Manifold / header fasteners

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Jorrocks
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Manifold / header fasteners

Post by Jorrocks »

I have run into a bit of a problem fitting my new stainless manifolds. I was wanting to use ARP bolts instead of the original studs which are in any event all mullered. However, as you'll see from the photos, I've run into a bit of a problem!
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The two inner bolts on the outer pipes haven't quite got the necessary clearance to drop into place. I think I could take a Dremel and grind away a tiny bit from the offending mounting holes, but is that a bodge too far?? An alternative might be these, but they're only 1.670 OAL compared to the original's 1.750, not sure if that will that leave enough meat to tighten them properly?

http://arp-bolts.com/kits/ARPkit-detail ... ordID=2045" onclick="window.open(this.href);return false;

The flange on the headers is 3/8" thick.
1972 Interceptor MkIII (128/4886)
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garyc
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Re: Manifold / header fasteners

Post by garyc »

Unless you are screwing into aluminium then 1.5 x the (bolt) thread diameter will be more than enough outside of aerospace work 1x thread dia in mild steel is the norm....with aluminium you try to get 2x thread engagement due to material softness

It looks like you may able to trim the bolts back and still achieve 1.5 x by your pictures.

If you think about it another way how deep is a nut that would fix the bolt be....thats a quick rule of thumb guide but is dependant on material
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Grant
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Re: Manifold / header fasteners

Post by Grant »

Eric, you need to put studs in the heads and then use brass long reach nuts... Andy or Robeys do a complete setImage
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jpmf
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Re: Manifold / header fasteners

Post by jpmf »

Grant wrote:Eric, yu need to put studs in the heads and then use brass long reach nuts...
Long reach nuts won't work in there either, don't ask how I know :wink:

They will work on all but four studs.
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Grant
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Re: Manifold / header fasteners

Post by Grant »

jpmf wrote:
Grant wrote:Eric, yu need to put studs in the heads and then use brass long reach nuts...
Long reach nuts won't work in there either, don't ask how I know :wink:

They will work on all but four studs.
Hello Justin :P
Maybe they are not called long reach then, but they are longer than normal nuts and are sold as a stud and brass long nut kit from the usual suppliers :wink: .. you've got me thinking now :? .. Dam sure that's what I used :?
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Re: Manifold / header fasteners

Post by Jorrocks »

Gary,
Thank you for that formula, I may try trimming the bolt a touch, but I think the ARP studs may be the way forward subject to confirming the relative lengths of the coarse & fine threads.

Hey Grant,
I don't think my engine had those tube nuts as standard (Maybe they were a MK2 fitment?), and as jpmf pointed out, they'd cause the same problem!

Justin,
How did you overcome the problem? I assume you're using tubular headers too?
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Grant
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Re: Manifold / header fasteners

Post by Grant »

Jorrocks wrote:Gary,
Hey Grant,
I don't think my engine had those tube nuts as standard (Maybe they were a MK2 fitment?), and as jpmf pointed out, they'd cause the same problem!
I put the studs and nuts on my MK3 convertible 440ci with the Headers Eric, the studs and nuts can be bought as a Kit from the usual suppliers... Why you no listen Eric!! :twisted:
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Re: Manifold / header fasteners

Post by Jorrocks »

:oops: Sorry Grant! If I can't get the ARP's to fit I'll talk to Andy!
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Re: Manifold / header fasteners

Post by jpmf »

[/img]
Jorrocks wrote:Gary,

Justin,
How did you overcome the problem? I assume you're using tubular headers too?
Four standard length brass nuts in the tight corners and long reach nuts on all d'others.
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Kevin Birch
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Re: Manifold / header fasteners

Post by Kevin Birch »

Studs are the way to go, when my manifold gasket went, I replaced the studs with bolts, but had difficulty sealing them as they go into the water jacket, and ended up with a little water loss past the threads. The studs are 3/8 UNC in the head and 3/8 UNF for the brass nut, I bought mine off Ebay, you'll need 2 lots, but will have some spares. Cut and paste this link:
http://www.ebay.co.uk/itm/Exhaust-Manif ... 2749.l2649" onclick="window.open(this.href);return false;
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Dino Fritz
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Re: Manifold / header fasteners

Post by Dino Fritz »

Hi everyone,

Maybe I’m looking at the problem a little differently, but I’d go to an exhaust place and get them to re-bend the pipe to give you the clearance you need. It looks like it turns a little too abruptly near the head (if I remember my Mopar Speed Secrets book, they should ideally come out straight for the first inch or so) and besides, you have a join around 6 inches away so it shouldn’t be that hard of a job. FWIW, I had a similar problem with my first set of headers, and when I figured out a way around it, the dummy fit then found that I couldn’t get a spark plug out. That was the point that I gave up on that set!

If this bolt is the only one you have a problem with, fix the bend I’d say - no more problems in the future if you have to take them on and off (don’t forget the trial fit the spark plugs and the leads too)!

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Jorrocks
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Re: Manifold / header fasteners

Post by Jorrocks »

Thanks all. I think Kevin’s link solves the problem!
1972 Interceptor MkIII (128/4886)
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