My ********* stud extractor broke it off with about 3 mm sticking out of the manifold. Knowing that I would have to drill through the stud I then filed it flush with the manifold to minimise the amount of drilling. Just to complete the picture I did all this under the vehicle with the downpipe moved slightly to one side.
Richard
Due in no small part to all your encouragement the Stud-from-Hell is no more.
8mm hole in place of stud lines up adequately with holes in gasket and downpipe. Calm is restored to Richard.Martin, many thanks but I do not need any 5/16" nuts - the remaining studs are 8mm x 1.25 threads which just needed a little fettling at the start of the threads. Goodness knows how the brass nuts I removed actually stayed in place as they are well over-size. The skirted 8mm nuts now fit perfectly.
Costs:
Initially about 10 of my chocolate HSS drills - majority being from a cheapo tin of JCB aero drills from MAKRO, but also a couple of 'green' Bosch HSS.
Then £17 for 4 x 2mm, 2 of each of 4mm, 6mm and 8mm HSS-G drills from Medway Tools and fixings. No idea what HSS-G is. Most of the 2mm are somewhere in the garden now.
Followed by £29 !! for 2 of each of the following in HSS Cobalt from Fixings and Power Tools Direct: 2mm, 4mm, 6mm and 8mm.
All of last Sunday, most of Tuesday evening (in the rain) and a couple of hours tonight.
Your time in reading my appeals for help!
I can't say for definite that the HSS-Co drills saved the day and, in fact, one of the 4mm drills blued.
There was something very hard in the mass of the stud which was nicking the cutting lips/edges of the larger drills. It was about 2.5 mm from the centre and wrecked the 6mm drills with ease, nicked the 8mm ones and did not affect the 2mm ones. Also I never managed to achieve that regular chip formation that large drills generate when cutting properly. They almost, judging from what was carried away by the lubricant, ground the stud out.
In re-assembling everything I note that the Y piece is pulling the downpipe away from the manifold. Should I attempt to pull the Y piece back into shape so that the downpipe is square to the manifold? The side that is lifting is the side that the stud has been removed from replaced with a nut/bolt. I can't remember if I explained that the stud had to be replaced because the thread had failed such that the downpipe could not be tightened against the manifold.
Also is there any benefit from adding some exhaust sealant paste to the new gasket?
Ta
Richard
That being the case it sounds like the exisiting studs are UNF. Compare the thread pitch of the new and old studs by holding them against each other - UNF threads are much finer than M8.
It's possible that someone has assembled the Y piece incorrectly beforehand and stripped the stud trying to pull the manifold etc. into place. It wouldn't do any harm to slacken the clips on the Y piece then retighten when you've got it lined up. You could also warm the front pipe to allow it to settle without strain by heating with oxy-acetylene then tightening things up while it is hot, any strain will then be released by warping the pipe slightly if you can't align the Y piece.
I wouldn't think it was necessary to use exhaust sealant but it won't do any harm other than making the joint surfaces harder to clean next time, the manifolds are usually a good fit to the head even without gaskets, which applies to most of them that I've worked on. Nice to see you've sorted it. :-)
Martin
Much to my onging regret I have only the torch, hoses and a selection of tips for oxy-actelyne kit but no gas. My infrequent need for it can't justify a contract for the bottles. Thus I cannot heat the Y piece thoroughly. I was thinking of pulling it into (or out of!) position with a ratchet strap.
Hopefully the 'next time' will be encountered by the next owner ;-)
, the
The gasket is between manifold and downpipe
Nice to see you've sorted it.
A total relief I can tell you!
Richard
No, don't get it to fit by straining anything. I can't remember where the joints are on this system but, at the very least, the final section that you are attaching to the manifold wants to be totally free when you bolt it up otherwise a leak-free joint cannot be guaranteed. Just loosening the clamp at the next joint (at the Y piece) may not be enough. You may need to waggle it about a bit at the joint to provide movement. Heat should not be necessary but is frequently helpful. In the worst case you may need to re-align the entire front part of the system if someone has previosuly made a real hash of it.
Don't spoil your efforts so far by trying to take shortcuts at this stage!
Agreed - don't do it - it's messy and unnecessary.
Hi Dougal
Joints are located as follows '//':
Head // Exhaust Manifold // Downpipe // Y Piece // Centre Box // Tail Piece
Assuming that the answer to the question!
The Downpipe to Y Piece joint is totally free.
As far as I can tell the legs of the Y Piece are too far apart. This means that one of the Downpipes must be turned slightly to reach the Manifold. The consequence of this that the mating faces are not parallel. This was, probably, the cause of the leak that started me down this route of endurance.
Richard
I think that you're facing an earlier hashed job although some pipes are not as accurately made as they should be.
It doesn't alter my previous comment - don't get things to fit by straining them and the most important bits to get seated correctly are the downpipe to manifold joints. Don't compromise those.
I'd be tempted to make the Y piece fully floating by loosening the joint to the other downpipe and even the Y piece support, too. That way the Y piece should have some freedom to rotate about a vertical axis and you may gain enough movement to get both downpipes to join the Y piece 'satisfactorily'. In effect you'll engage one down pipe more deeply into the Y piece than the other.
On or around Sat, 23 Aug 2008 11:16:17 +0100, Dougal enlightened us thusly:
I'll second that. I've had a pipe break on a minibus due to someone fitting the system wrongly and then jacking the pipe up to the manifold. This system had a bracket on the engine supporting the pipe and the pipe sheared behind the bracket.
Get enough of the system loose that you can place the manifold joints easily by hand, bolt the manifold pipes up and then bolt up joints down the exhaust system.
The problem is that the distance between the Y Piece-to-Downpipes junctions is too wide. This spacing needs to be reduced. I don't think that any amount of slack in the system is going to allow me to overcome that.
But you may (both) be right! Certainly I'm not intending to use bolt strength to pull the bits into the correct alignment. And it is the Y Piece that needs to be correctly aligned to the Downpipes not the reverse.
I would have to cut the bolts at the Y Piece to Centre Box slip joint and, possibly, on the undisturbed Downpipe (O/S) to Y Piece U clamp. But then they are bolts I can easily replace.
Duty in the form of Aunt's 85th birthday now calls so now more playing with the RR today.
Richard
Richard
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