Manifold heat shields

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TJS
Joined: Mon 12 Sep, 2005 20:05
Posts: 384

  Z1 roadster
Location: Bucks.

Manifold heat shields

Post by TJS » Tue 10 Apr, 2018 21:00

Has anyone replaced the combined exhaust manifold gaskets and heat shields on a DIY basis ?

They are not leaking however, the rear heat shield element is holed. The original metal weave laminate style has been replaced with what looks like thick grey cardboard. See below

Pondering the job this afternoon it seems the plastic header tank and ignition rail comes off and plugs out, under tray off and loosen the manifold / exhaust clamp before attempting to undo the 12 brass manifold nuts. Space is extremely tight and a snapped stud would be a disaster, probably resulting in removal of the cylinder head to rectify. No way could you drill it out and re-tap the thread with the head in situ.

Alternatively.

1. The car is due an Inspection 1 service and a 5 year / 7k mile cam belt so do I ask the BMW dealer to fit them at the same time ? Although if they break a stud and the head comes off I assume I will pay for it.

or

2. Just live with a holed heat shield and the associated OCD.

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felix
Joined: Sat 02 Jul, 2005 17:25
Posts: 539

  Z1 roadster

Re: Manifold heat shields

Post by felix » Wed 11 Apr, 2018 20:42

Given your garage how could possibly be even thinking there is more than one answer?! :)

a1z1
Joined: Tue 04 Sep, 2007 21:43
Posts: 134

  Z1 roadster
Location: Newark

Re: Manifold heat shields

Post by a1z1 » Wed 11 Apr, 2018 22:11

Hi Bluebaur has a solution that looks good and doesn't require removal of the manifold.

I changed the manifold gaskets on a z1 last year, Shall we say it was character building. :head:

There is a tool that allows the drilling and re-tapping of the cylinder in situ .. but you do need a 90 degree head drill.

The pictured broken stud is at the rear of the engine near the bulkhead.
Image

Image
ImageThe nuts and studs are available as a set.

Good luck!!
________________
1990 Red Z1 (Gone back to the motherland)
1991 Green Z1 (stolen by the wife)
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urzzz
Joined: Wed 18 Jan, 2017 14:56
Posts: 16

  Z1 roadster

Re: Manifold heat shields

Post by urzzz » Thu 12 Apr, 2018 20:08

I don't know anything about nuts or studs, but I wonder if your coolant is a bit low? I understood that the arrows marked the 'minimum'. No doubt would be picked up at Inspection 1 anyway, but maybe one to keep an eye on. Toby
"There are roadsters, then there is the Z1", Brett Fraser, Car Magazine Aug 1989
"The BMW is simply superb", LJK Setright, Car Magazine, Apr 1990
"It's impossible to drive without a smile", Rowan Horncastle, TopGear.com Sep 2017

sfh3l
Joined: Fri 02 Sep, 2005 17:07
Posts: 556

  Z1 roadster
Location: Buckingham

Re: Manifold heat shields

Post by sfh3l » Tue 17 Apr, 2018 11:28

My coolant always goes down when cold and up to the line when warm :-)

The studs do have a tendency to break, as well as unwinding themselves occasionally. I have not long ago done all of this on my 318is, where the manifold was cracked and needed welding. I got it off and removed all the studs to replace as a precaution. All came out like good boys and girls, so I was lucky.

Personally, I would suppress the OCD and live with it. It could be a bitch of a job (simple enough if all goes well) and my thoughts would be that sooner or later you'll need to do something that necessitates a head-off or engine-out job, at which point it comes into play as another little job to add to the list of things you'd do if you had to.

M20's tend to blow head gaskets and crack heads. One of us will, sooner or later experience this and that is a perfect opportunity to attend to nasties like this one. Till the, for me at least it is another of those dogs that continue to sleep soundly :roll:
Best regards,

Sam Lever.

Anyone who says money isn't everything hasn't found the right classic car yet.
Z1 - 3.0csl - 987 Boxster - Austin 7 Special - Rolls 20 - '72 911 - '95 318is
Black Sport Evo M3 & SG M3 CSL - now someone else's pleasure
Blue 2800cs - now someone else's pain
Old cars - the original "Not for Profit" organisation
Independent Financial Adviser in Buckingham
My Financial Blog

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Jet
Joined: Fri 14 Nov, 2003 16:24
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Re: Manifold heat shields

Post by Jet » Wed 18 Apr, 2018 08:11

TJS wrote:
Tue 10 Apr, 2018 21:00
They are not leaking however, the rear heat shield element is holed. The original metal weave laminate style has been replaced with what looks like thick grey cardboard. Just live with a holed heat shield and the associated OCD.
OCD is usually triggered by the 'visible', so as the gasket isn't the issue, and its the heatshield that bugs you out, cut away the shield leaving the gaskets in situ. Cut a new gasket leaving the shield, combine the 2 with an invisible join, no more OCD.

After 28 years and 30k miles, I wouldn't attempt to remove those nuts unless necessary.

sfh3l
Joined: Fri 02 Sep, 2005 17:07
Posts: 556

  Z1 roadster
Location: Buckingham

Re: Manifold heat shields

Post by sfh3l » Wed 18 Apr, 2018 08:42

[/quote]

OCD is usually triggered by the 'visible', so as the gasket isn't the issue, and its the heatshield that bugs you out, cut away the shield leaving the gaskets in situ. Cut a new gasket leaving the shield, combine the 2 with an invisible join, no more OCD.

After 28 years and 30k miles, I wouldn't attempt to remove those nuts unless necessary.
[/quote]

Couldn't put it better myself. Get therapy for the OCD TJS and don't worry about your nuts :D
Best regards,

Sam Lever.

Anyone who says money isn't everything hasn't found the right classic car yet.
Z1 - 3.0csl - 987 Boxster - Austin 7 Special - Rolls 20 - '72 911 - '95 318is
Black Sport Evo M3 & SG M3 CSL - now someone else's pleasure
Blue 2800cs - now someone else's pain
Old cars - the original "Not for Profit" organisation
Independent Financial Adviser in Buckingham
My Financial Blog

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TJS
Joined: Mon 12 Sep, 2005 20:05
Posts: 384

  Z1 roadster
Location: Bucks.

Re: Manifold heat shields

Post by TJS » Mon 23 Apr, 2018 11:34

Thanks to all for the advice and input. Hmmm...

I used the car yesterday for the first time in 18 months (good to see you Sam) and it runs perfectly. It's the rear heat shield which is holed, it just bugs me.

Image

Patching with the heat shield element of the new gasket is an option but there is not a lot of the old shield to rivet to. Having recently rectified a broken rear manifold stud on another straight 6 (Land Rover) I know what Ivor means about "character building". Luckily a nut could be tacked onto the remains of the stud and it came out. As usual the job evolved into a longer list of tasks on the "may as well why were are here" principal to include de-coke, head skim, new head gasket, water pump rebuild, manifold gasket, new exhaust values and stem seals. Something I would prefer avoid on the Z1.

On balance I don't think I am going to risk a problem on replacement but will fit a couple of thermal sleeves over the two plugs leads above the hole. They worked well on the TVR which had almost nuclear levels of engine bay heat. This will also give me time to attend CDO therapy, (the acronym letters need to be in alphabetical order) and attend to my other nuts.

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Jet
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Re: Manifold heat shields

Post by Jet » Mon 23 Apr, 2018 14:24

TJS wrote:
Mon 23 Apr, 2018 11:34
This will also give me time to attend CDO therapy, (the acronym letters need to be in alphabetical order) and attend to my other nuts.
:D :D

sfh3l
Joined: Fri 02 Sep, 2005 17:07
Posts: 556

  Z1 roadster
Location: Buckingham

Re: Manifold heat shields

Post by sfh3l » Mon 23 Apr, 2018 16:59

Good to see you too TJS. I'm glad the nuts are OK and I agree re the shields. In any case, I reckon you'd need a licenced asbestos removal contractor in to do it for you.....

Got as far as Chuny-sur-Semois, Belgium in one piece in the 911. Oh ye of little faith !:-)!
Best regards,

Sam Lever.

Anyone who says money isn't everything hasn't found the right classic car yet.
Z1 - 3.0csl - 987 Boxster - Austin 7 Special - Rolls 20 - '72 911 - '95 318is
Black Sport Evo M3 & SG M3 CSL - now someone else's pleasure
Blue 2800cs - now someone else's pain
Old cars - the original "Not for Profit" organisation
Independent Financial Adviser in Buckingham
My Financial Blog

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