manifold removal - stuck on oversize stud

[Zetomagneto]

With stuck, partly broken studs I've had success making up a flat steel bar with a hole drilled half way along to fit over the stud. Put the bar over the stud so the top of the stud passes through the hole and then MIG weld them together. The heat from the welding usually breaks the stud free and the bar lets you turn it out. The danger is if it doesn't work you will shear the stud as you try turning it.

It works well for studs that are broken almost flush.

Simon

Jansen, good tip.I usually use a penny washer placed over the broken stud then plug weld through the hole and build up quite a big blob of weld as this gets more heat into the stud, wait for it to cease being red hot then gently rock it backwards and forwards

[Ruairidh Dunford]

With stuck, partly broken studs I've had success making up a flat steel bar with a hole drilled half way along to fit over the stud. Put the bar over the stud so the top of the stud passes through the hole and then MIG weld them together. The heat from the welding usually breaks the stud free and the bar lets you turn it out.

Great idea Simon, thanks for sharing.


I have used one of these to successfully reach between manifold and stud for a clean cut:

https://www.toolstation.com/shop/p47042?...gI6uvD_BwE

You can replace the blade for a longer one if necessary...

[Chris KC]

With stuck, partly broken studs I've had success making up a flat steel bar with a hole drilled half way along to fit over the stud. Put the bar over the stud so the top of the stud passes through the hole and then MIG weld them together. The heat from the welding usually breaks the stud free and the bar lets you turn it out. The danger is if it doesn't work you will shear the stud as you try turning it.

It works well for studs that are broken almost flush.

Simon

I like the sound of this. Heard of people striking an arc on the stud before but actually attaching a bar gives you something to heave on. I think a sheared stud is likely with most of the suggestions above but we live in hope.

["Slack Alice" Simon]

If you have movement along the stud, any movement at all, it will come off with "conventional" methods.

Movement back and forth will eventually break down the seal and allow something like "Plus gas" in.

My local car spares shop suggested a mixture of acetone (nail varnish remover) and diesel, because they had no Plusgas in stock, which worked for me.

Patience is the biggest requirement.   If it is really bad it could take two or three hours of knocking it back and forth, heating, cooling and lubricating.

As I say, if there is ANY genuine movement (not stud stretching, loose in its hole, or twisting) then it will eventually come without more drastic measures. 

Simon

[JonE]

well, a combination of all of your replies has GOT IT OFF!!!!!! Thanks.

I did the freeze thing, the lever thing, the bejesus thing, and the thing which started to advance it more at the end was putting the large hammer gently but firmly onto the end of the manifold.. the wood block wasn't giving the necessary shock.

I can see that its confidence really that is required. Mine keeps skulking away into a warmer corner when something new crops up.

WHY the manifold was tightened down onto a large stud I'll never know. The stud is fine, so I'll drilled the manifold hole out a tad and willl file the stud so there is plenty of clearance.

Another stud next to it - convention skinny one - was loose to the point of being out by the time the manifold came off. Can I tap direct into the block oversize, or does it need to be helicoil? Or can I glue it in?

Now back to making the head lifting apparatus and widening the ports on the manifold...

[Chris Garner]

Jon,
My take is...
I would not drill out the manifold hole. Bad practice. I'd remove the stud. You've not said what the diameter is - 5/16"? If so use a stepped stud.
Regards the loose one, again I'd use a stepped stud. Better than a Helicoil.
Sounds as though all the studs need replacing. Manifold studs need to be sound, they are subject to extreme heat and the reliability to be done up tight to prevent leaks.
Chris

[JonE]

THanks. Ok, so how do I fit a stepped stud in the one with the loose hole if i dont helicoil? Drill and tap? (I have never done this before...)

Yes, I'm hoping the oversize one is a standard oversize so I can eventually put a standard stepped stud in. Its 0.3" diameter and the spanner I'm using is 1/4 little Austin one. The thread isn't the same as the head bolts...

[John Mason]

Jon E, Woodrow shows you how to make a jig to hold your drill in line when drilling the block for manifold studs. Also don't you need to drill and then tap a thread larger for helicoils or a stepped stud.

John Mason

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Chris, I am interested in you comments about stepped studs and helicoils. What are the advantages of stepped studs against helicoils. I am not an engineer and always thought they achieved the same result.

John Mason

[Chris KC]

A properly fitted helicoil is stronger than the original thread - my big ends are helicoiled for example and are tough as old boots.

However, there isn't much depth of metal here and if the operation isn't all done nice and square and straight the results may fall short. I have two helicoils in my manifold and they tend to annoyingly wind themselves out in to the water jacket behind when you do the studs or bolts up. Also harder to seal than a stepped stud I'd venture.

[John Mason]

Thanks Chris, well explained.
John Mason