Removing Snapped Exhaust Studs - HELP!

votejc · Post by **votejc** » Mon Mar 28, 2011 8:40 pm

Hello All,

Some of you may have seen my thread about me resurrecting my NC30 to it's former glory. Since my last post I bought a full Tyga system with a maggot can (and earplugs) and came around to fitting it today. After 20 years of abuse the front four manifold nuts weren't ever going to come off leaving the studs in one piece so all four have snapped off level with the collars on the front header pipes. There is enough thread on all four to get two nuts on to use the top as a locknut and unscrew them from the head and I have obviously WD40'd them as much as possible but wondered if there was anything else people have used that has worked if they had done a similarly stupid thing! Basically I want to make sure they are going to come out before I start trying to unscrew them again as if they snap off level with the head its a helicoil job. On all four that's quite a risk!

I have read bits and pieces about using a torch to heat up the stud and head and then shocking with a hammer before attempting to unscrew, also melting candlewax onto the heated stud as it draws the wax up the thread to act as a lubricant?!

Thoughts? Anyone?

Post by **Drunkn Munky** » Mon Mar 28, 2011 8:43 pm

They should come out with the 2 bolts locked together but if they dont heat it up.

Post by **carpman** » Mon Mar 28, 2011 9:21 pm

What are the manifold bolts screwed into ?

If its steel then heat very gently around the bolts (not the bolts themselves) and appling presure it should release the bolts

code2006 · Post by **code2006** » Mon Mar 28, 2011 10:23 pm

U r Lucky that u can get 2 nuts on them
When I broke a stud on my nc35 I couldn't even get 1 nut on so I had to drill the stud and use a bolt extractor

Post by **mick.mh2racing** » Tue Mar 29, 2011 9:46 pm

What about putting a nut over the stud then filling the middle with weld?

Post by **CRM** » Tue Mar 29, 2011 9:57 pm

mick.mh2racing wrote:What about putting a nut over the stud then filling the middle with weld?

Its safer and if you have access to a welder is far more likely to succeed that 2 nuts incase the remaining thread strips.

amorti · Post by **amorti** » Wed Mar 30, 2011 9:52 am

CRM wrote:
mick.mh2racing wrote:What about putting a nut over the stud then filling the middle with weld?

Its safer and if you have access to a welder is far more likely to succeed that 2 nuts incase the remaining thread strips.

+2.

I have done this on a CB-1, not only does it remove the risk that you strip the last bit of thread, the heat also helps free everything up. Pretty much fell out once we'd done this.

votejc · Post by **votejc** » Wed Mar 30, 2011 2:39 pm

Thanks for the help guys.

I managed to lock two nuts together on three of the four exhaust studs on the front head and they came out with surprisingly little resistance. The fourth one is still proving to be problematic though! I think its a case of speak nicely to someone with a welder. As soon as a nut is tacked on it will shift I am sure.

The rear bank manifold came out without too much fuss at all once I had removed the rear subframe entirely and wedged my hand and a 1/4 drive socket and flexi in there! Three out of the four took the studs out with them but I am not bothered about that. Just waiting on David Silver to pull their finger out and get the new studs out to me. Whilst I am waiting it's onto rejetting my carbs, raising the needles and drilling the slides so chances are I will be posting again asking for more help!

Wish me luck.