Technical Replacement CAT

[koalar]

hit a pothole with the exhaust clamp that's caused a crack in the CAT.

found one at the breakers for £30. Not easy as most breakers now take them off and cash them in.

New clamp 80p and gasket £2.50 plus vat. Still had a bit of silicon seal left for the join to the centre pipe.

As a bonus I got £10 back from the scrap metal man.

As a double bonus I now have two known working lambda sensors spare.

Put the exhaust clamp on upside down. Gives an extra few mm clearance.

 

[DaveMcT]

The catalyst outlet pipe should have a support bracket located ahead of the "cat back" pipe clamp. Mine had all but eroded away so made a new one from steel strip and an exhaust clamp.

If your's has no support bracket its possible that was the cause of the crack with the impact finally finishing it off.

 

[koalar]

hit the exhaust clamp quite hard. Smashed the tread of one side down to the squashed nut. Pretty big bang considering I was only going 2 or 3 mph


Not the first time I have hit it and it won't be the last. Ground clearance at the front is marginal on farm tracks sump also has a few battle scars.

 

[Pugglt Auld Jock]

Hi Koalar. Nice to see you solved your problem so economically. However I feel concern for you as you mention having "silicon seal" left over. Apologies if you know this already but, Silicon is poison to both catalytic converters and oxygen sensors. You should never use it upstream of either of these components.

I've become a bit obsessed with this since learning of it several years ago and now always make sure to buy "safe" products for use anywhere that cross contamination might occur. (so for cam cover, sump, etc - where it can leech into the oil - water pump, thermostat housings, etc - where it can leech into the coolant - and, especially, exhaust systems) anywhere that could end up in exhaust gas contamination.

I am currently using Loctite SI 5980 on things like cam covers, water pumps etc and ABRO exhaust cement (part no ES 332) on exhausts. I prefer if possible to fit cat/front pipes "dry" if possible (often a new gasket is all that's needed)

 

[koalar]

Hi Koalar. Nice to see you solved your problem so economically. However I feel concern for you as you mention having "silicon seal" left over. Apologies if you know this already but, Silicon is poison to both catalytic converters and oxygen sensors. You should never use it upstream of either of these components.

I've become a bit obsessed with this since learning of it several years ago and now always make sure to buy "safe" products for use anywhere that cross contamination might occur. (so for cam cover, sump, etc - where it can leech into the oil - water pump, thermostat housings, etc - where it can leech into the coolant - and, especially, exhaust systems) anywhere that could end up in exhaust gas contamination.

I am currently using Loctite SI 5980 on things like cam covers, water pumps etc and ABRO exhaust cement (part no ES 332) on exhausts. I prefer if possible to fit cat/front pipes "dry" if possible (often a new gasket is all that's needed)

valid point. I should have put a warning about using silicon seal upstream of the lambda sensors.

This is on the back of the CAT so downstream from both sensors.


The silicon seal I used came from one of the pound shops. Its now done several repairs over several years and still going strong.

 

[Pugglt Auld Jock]

The silicon seal I used came from one of the pound shops. Its now done several repairs over several years and still going strong.

Aye, a little goes a long way. Often dries up into a hard unusable lump in the tin! One of the things I like about the ABRO is that it comes in a "toothpaste" tube so as long as you remember to put the cap back on it doesn't dry out!

 

[DaveMcT]

It sounds like you need a bash plate on the car.


You could also consider a Mikalor type clamp which uses a band and bolt so has less sticking out to get smacked-off.

https://www.ebay.co.uk/itm/MIKALOR-...z8WPOWFwvqri9bSMnw:rk:1:pf:0&var=520480960076

My outlet pipe clamp had all but dissolved so I wonder if it was a galvanic issue between plain steel clamp and stainless cat outlet pipe. Who knows - it was probably >10 years old.