Removing bypass pipe

[Apothecary]

It's time I need to put my original cat and it's silencer back on.
Having removed the current Raceco silencer (plus the two spring clips connecting the current bypass pipe that's connected to the primaries), I'm now struggling to get the bypass free. I have soaked the four pipes at the joints in penetrating fluid and left for 24hrs to try and ease things but they are still not budging.

Any tips on how to free things sufficiently to pull the bypass pipe off?

Thanks

[Apothecary]

Typical! After posting I just went to have another go and it came straight off

[Scotland North AR]

Hi, I'd suggest leaving the silencer on and tightened up. Then use it CAREFULLY, to provide a bit more leverage and BFI. You can use the elbow on the back of the silencer to give a bit of rotation to it all. One refit you can use some stainless anti-seize compound on the four pipes and end of the bypass into the silencer. Mine comes off pretty quickly each time now.

[Scotland North AR]

Forgot to add, clean all the parts after removal and emery down any burrs.

[aerobod - near CYYC]

With the anti seize on the pipe, ensure it is labelled as Oxygen / Lambda sensor safe. Most of the copper based ones designed for exhausts should be.

[Beagler]

Why would you want to remove it,

A catalytic converter is an exhaust emission control device that converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction.

https://www.gov.uk/government/publications/modifying-your-vehicles-emissions/modifying-your-vehicles-emissions-the-legal-safety-and-health-implications

[ChrisC]

I think it's worth pointing out the Caterham cat in IVA implementations may not be as effective as modern car designs require.  Caterham don't actively heat the cat, and it's location at the end of the primaries half way down the car doesn't help it's heat retention either.  Without heat the reaction needed doesn't occur. It's also not monitored downstream by the ECU to ensure the reaction is happening. Basically it's not cutting edge emissions control technology, more bare minimum amateur car builders emissions loophole to maintain a cottage car industry. 

They can be made to work, heating then with revs for a few minutes before testing is often needed at MOT time and even IVA.  But they can fail due to pop and bangs happening in the delicate honeycomb structure.  You would need to be a scientist to workout the damage done vs the environmental cost of rare metals needed in the cat to give a definitive answer of the environmental point. 
 

Oh but should say, but it is the law to have one. 

[John Vine]

Re #6:

I think it's fair to say that most of us understand the rules (and indeed the chemistry).  For me, the key reason to use a cat bypass is to preserve the cat.  Like me, the OP has a Duratec with rollerbarrels.  The latter are renowned for producing pops and bangs on the over-run, indicating unburnt fuel in the exhaust.  This unburnt fuel can damage the cat to the extent that an expensive replacement is the only solution.  This happened to me some years ago on my R400D, and after my bank balance took the £600 hit, I was in no mood to repeat the exercise.

JV

[Beagler]

Removing the cat will certainly preserve it but the exhaust emission will not then benefit from its presence nor will the law be satisfied. 
I dont think that excuse would satisfy a Magistrate as a defence in law.

[John Vine]

I dont think that excuse would satisfy a Magistrate as a defence in law.

No, it probably wouldn't, but I'm prepared to live with the risk.

JV

[ScottR400D]

Yeah, I think most of us will take our chances.

If by some slim chance we ended up getting a tug, it would still be a lot cheaper than a new Cat, 

 

[Apothecary]

Thanks for the helpful comments. Does anyone have a link to a suitable antiseize compound?

 

[Beagler]

Surprised the Club sanctions it.

[paul richards]

"Surprised the Club sanctions it."

The club doesn't. 
 

If you have any beef why not Caterham who supply a bypass pipe?

[aerobod - near CYYC]

Permatex Ultra Copper is what I have used in the past, this is the European / UK equivalent: https://www.permatex.eu/product/supra-copper-gasket-maker/

It is primarily a sealant, but comes apart easily and ensures proper sealing of the 4 into 1 pipe for correct lambda sensor operation

[ScottR400D]

#13 What's it got to do with the club? 

[SLR No.77]

When I've had an issue in the past separating the silencer or collector from the primaries I've used a ratchet strap between the silencer and rear wheel to apply some steady pressure, then I've gently (and repeatedly) tapped the joints with a hammer. It takes a while to separate but works every time. I guess it's a sort if amateur impact driver in reverse!

Stu.

[Beagler]

I personally don't keep Bovines and Caterham will supply them for track use. 

[John Vine]

...Caterham will supply them for track use.

I think we all understand that as well.

JV

[Geoff Brown]

I wish I had such an attitude of moral superiority when it comes to not fitting a cat by pass.  

[Beagler]

Its not hard just legal. 

[Apothecary]

#6 not sure if the question was directed to me or others but for clarity, my reason for removal is because I wish to now use the car on the public road for which I will need a valid MOT certificate and a cat fitted. The Road Vehicles (Construction and Use) Regulations (Regulations 61(7) and 61A(3)) and the Road Traffic Act 1988 (Section 42) applies to use on the public road which a track is not of course.

Thanks again for advice on the mechanical aspects to those who have contributed. 

[Beagler]

My post was directed to anyone removing a Cat for road use. I did ask why and in the absence of a reply I assumed you were in that group. As you have clarified you are not please accept my sincere apology. I commend you for your compliance with the Regulation requirement. If it assists Rocol produce this anti seize spray used for ovens and very high temperature areas.

 

https://www.bearings-online.co.uk/item/2714/ROCOL/ROCOL-14015-Anti-Seize-Spray.html?vat_inc=true&gclid=EAIaIQobChMIh676_f-h9AIVC7TtCh1MrgNdEAQYBSABEgJDY_D_BwE

 

[Jonathan Kay]

[Beagler]

Thanks Jonathan.