major vibration/buzzing above 5,000rpm

[mgaut]

OK, so I appreciate that an internet forum isn't the best place to diagnose a problem such as this, but if anyone can relate to this I'd like to crack it.

A manifold was replaced last week, and now when driving (but not if you rev it out of gear) a rather worrying vibration comes from what feels like below the gearbox.

I accept the easy option is to take it back to where it was fettled, but if it's something simple I'll give it a go.

Anyone relate to this?

cheers

Mike

[BLUETHUNDER]

I would strongly suspect that the exhaust is rubbing against the chassis.Edited to add.I have had this,whenever a manifold has been worked on.

Edited by BLUETHUNDER on Sunday 21st September 18:03

[< FORZA WEST]

poor adjustment of exhaust or the weld of the new maniflod is touching chassis

[mgaut]

thanks guys.

what's the cure ??

Mike

[BLUETHUNDER]

mgaut said:

thanks guys.

what's the cure ??

Mike

It might cure itself.Mine has on a couple of occasions.Failing that,its then a four poster job and a bar and some heat.

[< FORZA WEST]

As bluethunder said, need to get it on 4 poster and see where its touching and either adjust the cats and centre section or warm the manifold and move it slightly

[trackcar]

you can put a link bar between the bolts on the flange of the manifolds to the cats to stop them moving independently .. also you have some side to side movement for the whole system if you slacken the gearbox mounts off and move it over away from the side that's touching .. because the gearbox mounts are near the back of the box and the whole lot is rigidly connected to the engine and hence the manifolds, then moving the gearbox over swings the exhaust over aswell. It's much better to move everything like this if possible and then re-tighten the flanges rather than try and strain the exhaust over on its own as is often the case .. that just leads to more premature cracking of the manifolds again.

[mgaut]

thanks Trackcar.

I have access to a pit so I'll take a look next Saturday.

Mike

[FarmyardPants]

Also check the centre exhaust mount. It's shaped like a rubber cotton reel. Push the exhaust up to see if it has come apart. Halfords sell a replacement.

[mgaut]

initial inspection reveals the 'new' manifold flange is touching the plate under the cats,and there is a"tie bar" between the two flanges.

I'll get it under an inspection pit later this week and see if I can manipulate the flange away from anything to vibrate against.

Thanks for all the suggestions.

Mike

[mgaut]

Apologies if this sounds a bit anal, but if anyone has an under car shot of the manifold/cats join and could post or email to me, that would help in knowing what it should/could look like.

cheers

Mike