K12 1.0 exhaust gasket and beyond

[RobinC]

Hello everyone!

First post, but I have found answers here before.

So, the local garage "couldn't find the problem" with my leaking exhaust, so I've watched some youtube videos and decided to fix it myself. The garage may have been put off my the very rusty exhaust manifold heatshield - I've broken that off now and have identified a leak from the exhaust manifold gasket. I figure if I have to take the manifold off to replace the gasket I may as well replace the rusty manifold along with the catalytic convertor and it's heat shield, so...

Can anyone recommend a good source for the parts in the UK?

The exhaust gasket seems widely available on the internet

The only manifold I've found so far is apparently included with the catalytic converter, made by Quinton Hazell

https://www.autodoc.co.uk/quinton-hazell/19339131

The heat shields don't appear to be available at all - so am I going to have to buy something such as this Nimbus GII Heat Shield material and form one myself?

Nimbus GII Heat Shield

Nimbus GII is a revolutionary heat shield material, it is manufactured from a double layer aluminium sheet (5.2mm thick) and is double formed. Its double layer aluminium construction gives Nimbus Lite gives a highly efficient thermal barrier with effective noise dampening characteristics. Its...

www.demon-tweeks.com

Any other advice also welcome

 

[RobinC]

So, an update - that catalytic converter doesn't come with an exhaust manifold, which is a shame as mine is deteriorating - it is the cause of my leak

Do I attempt to get it refaced professionally or is it Too Far Gone and time to be getting a new car?

It was going quite well, if slowly up until then. Although I did break a 12mm socket when undoing the manifold nuts. Luckily I live withing walking distance of a Halfords

 

[Micra Paul]

So, an update - that catalytic converter doesn't come with an exhaust manifold, which is a shame as mine is deteriorating - it is the cause of my leak
View attachment 87448
Do I attempt to get it refaced professionally or is it Too Far Gone and time to be getting a new car?

It was going quite well, if slowly up until then. Although I did break a 12mm socket when undoing the manifold nuts. Luckily I live withing walking distance of a Halfords

After detail inspection, if the manifold is crack free then it is normally reusable after joint face clean up. Same applies to the catalyst & its joint faces.

I use DIY paint scrapers to remove old gasket materials & check joint faces level/alignment on a flat surface.

A few hours DIY graft has always worked for me, cheaper & quicker than throwing unnecessary new parts at such an old vehicle.

Good luck

 

[Deleted member 31521]

Did you run in any trouble getting the manifold stud bolts out. and if so are the manifold studs still reusable.
Was removing mine a while back and gave up when the one near alternator wont budge just needs heating up more.

Looks okay once its flatten down again should be reusable. sometimes you can find new ones on ebay from germany ect that look to be in good condition if you do find that it does need replacing.

I found an original heatshield for the top of manifold but was unable to find a converter heatshield but did see one not so long ago that was brand new for a reasonable price would have gotten this if i had managed to get the manifold off.

 

[RobinC]

So, another update: The Micra is now A Project, and has been shoved off the drive to make way for our new car.

I managed to separate the manifold and the catalytic converter using a jig/fixture/stillage? I made out of some pallets to hold it still while I worked on the bolts with a breaker bar, a heat gun set to "600°C" and some Action Can penetrating oil. After a worrying snap - that I am starting to get used to - all 6 bolts came out in one piece.

After watching some YouTube videos, I ordered some rolls of emery paper and prepared a space in my shed. The bench top wasn't quite flat enough so I've improvised with a offcut of concrete slab and a piece of acrylic sheet, then clamped a length of emery paper on top it and worked the mating face of the manifold. Below is the result of 2 hours and 5m of 80 grit emery paper. Not bad for a middle-aged office worker...

But I need to get some more abrasive paper locally - I'm hoping to get the car running before the end of the week, when the tax and insurance run out, and so she can make it up our sloped driveway under her own power.

I can't remember how many of the manifold studs I have loosened - I took one out to measure it so I could buy new ones. Also bought fancy copper-flashed nuts. Starting to worry I won't remember where/how everything else went together

 

[RobinC]

So, this was almost the post where I show you it all back together and working - but I have been hampered by the gasket/sealing ring that was supplied with the new catalytic converter not being the correct one...

The old one was a conical compressed metal affair, that stopped the exhaust manifold and catalytic converter touching; the new one seems to be about 5mm square, 105mm outside diameter, and doesn't seem to make contact with the two parts when fastened together. I'd estimate the old one was about 115mm outside diameter (it fell apart on disassembly and was discarded).

I can't find a part number for the item on https://nissan-europe.epc-data.com/micra/k12e/162-cg10de/exhaust_and_cooling/208/20900/ and I'm not having much joy searching the rest of the internet.

Has anyone else had this trouble? What should I be searching for? Can I improvise with some other material? Is it actually necessary?

 

[RobinC]

Wait, I think I 've worked it out - put the metal ring in the manifold this way round and put the compressible ring on top, then put the cat on and bolt it all together. Once I have cleaned the threads.

 

[John_D]

Out of interest, the six tapped holes in the manifold, which I presume are M8, are they fine (1mm pitch) or coarse (1.25mm pitch)?

 

[RobinC]

Out of interest, the six tapped holes in the manifold, which I presume are M8, are they fine (1mm pitch) or coarse (1.25mm pitch)?

I've just cleaned them out and can confirm they are M8x1.25 - which is good as that's the only M8 tap I've got

Now it is raining and my dinner is ready - more news when I have it.

 

[John_D]

I've just cleaned them out and can confirm they are M8x1.25 - which is good as that's the only M8 tap I've got

Now it is raining and my dinner is ready - more news when I have it.

Cheers, that has helped a lot, I'm about to fit a new cat, onto a BX2 1.4 manifold, to my 1.2 Sport+, and need to source some new bolts (still waiting for the delivery of the manifold). I think I might go the stainless steel route.....
Regards John.....

 

[John_D]

Wait, I think I 've worked it out - put the metal ring in the manifold this way round and put the compressible ring on top, then put the cat on and bolt it all together. Once I have cleaned the threads.View attachment 88613

How did you get on with this? My replacement catalytic converter has just got a flat mating face to go onto the manifold and no location spigot that goes into the manifold, or is there a removable ring that has to be used from the original cat? The original cat is still on the car...