Nex Exhaust Manifold - Bolted Joint Paste?

[Metallo]

Hi,

I have a 940 Polar 2.0 Turbo SW - B200FT from 1997.

Recently the car started ticking under load, so I removed the Exhaust manifold an found a micro crack.
I purchased a new manifold and it is now on its way.

As you know, there is no gasket between turbocharge and manifold, it just slots in.
The same applies for the connection between the turbo and the downpipe.

Now, while checking the torque on the Volvo Pocket guide, I saw a note*
Use lubricant P/N 1161408 (please see my attached image).

Does anybody know if that lubricant was originally used by Volvo on both connections?

That lubricant is currently discontinued by Volvo, however it looks like the FEBI BILSTEIN High Temperature Lubricant P/N 26712 can be used as a replacement.

When I was inspecting the connection between the turbo and the manifold, I could see black carbon traces at the bottom, which clearly indicates a leak, and the nuts where all tight.

On other forums they think this should be used, but I cannot find evidence that this lubricant was used at the time by Volvo.

Also, if I search for that P/N in VIDA, nothing pops-up and I would assume that if it was part of the installation, it should be included in VIDA.

Thoughts?

Thank you guys, and I wish you all the best for 2022!

Alessandro

[Laird Scooby]

https://www.volvopartswebstore.com/p...5/1161408.html

It's $36 and i would guess an anti-sieze compound along the lines of copper grease. If someone can confirm what it is, that would give you a better chance of finding a suitable alternative to an expensive, limited stock item in the USA - Volvo don't seem to list it in GCP so chances are it's NLA from anywhere except the USA in old stock in a warehouse somewhere.

It's only for the threads anyway, it's not a sealant of any kind to go on the mating faces as the last thing you'd want is sealant falling down and either wrecking your turbo or blocking your cat.

[Metallo]

Hi Laird Scooby,

Yes I understand, you are probably right that it must be something like copper grease for threads.

On another note, surprisingly today I was delivered the new exhaust manifold at my door:

Volvo Box - Volvo plastic bag, P/N 3514440

What I observe is that the new manifold is rougher in its built, the hole to the turbo is smaller and off-centered, as well as the 4 holes to the head are smaller.

Do you think this is normal?
I looks like the new manifold is manually machined vs the perfection of the original manifold, which looks really industrially machined.

Any thoughts?

Do you think the smaller holes can actually have an impact on the performance of the car?

Also, the new manifold has a hole on the side where you are supposed to have a plug (P/N 986817) + gasket (P/N 11998), while the old one, was welded in the same point.

Anybody knows why there is now a plug on the new spare part?
Obviously, that needs to be plugged, but I'd like to know why that port is in there.

Thank you!

Alessandro

[Forrest]

On the subject of parts quality, it is not unusual for OEM parts nowadays to be inferior to the originals. Folk have reported the same on items like water pumps. I don’t think any of the OEM exhaust parts last like the originals. When our cars were built Volvo was a respected Swedish company. It was then bought by Ford. Now it’s owned by a Chinese company. Enough said.

As far as the high temperature paste is concerned, I think it is intended to stop the bolts burning and seizing. I suspect within reason any high temperature thread lubricant would do the job. I have taken to using something similar on Volvo spark plugs because of their extended service intervals.

[Laird Scooby]

Originally Posted by Metallo

Hi Laird Scooby,

Yes I understand, you are probably right that it must be something like copper grease for threads.

On another note, surprisingly today I was delivered the new exhaust manifold at my door:

Volvo Box - Volvo plastic bag, P/N 3514440

What I observe is that the new manifold is rougher in its built, the hole to the turbo is smaller and off-centered, as well as the 4 holes to the head are smaller.

Do you think this is normal?
I looks like the new manifold is manually machined vs the perfection of the original manifold, which looks really industrially machined.

Any thoughts?

Do you think the smaller holes can actually have an impact on the performance of the car?

Also, the new manifold has a hole on the side where you are supposed to have a plug (P/N 986817) + gasket (P/N 11998), while the old one, was welded in the same point.

Anybody knows why there is now a plug on the new spare part?
Obviously, that needs to be plugged, but I'd like to know why that port is in there.

Thank you!

Alessandro

Looking at your original manifold, it seems someone has port-matched it to the head for improved flow. With that in mind you might find the new one restricts performance a little but on the other hand, it may in fact improve it. On a n/asp engine it would definitely restrict it, however as the turbo relies on the hot exhaust gases passing through at high speed to spool it up, the increased port velocity from the smaller exhuast runners may do you a favour.

Is the hole tapped for an M18 thread by any chance? If so i would suggest it's for a Lambda sensor. If it's considerably smaller, it's possible it's for an exhaust gas temperature sensor.

The new manifold is definitely a lot more roughly cast than the original and as Forrest says, many parts have suffered in terms of quality over the years.

As for the exhaust manifold to turbo flange and the hole in it, again i wouldn't be unduly worried by the size/shape of the hole and it could once again do you a favour. It will almost certainly provide a measure of anti-reverse on the gas flow - in other words, once the gas is out, it can't come back in so has to go through the turbo. This works on the principle of Eddy Currents like when you move to the corner of a building in high wind because it's blowing you that way then you turn the corner and the wind is now blowing straight at you.

With all these thoughts in mind, i would be tempted to try it before condemning it and you might be pleasantly surprised. If not and you find it is restrictive, you could try port-matching :

https://www.motortrend.com/how-to/po...ngine-porting/

It's more common to port-match the inlet manifold to the head to remove restrictions and unwanted turbulence on the inlet side, usually the exhaust manifolds have larger inlet holes so there is an anti-reversionary step as the gases exit the head into the manifold already so normally the exhaust ports in the head are just smoothed out to improve flow without enlarging them much or altering the shape much.

[griston64]

Originally Posted by Laird Scooby

Looking at your original manifold, it seems someone has port-matched it to the head for improved flow. With that in mind you might find the new one restricts performance a little but on the other hand, it may in fact improve it. On a n/asp engine it would definitely restrict it, however as the turbo relies on the hot exhaust gases passing through at high speed to spool it up, the increased port velocity from the smaller exhuast runners may do you a favour.

Is the hole tapped for an M18 thread by any chance? If so i would suggest it's for a Lambda sensor. If it's considerably smaller, it's possible it's for an exhaust gas temperature sensor.

The new manifold is definitely a lot more roughly cast than the original and as Forrest says, many parts have suffered in terms of quality over the years.

As for the exhaust manifold to turbo flange and the hole in it, again i wouldn't be unduly worried by the size/shape of the hole and it could once again do you a favour. It will almost certainly provide a measure of anti-reverse on the gas flow - in other words, once the gas is out, it can't come back in so has to go through the turbo. This works on the principle of Eddy Currents like when you move to the corner of a building in high wind because it's blowing you that way then you turn the corner and the wind is now blowing straight at you.

With all these thoughts in mind, i would be tempted to try it before condemning it and you might be pleasantly surprised. If not and you find it is restrictive, you could try port-matching :

https://www.motortrend.com/how-to/po...ngine-porting/

It's more common to port-match the inlet manifold to the head to remove restrictions and unwanted turbulence on the inlet side, usually the exhaust manifolds have larger inlet holes so there is an anti-reversionary step as the gases exit the head into the manifold already so normally the exhaust ports in the head are just smoothed out to improve flow without enlarging them much or altering the shape much.

That new manifold looks very roughly cast ! Your original is what it should look like as it's the same as the one I pulled off my spare engine

The hole is probably an EGR port as the Lambda sensor goes on the exhaust downpipe

[Forrest]

Here’s a bit more information about the Volvo thread lubricant. This means a synthetic graphite lubricant would be the closest alternative. Maybe something like.

https://www.carbusonic.co.uk/Graphit...thread-grease-

[TonyS9]

Did you buy the new manifold from Volvo? There are some cheap Chinese copies about. The originals can be weld repaired very well, the chinese copies cannot.

A micro crack would not normally cause ticking, thats normally caused by the manifold-head gaskets.

The hole is for the EGR pipe which isn't used on your 97.

[Metallo]

Thank you all for your valuable comments.

Yes, I bought it from Volvo in Toronto.

I am disappointed due to the low quality of the cast. I paid the equivalent of £ 365.00 and would expect to have a perfect match of the original.

I have attached some close ups, including the one of the side port and the bag it was wrapped in.

I really have the impression that this has been hand made rather than industrial.

Alex

[Laird Scooby]

Originally Posted by Metallo

Thank you all for your valuable comments.

Yes, I bought it from Volvo in Toronto.

I am disappointed due to the low quality of the cast. I paid the equivalent of £ 365.00 and would expect to have a perfect match of the original.

I have attached some close ups, including the one of the side port and the bag it was wrapped in.

I really have the impression that this has been hand made rather than industrial.

Alex

Usually hand-made or hand-finished (i noticed some hand-finishing inside the port on your photo) are generally better than simple machine cast items. For less money you could have had a stainless header :

https://www.ebay.com/itm/202525431350

Got to say i wouldn't be happy getting that from Volvo, especially at that price!