Exhaust manifold for F8b

[pony-tail]

The leak is an exhaust gas leak - where the pipe bolts up to the manifold .
Every manifold (second hand) I have checked in the last 3 weeks (11in total) is burned on the cone where the exhaust pipe meets the manifold .the one that I have put on the machine is the least damaged one that I could find - but it still leaks . They all seem to become pitted and corroded on the cone where the pipe bolts up making them difficult to seal. They do not have a flange gasket (they are not designed to ) but machining off the cone and using a flat flange gasket is an option (albeit a very expensive one , requiring a custom engine pipe to be fabricated as well as the machine work )
At present it is packed with muffler putty which will last long enough to get a roadworthy cert, but is a stopgap repair at best.

[Brayden]

Worse case scenario you could use a 543cc F5A manifold. The ports are slightly smaller but it will bolt up.

As for the corrosion, I can't say I've come across that before. Do you live near the coast? I guess that the high salt content in the air wouldn't do wonders for anything made of steel/iron.

Personally, for all the hassles this has caused I'd be looking at a set of extractors!

[pony-tail]

About 400 metres from the beach .
I have sent an email with a couple of pics attached hope you can post them as it will show what I mean about the corrosion.

[Brayden]

Doesn't look that bad to me. I can see no reason that would not seal up.

[mowog]

You could go to Atkins Carlyle or Repco or engineering supply shop and buy a cone shaped grindstone that runs off your electric drill. I have a few that I use for valve grinding seats, I would suggest you take the manifold with you to get the right size and angle. I would think that there is something in the right size because the Suzi exhaust is not that big. It might cost a few bucks but would be cheaper than the engineering shops. Even try some of the secondhand machinery shops or your local hock shops, surprising what you can find at them.
For the male end of the manifold I have a drill sharpening thing here that is supposed to run off the electric drill. I have found they are useless but the grind stone looks like it might be perfect to do the male end (it is a concave shape)
A bit of imaginative thought might be the answer.
If it works let us know!

[mowog]

Also just a thought, I would be inclined to replace those studs they look a bit suss and are likely to strip on you.

[pony-tail]

Doesn't look that bad to me. I can see no reason that would not seal up

Actually the gas escapes through the pitted grouves caused by the corrosion and previous leaking exhausts . the flare on the pipe sits on the high spots leaving clear paths for the gas.

[Brayden]

In which case take Mowog's advice, and also note that there are conical grinding attachments for Dremel's that I find really good - moreso than the drill attachments because a Dremel can spin up to ludicrous speeds and just carve through old rusty surfaces.

[mowog]

The Dremel are great, wish I had one, but there would be a problem in getting a fairly good symetrical surface around the edge, if I am not mistaken the Dremel grindstones are quite small and you would have to be pretty good to get a regular finish that seals all the way around. Remember the seal depends on a perfect fit. A large grindstone will seat itself all the way around with little expertise (like with me)

[pony-tail]

I now have a very good F5 manifold on it it seals well.
The dremel did not work (it needed metal added not removed)
but I will still keep my eyes open for a good F8B manifold.