Repairing juction of exhaust manifold /cat (4 pipes)

Repairing juction of exhaust manifold /cat (4 pipes)

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cornish pasty

Original Poster:

135 posts

187 months

Friday 26th September 2008
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Hi guys, just redaing that people having problems with exhaust junction leaking(four pipes) had same problem and it sounds bit like tappets.Looked on Chimera pages and they had idea of placing 2 bungs up tail pipes,one with tube in it connected to compressor. I thought this was a good idea until I tried to source 60mm bungs on internet,they cost approx £18.00 each,so came up with my own ideascratchchin. Get and spray bottle with water in it add few drops of Fairy liquid,spray quite a lot around junction of pipes when engine cold. Now with the help of someone start engine,get assistint to gently restrict exhaust at tail pipes. If like mine both sides of exhaust leakingidea.Get small tub of fire cement from plumbers merchants (approx 500 grams),some fiberglass matting.Cut matting into approx 15mm long strands,take half handfull of fire cement and approx half handfull of fiber glass strands and mix together (damp hands before to make more pliable if needed, make plastacine like consistancey). Get special tool (see pic) paint roller, without roller.Mark roller and exhaust,to position of junction of the four pipes (so that you not ramming mix into cat).Now soak junction of pipes with water (fire cement sticks better to wet surface). You the roll a chipolatta sized portion of fire cement mix.You might want to ask your assistant to look away at this stage. Slide your chipolatta into wet juction,biglaugh now with special tool gently push into position, then take more fire cement mixture and fill in joint over the top of this (see pic)Wet area and smooth over. Job done, start engine for approx 1 min every now and then to help fire cement to set. Dont run engine to long as you dont want it getting to hot to quick ,It will go rock hard overnight. Cheers Mateys C/Pthumbup

cornish pasty

Original Poster:

135 posts

187 months

Friday 26th September 2008
quotequote all

cornish pasty

Original Poster:

135 posts

187 months

Friday 26th September 2008
quotequote all

Chimjunkie

2,879 posts

210 months

Friday 26th September 2008
quotequote all
Nice idea. The problem i would anticipate with anything like that is the stuff not expanding and contracting with the metal and therefore breaking up after a short time. Would prob stink for a bit too! I tried GunGum, worked for a while.

Chimjunkie

2,879 posts

210 months

Friday 26th September 2008
quotequote all
Rather than cutting the manifold clean in half to gain access for internal welding, then using a jig to hold it whilst being welded back together, could a large access hole be made using a plasma cutter? i.e no jig necessary. Anyone see a flaw in this idea? Assume precats are no longer.

cornish pasty

Original Poster:

135 posts

187 months

Friday 26th September 2008
quotequote all
Chimjunkie said:
Nice idea. The problem i would anticipate with anything like that is the stuff not expanding and contracting with the metal and therefore breaking up after a short time. Would prob stink for a bit too! I tried GunGum, worked for a while.
Hi Chimjunkie, Been plumbing and heating engineer for over 36 years used fire cement for sealing boiler flues and wood burners all these years, I would say it would withstand even higher temp than exhaust on Chimera. and no you cant smell a thing.(just using fiberglass strand not resin)It sets harder than concrete, and if you have ever tried to get it off you would know that sticks to metal work well(you must dampen exhaust first). I added the fiberglass strands to bond it even more, and to prevent fire cement from entering the cat,before it sets. Have used the car for approx 100 miles since I put it in, will keep you posted if it comes out. If you have this problem give it a try it will cost you less than £10.00 Cheers Matey C/P rotate

Chimjunkie

2,879 posts

210 months

Friday 26th September 2008
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Now that's a pretty good endorsement!

Edit to add: Cornish, can you do 1000miles this weekend please so I can make a decision on what to do with mine!!

Edited by Chimjunkie on Friday 26th September 21:05

Tahiti450

712 posts

236 months

Friday 26th September 2008
quotequote all
Chimjunkie said:
Rather than cutting the manifold clean in half to gain access for internal welding, then using a jig to hold it whilst being welded back together, could a large access hole be made using a plasma cutter? i.e no jig necessary. Anyone see a flaw in this idea? Assume precats are no longer.
Having done this job previously I tried initially "windowing" the collector to allow me to get the mig welder neck into the work area. This just proved frustratinga nd there was no way of confirming what was going on and checking that any cracks had been fully repaired. I ended up slicing the collector in half (thin cutting disc) having marked a cut line and made some alignment marks at right angles to ensure accurate reassembly. This allowed unrstricted access to the junction area, clean and grind the weld area and get properly penetrated welds which could then be tidied up with a die grinder. Welding the collector back together was straightforward (you dont need any jigs) once the marks were alligned and a couple of tack welds made. Neat welds and careful grinding back leaves a barely noticable scar. No need to disturb the pre-cats (less you want to, in which case they are easily removed) and my manifold has been fine ever since (did the job about 3 years ago). It sounds like a right palava but the job is actially quite straightforward (the most difficult bit is removing and refitting the manifold really).

cornish pasty

Original Poster:

135 posts

187 months

Friday 26th September 2008
quotequote all
Have just the tool if you would like to cut exhaust,designed to cut stanless steel up to approx 5"dia.(I used it to cut off old outrigger, and works a treat by rotating approx 45o around pipe)
But would still think the prototype pasty paste (patent pending) is still easier and worth a try first.

Chimjunkie

2,879 posts

210 months

Friday 26th September 2008
quotequote all
cornish pasty said:
Have just the tool if you would like to cut exhaust,designed to cut stanless steel up to approx 5"dia.(I used it to cut off old outrigger, and works a treat by rotating approx 45o around pipe)
But would still think the prototype pasty paste (patent pending) is still easier and worth a try first.
Really considering this. Just looked up info on fire cement! If the stuff sticks to the metal then i see no probs! Got to be worth a good temp solution at least. Going to wrap the exhausts again so wont show.

Get the patent app in!

Edited by Chimjunkie on Friday 26th September 21:54

cornish pasty

Original Poster:

135 posts

187 months

Friday 26th September 2008
quotequote all
Try it, send you "Martins Dairy pasty" by return of post if it falls out. (Secret pastys that Emits dont know about!!!)

Chimjunkie

2,879 posts

210 months

Friday 26th September 2008
quotequote all
cornish pasty said:
Try it, send you "Martins Dairy pasty" by return of post if it falls out. (Secret pastys that Emits dont know about!!!)
Is gonna take a lot to beat the apple pie i've just had lick

TVRobin

141 posts

211 months

Friday 26th September 2008
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I recently replaced both my manifolds with ones that had been decatted because my off side one had the same problem. Near side is fine if someone wants to buy it? BTW it had decatted itself (found the cat in the y-piece)! Have the y-piece as well.

Chimjunkie

2,879 posts

210 months

Saturday 27th September 2008
quotequote all
TVRobin said:
I recently replaced both my manifolds with ones that had been decatted because my off side one had the same problem. Near side is fine if someone wants to buy it? BTW it had decatted itself (found the cat in the y-piece)! Have the y-piece as well.
Not for me thanks. Unless it comes with a warranty and an installation cost reimbursement if it leaks!

Have some Fire Cement in my hands!! laugh

Chimjunkie

2,879 posts

210 months

Saturday 27th September 2008
quotequote all
Bit of a catch 22 on this one. Want to do the repair and wrap the exhaust manifolds before fitting back onto the car. But the Fire Cement instructions say get it up to maximum working temperature within 3-4 hours of application. Hmmmm. So, had to put manifolds back on without repair or wrapping.
Need them on to test if the engine runs after my rebuild. May then take them off again to wrap properly...

Oh how I love putting them on and taking them off.

tvrbob

11,171 posts

254 months

Saturday 27th September 2008
quotequote all
cornish pasty said:
Looked on Chimera pages and they had idea of placing 2 bungs up tail pipes,one with tube in it connected to compressor. I thought this was a good idea
Hi Grant that would be me. My manifold is still leaking, I was planning to swap for some ACT de-precatted manifolds but I could never bring myself to tackle the removal job.

I do like your solution and will think seriously about having a go at that.

Please consider writing it up with pictures to submit to Chimaera Pages. This sort of advice is perfect for that site

cornish pasty

Original Poster:

135 posts

187 months

Saturday 27th September 2008
quotequote all
Chimjunkie said:
Bit of a catch 22 on this one. Want to do the repair and wrap the exhaust manifolds before fitting back onto the car. But the Fire Cement instructions say get it up to maximum working temperature within 3-4 hours of application. Hmmmm. So, had to put manifolds back on without repair or wrapping.
Need them on to test if the engine runs after my rebuild. May then take them off again to wrap properly...

Oh how I love putting them on and taking them off.
Just move Sunday roast over to one side and stick in oven hehe

cornish pasty

Original Poster:

135 posts

187 months

Saturday 27th September 2008
quotequote all
tvrbob said:
cornish pasty said:
Looked on Chimera pages and they had idea of placing 2 bungs up tail pipes,one with tube in it connected to compressor. I thought this was a good idea
Hi Grant that would be me. My manifold is still leaking, I was planning to swap for some ACT de-precatted manifolds but I could never bring myself to tackle the removal job.

I do like your solution and will think seriously about having a go at that.

Please consider writing it up with pictures to submit to Chimaera Pages. This sort of advice is perfect for that site
Thanks for that will do, if I come up with any other ideas will post on site.yes

fatboychim

976 posts

250 months

Saturday 27th September 2008
quotequote all
Chimjunkie said:
Bit of a catch 22 on this one. Want to do the repair and wrap the exhaust manifolds before fitting back onto the car. But the Fire Cement instructions say get it up to maximum working temperature within 3-4 hours of application. Hmmmm. So, had to put manifolds back on without repair or wrapping.
Need them on to test if the engine runs after my rebuild. May then take them off again to wrap properly...

Oh how I love putting them on and taking them off.
I occasionally have access to an induction hardening oven (great for stripping powder coat of wishbones)Do you know what sort of temperature would they need to go to?

Chimjunkie

2,879 posts

210 months

Sunday 28th September 2008
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Product says working temperature. I thought best to do what Cornish suggested in the first post about running the engine for short periods to gradually bring the temperature up. Would have thought this is over 400 deg?