Sticking bolts...

Troels L · 14-09-2006, 07:17 PM

I want to remove the Cylinder head cover from a outboard.
But the bolts seem to be stuck. Does any of you have good advice for what to do, so that they do not break when I try to unscrew them ?

Kind Reagards

Troels

Burty · 14-09-2006, 07:37 PM

use a 3/8" ratchet and socket without extensions. hold the ratchet in one hand and bang the end with the other this should shock the bolt. if still no joy try banging the head of the bolt with a hammer

Troels L · 15-09-2006, 07:26 PM

I have tried but the bolts seem to break anyway ! As if the have become brittle somehow. Wil it make any difference to start up the engine, so it becomes varm ?

Matt · 15-09-2006, 07:58 PM

Mmm. Judicious use of a blowtorch can help, but I'd be really worried about warping the head - you have to get it fkkn hot to loosen up.

Troels L · 16-09-2006, 10:15 AM

Thank you for the reply. It sounds a bit worrying with the blow torch.

I will try to summarize my proplem:

On top of the cylinder cover is mounted a termostat housing.
When i opened the termostat housing the bolts snapped.

The bolts is fastened to the Cylinder head throught the cover.

I Drilled out the old bolts and used helicoil to refit the new bolts.

The termostat housing is not leaking, but the gasket between the cylinder cover and cylinder head is now leaking water.
So I want to remove the cylinder head cover to put in a new gasket.
But the bolts in the cylinder head cover is also snapping, when you try to loosen them !

What do you suggest I do

?

Any help will be very apreciated ...

Kind regards

Troels L

BluFin · 16-09-2006, 12:15 PM

Heat the block gently & get a can of the freeze spray for the bolt, .heat one shrink the other. If they dont normally come first time you are lucky if you can get away without a broken bolt, just hope they break high enough up to get them out without a helicoil.
make sure you you a non sezeing compound on the reinstall

Burnett · 20-09-2006, 12:18 PM

I had this on a bike engine once.

I built a little 'wall' of putty around the top of the sheared-off bolt and filled the resulting 'cup' with PlusGas. Left it about a week. I then drilled carefully into the remains of the stud and got it out with a screw extractor. Didn't even damage the alloy block it was screwed into.

PlusGas seems to be about the best penetrating fluid I've found.

Maybe consider using stainless bolts on the refitting? Should stop it happening again (as long as they're within spec for torque settings, etc)

I think a lot of it boils down to luck though. Hope you get on okay!

Troels L · 25-09-2006, 06:49 PM

Hello Burnett and Blufin

Thank you for your help.
I have removed the Cylinder cover. All the bolts snapped except for the 3 lowest ones.
I have orderd a new cylinder head cover and gasket.
As all the bolts have snapped so 15 mm threads are petruding the surface.
I am checking to see if it is possible to find bolts with a negative thread ( hollow ) ! or have them made.
These will be screwed down on top of the broken bolts to fasten the new cylinder cover .

If it is not possible to find such bolts, there is 16 snapped bolts to be removed ! Then I will consider to replace the entire cylinder head instead.

Kind regards

Troels

BluFin · 25-09-2006, 09:16 PM

Had a feeling it might go that way from you description sorry mate, dont mess with it get it to a machine shop & have them set the thing up & drill them out costs a few $$$ but cheaper than a head. dont try it with a hand held drill as the thing walks all over the place.

Burnett · 26-09-2006, 08:48 PM

Seconded.

Take the head to a machine shop. They can drill them out, as Blufin rightly says. It's also possible to get the remains out using spark erosion, but I've not had any experience of this myself.

Using a hand power drill and a set of stud extractors is just asking for trouble. You may be lucky once, but you've got to be lucky 16 times!!

I wouldn't mess around trying to get internally threaded studs made up. For one thing, if the original bolts are so weakened that they snapped when you tried to get them out you're hardly going to be happy to trust the broken remains to hold together.

Off topic, but funny:

Most misguided effort to save money I ever saw was at a motorbike dealer in the 80's.
Some guy had decided that he'd save the 80p cost of replacing a spark plug by building up the missing electrode with arc weld then filing it down.
Did it work? Did it bollocks. Fell into the bore, seized the engine! New piston, rings and barrel please. Ker-Ching!!

Troels L · 27-09-2006, 08:21 PM

Thank you for your advice. I will post the result in this threat as soon as I have spooken with the machine shop.

Burnett · 28-09-2006, 09:18 PM

I get the feeling that removing old marine fastenings is quite a science in itself!

Good luck. I'll keep my fingers crossed for you Dude!

BluFin · 28-09-2006, 09:28 PM

The Science is in the assembly......Use a good quality compound like Neverseize, (high nickle content) or other brand products, Rocosol, ect, ect,ect.
Will save you a lot of heartache a year or two down the road

Troels L · 23-05-2007, 11:25 AM

Better late than ever..

I spoke to two machine shops about drilling them out or making internal studs.
The pricing for drilling was quite high. About 100 £..
Decided to order new parts from the US and change the entire cylinder head, including cover, thermostat housing etc.
All changed to 2006 parts ( they are identical ).

Allthoug the cylinder was in good working order, The bolts for the head itself cam out fine, and it seemed like the easiest solution in the end.

BR

Troels