Blown manifold

[number 7]

Well I've now discovered the source of the extra noise mines been making recently. Not the manifold gaskets - changed both sides a few weeks ago and re-checked for sealing, not the manifold to silencer, re-did that joint. I found a 15mm dia hole in one of the downpipes, well obscured by the adjacent pipe. I would say this is a direct result of using manifold heat wrapping, which I removed a year or so ago. I seems to encourage the surface to crumble, whilst the portions of the pipework which I hadn't wrapped are still fine. Not really repairable either. Ho hum.

7.

[wedg1e]

Can ye no MIG a slab o tin over the hurl?

[stever]

Yeah what he said - get it welded!!

[number 7]

my welding is pretty amateur to say the least, and the metal all round that area is badly corroded - not just surface stuff. I'd probably end up burning the pipe clean through.
The manifold is dated 1998, and thats more or less when I fitted it, so its done quite well.
7.

[leorest]

Holts exhaust repair bandage from Halfords. My down pipes are virtually made of the stuff. That and old beer cans!

Note to self... must get new manifolds

[Phart]

Hmmm beer cans - to fix the car. Great solution... Any preference on the beer?

[SLB]

Tried heat wrap on my SEAC and it was a disater. You could see the manifolds glowing red underneath, but they all distorted and the surface crumbled. Brand new manifolds + heat wrap lasted about 1500 miles before starting to blow.

[leorest]

Phart said:

Hmmm beer cans - to fix the car. Great solution... Any preference on the beer?

Guinness of coarse

[number 7]

Anybody wanting a manifold in a hurry is going to be dissapointed
Tried TVRcarparts: they only have the small flange versions, nothing at RT Racing, ACT, JP Exhausts or David Gerald, although all can get them made within a couple of weeks. Last chance is Tower View, unless anyone can suggest an alternative?

7.

[wedg1e]

number 7 said:

my welding is pretty amateur to say the least, and the metal all round that area is badly corroded - not just surface stuff. I'd probably end up burning the pipe clean through. The manifold is dated 1998, and thats more or less when I fitted it, so its done quite well. 7.

So you have nothing to lose then
What you got, oxy-acet or MIG? Cheap MIG sets are often coarse on their power settings, but with patience and avoiding getting too much heat going it is possible.
My welding's crap as well, but it doesn't stop me trying...

[number 7]

wedg1e said:

So you have nothing to lose then What you got, oxy-acet or MIG? Cheap MIG sets are often coarse on their power settings, but with patience and avoiding getting too much heat going it is possible. My welding's crap as well, but it doesn't stop me trying...

Its a MIG set. The other problem is that the hole is directly facing the adjacent pipe, so access is tricky, but I might give it a go anyway.

7.

[leorest]

number 7 said:

...they only have the small flange versions...

Didn't know there were different types. Are they interchangeable? What are the pros/cons? Apologies for my ignorance, but if I don't ask I'll never learn.

[number 7]

leorest said:

number 7 said: ...they only have the small flange versions... Didn't know there were different types. Are they interchangeable? What are the pros/cons? Apologies for my ignorance, but if I don't ask I'll never learn.

Because the larger engined versions had larger exhaust ports (not sure whether this was a Rover or TVR thing) TVR had separate manifolds for the 3.5's and the bigger versions. The difference is in the size of the rectangular flange where it meets the heads. On the 3.5 versions (part numbers beginning 035) they are c. 23 x 33 mm. On the part numbers beginning 042 they are c. 27 x 38 mm. The bigger versions therefore avoid the exhaust gas hitting a step as it exits the ports.

7.

[leorest]

Thanks. That's another thing learnt!

[wedg1e]

Best check mine then. Maybe the other 75 bhp is being held up that way

[SLB]

My old SEAC had had the smaller ones from new, changed to the bigger ones which did seem to improve things a tad.

[gsx600]

So when you order from RT or ACT etc what size do they give, as I never mentioned engine size on last order ?

[FrenchTVR]

Paul,

Bring it over and I'll happily weld it up for you. Have gas as well as Mig which may be easier if it's really thin.

Mick

[number 7]

gsx600 said:

So when you order from RT or ACT etc what size do they give, as I never mentioned engine size on last order ?

I think the aftermarket all use the bigger sizes now.

7.

[number 7]

FrenchTVR said:

Paul, Bring it over and I'll happily weld it up for you. Have gas as well as Mig which may be easier if it's really thin. Mick

I might take you up on that. I've got an older manifold which I started to wonder could be hacked apart for the section I need, and welded over.

7.

And YHM.

>> Edited by number 7 on Sunday 9th April 20:46