Gutted from Kent

Myford · Apr 12, 2010

Just put the head back on my 850, & in the process of tightening it down with nice shiney SS bolts, the centre bolt has gone tight & I think picked up, I don,t think its right down, & now it won't undo, I have a feeling that when I try, its going to snap. so Ive now gone from thinking about having it running again this week, to ripping it down again. STUPID, STUPID, STUPID.
Terry

swooshdave · Apr 12, 2010

That is the one place I'd think twice about SS. And this from someone who puts it everywhere.

Hope it works out.

lrutt · Apr 12, 2010

SS fasteners are funny like that. My rule of thumb is to always use antisieze with SS, especially on AL.

Myford · Apr 12, 2010

Yeh, what I'm really annoyed with myself about is the fact that you can't even see that bolt, It just came with the set & I just blindly put it in.
It's not into ally', it goes into the barrel.
I'll have a go tomorrow at "working" it back out, but I don't hold out much hope.
Terry

swooshdave · Apr 12, 2010

Best case is that you pull the head and there's enough sticking out to back out.

Worse case... well, let's not go there.

rustynuts · Apr 12, 2010

I learnt a long time ago never to use SS fasteners in crucial applications like this, and restrict their use. The friction caused by the galling which can happen as you tighten them will mean that even though you may have torqued them to the correct setting, they will not be providing the expected clamping force. When I tried them on my head I had big oil leaks until I got rid of them. I have also seen cracked engine mounting lugs caused by SS fasteners that were torqued correctly but were still loose.
Bad luck to get a complete seizure before you were fully torqued up. You might just about be able to get a gas torch down the hole to get some heat in there to try to free it. Alternatively, Ihave also seen a freezing liquid for sale, but don't know if it is any good.

ML · Apr 12, 2010

With blind bolt holes, such as those in the barrel make sure to clean them out and not have any debris or in particular oil inside as this can cause hydraulic lock, in other words the bolts does not bottom out as its pushing against incompressible liquid.

Mick

Flo · Apr 12, 2010

A stainless bolt shouldn't pick up (gall) in cast iron.
You have either cross threaded it, or more likely the thread on the bolt is wrong or oversize. The amount of shoddy pattern parts available today is reaching epidemic proportions.
If you can get it out, use your standard bolts all over the head & maybe just replace the outer 4, the ones you can see, with stainless. Make sure they fit first.
Don't use stainless studs or bolts where it is important, they can snap.

bpatton · Apr 12, 2010

There was an article in the Roadholder years ago by some maven about using stainless headbolts. His opinion was that they can cause problems by galling, stretching, and seizing. Generally screwing up at the task of getting predictable clamping force in one place where it's important. Later I've read that there really isn't anything wrong with stainless, it's just that you never know what you're getting. It's up to you, but it's a good idea to coat the threads on all the head nuts and bolts with anitseize, whatever they are, and wipe off all you can with a rag. It seems to leave enough. I've used stainless headbolts and washers that worked fine. The washers however welded themselves to the head and are there for good. :?:

Keith1069 · Apr 13, 2010

It depends on the grade but most of what is sold is low cost EN304 which has a much lower tensile than normal steel bolts. There are better materials such as 316 though that is primarily improved corrosion properties but a slightly higher tensile also. I think the rule is never use these on cyl heads or where a relatively high torque is needed. I use SS nuts on the engine studs but retained std steel for the 5 main fasteners. I did have a set of SS bolts on the engine to cradle and no matter how I tightened them they would always turn and did not clamp as they should.

Chris · Apr 13, 2010

Hi
Sorry to hear your news I hope you get the bolt out.
I fitted RGM head bolts to my alloy big bore & you could see the flame shooting out between the barrel & head after a short ride. Never sorted them, I believed that they stretched. Fitted standard parts & the problem never reared its head again.
Chris

Myford · Apr 13, 2010

Well I got it back out today, huge sigh of relief. I put the quarter drive torque wrench set to a tadge over the correct setting on it, & worked it back & forth, never going over the setting, & slowly but surely worked it back out. Yesterday it was so rock hard tight I didn't think I had a hope of getting the #ugger out.
So now if amal pull there fingers out in posting my new floats I should have it running very soon

Myford · Apr 13, 2010

By the way the bolts were from D middleton, & the 4 outside ones went in fine, now I've got it out the middle one looks to be oversize. The old one has now gone back in with no probs.
Terry

B+Bogus · Apr 13, 2010

I'm relieved to hear you got it sorted. By the sound of it it wasn't galling after all?

A relieved user of stainless fasteners

Myford · Apr 13, 2010

It didn't look it when it came out, but, it tightened up before it hit the bottom, & when I tried to back it out it went for a turn & a bit then came up hard to a stop. Thats when I hit the worry button.
Terry

Gutted from Kent

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