The V8 Owners Forum -

While stripping the Rv8 I bought I noticed that one of the exhaust manifold bolts has snapped off (pity I didn't notice it when I bought it). He'd obviously run the engine for a while like that, but what is the downside?

As I see, my options are:
- Leave it and I hope I don't lose too much power
- Try to drill it out (never had any luck doing this on my old pinto head)
- Buy a 2nd hand head to replace this one.

The options get more complex and expensive

What would be your advice?
Thanks
TimN

Depends really on your skills and accessibility. If you can weld a nut onto the remains, the heat will often break the corrosion or whatever that caused it to shear. Or very carefully drill it out and fit a helicoil. But before that, try a parallel sided stud remover. The tapered kind I'm not too keen on.

I agree with Dave, if there is a bit of stud proud of the surface or if it's level, place a nut over the stud and weld into the nut to fuse the stud to the nut. As it cools it shrinks and normally you end up being able to turn it out by hand, or at least with minimal effort.

What is a "parallel sided stud remover"?

[edit] - can't weld ;-(
I'll try to drill and see how far I get.
Thanks

hi the extractors are made by kd tools,they are very good ,firstly make a drill bush ,say your stud is 3/8 dia,get an old bolt and drill 1/8 drill through it place the bolt in the manifold and drill through the bush through the broken stud ,so that you drill right in the centre of the stud,once you spot the centre remove guide bush and keep drilling until you break through the stud,or mark the depth of the hole on the drill ,remove another head bolt to get the correct depth of hole, after you break through the stud make a note of its length,now drill with 5/16 only half way down the stud ,your only trying to weaken it now use the small extractor in the 1/8 hole,and try and remove,dont use to much force,if it doesnt shift keep drilling down a bit at a time,and re try the extractor hope this helps it has always worked for me.

I hope I am not sounding patronising, but having done this a few times before.........

If the stud has sheared off square or close to square, you will be easier off. If it is at an angle, then you will need to angle drill a bit to expose the centre of the stud for the next bit....
I would remove the manifold first, but the idea of the bush is another approach that has merit, too.

Get a nice sharp centre punch and carefully find and mark the centre of the stud. Then, using a small drill, about 2mm drill as straight as you can down the stud using a lot of oil to keep it cool. Then go up in increments of a mm at a time until you are close to the stud size or if you think you are going to go into the head, an Eezy-out will then do the dirty deed for you, and the oil and heat from the drilling will have helped your cause substantially, too....

The tapered Left Hand Thread extractors are for me better than the straight edged ones, but be careful whichever one you use, they are brittle and if it breaks then you have just compounded your misery a hundredfold....

Measure twice, drill once. It only sounds daunting.

Thanks for the info. I agree heat is what I need to loosen things up a bit. My worry is the stud removing snapping inside the bolt. Many years ago I had an old pinto engine with a snapped stud and followed your method. Trouble is when the remover whet in, it snapped off ;-( I bought a new head which was just as well as the old one wasn't set for unleaded fuel - maybe I bought cheap stud removers - any recommendations?

This time I will blow torch the sucker first for a few mins!
TimN

At least the head is aluminium rather than the pinto cast iron.

The thread is also fairly coarse 3/8" UNC.

If you warm it gently and try and work some lubricant in WD40/Oil, time is also useful, i.e. warm it oil it, walk away for the day and repeat

Is the engine out/head off? nice if you can set it up so the offending stud is vertical.

Take your time and don't rush if you can

Good luck

softdash3.9 wrote:At least the head is aluminium rather than the pinto cast iron.

The thread is also fairly coarse 3/8" UNC.

If you warm it gently and try and work some lubricant in WD40/Oil, time is also useful, i.e. warm it oil it, walk away for the day and repeat

Is the engine out/head off? nice if you can set it up so the offending stud is vertical.

Take your time and don't rush if you can

Good luck

What he says, plus 1.
Especially this bit...
Take your time and don't rush

Centre punch on the edge and tap it around carefully at an angle if it is flush, it's unlikely to be that tight. I managed to get flywheel bolts out this way and it should be much looser then that.

Alan

Interesting idea. So this will simply loosen the rust and hopefully allow me to get some pliers on it to turn it.

I'll let you know how I get on.
Thanks!
TimN

OK...so this is an engine you are stripping ? ie it is in bits.

If you are in any doubt about your ability to repair this, just take it to any decent machine shop and they will be able to do it for a few quid.

If it is actually still in a car and running...if the manifold isnt leaking, I really wouldnt worry too much.

I'm stripping it, so you're right if I can't get it out then there is a machine shop down the road from me!
Thanks
TimN

timnutt wrote:I'm stripping it, so you're right if I can't get it out then there is a machine shop down the road from me!
Thanks
TimN

But also bare in mind....you dont want to damage it further making a repair even more difficult.

Sometimes snapped studs/bolts can be a real pain, and it's easy to damage trying to repair. Just depends what tools etc you have access to.

timnutt wrote:Interesting idea. So this will simply loosen the rust and hopefully allow me to get some pliers on it to turn it.

I'll let you know how I get on.
Thanks!
TimN

If there is a bit sticking out, take it to somewhere who can weld and get them to tack a nut on. The heat of the welding will break the corrosion. It will then unscrew. Cheaper and better than attempting to drill out.