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Header Hack

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Greyhounds_AMX View Drop Down
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    Posted: Jun/10/2016 at 1:53pm
I’ve always wanted headers on my '68 AMX but didn’t want the associated leaking gaskets, leaking flanges, bottoming out, etc. It seems some brands have better flanges than others so gaskets may not be an issue, but collector flanges still are a trouble spot. And my car sits LOW, so I’m going to bottom out any stock headers.

 

I decided to re-shape a set of headers to form fit my car using an old set I had laying around. I got these at a swap meet as part of a $60 package deal, and the other parts (including a Machine manifold) were what I was after, so IMO they were free. I tried to sell them at NAMDRA and had no takers at $80, so they’ve been sitting on the shelf for 10+ years now. They were in very good condition and ceramic coated, so I had that blasted off since I expected to be doing a bunch of welding on them.

 

After test fitting the driver’s side it was apparent that the forward bends near the oil pan needed to move up about 1.5”, and the collector needed to come up about 2.5” and move out toward the rocker a few inches to give some clearance to the clutch release arm. You have to look past the hanging exhaust pipe to see the relationship between the header collector and the frame - it’s angled down quite a bit.

 

I mounted a spare cylinder head on my welding cart at the same angle as the heads are on the block, and arranged some wood to indicate the original elbow and collector position. Then I sketched the required positions based on how far up I wanted to move, and started trimming the tubes accordingly.

 

 

There was a problem though, in that the pipes hit the Jeep slave cylinder before I could get them up where I wanted them. I moved everything up intil it pretty much contacted the slave, but the collector was still hanging too low.

 

 
 
 
The solution was to move to a “pull-type” slave from Wilwood instead of the stock push type slave cyinder. There are a number of pull-type slaves available from Wilwood, CNC, Howe, Coleman, and Speedway. Of them, the Wilwood has the longest travel and has the same bore size as the stock Jeep slave that I’m replacing. It’s $82 at Jegs/Summit. Here’s an example of a pull-type on a T5. I don’t have mine mounted yet.

 

 

With the slave out of the way I could pull the collector up nice and tight to the floor. The two center pipes simply got shorter and got a slight angle to roll the collector out toward the side of the car, and the font pipe was reconnected using the original elbow trimmed down to fit. The rearmost pipe was heated with a torch and stretched to meet up before welding. Now the lower elbows are about level with the crossmember, and the collector is as close to the floor as practical.

 

 

On the passenger side it only needed to move up (about 1.5" up at the elbows and about 2" up at the end of the collector), but it was obvious that the stock starter would prevent moving the pipes upward the same amount as the driver side. I opted for an Alterstart reman mini starter because it has a bunch of mounting orientations and the motor is mounted up high, away from the header heat. And it’s cheap, like me.  LOL

 

More to come...

 

 



Edited by Greyhounds_AMX - Jun/11/2016 at 5:25pm
Chris ("Mojo")
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Post Options Post Options   Thanks (0) Thanks(0)   Quote THE MENACE Quote  Post ReplyReply Direct Link To This Post Posted: Jun/10/2016 at 2:33pm
If you want to never have to replace the collector gaskets you can use something like this!


It's an OE style conical seal and heavy duty flanges. It not only won't blow out like the flat gaskets do, but also allows for some engine movement without putting unwanted stress on the header tubing which can eventually cause tube cracking.

Dennis
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Post Options Post Options   Thanks (0) Thanks(0)   Quote White70JavelinSST Quote  Post ReplyReply Direct Link To This Post Posted: Jun/10/2016 at 2:49pm
X 2 on Dennis' suggestion.

I'm guessing the collector is 3" on your headers. There's a myriad number of "ball and socket" or "ball flange" collector kits available. Jeg's, Summit, lots of places to buy from too. There are two bolt flange and three bolt flange varieties.

Post up more photos, I'm real curious on this one as I've got a set of Hedmans that are NOS, but the welds at the header flanges are real crappy, the flange itself is too thin to resist warping and the collector flanges are not ball and socket type. I bought a set of thick header flanges and a 3 inch ball and socket collector kit to redo the headers exactly as you are.

BTW, nice work, very pretty welds.


Edited by White70JavelinSST - Jun/11/2016 at 11:09am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote motorhead_1 Quote  Post ReplyReply Direct Link To This Post Posted: Jun/10/2016 at 5:57pm
nice work! looks tight, were you able to weld 360 around the header tubes?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jrsjav Quote  Post ReplyReply Direct Link To This Post Posted: Jun/11/2016 at 11:49am
Remflex header gaskets are the real deal, I really like mine.






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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greyhounds_AMX Quote  Post ReplyReply Direct Link To This Post Posted: Jun/11/2016 at 5:05pm
Thanks guys. It's been a fun project so far.

It was kind of tough to weld between the two center pipes, but I used two rear axle leaf spring wedge plates to open the gap between the two pipes slightly and that helped.

I considered using the ball and socket setup at the collector, but heard a few problems with them. Next thought was the setup like Dennis has except with spring loaded bolts, as I see that on lots of Imports and it seems to work well. But it's typically only a single pipe so rotation around the joint is possible, but when you add a second pipe to the mix like in a V8 application there wouldn't be rotation, but translation.

With that in mind I've decided to us a flex joint on each pipe. The flex joints alone should relieve enough stress to let the gaskets live longer, but I'm getting rid of them as well. The plan is to weld reducers right to the collectors, follow that with the flex pipe, and then join that to the rest of the system with a stainless band clamp.


Chris ("Mojo")
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jun/11/2016 at 6:09pm
Menace's idea was mine for my custom headers, though i will be doing the old 70s Vette style through air vents. Yep, i know our cars dont have air vents behind the tires. But who sez a Humpter can't. I have removed the fresh air box at both ends of my cowl to help facilitate for room and ventalation of the extra heat behind the fender.

I never liked the tri bolt collector with flat flanges. Doing offset grouping with ball socket design allows both for good sealing and ease of mating if off angle by a wisker.

Though Greyhound, does a great job ironing out issues like pro.

Great to see fixes not patches.



Edited by 304-dude - Jun/11/2016 at 6:12pm
71 Javelin SST body
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel Machine Quote  Post ReplyReply Direct Link To This Post Posted: Jun/11/2016 at 10:14pm
Nicely done. Nice O'scope too!

-Steve-

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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2016 at 11:29am
Really good job! The same technique would work for using a Jeep six cylinder header in a car. 
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote raceral Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2016 at 5:29pm
This style of clamp is also an option.

Al
1969 390 AMX Black,leather, air, 8-Track, auto...
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