Precat removal - How I did it...

Anonymous · October 22, 2006, 11:33

I've had my 03 Roadster (23k) for nearly a year now.
MR T warranty now expired so I've been living with the nagging worry of the precat issue for a while.
Decided that no matter how small the risk - if the were out then there was no chance of them killing the engine. I looked around for garages to do the job - most places were quoting £120-£160.

I've done a fair bit of maintenance on my old cars (changing oil, brake pads, calipers etc) but nothing on the roadster so was a bit nervous about setting to my pride and joy with a hammer and chisel.
Well - after a few days of liberal plus-gas application (that stuff really is great) I've just managed to remove my manifold and gut the dreaded ceramic killers.
All in all it took around 3.5 hours and I'm pleased to say that all the bolts and studs came off without any problems. Well, except the cat to manifold studs - those boys were well and truly seized on.
After half an hour of straining with a breaker bar my father came up with an ingenious and thrifty solution.

Behold Wonder Tool! s:shock: :shock: s:shock: s:shock: :shock: s:shock:

Say Hello To My Little Friend!

A 12v impact driver. Cost £5.99 from woolworths! I was highly sceptical at first but was soon proved wrong. One quick buzz with this baby and each of the three studs whizzed straight off.
Best £5.99 ever spent - who needs air tools!!!!?

BTW - My precats were in 100% condition - well until they felt the wrath of my lump hammer.

Graeme · December 30, 2006, 12:19

I can't seem to get my manifold off my engine. I've got the cat & silencer off and out the way, but the 5 nuts that hold it onto the engine don't want to move. I'm putting on plenty of WD40 and leaving overnight. I've even tried a 6-sided socket to reduce the likelyhood of rounding off the head (a star shaped one did start sliping and burring the nut) I don't want to snap the stud off as this would be very hard to fix without dropping out the engine.

I might have to just gut the precats and leave the manifold on, but I don't like the idea of this. I was thinking of getting a che's manifold on the GB and this would not be possible if I give up now.

I just don't want to do a half arsed job of it. Anyone have any advice of how to get these 5 nuts off? Is PlusGas much better than WD40 - is it worth trying? I've never even heard of it before this forum.

Thanks
Graeme

Anonymous · December 30, 2006, 13:33

Plusgas is a million times better, as it's a proper penetrating oil. Get yourself some and try it, as those nuts usually aren't too bad.

Graeme · December 30, 2006, 15:12

Just been out to buy some plusgas and given it a quick spray. I'll let it try to penetrate overnight before it try undoing them as I can't really start putting it back together until I have a replacement main cat. Enid B has one to get rid of, he PM'd me about it so I PM'd him back and he's not replied yet. I'm gonna have to buy one from somewhere else soon 'cos my car is off the road until it is fixed and I don't have another mode of transport (apart from lifts from mates/family) s:(

s:(

If I still can't get it off using the plusgas and my socket set, would it be worth trying something like this as simon did (above), or can i get the same effect using my own brute strengh. grrrr. s:lol: :lol: s:lol:

Graeme

Graeme · January 3, 2007, 21:42

Quote from: "garystorey"Around 4 weeks ago the car made a noise like someone had thrown something at a panel whilst passing. This was whilst I was accelerating, then a week or so later whilst reversing out of my garage, from cold I heard another mechanical sound.

This is exactly what happened to me. I was on my way home from work accelerating down a country road when I heard what sounded like a big stick hitting my passenger door/wing. I even pulled over to check the body over for marks, it was that loud. That must have been the precat going down into the main cat.

4 Days later, I started the car (which took a bit of persausion by me flooring the accelerator which is not normally neccesary) to get it out of the drive and it sounded a "mechanical" sound, kinda like a tapping. About 30-40 miles later, my main cat got completely blocked and I lost all power.

Are these noises common when the precat fails, or is it just a coincidence that both me and Gary had them?

Anonymous · January 6, 2007, 19:21

Graeme - Did the plusgas do the trick?

If not I can't recommend those little 12v drivers enough. I was very pessimistic but it really did the trick - frrrumphhh! straight off. Use a good quality impact driver socket though or it'll chew the nut like a good un!

good luck! s:D

s:D

andywood · January 16, 2007, 14:45

All

Excellent info on this issue - have a used 2 from Mr T with 1years warranty but am definately planning on removing pre-cats at some time this year.

One question which I think has not been posed or answered in all I have read on the site:
The cleaning up of 'cat-bits' from manifold is recommended by high pressure water jet or air-line. Is this definately up to the job as I don't want to risk any fragments getting back into the engine i.e. the phrase 'if it ain't broke don't fix it' springs to mind! I don't want to create a problem where there isn't one already.

Is the cleaning up by air-line or jet wash as per the original post on this thread definately good enough, or has anyone found an alternative or effective method?

Cheers very much!

markiii · January 16, 2007, 14:54

just used a hosepipe

done taht on around 30 of them now and no problems to date

roger · January 16, 2007, 14:56

I used ordinary hose-pipe, on both gush and squirt. So far so good!

The cat material doesn't seem to be "glued" to the inside of the manifold, so as long as the pieces are small enough to be washed out, they will be.

Not heard of any other method.

Anonymous · January 16, 2007, 15:02

Quote from: "roger"gush and squirt.

Is that an age thing Roger s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:

If you are that worried why not replace the whole thing with a Che or something similar, which will give you a little extra power.

Rob

roger · January 16, 2007, 15:09

Quote from: "FGRob"
Quote from: "roger"gush and squirt.

Is that an age thing Roger s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:

No comment

s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:

Anonymous · January 16, 2007, 15:19

Quote from: "Graeme"If I still can't get it off using the plusgas and my socket set, would it be worth trying something like this as simon did (above), or can i get the same effect using my own brute strengh. grrrr. s:lol: :lol: s:lol:

Graeme

has anyone actually used that partucular model by chance?

m http://cgi.ebay.co.uk/Challenge-Xtreme- ... 0067141095 m

aaronjb · January 16, 2007, 15:27

Well compressed air should work as well.. though you might succeed in creating a lovely dust-cloud in your garage with that method s:)

s:)

andywood · January 16, 2007, 18:09

Cheers guys

Sounds like there is enough experience behind the hose-pipe technique, I can now go ahead and squirt with confidence s:lol: :lol: s:lol:

Anonymous · February 2, 2007, 13:08

Hmmm - Just been reading this whole post ....Are there many people on here with older 2's that have done 40k/50k or more without any problems at all?

Mines 2002 with 22K miles but I feel like i'm driving a timebomb after reading this s:lol: :lol: s:lol: s:roll: :roll: s:roll:

Cheers,

Liz · February 2, 2007, 14:16

Mine were looked at when the turbo was fitted at just below 70K - they were fine!

peppyuk · April 14, 2007, 18:24

Removed mine at 76k and they were A1.

Anonymous · April 17, 2007, 10:23

Finally got round to removing the manifold last night on my year 2000 36,000 mile 2 (after soaking all fixings in oil for 3 days), and the cats both look A1, to my great relief. So yes they can survive intact!
They will be out tonight though and I shall definitely use water to wash out the manifold - the thought of all that dust if I use air, and what will be in it fills me with worries - I can`t hold my breath for that long!
Incidentally, I didn`t have a special O2 sensor removal socket, but used a 22mm ring spanner with no problem.
nicam
added;
Everything back together with no problems - used new gaskets (about £24, but feel that the block to manifold gasket could have been re-used, but would suggest that the manifold to flexible pipe gaskets are always replaced. Comparing the new and old, they crush to fit as you tighten the joint up so should be 1 use only.
Sounds a bit "throatier", but maybe thats wishful thinking!

Anonymous · May 17, 2007, 20:54

I am about to attemp this procedure but are there any torque specs when reassembling? The exhaust manifold, headtsheild, and o2 sensor torque specs? If anyone has em let me know.

carl_evs · May 17, 2007, 21:27

3 White Knuckles!!! Hehe

Anonymous · May 17, 2007, 21:49

So no specs just as tight as possible?

aaronjb · May 17, 2007, 21:57

O2 sensors - 44Nm (33lb/ft)
Manifold->head nuts - 44Nm (33lb/ft)
Cat->Manifold nuts - 62Nm (46lb/ft)

Looks like Manifold support->manifold is 49Nm (36lb/ft)
Manifold support->engine block is 37Nm (27lb/ft)

No torque specs on the heatshield bolts shown on the diagram, so it would be from the standard torque table - 25-30Nm should be more than adequate.

spit · May 17, 2007, 21:58

Manifold nuts have a spinning washer face and relatively low torque setting (37Nm/27ftlb).

Man to Cat are locknuts to between 62Nm/46ftlb, the man-cat stud bolts should be re-usable, but if you replace the old ones, the new ones go in at 43Nm/32ftlb.

Heatshield - whatever you can get away with.
O2s - nipped. Handy to Copaslip the thread too so you can get 'em out again s:wink: :wink: s:wink:

*edit - well, one of us is right s:wink: :wink: s:wink: *

aaronjb · May 17, 2007, 22:02

Well at least we agreed on one set of specs s:lol: :lol: s:lol:

I blame my copy of the BGB s;)

s;)

I'd agree on the O2 sensors - there is no need for them to be tight, just up enough so that the washer seals against the bung face or you'll never get the buggers out again s;)

s;)

spit · May 17, 2007, 22:06

I've been supplied with two different types of manifold nut by MrT for the '2 - one with the captive washer and one without - maybe that explains it.

Anyhoo, its barely a finger of fudge difference s:wink: :wink: s:wink: