Omega Owners Forum
Chat Area => General Car Chat => Topic started by: MarkG on 29 September 2013, 06:02:50
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I fitted a new exhaust to my car yesterday. The old one was 3 ½ years old and was from Eternal. It had been really very good, nice and quiet with none of the booming you get from other pattern exhausts. The joint between the back box and one of the pipes had rotted through but otherwise the rest of the exhaust was still in pretty good shape. Eternal don’t supply these any more so my new one was from eBay, cost £91 delivered from Poland and when it arrived it was obvious it was by the same manufacturer so I was quite pleased.
Out of curiosity I decided to get my angle grinder out to cut up the old exhaust and find out what is inside those boxes.
First the back box. Exhaust gases go left to right. It was much harder to cut through the steel case which was double skinned and about 5mm thick than I expected. Wadding was in both ends and you can see the baffle pipes sticking into the box which are the pipes with holes drilled in them.
(http://i260.photobucket.com/albums/ii17/markgriffiths/Backbox.jpg) (http://s260.photobucket.com/user/markgriffiths/media/Backbox.jpg.html)
Next the middle box. Exhaust gases go left to right. Once again, it took a determined effort to get into this box and it was much harder to cut through than I expected. Double skinned steel again and about 5mm thick. Lifting the outer double skin revealed a layer of wadding which I moved out of the way to find the case of an inner chamber. I cut through this which was also 5mm and double skinned to see what was inside.
(http://i260.photobucket.com/albums/ii17/markgriffiths/Middlebox.jpg) (http://s260.photobucket.com/user/markgriffiths/media/Middlebox.jpg.html)
This pipe baffle you can see below is on the inlet side. It points into free space inside the chamber.
(http://i260.photobucket.com/albums/ii17/markgriffiths/MBoxcloseup.jpg) (http://s260.photobucket.com/user/markgriffiths/media/MBoxcloseup.jpg.html)
By now I had run out of enthusiasm for cutting another hole in the outlet side but peeking through the hole I had already cut, I could see a straight baffle pipe. So because the inlet and outlet baffle pipes are not aligned, the gases swirl around inside this inner chamber before exiting. There is also more wadding at each end. So now you know!
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chrisgixer and I cut some open, can't remember if is was the noisy no-name off mine, or from his. They were in much worse condition, with the baffle pipes rusted through.
I think chrisgixer posted up the pics somewhere, although I know we run out of cutting discs doing it ;D
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Yeah, buggered if I can find the link though. :(
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Ah, that sound deadening material is currently making a bid for freedom out of the back box of my 2.6 ;D
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
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Nice neat cuts , mine cuts were all over the place ;D Center baffle was all collapsed and rotten in mine :(
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
Yeh, I pull it out when it appears! I've got an ETS system en route to me as I type, just hope to find enough time to fit it next weekend...
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
I think dbdb is suggesting the blocked exhaust backed up through the egr and pressurised the crank case.
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
I think dbdb is suggesting the blocked exhaust backed up through the egr and pressurised the crank case.
Ah, past the piston rings? Gotcha. Would have thought the whole thing would stopped before then?
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And back up the breathers.
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
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So they look like they're built like tanks but rot like cheese...... :-\
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So they look like they're built like tanks but rot like cheese...... :-\
My s/s system hasn't rotted ::) ::)
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So they look like they're built like tanks but rot like cheese...... :-\
By the nature of exhausts, they rot from the inside, which is why they tend to look good and solid, then just fail almost overnight...
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
I have zero experience with Egr's so no idea if the theory is viable....? :-\
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
I have zero experience with Egr's so no idea if the theory is viable....? :-\
EGR feeds exhaust gases into the intake manifold, not the crankcase so no, it's not viable.
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
I have zero experience with Egr's so no idea if the theory is viable....? :-\
EGR feeds exhaust gases into the intake manifold, not the crankcase so no, it's not viable.
And only if cold, as the egr operates to pre warm the engine, or warm it up quicker?
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
I have zero experience with Egr's so no idea if the theory is viable....? :-\
EGR feeds exhaust gases into the intake manifold, not the crankcase so no, it's not viable.
And only if cold, as the egr operates to pre warm the engine, or warm it up quicker?
No. Its there to reduce NOx on hot engines, and reduce cc on diesels when cruising.
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
I have zero experience with Egr's so no idea if the theory is viable....? :-\
My 'theory' was that the blocked exhaust back pressure made the EGR leak. That seems plausible to me. I mentioned that the cam gaskets went about the same time and may have had the same cause, meaning blocked exhaust rather than the EGR as the direct cause. There is always some blowby past the pistons into the crankcase, a blocked exhaust would definitely not improve it. However a clogged and open EGR would increase pressure in the air intake and don't the breathers connect to that?
Anyway I only quote what happened to me - the cam gasket went about the same time so unlikely as it may seem I remain suspicious. I have always been dubious about breathers getting clogged enough to blow a cam gasket, everyone seems to treat that as gospel but I am not sure mayo has enough resistance to do that.
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Its not the mayo per se which causes the problem.If left long enough it hardens and thickens into a substance not unlike like the carbon we used to have to clean out of 2 stroke exhausts.Thats when the pipes get really blocked and cause excess pressure,thus knackering the cam cover gaskets. :y
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Thanks that makes more sense. Incidentally I cleaned my breathers at 70K, or rather I went to, but they were spotless. I doubt any previous owners had cleaned them but maybe.
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Someone must have.After 70k you would need a small kango. ;)
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Someone must have.After 70k you would need a small kango. ;)
Nope, not if the oil has been well maintained :y
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My 3.2 breathers are also spotless at 54k. It has been well maintained, and also by me, and I only use premium fuel. 8)
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Someone must have.After 70k you would need a small kango. ;)
There should be oil present, in the breathers, plenum, and inlet manifold. If totally clean, they may be blocked...?
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Watch out it doesn't block the exhaust I think that's what made my EGR leak and may have blown my cam gasket, all happened at about the same time on my last mig.
How does that happen :-\
Magic ???
I have zero experience with Egr's so no idea if the theory is viable....? :-\
EGR feeds exhaust gases into the intake manifold, not the crankcase so no, it's not viable.
And only if cold, as the egr operates to pre warm the engine, or warm it up quicker?
No. Its there to reduce NOx on hot engines, and reduce cc on diesels when cruising.
Correct althoguh diesels also use it to shorten the warm up cycle to (diesel will run 100% EGR on idle for instance)