular blade for my 12” wood working chop saw. It is DeWalt #DW7739. It is billed as a low rpm dry cut blade for stainless and is rated for <1800rpm. I was skeptical at first because I thought it was extremely doubtful that it could work as a dry blade due to heat, but it does and cuts very accurately, producing very square and clean fitting joints with just the aid of a couple simple wooden fixtures. You do need a speed control for the brush motor to reduce the speed to ~1500-1800 rpm. This de-rates the power of the saw a bit but it works fine on 2” 16-18 gauge stuff. Takes about a minute per cut.<o></o>
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That’s a great idea Randy. Do the flexible sections you used hold their shape well and can they be reused/re-bent multiple times? What was your source for these flex sections? Typical retailers?<o></o>
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Best,<o></o>
Kelly <o></o>
I think they would be great for the layout work, routing and making equal length segments etc but I have my doubts just how accurate they would be. A small positioning error stacked up on a bunch of segments would still likely mean a fair amount of fitting.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" /><o
></o><o
></o>Agreed. The kits are not priced such that an individual could cost justify them for a single or even several builds. The individual plastic pieces themselves are penny parts but I’d imagine the tooling was a substantial investment since they have a number of radii and diameters to accommodate. <o
></o>Professionals who are in the business of building custom headers might be able to justify the price. It’s hard to imagine they are selling very many of these kits because the number of people in the pro category compared to the number that would buy for a one or two time build must be quite small. This really begs for some basic marketing analysis but I suspect they could produce a better return on that tooling investment by dropping the price. This would mean more revenue at lower margin but I would have to think the margin could still be quite good at lower price. Maybe they just don’t want to deal with that volume of customers?<o
></o>Also, for cross over 180s, you need a bunch of it; say enough to layout 12 ft per side or preferably 24 feet for both sides because some of the most significant challenge is laying out the cross over pipes from each bank to the collectors. The “Pro-Kit” does contain 240” of block but what would be the chances it was the pieces you’d need?<o
></o>Scrap cost for a single build, even in stainless, would be very small compared to the acquisition price of the kit and in mild steel, forget it.<o
></o><o
></o>I agree with the ripe to be copied part and that is the threat of not doing your pricing homework as suggested above. Even though it’s represented as patent pending, even with such competitive protection, it would still be a solution looking for a problem to solve at that price?<o
></o><o
></o><o
></o>$1850 for stainless 180s ready to go? Not that they would stand a chance of being available for my combo but who is offering stainless 180s ready to go for that price?<o
></o><o
></o>I have a nice vertical bandsaw but bought an 80 tooth Ti/Carbide tipped circular blade for my 12” wood working chop saw. It is DeWalt #DW7739. It is billed as a low rpm dry cut blade for stainless and is rated for <1800rpm. I was skeptical at first because I thought it was extremely doubtful that it could work as a dry blade due to heat, but it does and cuts very accurately, producing very square and clean fitting joints with just the aid of a couple simple wooden fixtures. You do need a speed control for the brush motor to reduce the speed to ~1500-1800 rpm. This de-rates the power of the saw a bit but it works fine on 2” 16-18 gauge stuff. Takes about a minute per cut.<o
></o><o
></o><o
></o><o
></o>That’s a great idea Randy. Do the flexible sections you used hold their shape well and can they be reused/re-bent multiple times? What was your source for these flex sections? Typical retailers?<o
></o><o
></o>Best,<o
></o>Kelly <o
></o>I The kits are not priced such that an individual could cost justify them for a single or even several builds. <o
I disagree - if I were building my own headers I"d buy them.
Lots of people will buy it to make things easier on themselves.
For example, I spent $450ish for a plastic LS block to help me visualize a few mockup pieces. Could one justify the cost of the plastic block - no - but it makes things easier for me so I don't care about its cost.
Sorry about the thread ressurect, but it was the closest I got in the search to what I needed.
My question is around the exhaust 'pairing'. What I mean is that there are two sets of collectors, and each has 4 pipes going into it, 2 from either bank. Question: what factors go into which cylinders feed into which collector, or put another way, which cylinders are paird together and why? I'm guessing the firing order makes a difference, so whatever camshaft is run will make a difference to the way the exhaust is built.
Can anyone give the firing orders and the cylinder pairings that are optimal?
Thanks,
eggs
My question is around the exhaust 'pairing'. What I mean is that there are two sets of collectors, and each has 4 pipes going into it, 2 from either bank. Question: what factors go into which cylinders feed into which collector, or put another way, which cylinders are paird together and why? I'm guessing the firing order makes a difference, so whatever camshaft is run will make a difference to the way the exhaust is built.
Can anyone give the firing orders and the cylinder pairings that are optimal?
Thanks,
eggs
Seymour Snerd
Lifetime Supporter
I think you'll find your answer it this thread:
http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/24933-crossover-exhaust-question.html
http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/24933-crossover-exhaust-question.html
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Big-Foot 
I've used flexible exhaust tubing on couple of occasions to model a particularly tough tube
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Sorry Keyy - Just saw this..
Yes they held their shape very well, but the radius was not as tight as some of the J/U Bend tubing I could buy.. I bought it from JC Whitney - but it's gotta be maybe 10-12 years ago. I would suspect that you could find it at some of the local auto retailers.
And yes, they could be re-used, but I cut the tube to length sometimes - which makes the reusability somewhat of a challenge.
I've used flexible exhaust tubing on couple of occasions to model a particularly tough tube
</TD></TR></TBODY></TABLE>
That’s a great idea Randy. Do the flexible sections you used hold their shape well and can they be reused/re-bent multiple times? What was your source for these flex sections? Typical retailers?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" /><o
<o
Best,<o
Kelly <o
Sorry Keyy - Just saw this..
Yes they held their shape very well, but the radius was not as tight as some of the J/U Bend tubing I could buy.. I bought it from JC Whitney - but it's gotta be maybe 10-12 years ago. I would suspect that you could find it at some of the local auto retailers.
And yes, they could be re-used, but I cut the tube to length sometimes - which makes the reusability somewhat of a challenge.
