Fitting Aftermarket Exhaust Manifold/Headers

AliK

AliK

Vehicle Dating Officer
Staff member
Club Member
SeanDezart said:
Why not attach it to the LHside chassis rail ?
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Wot he said! Just look at where your brake line is and you will see that you can piggy back onto the chassis rail without drilling holes. I wouldn't tie anything to the header - just too much vibration and heat which you may cry about in the future.

That heatshield stuff is the same as I'm going to use.

atomman said:
I replaced my studs with stainless items with a Allen key hex in the end and used copper exhuast nuts to hold it all on,
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I also used the ginger nuts - just be mindful that they do discolour with heat if that matters to you!

One word of caution on stainless: if you read up about the nobility of metals you will note that Stainless steel studs and aluminium in the head will produce a galvanic reaction welding them together at the atomic level over time.

https://www.bssa.org.uk/topics.php?article=89
 
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uk66fastback

uk66fastback

Club Member
https://www.zcar.com/forum/10-70-83...old-exhaust-header-manifold-bolts-m8-m10.html

For an indication as to torque specs ...
Is there room to KEEP the original heatshield (I presume you can still refit that with Sean's header) AND then cover that somehow with the stuff you're getting - or maybe there just isn't the room.

My old V8's JBA long headers didn't half create some heat 'down there' (and from FOUR pipes per side of course, not SIX on the ONE side)
 
Woody928

Woody928

Events Officer
Staff member
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SeanDezart said:
Why not attach it to the LHside chassis rail ?
Click to expand...

AliK said:
Wot he said! Just look at where your brake line is and you will see that you can piggy back onto the chassis rail without drilling holes. I wouldn't tie anything to the header - just too much vibration and heat which you may cry about in the future.

That heatshield stuff is the same as I'm going to use.
Click to expand...

Thanks chaps, I'm now on the same page and now fully understand the much better idea! I'll give it a go.

Any idea how much meterial I'll need? (I havent got immediate access to the car immediately to measure up)

uk66fastback said:
https://www.zcar.com/forum/10-70-83...old-exhaust-header-manifold-bolts-m8-m10.html

For an indication as to torque specs ...
Is there room to KEEP the original heatshield (I presume you can still refit that with Sean's header) AND then cover that somehow with the stuff you're getting - or maybe there just isn't the room.
Click to expand...

Perfect, thanks Mike :)

I hope so as that's my plan, I want to fit the headers and keep the stock shield ontop of this Nimbus heatshield material. Mainly as it hold my throttle return springs so is very useful, I think it'll be tight but fingers crossed. I'm sure I'll report back soon enough.
 
SeanDezart

SeanDezart

Well-Known Forum User
uk66fastback said:
Is there room to KEEP the original heatshield (I presume you can still refit that with Sean's header) AND then cover that somehow with the stuff you're getting - or maybe there just isn't the room.
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I don't believe that the stock heat-shield can adequately protect twin carbs from 6x protruding larger (therefore surface) pipes compared to 2 non-protruding smaller stock downpipes.

I also believe in keeping the heat off/away not only from the carb bodies but the inlet pipes too !

That means a full shield from the head to the chassis rail - think about it - do you only half wrap the headers, do you only half ceramic-coat them ?
 
uk66fastback

uk66fastback

Club Member
I was forgetting about the return springs ... so the heatshield will go OVER the flexible material that you're attaching (somehow). Got you. It'll be interesting to see what arrangement you come up ... what have other people with headers done?
 
SeanDezart

SeanDezart

Well-Known Forum User
Simples - you perce the shield, protecting the hole with a wahser each side and attached the return spring to them.
 
Alphabettispaghetti

Alphabettispaghetti

Club Member
SeanDezart said:
I don't believe that the stock heat-shield can adequately protect twin carbs from 6x protruding larger (therefore surface) pipes compared to 2 non-protruding smaller stock downpipes.

I also believe in keeping the heat off/away not only from the carb bodies but the inlet pipes too !

That means a full shield from the head to the chassis rail - think about it - do you only half wrap the headers, do you only half ceramic-coat them ?
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You’d never fix from the engine to the chassis rail as all that torque movement has to go somewhere.
 
SeanDezart

SeanDezart

Well-Known Forum User
franky said:
You’d never fix from the engine to the chassis rail as all that torque movement has to go somewhere.
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You're right, as usual.
 

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SeanDezart

SeanDezart

Well-Known Forum User
franky said:
im not following. Just whatever makes the individual/owner happy.
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I think, sometime, in the last few months, you've misplaced your sense of humour and become very cynical, a nay-sayer whereas before anything was possible.

Whatever the shyt is that's got hold of my mate France I commend thee to leave - in the name of the Lord Z and the holy church of L - begone so that Fleece-man can live life and laugh.

You need to drive a Z - get those veins working again mate.:)
 
AliK

AliK

Vehicle Dating Officer
Staff member
Club Member
franky said:
so what happens when the engine moves?
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Interesting question Mr Franky, I thought the same when I saw Zs with heat-shields as Sean has posted. From what I saw in the flesh, there is built in slack to allow for some movement. I.e. The shield can flex on one of it's fold lines.

You'll never fully get rid of convection, but that config diverts it away from directly up. Experimenting with different home made heat-shields (none of which I've liked enough to keep) I found with my current MSA header that reducing radiation had the biggest single effect on reducing temps on carb bottoms.
 
jonbills

jonbills

Membership Secretary
Site Administrator
Fwiw, I used to have a shield from head to chassis but it really got in the way.
I swapped to the per-carb heatshields you can get for Webers and Dellortos a year ago and didn't have any heat related problems last year.
 
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