Help - cylinder head stud damaged

[csmacg]

I've read some great advice on here and I'm hoping there's some more out there!

I have a 1915cc, 4 speed, water boxer engine which I've taken out and it's on a bench. I needed to replace a blown gasket on one side which I did with help, and while at it, we replaced the piston rings and seals. Good as new!

I thought it would be worth doing the same on the other side of the engine but 1 of the 8 cylinder head studs was jammed (corroded) into the cylinder head and would not budge. We heated it, oiled it, banged it... But it would not budge a mm. In the end we cut the stud to release the cylinder head. After about 10 minutes of working it, I have unblocked the hole (of white / grey powder - must be corroded aluminium from poor coolant mix) and we've removed the cylinder head bolt from the cylinder head itself.

I have a friend who has welded a nut onto the remains of the bolt but it won't budge! So I am left with a refurbished half an engine and an open side with 7 1/2 cylinder head bolts!

Can anyone advise me of someone who can remove the 8th cylinder head bolt, without stripping the engine down further, and re-thread the hole if necessary, in Dorset or South?

Please help - I can't afford another engine!
Chris.

[300CE]

Hi Chris, might be worth giving Ollie a call at Beetle Magic (based in Dorchester) - 01305-852338 or try Simon at VW Bus Bits (in Crossways) as he maybe able to point you in the right direction (01305-854828).

[csmacg]

Thank you - I had a chat with Ollie on the phone and he offered the advice we've taken. My current plan is to wet the threaded end with ZX-54 and make up some rust penetrator (50% acetone 50% Automatic Transmission Fluid) and 'bathe' for a week or so to try and loosen it. If that doesn't work I'm not sure what we'll try next...

[Bigjcc55]

Have you tried the impact stud remover yet?

[itchyfeet]

I'm no expert but I have listened to what2d, he got one stud out for me that was snapped at the bottom ( didn't see him do it) and I watched him do some exhaust studs.

He says the key it to get the stud cherry red, it's the heat that breaks the corrosion, you may have welded a nut on but as the stud is long still you won't have heated the thread at the bottom enough.

You need to get the part of the thread into the aluminium cherry red.

I though it would damage the aluminium but he said no, not sure why not or if steps are needed to protect the aluminium?

When you have done that get a T bar on it so that the force you apply is balanced, then first apply pressure doing it up then undoing, if it starts moving stop, then repeat doing it up and undoing it, it's the slow repeated small movements that helps it come out without snapping off again.

he kind of said that last post on your other very similar thread...(He has a bit of a weird penchant for this)

https://club8090.co.uk/forum/viewtopic.p ... 4#p8032735" onclick="window.open(this.href);return false;



hope this helps

[CovKid]

Not sure how applicable this might be but with some stuck bolts its sometimes possible to drill a very small pilot hole into the unseen threaded area from another angle and work penetrating fluid in through there. Agree on heat though. Lots of tips on youtube on how to do it well.

[Bigjcc55]

The glowing stud in the picture took almost two hours to finally come out even with that amount of heat on it. I think in total it took around seven hours to get three studs out.
The rest of them in that half and the other half come out in under ten minutes with the impact stud remover, iv'e used it on another two engines with the same success.
Do you have much stud left to grip?

[colinthefox]

For what it's worth, here's my (admittedly limited) experience of a very similar situation. I had plenty of stud to grab hold of, so I used heat from a blowlamp and force from a stillson wrench, but it wouldn't budge, and I felt that any more force would break the stud. So I ground the top of the stud flat, and at the same time as using the same amount of heat and force as before, a mate gave the stud a good square smack on the head with a hammer. The shock shifted the stud a little, and after twenty or so smacks was loose enough to turn.

All I can say is that it worked for me.

[123-jn]

Heat is good exactly where this picture shows but the stud will move before it gets that hot. Just a blow torch will do it played onto the base of the stud and the alloy around it. As long as you have enough stud to turn with a T bar . 10-15 mins of a blow torch gets it smokin hot and with mine this was enough for all the broken ones to break loose.

[toomanytoys]

The glowing stud in the picture took almost two hours to finally come out even with that amount of heat on it. I think in total it took around seven hours to get three studs out.
The rest of them in that half and the other half come out in under ten minutes with the impact stud remover, iv'e used it on another two engines with the same success.
Do you have much stud left to grip?

And people question the real cost of a proper wbx rebuild when that amount of time can be needed to "just remove a few studs"..
If I was building an engine with that case.. it would have gone on the "stuff to be used in desperation" pile and another case selected..
Good perseverance..

[what2do]

Itchy has mentioned the one thing that often gets overlooked. Don't try to apply too great a force when undoing the stud/nut, try to 'tighten' it a little the rotate the T-bar both clockwise and anti clockwise. It's similar to tapping a thread, the corroded stud sometimes need to cut it's thread again as the original is full of corrosion. By 'tightening' it, you're allowing the stud to free up some of the crud rather than it binding as you try to unwind the stud.

Hope that makes sense. And yes, some broken studs take minutes whilst others take many attempts and curses.

Whatever method people use, we all share the same sentiment when the bugger finally comes out. Don't forget to clean the casing with a tap to ensure the new studs aren't torquing up prematurely.

[itchyfeet]

I cleaned the casing thread with a tap as the new stud would not thread in but then the stud was too loose, I was concerned that it would thread in further than the correct depth when the nut was added, as the nut is domed you would not notice and the nut may then not have enough stud threads to take the torque.

So I stuck it it with dirko but I think a better solution would have been to clean the thread one turn at a time until you were almost at the correct depth then use the tightness of the last turn to lock the stud ( in fact thas what i was trying to do but got went too far)

also thinking about the dirko wouldn't that stop coolant entering the thread and help prevent corrosion? might be a good idea, just possible those really hard to get out studs have been replaced before and threads opened up.

What do others do about this?

[csmacg]

Update:
Thank you all for your ideas and help. I have the bugger out! In the end I welded a nut onto the end of it, heated it to extreme and it failed to budge. I then 'bathed' it in rust-penetrator and oil for about 2 weeks, spraying into the base and trying everyday to remove. Finally, I bought something like 'shock and unlock' from Halfords. It cools the metal and has rust penetrator. Finally, I 'tightened' the stud and there was a loud crack. I thought I'd snapped it, but it then just unscrewed and came out clean. Despite a bit of pitting on the outside, it was actually a solid stud. Lovely. We then cleaned out the screw thread (re-tapped) and have bought a new stud. The engine has now been rebuilt (new pistol rings, gaskets etc) and is back in the van. I am now trying to remember where all the wires came from… and why my alternator is not wired up the same way as the Haynes manual says it should be.

Thanks again for all your great advice. I want to get her on the road as soon as I can - the family are counting on it!