190e Exhaust manifold stud prob

[TheJim]

Hello chaps, rebuilt the top of my engine AGAIN (nice of merc garage to let me know they have changed the design of the head bolts and the new ones need washers-which they neglected to supply- oh how I laughed) and I am trying to refit the exhaust manifold to the head. I had to remove the studs from the head when I took it all apart because the threads were nasty. All the new studs are in apart from one which does not want to take the thread. It starts to go in and then it goes loose after a couple of turns. Any ideas on how to get it in without knackering the thread further? It is weird that it is being problematic as the old stud came out clean.

If it gets to worst case scenario, ulp, how critical is one stud being duff? It is a substantial casting and I guess the exhaust shouldn't blow.........

 

[maddog]

Hello chaps, rebuilt the top of my engine AGAIN (nice of merc garage to let me know they have changed the design of the head bolts and the new ones need washers-which they neglected to supply- oh how I laughed) and I am trying to refit the exhaust manifold to the head. I had to remove the studs from the head when I took it all apart because the threads were nasty. All the new studs are in apart from one which does not want to take the thread. It starts to go in and then it goes loose after a couple of turns. Any ideas on how to get it in without knackering the thread further? It is weird that it is being problematic as the old stud came out clean.

If it gets to worst case scenario, ulp, how critical is one stud being duff? It is a substantial casting and I guess the exhaust shouldn't blow.........

If you can get in there you could drill and then helicoil it but i would reccomend leaving the bolt out as its almost certain to blow.

 

[TheJim]

Drilling out is a no go frankly, that cylinder head is going nowhere! But you reckon I should leave the bolt out?

 

[maddog]

Drilling out is a no go frankly, that cylinder head is going nowhere! But you reckon I should leave the bolt out?

sorry mistyped i WOULDNT leave the bolt out

Bodging ideas

Metal putty - Clean out the thread as best as poss, fill with metal putty ie JB weld etc screw in stud, tighten as much as you can, leave to go off and see if it holds

If the thread is reasonable you could try studlock and crossing your fingers.

The only proper fix is to re-thread it

 

[TheJim]

Studlock, now there's an idea. I had forgotten about that stuff.

Cheers!

 

[television]

Why not re - thread the hole to the nearest next size up, any thread will do, open up the hole in the manifold for clearence and use a bolt.

Malcolm

 

[maddog]

Why not re - thread the hole to the nearest next size up, any thread will do, open up the hole in the manifold for clearence and use a bolt.

Malcolm

he will still need to drill the old thread out though in which case he may as well helicoil it

 

[mercw126man]

I used to sell Loctite and similar types of 'anaerobic' adhesives. Depending on where the stud is located, I'd recommend that you don't use Studlock, as these types of products will not stand the temperature that the exhaust manifold will reach. You'd get away with it on the inlet manifold where temperatures are lower. The suggestion of drilling and tapping out to the next convenient size is a good one.

Good luck!

 

[turnipsock]

Remember this will get pretty hot because it's attached to the exhast manifold. Any bodge jobs would have to stand the heat.

Helicoil is really the only option.

Jim, which stud is it?

I have put helicoils into my head (the one on the car) before. With the kit you just need a battery powered drill and I would recomend getting one of the T piece handle things to hold the tap.

 

[television]

As the hole is empty, no drilling required you could just run a 2mm larger tap through the hole. I have loads of taps if you want one.

Malcolm

You have to tap it anyway to fit a helli coil

 

[maddog]

Studlock will cope with the head as the thread is in the head not the manifold.

I have helicoiled more exhaust studs than i care to recall and usually use stud lock on motorcycles where the exhaust studs often snap or strip due to thier location.

JB weld also copes with heat very well

 

[television]

I hear you can earn good money these days doing stud work.

Malcolm

 

[TheJim]

The problem is that I can't get to the hole as it is one of the lower ones and is nigh on inaccessable. I couldn't break the joint between the manifold and the downpipe so I undid the manifold instead. To rethread it means taking off the head again, I fear. The manifold doesn't move much, so I don't think I can push it out of the way to work on the thread...... Oh, balls.

 

[maddog]

Many years ago a mate over tightened his exhaust studs on his 1300 escort and not only broke the stud but part of the casting came away.

We cleaned it up and stuck it back on with JB weld and the car was fine for two years at which point he sold it.

I would try the same if it doesnt work you can drill it out and either way if you cant bodge it you will have to remove the head

 

[television]

Just had a thought , its a long shot,but did you try any of the other studs in the hole. you could mic up the faulty one and compare to a new one.
Maybe a new one with stud lock would just give enough nip,without over tightning.

Malcolm.

Many years ago I put cooking foil in the hole on a Hillman imp, that held

 

[maddog]

Many years ago I put cooking foil in the hole on a Hillman imp, that held

a man after my own heart

 

[TheJim]

I am just going to have to give it a go and see what happens.....
Wish me luck!

 

[tom7035]

Try cutting a hacksaw slot lengthwise down the threaded portion of the stud and find/make up a sliver of metal just a 'squidgin' thicker than the hacksaw slot. Chamfer the end of the sliver so it fits into the slot prior to starting the stud into the hole. As you tighten the stud, the sliver will 'bottom-out' in the stud-hole and force its way into the slot thus 'thickening' the stud in the hole as you tighten it up. (I think you can grasp the idea, and it will need some measuring up, but worth a try).
Cheers, Tom.

 

[Bumper]

why not just get a tap and re-tap it with a courser thread

 

[TheJim]

Managed to get the bugger in, the first bit of thread was knacked and I couldn't get the stud past it. So I figured a last ditch attempt before stripping it all down and tapping the thread might be worth a whirl.
So I hit it with a small hammer to get it past the dodgy bit of thread, from then on it went in fine.

You can't beat an Irish screwdriver sometimes!