Exhaust manifold whistle

[land864]

I must have the most talented D2A out there

I fixed the sunroof whistle( it was Dixie by the way you other model lurkers an[bigsmile]d ) and now I have one caused by the exhaust manifold studs

At least , the one closest to the firewall

I have lost the nut off that stud

I know the studs stretch and that's why the nuts fall off

I also know , they can be a drama to remove and refit

As a quick but good fix , can I just screw a nut back on , maybe with washer/s to get the extra bite and even fit another nut on top of that for locking purposes?

Anyone know the size and thread of that nut so I can just go and buy 2

Thanks

Pete

[jasonharrison]

If the stud has stretched be careful torquing the nut back on as you may end up snapping the stud. (worst case you'd need an easy out to remove whats in the head)

Fairly certain they're a standard M8 thread

[ScotchRocks]

I had my studs bored out to M10 when I got some other work done on the head as a fix for the common manifold problems. Not sure how cognisant of the vehicles history you are.

[PhilipA]

I have lots of mods which bring my exhaust temp up to 750C on occasions.

So far after about 5000K my manifold is straight with no whistles and full boost 20PSI.

I did the following- de webbed the manifold, had it milled straight, ovalled the end holes most at the ends and reducing towards the middle, ceramic coated the manifold inside and out, and used Mercedes Benz studs which are available on Ebay with Bellville washers and copper coated nuts.
Seems a lot to do, but if you have mods, will hopefully help with reliability.
Regards Philip A

[clintooo]

I had lost my rear nut too. No whistle, but I did have a black residue. I didn't realise they fall off, I just assumed someone forgot to put it back on.

I put on another nut months ago and it has sealed it up.

[land864]

Thanks team

[Tins]

Standard M8 x1.25. Bet it breaks though. Much easier to get it out BEFORE it breaks. Ask me how I know...

[twr7cx]

Remove your exhaust manifold, have the face skimmed back to flat, reinstall. I'd recommend replacing studs and nuts while doing it. If it's leaking and lost nuts then it's already warped.

[Tins]

Remove your exhaust manifold, have the face skimmed back to flat, reinstall. I'd recommend replacing studs and nuts while doing it. If it's leaking and lost nuts then it's already warped.

Ceramic coat it at the same time.

[twr7cx]

Ceramic coat it at the same time.

Agreed, it definitely has made a significant difference to the EGT on mine since installing a ceramic coated manifold.

[land864]

So Size is M8
What thread?

[Tins]

So Size is M8
What thread?

Pretty sure it is 1.25.

[land864]

Thanks team
I went through my stock of spare nuts and bolts and found an M8 with the right thread
Put it in
Tightened it up
Hey presto
Whistle gone
😊😊

[twr7cx]

I went through my stock of spare nuts and bolts and found an M8 with the right thread
Put it in
Tightened it up
Hey presto
Whistle gone

Your likely going to be up for a snapped stud shortly then. If it threw a nut off then it's likely that the manifold has warped (super common TD5 motor problem). If you've put a new nut on and tightened it then your trying to flex it back to straight and causing stress. It's great that it's stopped whistling for now, but how long it'll last, and how much harder the repair job has become for next time could be the cost.

But maybe I'm cynical about it having moved onto my 4th manifold in the 253,000km life of my vehicle...

[Tins]

Your likely going to be up for a snapped stud shortly then. If it threw a nut off then it's likely that the manifold has warped (super common TD5 motor problem). If you've put a new nut on and tightened it then your trying to flex it back to straight and causing stress. It's great that it's stopped whistling for now, but how long it'll last, and how much harder the repair job has become for next time could be the cost.

But maybe I'm cynical about it having moved onto my 4th manifold in the 253,000km life of my vehicle...

X2. The manifold needs to come off, be faced, and preferably ceramic coated. It helps to do a few more things as well, all well documented on various threads here. Removing a broken stud is MUCH harder than replacing it before it breaks, which it WILL do.

[timdo1]

Out of curiosity, when does it whistle. Mine has started whistling in 1st and 2nd gears only sometimes. Usually if its been sitting still for a little bit say at lights or just starting off in the morning. I assumed i had split a turbo hose, but could I have the same issue.

[land864]

Whistles when cold
Good points by all though
Ill get the machining and studs done when a few $ come in

[knuts2au]

Just logged on to do a search on exhuast nuts and here is this thread. Missing the rear stud nut, might try and get the stud out and replace it. Go a 5.5hr trip on Thursday to Geelong then leaving it with a friend to drive while away so don't want any hassles.

[Tins]

Just logged on to do a search on exhuast nuts and here is this thread. Missing the rear stud nut, might try and get the stud out and replace it. Go a 5.5hr trip on Thursday to Geelong then leaving it with a friend to drive while away so don't want any hassles.

Pull the manifold. It's much easier that way, the manifold is warped if the back nut is off, the rear stud at least needs replacing before it breaks. Don't, whatever you do, replace the nut before you have dealt with the issue, which is that your exhaust manifold has warped. A VERY common issue, and there is really only one way to fix it. Trust me, getting a broken stud out of the head is MUCH harder than dealing with it now.

Better to drive it the way it is for now. It isn't an expensive job to pull the manifold, face it straight again, and replace the studs, which is the minimum needed. It can get VERY expensive if you need to take the head off because you can't get the broken stud out in situ.

[land864]

To get manifold off , machined and studs all done , I was quoted $450

Does that sound right?

[Tins]

To get manifold off , machined and studs all done , I was quoted $450

Does that sound right?

At $100 plus an hour, plus the machining, plus the gaskets, plus the studs, with a little cushion for unforeseen breakages, yep, sounds reasonable to me. Ask how much to get it ceramic coated while it's off. Mine was $100, but it wasn't well done.

[twr7cx]

At $100 plus an hour, plus the machining, plus the gaskets, plus the studs, with a little cushion for unforeseen breakages, yep, sounds reasonable to me. Ask how much to get it ceramic coated while it's off. Mine was $100, but it wasn't well done.

Or if you want a quicker turn around grab a spare manifold. Have it machined and ceramic coated and then you can just swap them over.

I agree that the price is reasonable.

Proper, decent ceramic coating is expensive. John Lynch of Jet Hot < www.jet-hot.com.au - Hi Performance Coating (http://www.jet-hot.com.au) > quoted me $325.00 + GST for the full clean and coating service, late last year. He's done plenty of TD5 manifolds before. That is what I would expect to pay for a proper job of it.

[Tins]

Or if you want a quicker turn around grab a spare manifold. Have it machined and ceramic coated and then you can just swap them over.

I agree that the price is reasonable.

Proper, decent ceramic coating is expensive. John Lynch of Jet Hot < www.jet-hot.com.au - Hi Performance Coating (http://www.jet-hot.com.au) > quoted me $325.00 + GST for the full clean and coating service, late last year. He's done plenty of TD5 manifolds before. That is what I would expect to pay for a proper job of it.

Yep, my $100 job started flaking off. I guess you get what you pay for. But I believe that it's worth it, as it lowers underbonnet temperatures considerably.

[clintooo]

I've just ordered an exchange machined and ceramic coated manifold from APT. Cost was $550 plus freight. Hopefully I should get it next week, so I'll post up some pics. I also ordered a set of wurth studs and nuts from that ebay guy in the UK.

However, I just noticed some guy is selling a brand new manifold for $125

https://www.gumtree.com.au/s-ad/launceston/engine-engine-parts-transmission/brand-new-land-rover-td5-exhaust-manifolds/1148818699

I would have gotten that had I seen it before. So could be an option for you, buy that and get it coated. Assuming he will post it.

[Tombie]

Jet Hot did the work for me all those years ago..
Still going strong [emoji41]

[Tombie]

I think those manifolds are the Chinese knock off ones. Caveat Emptor...

[clintooo]

oh, I didn't realise there were chinese knock offs. available Does make sense, as I was wondering why he had 2.

Lucky I went with APT first up then :)

[land864]

So $775 all up
Does the ceramic coating improve performance ?
Good point on the underbonnet Temperature
I reckon I kept cooking the second battery in my old
D2 because of the exhaust being next to it
I even had a special twin skin heat shield made up

[Tombie]

Land864. Yes the turbo gets it a bit warm, was sensible to fit a shield.

If you're not using the battery often that helps cook them as well

[clintooo]

Does the ceramic coating improve performance ?
p

it says so on the internet. So it must be true :).

I figured on balance there might be some gains, but perhaps none that I would notice. I do think it will help in reducing the heat buildup and hence chance of warping the manifold, which is probably of more benefit.

[Tins]

So $775 all up
Does the ceramic coating improve performance ?
Good point on the underbonnet Temperature
I reckon I kept cooking the second battery in my old
D2 because of the exhaust being next to it
I even had a special twin skin heat shield made up

Performance?? No. Longevity of the repair? Yes.
The underbonnet temp thing cannot be over emphasised.
I have my old manifold here. It will get machined, it will get the holes, all but the middle ones, drilled to 10 mm,
it will get coated properly. Folk talk of dewebbing. I don't know about that. Then it will be put back on.
People talk about bigger studs, at least on the outer ports. There are many threads on here weighing the pros and cons.
In the end, it's up to you. Just don't ignore it, as it will hurt more later on.

Move the second battery. There's a bloke on here, Carl somebody ( sorry Carl, I just can't bring it up now ) who makes a battery tray that replaces your one, that takes two batteries side by side. Then you can use the one that cooks to hold something else, like a compressor.

[clintooo]

what did you find was the best technique for removing the studs?

I was thinking warm head would help with some expansion of the head to perhaps ease out the bolts. I was going to go the double nut method to wind them out rather than a stud extractor or welding a nut onto the stud.

I was also thinking of using freeze n release. But I wasnt sure if you could use that on a warm head. Although I guess warm ali head and freeze the bolts would help. but just not sure how localised the cooling will be and if I will damage the head in anyway? I will continue to hit the nuts with penetrant over the next week. But I guess that is probably not going to penetrate down the stud.

[land864]

Thanks John and all :)

[Tins]

what did you find was the best technique for removing the studs?

I was thinking warm head would help with some expansion of the head to perhaps ease out the bolts. I was going to go the double nut method to wind them out rather than a stud extractor or welding a nut onto the stud.

I was also thinking of using freeze n release. But I wasnt sure if you could use that on a warm head. Although I guess warm ali head and freeze the bolts would help. but just not sure how localised the cooling will be and if I will damage the head in anyway? I will continue to hit the nuts with penetrant over the next week. But I guess that is probably not going to penetrate down the stud.

The double nut method works if they aren't frozen in. I was told to try and wind them in a little first. I had very little trouble, except for the broken one, which caused no end of dramas, which is why I recommend getting it done BEFORE it breaks. If I ever get another TD5 car, it will be the first thing I get done, and it will get done as soon as I can organise it.

Oh, on a different note. Don't get tempted to get on of those shiny stainless manifolds off Fleabay. They don't fit, at least not on a Disco. Ask me how I know....[bigwhistle]

[Tombie]

They don't last either.. they crack and fail.
Allisport tried multiple permutations before going a cast version.

[rick130]

So do we elongate the end couple of holes or just drill them out?
My die grinders and compressor are about 8 hours away....

[rangieman]

So do we elongate the end couple of holes or just drill them out?
My die grinders and compressor are about 8 hours away....
I drilled all mine bar the centre 2[wink11]

[Tombie]

For the record - good Ceramic coating, slotted webbing, standard size holes and stock studs...

10 years tuned right up without a problem... towing 3,000kg in 40c regularly etc as well.

[PhilipA]

Ditto with ceramic inside and out, elongated holes and ends 10 mm, completely removed webbing, remap, Mercedes studs with Belleville washers.

About 5000Km now including towing up the Alpine Way NSW (steep) for 20Km and several +700C excursions, although now keep it under 700C with Serck intercooler.
Regards Philip A.

[twr7cx]

Performance?? No.

You are correct, there is no performance benefit in terms of the motor having more power or torque, etc, but I found there is an indirect benefit of performance once my ceramic manifold was fitted. As it significantly reduced the EGT I was able to give more throttle, or throttle for longer, on some of the hills resulting in the vehicle traveling up faster or quicker. That's a performance benefit side effect. There's a hill on the highway on my way home from work or the city each day, previously I would have to back right off about 85% of the way up due to EGT getting too high, now I can leave the vehicle on cruise control at 110km/h and even when I hit the peak EGT is still low enough not to be a concern. Same pyro probe and gauge fitted at the same location on the manifold.


with Belleville washers.

Where did the washers come from?

[PhilipA]

Where did the washers come from?
I cannot remember now but it was an Oz seller and they were pretty expensive.
They are on ebay.
Just a tip , the small sizes which go on the studs are not all that strong so maybe 2 will be needed for each nut.

Regards Philip A.

[Tins]

You are correct, there is no performance benefit in terms of the motor having more power or torque, etc, but I found there is an indirect benefit of performance once my ceramic manifold was fitted. As it significantly reduced the EGT I was able to give more throttle, or throttle for longer, on some of the hills resulting in the vehicle traveling up faster or quicker. That's a performance benefit side effect. There's a hill on the highway on my way home from work or the city each day, previously I would have to back right off about 85% of the way up due to EGT getting too high, now I can leave the vehicle on cruise control at 110km/h and even when I hit the peak EGT is still low enough not to be a concern. Same pyro probe and gauge fitted at the same location on the manifold.





That's interesting, I hadn't thought it through that far, and my D2 doesn't have the EGT monitored. The D1 does, and I've got so used to it that I'll have to do something about it on the TD5 when it comes home. Thanks for that.

[rick130]

That's interesting, I hadn't thought it through that far, and my D2 doesn't have the EGT monitored. The D1 does, and I've got so used to it that I'll have to do something about it on the TD5 when it comes home. Thanks for that.

By keeping the heat in the manifold there is more energy to spin the turbine.
It's heat energy that does our work, as the gasses expand the heat energy (enthalpy) is converted to kinetic energy spinning the turbine.

A similar effect is if you coat the dump for about 3' after the turbo, gas velocity is higher than an uncoated pipe (heat energy is retained, as the gasses continue to expand they cool and lose velocity) so it scavenges a little better as the lower backpressure helps the turbine (and hence compressor) spin a little faster.

I think it was Beaudesert Exhaust I spoke to once about ceramic coated dumps. I was quizzing the owner on coating dumps as I wanted to do this on the Defender.
It was a totally unexpected side benefit, they were only looking for lower underbonnet temps in GU Patrols and they made slight power gains, so they backed to backed it against uncoated dump pipes and it was a consistent boost and power improvement.

[Tins]

By keeping the heat in the manifold there is more energy to spin the turbine.
It's heat energy that does our work, as the gasses expand the heat energy (enthalpy) is converted to kinetic energy spinning the turbine.

A similar effect is if you coat the dump for about 3' after the turbo, gas velocity is higher than an uncoated pipe (heat energy is retained, as the gasses continue to expand they cool and lose velocity) so it scavenges a little better as the lower backpressure helps the turbine (and hence compressor) spin a little faster.

I think it was Beaudesert Exhaust I spoke to once about ceramic coated dumps. I was quizzing the owner on coating dumps as I wanted to do this on the Defender.
It was a totally unexpected side benefit, they were only looking for lower underbonnet temps in GU Patrols and they made slight power gains, so they backed to backed it against uncoated dump pipes and it was a consistent boost and power improvement.

Makes perfect sense when you think it through. What about the turbine housing? You coat that as well?

[rick130]

Makes perfect sense when you think it through. What about the turbine housing? You coat that as well?

In racing they do, but I think everyone's scared of cracking the housing on a road vehicle.

The ceramic coating seems to be a good compromise between insulation and transfer, if you exhaust wrap a cast iron turbo manifold it will crack as too much heat is retained.