Exhaust Studs

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Ant-t
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Exhaust Studs

Post by Ant-t »

I'm starting to free up my exhaust fittings in prep to replacing the system which has been on the van for a long time. I've now freed up 4 of the nuts but I have 4 more to go that are extremely corroded. I'll need to replace both the nuts and studs for these but I'm at a loss how to get them out of the engine block. Any pointers or techniques?
1983 DG Kamper 2

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itchyfeet
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Re: Exhaust Studs

Post by itchyfeet »

you might have to cut the old nuts off
once exhaust off usual trick is weld a mild steel nut on what's left , an M10 is best as it slips over the stud
all the heat from welding helps to release the corrosion.
If that fails then it's a drill out job.
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
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Ant-t
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Re: Exhaust Studs

Post by Ant-t »

Thanks for that, hopefully the welding heat will losen the studs
1983 DG Kamper 2

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Mr Bean
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Re: Exhaust Studs

Post by Mr Bean »

Yes that welded nut system is the process I have used many times in the past using an arc welder but not so far in situ in the vehicle and not on this vehicle.
I now have a TIG welder and wonder if anyone has any experience with TIG for this application?
I guess there must be issues with earthing and stray currents in both systems with in situ work and I wonder if any electrical resistance between the stud and aluminum cylinder head could further damage the thread within the head?

Sadly my engine was re-installed with bolts rather than studs and one feels loose/stripped already so it looks like some helicoiling or stepped studs may be on the cards :roll: . I am following the "let sleeping dogs lay" theory so far in my WBX as the leak is minimal.

Did I see a thread where a firm who fitted their stainless exhausts repairing the fixings in with the price. anybody know?

CS
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"A quiet shy boy who took little part in games or sport"
88 High top 2.1 WBX

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itchyfeet
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Re: Exhaust Studs

Post by itchyfeet »

CS a leak at the head can errode the aluminium which in time means you need a new head
Maybe don't leave if too long.
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
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maxstu
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Re: Exhaust Studs

Post by maxstu »

Completed this not so grisly task myself recently.
So are the four remaining culprits studs and nuts, or bolts going in to head instead? Stud and nuts dead easy. Disconnect battery. Remove local anxcillaries ( l removed thermostat, air box & PAS pump) to give you plenty of room. Then destroy exhaust close to studs with cutting blade/angle grinder leaving a few cm left. Carefully nick each nut lenghtwise with same cutting blade and with a very sharp cold chiesel and club hammer split each nut. Two taps did the trick. One each way.Then run a M8 die set along each exposed thread with plusgas to clean up.

If bolts are the problem forget about using heat or welding techniques if outside with engine in van. Tried it and waste of time.

Cut off top of bolt. Remove exhaust and carefully remove rest of bolt flush to cylinder head using same cutting disc/angle grinder combo. Buy a decent centre punch and three or four new quality drill bits starting 2.5mm to 5.5mm. Go to a DeWalt dealer or similar not B&Q......Also make sure you buy a top quality tap and die set. Im talking a real good set. Or rent a set.
Get yourself comfy for this long task. As my buggers were gearbox side (cylinders 1&3) l made a pillow to support my head. ..and next time l would consider removing driveshafts too...and from under van (if best for you) hit old stud dead centre with new punch. The rest of the task is likely known to you...but heres a few pointers. Drill slowly and often remove to lubricate bit and old stud. Do not overdrill depth. I did mine to just under 20mm and new stud hold really well. Once drilled to 5.5mm diameter clean out with M8 tap set. Take much time doing this (l took about 40 minutes for each tap) task. Very slow windings and reverses (half turn clockwise quarter turn back)and remove tap frequently while using loads of plusgas. One last thing. I deliberately jammed two nuts on M8 tap and used a rachet spanner to turn tool. Gives far more initial bite and feel compared to tap handle.
Good luck and happy to take a call from you if you need further pointers
Stuart 07961 423324
MaxStu
1989 DJ 2.1 Auto Leisuredrive rusty bucket.
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Ant-t
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Re: Exhaust Studs

Post by Ant-t »

Thanks for that write up, I'll need to check but I think that my remaining 4 are studs and nuts. They're on cylinders 1 and 3
1983 DG Kamper 2

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maxstu
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Re: Exhaust Studs

Post by maxstu »

Cold chiesel and hammer it is then.
Good luck :ok
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"Blissfully happy in your presence".

jswagger
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Re: Exhaust Studs

Post by jswagger »

Not sure if it's too late, but I had some extremely (!) stubborn studs and used a stud extractor to get them out.

This very one.

https://www.machinemart.co.uk/p/pro57-4 ... actor-set/" onclick="window.open(this.href);return false;
1988 Caravelle 1.9 DG Auto

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Ant-t
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Re: Exhaust Studs

Post by Ant-t »

Thanks for the tip ^^^ I'm buying my exhaust parts in preparation for my exhaust replacement
1983 DG Kamper 2

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