Exhaust assembly paste?

[mole42]

Using standard manifolds I heard it's best to use an assembly paste / sealer material when mating the manifold to the head. Are there any recommended products?

Please don't suggest gaskets, I've been there.

[new to this]

I've never needed any exhaust paste just the gaskets, are you sure the face surface of your manifolds are flat

Dave

[NeilR]

Nothing wrong with gaskets, mine have been on for years, at least 25k miles.

I do use studs with brass nuts though (UNC one end & UNF the other), not those UNC bolts.

[jbuckl]

Better quality manifold to head gaskets have been made now…. Previously they were incorrect material & collapsed over time.

I would not use paste.

Originally oily sooty carbon did the job.

[mole42]

are you sure the face surface of your manifolds are flat

Dave

No, the manifolds rock slightly on the head. I haven’t investigated where the problem lies yet but the heads are new to me having been rebuilt by a RR Merlin mechanic so I’m more inclined to suspect the manifolds which I’ve (ab)used for the past 50,000 miles. I used gaskets on these manifolds last time I did the heads and found that the manifolds didn’t seal as well as I expected them to.

[mole42]

I do use studs with brass nuts though (UNC one end & UNF the other), not those UNC bolts.

That’s a grand idea - I can see a session at the lathe coming up…..do you use washers, only the holes in my manifolds are quite a bit larger than ‘clearance’?

[new to this]

No, the manifolds rock slightly on the head. I haven’t investigated where the problem lies yet but the heads are new to me having been rebuilt by a RR Merlin mechanic so I’m more inclined to suspect the manifolds which I’ve (ab)used for the past 50,000 miles. I used gaskets on these manifolds last time I did the heads and found that the manifolds didn’t seal as well as I expected them to.

Put a steel rule on its edge and check for flatness of the exhaust manifold, they may need skimming

Dave

[NeilR]

3/8 UNC end into the head, 3/8 UNF end through the manifolds + yes I do use washers, ordinary steel ones.
The stud on left hand front lower has to be shortened somewhat - the really awkward one.
No lathe work necessary.

[mole42]

Lathe work? That’s how I machine threads on a stud. I’d rather do that than use a die……but will these ready-made ones do the job?

https://www.ebay.co.uk/itm/325526764284

[NeilR]

They might, you need 14.

I used RV8 ones from Rimmer's. Have done at least 4 engines with those.

Seem to be listed as for TV8 Tubular manifolds, look prettymuch the same as I used.

https://rimmerbros.com/Item--i-RS1041FK

[Chris01573]

Better quality manifold to head gaskets have been made now…. Previously they were incorrect material & collapsed over time.

Hi Julian, who supplies gaskets that are the newer correct ones ?

[jbuckl]

Hi Julian, who supplies gaskets that are the newer correct ones ?

Sorry, I’m stuck with that… last ones I got were also supplied in the old incorrect material!

not worth fitting so I didn’t.

Manifolds leaked

so I removed them again & used a putty like exhaust paste … only a light smear and bingo… sealed nicely.

i will search for the metalised gaskets again, but the photos aren’t always what they send it seems, sadly.

ensure you have suitable mini ratchets to access the bolts.

consider sas aluminium anti seize.

dont use copper slip.

stainless bolts may gall / cause galvanic corrosion.

sas anti seize seems to work though