The Triumph Dolomite Club - Discussion Forum

I'm struggling to see anything wrong with your old one that a quick wire brush or run with a die nut won't fix.

The rimmers one is too long of shank, and the threaded part is too long as well. It will stick out too far and foul the wing and bottom out
on the thread in the head, running the risk of damaging the thread in the head as its tightened.

Send it back and get the right ones, or re-use the old ones. Try another supplier.

Jonners

I would carefully try one of the new bolts, it may be a better design?

Failing that, if the condition of each is the same as the bolt in the photo, I would do as Jonners suggested and reuse these.




Ian.

Unfortunatelly, I had some of the old bolts cut off to bring the manifold out so can't re use all of them...
I'll try one on but I don't see why Triumph would have intentionnally designed shorter bolts...

If it doesn't fit, do you know where I can get proper bolts from?

The last set of bolts I got from rimmers to fit my manifold fitted fine ( although I did not measure new against old ).

I think I got some from my local hardware/fastener stockist.

I measured the bolt threaded part sticking out of the manifold 2,4cm which is the exact same length as the thread hole in the engine, so maybe they ll fit ok.
I tried to spin the new bolts in gently, just by hand but it gets tight half way through, i guess some rust must be stuck in the thread, what should i use to get the thread clean? a tapping tool?


Another issue... I just realized that along with one of the old bolts, a bit of thread from the engine came out with it
Had helicoils been fitted in already?
I have about 5mm of thread that came off, do I need to do something about that?

Unfortunately that looks like a part of the thread from the head. Looks like you will need to helicoil that one at least.

This happens because the bolts can bottom out in the thread or they have been over tightened.

You will need to fit a helicoil in to repair that. What thread is up to you....You can use some coarse threaded metric equivalent.

Sadlly to do this means getting access to the engine or cylinder head. You may have to take it out...

When you replace these bolts be very careful with the torque setting when you do them up,
If you do have a stiff bolt you need to run a tap down the thread to clear it. You can make your own thread cleaning tool by cutting slots down a bolt
with the same thread.

When you fit you manifold be sure the jointing faces are flat. It may be worth having a very light skim of the manifold so you dont have to make the bolts
pull it flat to the head face.

Jonners

Thanks john, i just cleaned the threads with homade tap with one of the old bolts works nicely:)

I dont know what option i ll go for yet but i wont be able to get the engine out (dont have the gear or room)
"Luckily" the broken thread is the second from the left,one of the easiest to access, but still my drill is too big to get past. I'll see if i can borrow a smaller one from someone.
If not, I'm wondering if i could leave it as it is as i have 5mm of broken thread out 2cm thread.
So still 1,5 of thread, i tried fitting a new bolt in and it fits nicely and appears strong enough.
What do you think? Would it really be risky?

Tom, I've resized all of your photos in this thread to make it easier on everyone's eyes.

I can't offer you much more advice other than giving the bolt threads a light coating of thin oil (the 3 in 1 type oil). Removing and replacing the exhaust manifold on the 1850 wasn't too bad so I would imagine that doing the job on a Sprint will be worse because there's less room and the LHD layout certainly doesn't help!

Thanks for the resize

If you havent lost too much of the thread you may get away with it. You could also try some "chemical metal".

Do that bolt last....

Will a stud fit? It may make it impossible to fit the manifold but I do this on 1850's. The stud doesnt rotate in the damaged thread and will hold with a nut.

You can then fit the stud with chemical metal which will set and help to hold it.

I guess if it doesnt seal you can take the head off. The worst part of this job is the downpipe flange and you have sorted that one...

Jonners.

I did not understand all of the chemical metal part, the manifold stud seems to hold well even with one quarter thread off,
what you mean is that I should apply some Chemical metal on the stud thread (as with loctite)? Would it be possible to take it out if needed after that?

ps: Do i need to put some high temperature loctite on the manifold studs?

You do not need to use Loctite on the bolts , if the bolt tightens up ( the one with thread on the bolt ) fit that one last as Jonners said , I personally would not use chemical metal on the thread if it tightens up as you may have a problem afterwards if you have to clean it out if you encounter any more problems

Ok i'll try it like that, thanks