My exhaust has arrived but it has longer headers on it than the stock exhaust so the studs are too short.

I have removed 7 of the 8 studs with mole grips but the 8th just won't budge. I've tried WD40, I've tried tapping it with a hammer. I've even tried applying a bit of heat. I don't have a welder so I can't weld a nut onto it.

How can I get it out, without having to remove the engine?

[Edited on 16-10-2005 by smart51]

Have you tried putting two nuts on the stud and locking them together then using the inner one to undo with???

yes. No matter how tight the two nuts are, they turn without turning the stud.

To be honest, the remaining stud's thread is all ground away by the mole grips except the first 3 or 4 turns.

When you heat up the stud did you let it cool on its own?? Or try warming stud up and then cooling quickly with water it will make it shrink quicker

you need (if cast iron head) to apply heat to the head, around the the stud but not to it, until the head iis cherry red around the stud, then it should come out very easily.


enjoy

The head is aluminium and the rocker cover is magnesium. Both are painted. What else can I try?

You can try drilling a hole in the end of the stud, tapping it with a reverse thread and screwing a reverse threaded bolt into the hole.

Not the simplest option but it means you will not damage your head.

Maybe this is tooooo obvious but why don't you buy some stud extractors.

Only around £15 for a set from Machine Mart and a hell of alot more effective than mole grips.

Just a thought.

If this was my engine, and I was starting to think that I was approaching the limit of my knowledge and/or ability, I would take the head to a local machine shop and ask them to sort it out.

Either they would get it out with the skills they have, or they would chop it off and use a spark-erosion machine to cut the stud out. Last time I had this done (on a model steam engine cylinder block) it cost me a fiver - if you're not in a hurry, it's a job they can set up and leave to run in the background, so doesn't cost so much in man-hours.

There's a point where you're risking the cylinder head, with the resultant high cost of fixing the results of a cock-up - and an expert with the correct tools could sort it for far less pain!

rgds,
David

P.S. Stud extractors are the work of the devil! Only thing worse than a broken stud, is a broken stud with a broken stud extractor stuck in it!

[Edited on 16/10/05 by David Jenkins]

I've heard of people having some success with these Draper tools. . Worth a punt and if you break it off then go for the spark erosion ot drill it out and tap it.

Hi

You could try filing 4 flats on the stud and using a tap wrench on the flats.
Because you can push from both ends it's a true twisting force, unlike
your moles which tend to want to bend the stud (and slip).
While holding force on the tap wrench get someone to hit the end of the
stud with a hammer to shock it.

I hate stud extractors too. They swell the stud and make it even tighter.

Last resort is drill and tap. (got the tee shirt ect.)

HTH

Paul G

I don't mean the sort of stud extractors that Pete has just posted.
I'v never used one of those. It looks good.

[Edited on 16/10/05 by 907]

I suspect tyhe type of stud extractor Paul is talking about are the Easyout type , DO NOT USE THEM . They break very easily and are very hard to drill out . Get hold of the 1/2" drive type they should work, if the stud breaks then you may have to very carefully drill out and retap Spark erosion works very well but the only place I know that does it tends to be expensive. Be patient , it should come out.

We had identical problem on our first blade engine. We tried everything, including welding a nut to it, but it just kept shearing off. Eventually there was nothing left to weld to, so we resorted to drilling the stud and then applying copious amounts of WD40 before attempting stud extractors but they just snapped. In the end we bit the bullet, took the engine out, ground off the lug with the stud inside and had a new lug built up by aluminium welding. We then drilled and tapped a new hole and never had a problem after that.

Its probably not what you wanted to hear though cos it does involve removing the engine. It's all relatively quick and easy (if you know someone who can do the aluminium welding) and could be your last resort

Scared by all the talk of spark erosion and spurred on by the fact that no-one at work has got a stud remover, I bit the bullet and bought one. £18 for the remover set and £16 for a 1/2" ratchet (my socket set is all 3/8 and 3/4).
The stud came out really easy, one I tried it on the last remaining bit of thread. I knew there was a reason I left a bit.

Put on the exhaust, loosly fitted the M8 x 40 cap screws I'd got, tightned them up. Damn. 1/2mm left to go and they bottom out. 1 by 1, replaced them with ones treated to a minute with an angle grinder. Fine. Exhaust on.

Next, start the engine for the first time with an exhaust Damn. Battery has gone flat. Left it to charge. I WILL get to run this engine if it's the last thing I do.

theres always something!

A steel stud in a a alloy head will almost always come out provided you don't snap it flush.

DON'T USE EAZY OUTS -- they will just cause more trouble.


Try soaking in the area of the stud in vinegar for 24hours, then try a proper stud extractor the type the grips the stud at its base.

If that dosent work with an exhaust stud you could try local heat - it has to be a quite "sharp" heat from a fine flame ie oxy-acetelene or oxy-propane.

If you haven't access to oxy-acetelene try MIG welding a nut onto the stud.



[Edited on 18/10/05 by britishtrident]