Minor 100 exhaust fitting non standard manifold

[GavinL]

Hi, my wife has recently bought a '68 Minor 1000, with a very noisy exhaust ( it has a cherry bomb silencer which leaks!). We want to change it, but the complication is that it also has twin SUs, so it doesn't have a MM combined manifold, but i suspect MG Midget inlet and exhaust manifolds. i've attached a photo. My question is, will a standard MM exhaust fit onto this manifold - is the connection position the same as a MM manifold, as i don't have access to one to compare it with. Any advice welcome.

[firedrake1942]

It looks much much lower than the standard exhaust and from the looks of it the one you have there has been butchered near the lip to make it fit anyway. It also looks like it is fouling the bulkhead aperture so you will be getting drum and vibration as well. Two solutions spring to mind. Butcher a new Minor exhaust to fit this manifold, or change the manifold / carb set up. If the latter much will depend on what head is currently fitted etc.

[philthehill]

The manifold you have fitted is a 1275cc Midget in which the exhaust exit is angled forward.
The angle and connection position is totally different to a Minor - so to answer your question the Minor exhaust will not fit this manifold.

You have 4 options:-

1. Purchase a late Minor inlet/exhaust manifold and separate the inlet from the exhaust.
There is not too much metal between the exhaust and inlet tracts so care needs to be taken so butcher the inlet manifold preferably.

2. Purchase a three branch manifold and mate it to the rest of the exhaust system.

http://www.maniflow.co.uk/index.php?vie ... tegory=209

http://www.morrisminorspares.com/engine ... ss-p830059

3. Purchase an early Midget 1098cc exhaust manifold. Pt No: 12G420.
http://www.moss-europe.co.uk/shop-by-mo ... 098cc.html
'e' bay may be a source for this item.

4. Revise the existing exhaust pipe tract

My preference would be to purchase a three branch manifold which is available from the usual suppliers.

[greendefender123]

20170411_160404.jpg (709.85 KiB) Viewed 3599 times

If this the right one you can have it for a really good price as I don't need it. Hopefully Phil will advise.

[philthehill]

greendefender
Unfortunately the manifold you have pictured above is still the wrong one in that the exit is pointing forward.
It is the same as the one already fitted.
If a standard MG exhaust manifold is to used it must be at least the 948cc or 1098cc one.
Phil

[greendefender123]

That's a no then . Cheers

[Chipper]

There's a 5th option; use a 948cc Minor's exhaust manifold, which has unboltable (alloy) inlet & (cast iron) exhaust manifold sections; I've satisfactorily used a 948cc cast iron exhaust manifold with the inlet bit blanked off with a steel plate for my Midget-engine Traveller - which hooks up to the standard Minor exhaust nicely.

You could also, as stated above, use a standard 1098cc cast iron one-piece manifold, with the inlet section carefully cut off to allow the fitment of twin carbs.

[GavinL]

Many thanks for all the responses. Now I know it is a Midget manifold and I can't fit a standard MM exhaust to it, I may have a solution - I've just bought an alleged Morris Minor manifold on eBay which apparently is stamped with 2A898 08 ( I've still to collect it) pictured below. Could I cut the inlet part off this and use the exhaust part? It appears to point in the correct direction I think?

[philthehill]

Yes you can cut the manifold but remove the inlet side carefully - as I said above there is not enough metal between them to make two separate manifolds. In the process the inlet section will be destroyed so as to enable the exhaust to function as required.

[GavinL]

Thanks Phil, I picked up the manifold today, it's ref is 2A896 which a search on eBay suggested it is off an A35/A40 or early mini, and is equivalent to 22A1141, but I've no proof so would be interested to know if anyone can confirm this.

[philthehill]

The evidence I have found suggests that it is indeed from a A35/A40/Mini.
As regards the 22A1141 I have yet to find the part number listed.

Whilst the manifold you have purchased will fit you may find it a bit restrictive as regards exhaust gas flow on the 1275cc engine but it will be better as regards suitability for your Minor.

For a longer term consideration use a 1275cc Marina exhaust manifold (inlet side removed) and the adapter front pipe from ESM if you do not want to fit a three branch exhaust manifold.
http://www.ebay.co.uk/itm/12G787-Morris ... Swj25Y8N7W
http://www.morrisminorspares.com/engine ... ss-p830058

Phil

[GavinL]

So, I've now modified the manifold I bought on eBay as per the attached, which I've checked and it will fit with the Midget inlet manifold. Just to fit it now.

[philthehill]

Well done.

[GavinL]

So, modified exhaust manifold fitted, and new s/s exhaust fitted. However like some others I'm concerned that the standard mounting supports are both at the rear, leaving the front unrestrained. I've installed a support near the front, different from the solution illustrated elsewhere on this forum. My solution is similar to the MG Midget, and consists of an angle bracket fixed onto one of the engine cable restraint mounting bolts.

[ampwhu]

where you've cut the inlet part away, how does that fit against the inlet manifold? is it welded together? looks to me like it would leak at the part cut away?

[GavinL]

Where I've cut the inlet manifold away I've left the material that was between the inlet and exhaust tracts intact. I've checked it against the twin SU inlet manifold and there is about 5mm clearance.

[ampwhu]

I'm confused. what you've cut away would have been joined to the cylinder head with a gasket to stop a leak. now you have a larger hole which would be left open would it not?

[philthehill]

I think that you will find the cutting is an optical illusion in that it looks worse than it is. It is not open.
There is even when the inlet manifold element is carefully cut away plenty of metal remaining.
The exhaust manifold centre part is held to the gasket/head by the flanges which can be seen either side of the exhaust centre part.
The inlet manifold has identical flanges and the inlet and exhaust manifolds are held to the head by the manifold washers/nuts.