Thanks Dicky - I like both those suggestions I have a 7mm nut die already so maybe that should be my first plan of attack. Will however look to see exactly how much thread there is left intact and go for the long nut option if I think there is enough intact that is still strong enough. Thanks Pickles - will update how it goes and what solution I use when I get to it - hopefully one day next week!
Very true Dicky Have just ordered both a long 8mm nut and a brass 7mm nut off eBay. So lots of options - will see how it goes and which one seems most appropriate when I do it!
Want a proper bodge? Cut a chunk out of the collar part of the heat exchanger to expose more thread when it's fitted. There you go - I did say bodge. lol Ask @rickyrooo1 He did this rather than risk breaking something and having to take the engine out and apart. It was quite a while ago now and worked a treat.
been like it for over a year....... it can stay like it now until the engine comes out due to failiure......
Alternatively... With the HX out of the way I find I can get 2 open ended spanners on two locked togeter nuts on the stud. This is what I do, usually with success, though not always. Rock to and fro with both spanners and you can move a little, the stud isn't unscrewing but it's twisting slightly. Don't atempt to unscrew it, but keep on doing this firmly, but not in danger of breaking anything. You think you're getting nowhere, but bit by bit more of the part of the stud inside the head will be twisting and breaking the hold. You might have to do this for 10 minutes or more, but while you are, keep in mind how long the job will take if you have to remove the engine and head. You can do same with a good pair of molegrips, but if you go this route it's do or die - what thread there is, will be destroyed.
Got the whole exhaust and heat exchanger system stripped off today and could then have a good look at the dodgy thread. Not a great picture as can't get a side angle to show the threads properly - but you can see the blackening where the joint was leaking! There is actually more thread intact at the end of the stud than I thought (about 5 threads worth) and so I think I'm going to go for the long nut option (or maybe normal nut with washers to get over the threaded but and not try and get the stud out. I might also take a bit off the heat exchanger collar so that it exposes a bit of thread past the threaded bit and then the long nut can use that too. Looking at all the other studs many of them are looking very rusty with threads beginning to go, and so I'm just hoping I can get it all back together tight enough for no leaks without stripping any more threads. Nick...
Your at the point of take it out and risk it or.... If I had gone to the trouble of removing all the exhaust I'd be looking at taking that out. Plus gas it lots, heat it with a blow lamp. Give it a few gentle taps on the end if poss. Double not method might work if theres enough thread, If not you might get a short nut on followed by a long one! Dont go gung -ho with it but slowly tiny initial movements and plenaty of gas - heat it, cool it, It should go!!
