4 replies to this topic

[fenton]

I broke an exhaust stud last night. I've been soaking them in penetrating fluid since i took the engine out and i couldn;t resist having a go at them. One was undoing real easy to my delight, went a little tight and snapped with hardly any effort. With hindsight i think i should of stopped and re soaked and left again.

The stud has snapped off with about 20mm protruding from head so i am hoping to be able to get a good purchase on it when i've got the manifold off.

Has anybody a recommendation for a brand of stud extractor that they've used and would be the best option.
shane

[hilly]

Shane

If you have 20mm or so sticking out then you want something like this

Clicky

Also heat up the area of the cylinder head around the stud with a blow torch as it will make it much easier to get the remains out due the differing expansion rates of alloy and steel.
I managed to get a broken M10 tap out from one of my rear caliper brackets by heating it up and plenty of oil, and that snapped off below the surface!!!!!

Hilly

[molemot]

Extracting studs is always easier if you heat them up..an oxy-acetylene torch CAREFULLY wielded on the stud usually enables you to get it out OK. Obviously don't melt the alloy head or set fire to anything!! I used to own an Airtourer light aeroplane, and every year we had to take the exhaust off to get it pressure tested, as it used the exhaust heat to heat incoming air for cabin heat, and you needed to make sure ther was no carbon monoxide leaking in...unless you heated up the exhaust studs, they'd snap for sure, and getting them out of a Lycoming cylinder was horrendous!!

[fenton]

Cheers guys managed to tease a couple more nuts off tonight. ( That sounds rude doesn't it. )
i'll get the extractor ordered later.

[markd]

I would just soak it thoroughly and give it a few days while reapplying. Then use a propane or mapp gas torch. I would not use oxy-acetalene-it is too hot and will destroy the aluminum.

Also, I would not use the type of extractor that you drill a small hole in the bolt and twist in-if the extractor breaks, it will be nearly impossible to drill out the hardened tool steel.

I have worked on many corroded marine engines in the past. Sometimes you can file "flats" on both sides of the stud and get a wrench or vice grip on it. If all else fails, then grind it flat, center punch it, and drill it out. I think cobalt drill bits work the best. I never had any luck with the yellow tungsten coated.