Replacement Exhaust Manifolds

[dtpugh]

I have a 1999 4.0L, and both manifolds need replacing due to the normal reasons i.e. hole where the 4 pipes meet.

I now have the choice of going OE manifolds or upgrades from ACT etc.

What are peoples opinions to the route I should go.

Dave

>> Edited by dtpugh on Sunday 31st July 21:04

[Wildfire]

Upgrades from ACT, then you can De Cat with ease and they look cool

[zippee]

When mine went earlier this year I went for the de-cat stainless ones from ACT. Firstly they look so much better when viewed through the bonnet slats.
Secondly they're a heck of a lot cheaper the OE ones which are about 4-500 plus VAT EACH!!!!!

[victormeldrew]

dtpugh said:

I have a 1999 4.0L, and both manifolds need replacing due to the normal reasons i.e. hole where the 4 pipes meet. I now have the choice of going OE manifolds or upgrades from ACT etc. What are peoples opinions to the route I should go. Dave >> Edited by dtpugh on Sunday 31st July 21:04

Is that a normal reason? A new one on me, I thought they were stainless steel?

[V8 Archie]

Yes, a normal reason.

And yes, go for the de-cats from ACT (about £525 + VAT for the pair). 5 hours fitting.

Actually the ACT pipes are cheaper de-catted. Mainly be de-catted is not strictly correct. They are made without cats. If cats are required they are cut and cats added which obviously costs extra.

There may be a bit of lead time, but you'll probably be OK for a while even with the holes.

[dtpugh]

victormeldrew said:

Is that a normal reason? A new one on me, I thought they were stainless steel?

I believe it is and the orginals are not stainless steel, at least they are not on mine.

Dave

[tacoma]

zippee said:

When mine went earlier this year I went for the de-cat stainless ones from ACT. Firstly they look so much better when viewed through the bonnet slats. Secondly they're a heck of a lot cheaper the OE ones which are about 4-500 plus VAT EACH!!!!!

Hey Tony,

any pictures of that upgrade?

mike

[rooster]

tacoma said:

zippee said: When mine went earlier this year I went for the de-cat stainless ones from ACT. Firstly they look so much better when viewed through the bonnet slats. Secondly they're a heck of a lot cheaper the OE ones which are about 4-500 plus VAT EACH!!!!! Hey Tony, any pictures of that upgrade? mike

I can vouch that they look fantastic!

[radzoule]

dtpugh - how are you sure they've gone where the pipes all meet? I thought the only way to check was to take them off and fill them with water?!

I just ask because mine is def. blowing somewhere, and i can't tell where its coming from!

[jonathant]

my local got out their high tech stethoscope and bit-of-tubing and had a poke around when my manifolds were blowing.....

[2 sheds]

Tis true that the TVR manifolds tend to crack or even rot from the area where the 4 primaries meet, the only way to repair this is to cut the cat chamber off and internally weld , we are finding that a lot of them are beyond repair though.

The TVR manifolds are stainless but a very low grade, to be fare though they do last about 10 years which is pretty good.

[dtpugh]

radzoule said:

dtpugh - how are you sure they've gone where the pipes all meet? I thought the only way to check was to take them off and fill them with water?! I just ask because mine is def. blowing somewhere, and i can't tell where its coming from!

I used a bit of tubing listing at each exhaust port and then listen to the section where the 4 pipes join. It was much louder by the joint.

It started off last year and I took it a main dealer in the midlands. They changed the gaskets and said that there was corrosion on the head on the rear port. They said that they have sealed it now and if it went again, the head would need to be removed and the head exhaust port faces would need to be skimmed, cost about £2K.

Needless to say that the tapping noise returned near enough straight away. This year after attending quite a few track days I decided that I had to fix it, it was really starting to irritate me.

I am still a novice at the mechanics, but I find it very enjoyable getting my hands dirty after a day in the office. Having replaced heads on a couple of other cars now and bearing in mind the £2K estimate, I decided to do the job myself.

I removed the manifold and inspected the exhaust ports, I could not find any evidence of corrosion with the ports on the head Looking from underneath the car I could see the sooty trails of exhaust leek on the rear port. Inspecting the manifold flanges it was obvious that rear flange was not inline with the others. A manufacturing fault! So off I went and got the manifold exhaust flanges skimmed on the manifold cost £100.

Fitted to the car, although the tapping noise had reduced, it had not gone completely.

After reading comments here or somewhere else (can't remember) used a tube on each port to listen for a leak. I identified that it must be a leak where the 4 pipes meet. I had solved the problem on the rear port only now to have a leak in the 4 pipes joint. It might have been there before or the skimming the exhaust flanges could have cracked a weld.

This week I had my suspension changed at Joospeed. I asked Joo to confirm that the exhaust manifold had actually blown as they are not exactly cheap. He confirmed that it had indeed blown and then told me he checked the other side and told me that indeed both sides have blown

My hearing was telling me that it was one side, so I only checked that side. It just shows you that the sound bounces around in the engine department and deceives you.

I obviously will not be returning the main dealer. Even though I probably wouldn't anyway now. But I am totally pd with them.

Dave

>> Edited by dtpugh on Tuesday 2nd August 20:33