Exhaust Manifold Leak

Exhaust Manifold Leak

Author
Discussion

jamescooper47

Original Poster:

89 posts

124 months

Saturday 11th January 2014
quotequote all
Nice to see the sun today, and first time i've driven the new weapon with the top off.... What a laugh, what a noise!

However is does multiply the effect of a slightly leaky manifold.... clearly heard at small throttle openings.

The question is > Is this really a massive job? How much would a TVR specialist charge to change them rather than the faff of losing many layers of skin, and many hours of graft in an upside down position?

Is it really worth doing when the leak isn't really that big? Front 2 cylinders on off side?

Or considering the leak is only on the off side with the most space around them, is it worth just giving it a go?

Hope you all enjoyed the sun today too.....

QBee

20,903 posts

143 months

Saturday 11th January 2014
quotequote all
TVR experts are used to diagnosing where the problem is with a listening tube, whipping the manifolds on and off, and have all the right odd-shaped spanners for getting at the bd bolts. They won't charge you a lot. You will struggle with it unless you are very competent mechanically.
The usual fault is at the 4>1 union. Once the manifolds are off the car, a welder will cut the manifold open, weld the fault and weld them back up for about £100.
One further thought for you - if you have any thoughts of decatting, now's the time to start it. You can remove the pre-cats very easily when they are cut open. It's an hour's hard hammering per side to do it later. Pre-cats out improves the noise,reduces under-bonnet temperatures, and it still passes the MOT.

roseytvr

1,788 posts

177 months

Saturday 11th January 2014
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Not a lot to it if your half decent with spanners. It does need doing though - the leak will eventually burn a trace on the head. It's much easier if you jack the car up and drop the exhaust and starter motor. Also change the bolts to stainless steel arp bolts and nordlock washers

s p a c e m a n

10,752 posts

147 months

Saturday 11th January 2014
quotequote all
Buy some release fluid and start spraying now hehe

MADMAX2

2,336 posts

193 months

Saturday 11th January 2014
quotequote all
s p a c e m a n said:
Buy some release fluid and start spraying now hehe
hehe

EGB

1,774 posts

156 months

Saturday 11th January 2014
quotequote all
9/16 or 14mm S spaners are a help. ReTighten new manifold bolts after a short hot run. Uvernight soak bolts with WD40 or similar before unscrewing. Even some diesel.

QBee

20,903 posts

143 months

Saturday 11th January 2014
quotequote all
Get a proper man in. I tried to help my TVR guy bolt one back on, as we were up against a deadline. I managed one bolt in ten minutes, couldn't reach most of the rest. He took over and did the other seven in less than ten minutes.

Mr Supercharged

494 posts

156 months

Saturday 11th January 2014
quotequote all
I've just done mine. The best advice I can give you is to take both manifolds off and replace gaskets and use the reduced head size (3/8 AF) ARP bolts and washers that Tim does at ACT. This makes the putting back on job a lot easier. The standard bolts don't allow you to get a ring spanner on in several positions.

I also arranged to have my leaking manifolds re-welded at JP Exhausts, through Tim at ACT due to them leaking. They have the correct jigs for the manifold which means they fit after welding without fuss! The issue is the way in which they were originally manufactured by TVR. Instead of welding all of the primaries into the collector fully circumferentially from the inside at the factory they just welded the centre cruciform and then the rest of the circumference of each primary into the collector from the outside. This then relies upon overlap of the internal and external welds for a complete seal. And in many cases they never achieved this which is why you get the white residue evidence of a leak!

JP Exhausts also replaced the pre cat section with a section containing a nozzle.

The easiest way to detect a leak site is to mix a 80% fairy liquid / 20% water mix. Use a paint brush to slap it on over the manifolds and gasket areas while the whole thing is cold. Then shove an air compressor gun up the exhaust, blank off the other exhaust and plenum butterfly and shoot air up it. You will then get lots of bubbles form at the leak sites.





Goaty Bill

1,779 posts

150 months

Sunday 12th January 2014
quotequote all
QBee said:
Get a proper man in. I tried to help my TVR guy bolt one back on, as we were up against a deadline. I managed one bolt in ten minutes, couldn't reach most of the rest. He took over and did the other seven in less than ten minutes.
+1
This all day long.

Of course it's 'easy' enough for an experienced spannerman.
And if you really want to know your car then there is no other choice is there? - get at it!

But it's still the best £100-£150 (each time) I have ever spent on the car; having someone do it who knows what they are doing.

As for removing the pre-cats, I finally had it done while the engine was out.
It doesn't reduce under bonnet temperatures a little bit; the difference on mine was huge.
Worth every penny, assuming you have the pennies to spare.

jojackson4

3,026 posts

136 months

Sunday 12th January 2014
quotequote all
Goaty Bill said:
QBee said:
Get a proper man in. I tried to help my TVR guy bolt one back on, as we were up against a deadline. I managed one bolt in ten minutes, couldn't reach most of the rest. He took over and did the other seven in less than ten minutes.
+1
This all day long.

Of course it's 'easy' enough for an experienced spannerman.
And if you really want to know your car then there is no other choice is there? - get at it!

But it's still the best £100-£150 (each time) I have ever spent on the car; having someone do it who knows what they are doing.

As for removing the pre-cats, I finally had it done while the engine was out.
It doesn't reduce under bonnet temperatures a little bit; the difference on mine was huge.
Worth every penny, assuming you have the pennies to spare.
Bill for MCC chairman ( master of the mods )

Chuffmeister

3,597 posts

136 months

Sunday 12th January 2014
quotequote all
For goodness sake, it's a pair of manifolds! Have a go yourself. They're a pain in the arse, but you'll feel a great sense of achievement when you've done them and cold beer in the evening will taste so much better! I didn't bother with ARP bolts. I slotted the bottom of each manifold and used studs. Super quick to get on and off now, with less time under the car.

No need to drop the exhaust or remove the starter. Do disconnect the battery though and loosen the bracket connecting the Y-piece to the exhaust. It's easy to drop a spanner on the starter!

Honestly Goaty and Qbee, where's your sense of adventure! wink

QBee

20,903 posts

143 months

Sunday 12th January 2014
quotequote all
I wouldn't dream of speaking for Bill, but I am ancient, have constant backache, don't have enough garage space to work on the car, intensive (ie the opposite of extensive) tool kit, arthritic hands, lack the detailed knowledge, busy with my accountancy practice, and I have the world's best TVR indie available to do a proper job. I will do odd bits, but anything near the engine or anything safety related I leave to the experts. Sorry Christian, but that's how it is for me. My car is out in all weather, i did about 40 miles, roof off, yesterday, will take it out again today, and I have enjoyed every minute of driving "Niggles" for the 16,000 miles I have done since May 2012.

But I respect you guys for looking after your cars yourselves, so am happy to share what theoretical knowledge I do have. Just don't hand me a torque wrench and expect me to know what to do with it.

jamescooper47

Original Poster:

89 posts

124 months

Sunday 12th January 2014
quotequote all
As usual, the wealth of knowledge here is so useful..

Thanks all,

For the sake of mucking about, waiting for dry weather etc etc, for £100-150 /Sounds like a bargain to me..

Although that cash would give me another 10-20 minutes of blapping through the countryside... ;-)


ChimpOnGas

9,637 posts

178 months

Sunday 12th January 2014
quotequote all
Just to share my experiences, I have ARP bolts which certainly make the manifold job easier now.

I went with the Nordlock washers to try and keep them tight, these washers do work but are not the 100% fit & forget solution I'd hoped for.

I still find I need to nip up one or two of the ARP bolts every 6 months, fortunately they always seem to be the same two and are the easiest ones to get at, I plan to put a tiny smear of firegum on the threads of these troublesome two next time.

The real secret to making the nasty manifold job much easier is my long slim 3/8" Snap-on six sided ring spanner that also has the ideal offset, its not a semi open brake pipe spanner but a full ring and unusual in being six sided, I believe its a bleed screw spanner.

Being 15" long & six sided you can really put some torque on the ARP bolts to get the Nordlocks to ramp up without fear of slipping on the bolt head, it must be said the ARP bolt heads are hard as hell too.

Six sided ring spanners are rare because you dont get the small repositioning increments you do with the normal 12 point ring spanner design, but you can see the clear location advantage they offer here.



Where a twelve point socket or ring spanner puts the torque through the fragile corners of the nut or bolt head, a six sided socket or ring spanner puts the torque through all six of the broad flats of the nut or bolt head massively increasing the surface area the torque acts on thus significantly reducing the likelihood of slip.

Fortunately the increment thing isn't a big issue in this case, and with this one invaluable spanner I can whiz around all 16 bolts in 30 minutes, the combination of the right bolts with the right spanner was definitely the answer for me.

The Nordlocks on the other hand are only about 70% effective in my experience, but they are better than traditional spring washers that lose their spring tension in the high heat environment & become no more effective at locking the bolt than a flat washer.

s p a c e m a n

10,752 posts

147 months

Sunday 12th January 2014
quotequote all
That's a point, you have checked that all of your bolts are tight haven't you. My ones were a right bd on number 8, had to tighten them a few times.

spend

12,581 posts

250 months

Sunday 12th January 2014
quotequote all
Mr Supercharged said:
I also arranged to have my leaking manifolds re-welded at JP Exhausts, through Tim at ACT due to them leaking. They have the correct jigs for the manifold which means they fit after welding without fuss! The issue is the way in which they were originally manufactured by TVR.
I was under the delusion that JP manufactured them for Blackpool in the first place?

QBee

20,903 posts

143 months

Sunday 12th January 2014
quotequote all
That's partly my point. My TVR guy seems to know how to tighten them so they ARE fit and forget. I certainly don't.

For example, Alun450 and I changed my front brake pads between track days last April. We did one side each, took for ever. Felt a great sense of achievement. Took it up to 150 mph the next day on the airfield track day, max braking, all well
A few weeks later I heard a strange clonking from the front offside of the car. Took the wheel off to discover one caliper bolt missing and the other one half undone. yikes that was the one I had done. Lack of knowledge or the right tools. No knowledge is a dangerous thing.

ChimpOnGas

9,637 posts

178 months

Sunday 12th January 2014
quotequote all
The answer to loosening manifold bolts may already be here.



http://taylorvertex.com/vibe-lock/


And Remflex gaskets have a good reputation in the States.



http://catalog.remflex.com/LAND_ROVER_EXHAUST_GASK...

I'd say they'll be the standard port size though.


Goaty Bill

1,779 posts

150 months

Sunday 12th January 2014
quotequote all
jojackson4 said:
Bill for MCC chairman ( master of the mods )
Yes it's true; removing your pre-cats receives the coveted Goat Seal of Approval.

jojackson4

3,026 posts

136 months

Sunday 12th January 2014
quotequote all
Goaty Bill said:
jojackson4 said:
Bill for MCC chairman ( master of the mods )
Yes it's true; removing your pre-cats receives the coveted Goat Seal of Approval.
What about that cross bolting shout chill