Exhaust Manifold.

[oakall2]

I have removed the manifold and find that previous repair at the exit to the manifold has broken down. I have found a blacksmith who will do his best to make satisfactory repair. If this fails has anyone used an "off the shelf" steel manifold from an MGA, B or other B series engine cars ?

They look very expensive so what else could I do ?

Many thanks in anticipation

Harry

[noddy]

Hi Harry,
Cracked/broken manifolds can be a real pain  - you have my sympathy.
Your best option is to see if you can find a second hand one for sale on ebay - they do come up occasionally - also try Bob at the club spares!

As for alternatives, non of the MGB ones fit - they have two downpipes exiting right onto the chassis rail - and I doubt v.much if any of the 'sports systems' for the MGB would fit either!
Now an MGA one will fit - I have done it! However not for the feint hearted ! The manifold exits very close to the chassis rail and has to do a sharp 90deg bend to then run parallel to the chassis (using the MGA downpipe) you then have to make up a one-off system, as the bore is bigger and the manifold wont mate up to the original pipe! it will run very close to the chassis and bellhousing.
It does work though - and makes a great sound!




As for other applications - the MG Magnette may work - but I have never checked it (I think its similar to the MGA one). All the others will fit - but usually have a single carb built in - i.e Wolseley 1500!

Good luck and let us know how you get on.

Roger

[silverstreak]

If he is still in buisness Wolsley 1500 spares?

[canuck]

Harry

Roger is spot on, fitting an 'off the shelf' exhaust manifold/header will need to be another Riley cast manifold. These pop up on eBay very often.

I looked long and hard at this dilemma.

I am fitting a 1800 engine to my Riley this winter and understandably the larger capacity engine, (1800 versus 1500) requires a larger diameter exhaust system to breathe properly.

The solution for me was a bespoke mandrel bent steel tube header.

The issue is the for aft chassis rail and where the exhaust pipe must exit through the bodywork.

I doesn't end here of course as I need a larger diameter exhaust system and silencer.

B

[bobthescrapman]

Hi Harry,
We do have a couple of cast iron manifolds in stock, one of them may even be new.
Cheers,
Bob.

[oakall2]

Thanks for the info Bob. The Forge at Bringsty Common have mended my manifold which I will collect this lunchtime. It is good to know that another is available - just in case.
Harry

[canuck]

Harry

FWIW these cast iron exhaust header design are prone to cracking through time and heat cycles.

What actually happens is the length between the mounting holes shrinks and stresses the Y joint of the casting. MGA and other type Y design suffer the same fate.  You can help to prevent this by elongating the holes with a small diameter round file.

Dollars to donuts the cars that suffer failure this are not using the exhaust pipe support at the front either. 

If you are able to find a 'young' exhaust manifold this would be good.

B

[oakall2]

It gets refitted tomorrow with the re-furbished carburettors etc.. The joint between the cast iron and the pipe section that goes into the main exhaust pipe has been very well done, so we hope for the best. I was fortunate that the chap at The forge would do it as he only takes commissions for metal work.
Harry