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MG Midget and Sprite Technical - Attaching a Weber to Manifold

Picked up a manifold for my Weber off of ebay the other day. Woohoo!

As it was used it didn't have any gaskets or anything. I have a manifold-head gasket. For the Weber-manifold gasket I am wondering if people deem it critical to use the rubber mounting plates? (Misab plates?!) Or are they just for highly strung race engines?

My options... buy some of these fancy things for circa �12 and wait a week. Or make some gaskets for free from some thick gasket paper I already have.

Interested in peoples opinions on this.

Cheers,
Malcolm
Malcolm Le Chevalier

Buy them they are critical!

They reduce the vibration to the carb and let it work.
If you don't fit them then you will have all kinds of trouble seting it up
Onno K

Roger that! Cheers Onno! :-D

Malcolm
Malcolm Le Chevalier

I have fitted these rubber mount:

http://atspeedracing.co.uk/products/index.php?main_page=product_info&cPath=103_145_158_206&products_id=622

To ensure the mount is not over compressed, I was recommended to tighten the nut until a ~ 15 thou gap remains between the cup washers.

HTH
Doug Plumb

along with the Misab gasket you need to use special spring washers on the retaining studs. It's vital to prevent the vibration causing cavitation and frothing of the fuel in the float chamber.
David Smith

The kit the link refers to includes rubber washers which are partially compressed between cup washers to give some movement to prevent fuel frothing etc. I assume it is a modern alternative to using the more traditional Thackery washers that David refers to which are here:

http://atspeedracing.co.uk/products/index.php?main_page=product_info&cPath=103_145_158_205&products_id=621

HTH
Doug Plumb

This is all very interesting. I'm just finishing up a Spitfire rebuild for a friend, and her engine's fitted with a 40DCOE, which is just screwed onto the manifold in the usual way. So do these flexy mountings really make a difference?

-:G:-

Gryf Ketcherside

Both Vizard and Stapleton state that it is important to prevent fuel frothing by correctly mounting [ie flexible] a DCOE.
Doug Plumb

Gryf,

What spec is the engine and jets in the carb? I have taken a guess at what they might need to be, would be good to get a comparison if possible...

Is it 1300 or 1500 Spitty?

Cheers,
Malcolm
Malcolm Le Chevalier

Thanks - my new soft mount kit is in the mail.

-:G:-

Gryf Ketcherside

Oops... Missed your question, Malc. It's a 1500. The engine's a '75 model, and the Spit itself is a '79.

-:G:-
Gryf Ketcherside

LOL! I have always been aware of the "springy" mount pieces for a 45 DCOE. However, in a complete kit, there is usually included a "steady rod" (it's actually strap steel) that bolts to the bottom of the carb and the other end is bolted to the block. Never have I seen the springy mounts available for the steady rod.

There must be a reason, right?
JM Morris

Still there Gryf?

You know/remember what spec the engine is and what jets you are running in the Weber?

Going to be running a 40 on my 1500 also. Wasn't sure if I should be running 40 or 45, but Onno offered me a 40 for a good price.

I have just guessed some jet sizes based on guesstimate averages from various internet sources! Would be good to get another comparison.

Cheers,
Malcolm
Malcolm Le Chevalier

This thread was discussed between 28/07/2013 and 06/08/2013

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