Horrible noise after head job!!

[s car go]

Theres always a but......
She runs lovely,but I have a nasty noise coming from the exhaust/turbo area when the revs are punched.It sounds like someone jabbing a pencil or screwdriver in to a fan blade. If I bring the revs up slowly it starts about 2-2500 RPM.On a very short test drive it started from as low as 1200 RPM.
Any suggestions or advice appreciated.

Regards

Mark

[POPEYE]

Dry turbo? is the rocker cover breather connected to the inlet ducting?
(left a screwdriver in the turbo?)

[s car go]

Breather connected,and I've had the inlet,and turbo pipe off again,and checked for obstructions!

My thoughts are,has the steam down the exhaust pipe when the head went knackered the turbo?

[BUSHWHACKER]

Any play in the turbo's impellor? Does it spin freely by hand?

If the noise is there when the turbo is producing boost pressure, it could be the metal gasket between the turbo and downpipe. They can squeal like a banshee.

[s car go]

Any play in the turbo's impellor? Does it spin freely by hand?

Not sure! I had a look down the "black hole" this evening but I could'nt see the impellers.
I'll have to strip it out in the morning,as I'm almost convinced it's the turbo making the noise.
Found if i bring the revs up slowly all is quiet,but if your holding at about 2k and you suddenly blip it,it rattles something chronic.

Cheers

Mark

[s car go]

Noise gone!!!

Bushwacker,
It was indeed the gasket betwen the manifold and the turbo flange.It appears my mistake was to tighten the manifold to head bolts followed by the manifold to turbo.As I was removing all this morning I noticed a small amount of rotational give in the manifold to head area. Smear of exhaust paste and did all the bolts up gradually and problem gone.

Regards

Mark

[NiftyNev]

Did not reply because I was having trouble getting over the thread title.

Nev

[POPEYE]

[QUOTE=NiftyNev;774048]Did not reply because I was having trouble getting over the thread title.

Nev[/QUOTe

[s car go]

Did not reply because I was having trouble getting over the thread title.

Nev

Erm yeh!! Maybe I could have phrased that a little better!!

[Webbo]

Erm yeh!! Maybe I could have phrased that a little better!!

I had exacly the same after my " Head Job " It turned out to be the large air feed pipe across the top and into the turbo, it all looked OK but was delaminated inside and was sqeeling as you described, worth a try.