Inlet Manifold Stud Advice Please !!!

[kvc2308]

Hi,

I have been having problems with the stud holding on the Stromberg carbs, it has striped the thread once, so I fitted a helicoil with stud lock etc..., now it looks like it is happening again. The carbs seem to have come slightly loose again resulting in air being sucked in under hard acceleration causing a stutter.

Any advice on getting a better fixing into the inlet manifold ? Has anyone try fitting the stud into the helicoil with something like chemical metal ? My concern is the metal has become too soft with age and the whole manifold will need changing. Or is there any additional fixings that can be made to beef up the single stud.

Any advice gratefully received.

Thanks,

Kevin

[stagmuffin]

cant understand why it wont hold unless its striped the thread again that holds the coil ally work hardens and doesn't soften unless its annealed . I would try to go up a size then reduce down with a bushnut .liquid metal may work and so could a lot of other bogit and fixit adhesives and compounds but I wouldn't be happy with a fix like that with extremes of temperature its likely to happen again .
steve

[stag8manod]

Hi Kevin, My suggestion is clean the hole out back to clean metal and get an experienced aluminium welder to tig (tungsten inert gas) weld it back to solid, redrill and Helicoil back to standard. Cheers Ian A

[kvc2308]

Thanks for the quick response guys - both as I had thought really...... I am going to try and skive off work a bit later on and take the carbs off to have a better look.

Steve - I have seen the bush nut inserts you are talking about (normally made of brass) - but have no idea where to get them - any ideas ? I have had a good old google but nothing really shows up......

I'm guessing TIG welding is too risky in place and would require the manifold to be removed - something I didn't really want to do.

[V Mad]

I would be sirprised if the Helicoil insert has failed. Maybe it could have got mangled when you put in the stud? I have sometimes found that the end of the coil can catch on a bolt thread. I hope when you look it is something you can easily fix.

If worst case the manifold is knackered, you could just replace the manifold for another, they are not really expensive.

[stag8manod]

Welding ln place shouldn't be to difficult or dangerous. The biggest problems I see is the heat sink by still being bolted to the engine and getting the car and welder in the same place. Cheers Ian A

[elvimto]

Kevin,
if you need a bushing,I may be able to find something for you over here since we still are on the standard threads i.e nc nf etc.
let me know
Stuart

[wilf]

Note to self - take it easy tightening that nut!

[elvimto]

Kevin,
are you talking about the single stud that holds the adapter on to the manifold or one of the studs that bolt into the side of it??

Stuart

[kvc2308]

Kevin,
are you talking about the single stud that holds the adapter on to the manifold or one of the studs that bolt into the side of it??

Stuart

Yes, it's the single 3/8 UNC stud in the middle holding the carbs onto the manifold.

I've not had the car long and have been doing bits & bobs to it, it kept stuttering when hot and under hard acceleration, when looking round the carbs I was leaning on the air box and the whole lot moved round and wobbled slightly, so I tightened the nut holding them down and everything seemed to run perfectly...... Until we went for a nice long run, the engine was running at temp for quite a while so everything was good and hot, then the stuttering came back, pulled over took a look at the carbs and they where really loose again, tightening the nut just pulled the stud out so that's when I fitted the Helicoil, along with new o-ring, fibre washer etc...

Everything seemed to be perfect again, and have done a few local trips out, I changed the steering rack at the weekend, so went for a really good drive on Sunday in the glorious sunshine - annoyingly after about 45mins there was a bit of stuttering again under hard acceleration, when we got back home I had a quick check of the carbs and they ever so slightly loose again, I have managed a slight turn of the nut to tighten them down - but now fear it will just pull the stud out again.

I am a bit concerned about buying a second hand / re-con inlet manifold in case this happens all over again.

My thoughts are to replace with stud with slightly larger diameter threaded rod so that I can tap the manifold in further and have more thread in contact with the manifold - this surely must make for a more secure fit ??!! Is there anything else I could use instead of stud lock to make a more permanent bond ??

[V Mad]

I am a bit concerned about buying a second hand / re-con inlet manifold in case this happens all over again.

Absolutely no reaon for that to happen unless there is something wrong with the stud, or you have not screwed it in far enough, or you have over tightened it. Never had a problem with this. The thread is coarse which should be very strong.

[Delayed Steve]

Had the same problem a few years ago , I had mine welded up drilled and tapped at a local engineers , I've had no problems since .
Steve

[KOY 23]

I am a bit concerned about buying a second hand / re-con inlet manifold in case this happens all over again.

Also you know that your manifold fits.

[kvc2308]

Thanks everyone for the advice - I think getting it welded up and re-tapped makes the most sense, I'm all for re-conditioning existing parts like Koy23 says - I know this manifold fits. Having just fitted a re-con steering rack I now have problems with the High pressure hose sealing onto the rack - never had this on my old one, and I would have been better off getting the original re-conditioned - Oh well that's another story.....

[Bob Heritage]

If you do decide on going down the larger stud route, check to see if you can get the spanner on the nut, there's not a lot of room in there.

Bob