'How to' move drivers collector 1.5-2" away from the en

[Modern Motorsports Ltd]

OK, I'm finally going to get going on my resolution to improve upon my current restrictive header/exhaust system.

 

I've got some Hooker 2100's enroute (1-5/8's shorties) which I've driven in enough combo's to be quite happy with, especially once on my mill.

 

On my 280ZX my drivers side steering rod forced me to move the drivers side collector outward ~1.5" by bending/torch etc....OK job but not eager to do again as the same handy tools aren't available and I'd like a different solution.

 

So who's got what ideas? An angle milled flange, even welded up to new headers allowing me to port match and a 10-15 degree angle should give me all the 'outward' displacement I need......then spot milling on front side so bolts sit flat or....milled 'reverse angle washers'?

 

A spacer at my header/head interface with a milled angle on it........~10 degrees would give me near an inch-1.5" depending on how long your headers are (1" outward per each ~6" in length)..........then I need a reverse angle on the other side so the bolts sit flat as well..............

 

Local guy did a million dollar looking aluminum angle milled 'spacer' ~1" thick to just what I'm suggesting......and he made reverse angled 'washers' to sit under his bolts......but he's a machinist and his TOTAL Z suspension is all adjustable heims..........as much $ in his heims alone as my whole suspension likely.

 

Any and all ideas welcome....my steering will NOT easily take an extra Ujoint as only alternative route takes it right thru my motor mount which does not easily have room to accomodate this.

 

And has anyone ever used the 'bell' ends on their headers or pipes? The compression style/no gasket ends? I'm wondering why not as they just look more leak free and friendlier to re and re.....do they just cost more?

 

Here's a pic of the flanges I'm talking about...they seem easier to seal/service and less sensitive to 'precise' geometry?

 

The header on the far right is the 2100 I'm getting.

[jeromio]

I've done this before on a different project. The simplest thing to do is to cutt off the flange, trim the ends of the pipes (angled so it moves the collector where you want it), then weld it back on.

 

You can sawzall the thing off, leaving a cm or so of metal (on the top in this case) to then play around with optimizing the angle. Then measure it, cut, trim to that angle, weld it back on. You obviously have to have the thing re-coated (if it was coated to begin with).

 

Your pipes will end up being about 3/8 to 1/2 inch shorter, but that usually isn't a problem.

[Modern Motorsports Ltd]

The simplest thing to do is to cutt off the flange, trim the ends of the pipes (angled so it moves the collector where you want it), then weld it back on.

Thanks, I've been thinking on this one before and I'd likely have a new flange cut which matches my edelbrock rpm ports. The header flange is roundport and my headers square...might be able to just port the header flange already on them depending on what port size they are now. Thanks! I'd pretty much assumed I'd have some custom work done and get them recoated once I was satisfied they were working as desired. I much prefer the weld 'once' solution you suggest for it's simplicity. I'll have the O2 sensors put in at the same time:)

 

Related to my potential task....what's the best bang/buck sawzall??

[Guest Anonymous]

A small pie cut of a .25" or so (or whats needed to move it wherever) and reweld it? Just a thought.

 

Regards,

 

Lone

 

Ps: I like Makita or Milwaukee sawzalls. For a jigsaw to be used for metal, we had GREAT luck with porter cable they positively rocked on 16-18 gauge steel although the small bearings inside will need replacing, but that was after a year of constant usage, you didn't ask about a jigsaw, but I'd have to imagine that porter cable (previously rockwell btw) would have a good sawzall as well.

[jeromio]

I'm pretty happy with my DeWalt. But, if I were to buy one now, I'd buy the PorterCable (they didn't have one when I bought mine). They have one that has the quick release, high amp motor and it's reasonably priced.

 

Milwakee is always a good bet (if you can afford it - tend to be more expensive).

 

Oh, and this may be a stupid comment, but it almost sounded like you were suggesting porting the flange before welding the tubes on. That may not work so well. Ideally, you have the tubes running inside the flange, such that they actually mate to the head ports. Obviously you can just weld the tubes to the outside of the flange (provided the flange has relatively small, head sized ports). But by the time you weld the tubes on, you'd have to re-port the header anyway. Also, with Chevy headers, since those inner tubes are real close together, it's harder to do the welding on the outside. Also also, the weld beads on the outside may interfere with the flange bolts.

 

Here's another stupid comment (but better safe than sorry)- the flange needs to be bolted to like a steel I-beam or something (maybe an old head) when you weld on the tubes. Warpage sucks.

 

I just re-read that and it sorta sounds like I'm bein a know-it-all dork-butt, but, like I said, better safe than sorry.

[Modern Motorsports Ltd]

So anyone ever used those flanges pictured up above? The flared 'bell' flanges???

[Guest Anonymous]

I don't believe I've seen that sort of collector, but from the looks of it, I love it, header collectors gaskets suck, I'm almost ready to go with cast exhaust manifolds because I hate the leaks so much. Those look like they'd be exspensive though...

 

Regards,

 

Lone

[Guest greimann]

As an alternate solution to the steering shaft problem, has anyone tried to relocate the shaft using u-joints and support bearings? Borgeson makes all kinds of shafting, bearings and u-joints for street rod applications.

 

http://www.borgeson.com/systemdesign.htm

 

p.s. OOPS, just reread your "no u-joint" comment.

[Modern Motorsports Ltd]

Great stuff guys I'm enjoying asking some q's

 

I got my headers/ended up getting a new/painted set to modify and then coat once modified.

 

But after doing measurements on my present setup and proposed headers I'm not dead certain of the precise modification required as the angle of my header/head flange is not dead vertical so nailing down the collector angle/lateral distance requires a uniform flat plane......long story short I've got 1-3/8's tolerance total to fit the collector into so ~5/8's per side which is not too much considering I need the collector pulled out ~2.25" and my rides my daily driver..

 

And looking at Hooker's welds they look so fine, already fully finished on inside etc. Seems a rewelded flange might be a lot of work let alone porting that flange after (thanks for the procedural tips Jeromio!). I'll get the welders thoughts on it but an aluminum angled 'sandwhich' is looking more attractive. I can have it made/angle milled to my guesstimated 13.8 degrees and then test fit it all up.

 

A few big advantages here IMO:

-very easy to have this flange remilled sharper or softer if it's not bang on the first try and aluminum's quick to mill so not too pricey at all (ie. not like rewelding a flange or having my car down for multiple days)

-ease of port matching the aluminum to my heads one side and header flange on other..

-if ever required I could easily replace that header without tossing away big mod $ and can easily put another identical Hooker (or other) in it's place (if so I'll likely return my painted set for a coated set)

-last and least but perhaps of some use is once done it could then be replicated for others to use if desired as 280ZX header solutions are not a dime a dozen

 

The assembly would take a bit of finesse/double gasketed etc but once done it should seal up and be a fine solution?? I assume 6061 aluminum should be used to resist warping vs. plane aluminum?? (planned flange would be ~5/16's on top side and 13/16's thick on bottom side, ~2-1/8" tall etc).

[jeromio]

I think your third point is the most compelling argument for this solution.

 

Pretty cool that you can get the machining done so easily. I don't have a mill (anymore - dumbass me left all my toys behind and took a "better" job based on salary in what was (2 yrs ago) the booming telecom industry - oops). Don't have any friends who have them either. Welding is easier for me and so every mod seems like a welding job .

 

Keep in mind that you'll have to either get some angled washer pieces made or counter bore the flange to the same angle as your new plate. I'm also a little leary of the 2 gasket situation.

 

As to the trials, you might try milling the necks of a couple header bolts - narrow the shafts near the head, round the bottoms of the heads - as a way to "mount" the header in place while allowing some wigglin'.

[Modern Motorsports Ltd]

Pretty cool that you can get the machining done so easily.

Well weighng it like I noted above I know it'll take a lot less time to have a piece of flatbar angle milled than the full welding operation so will be cheaper as either rate is hourly and seems to be more suited to my needs (perhaps anyones?). The welding and iron porting would be quite timely and not such a welcome task.

 

The washers will be a similar smaller piece of flatbar that I just cut up and might even contour side lips to 'hold' against header to prevent rotation during install or have flat sides cut so I can hold it square with a 7/16's wrench (for ie.) as I tighten header bolts. I have seen double header/adaptor solutions on some pretty custom rods and in practise race cars that didnt have sealing issues that they passed on. The hooker flange is very beefy and face is milled flat so all looks promising. Separate 'pieces' for the adaptor would be cool (ie. 3 pieces, centre and two outers) but invite install and sealing/uniformity issues I'd fear.