weber misab plates how tight ?

[pad4]

Any one know what to torque the mounting bolts up to on weber carbs running misab plates ?

cheerz

Pad

[Smiffy]

You need the correct washers, there are two types available. Thackery washers or the crap rubber with metal caps variety. The Thackery type you tighten up until the start to compress the washer together, but not so it bottoms out.

[pad4]

another job for Blyton - I got the rubber ones on at the moment

cheers

Pad

[ivor badger 2]

The official setting is to tighten the nut until there is a 0.025" gap between the coils of the washer.

[LMM76C]

So the Cosworth ones are crap are they?
Not in my experience.
I have lost count of the times I broke Thackery washers on competition cars, however carefully they were originally tightened. Gave up on them long ago.

[Smiffy]

So the Cosworth ones are crap are they?
Not in my experience.
I have lost count of the times I broke Thackery washers on competition cars, however carefully they were originally tightened. Gave up on them long ago.

In my experience yes they are the rubbers deteriorate and will be even worse with modern fuel. If your breaking 'em your tightening them too tight, as for any correct measurement. Where would you measure it, plus 0.0025" wouldn't allow the carb to move. Which is the whole idea of the mounts.

[ivor badger 2]

In my experience yes they are the rubbers deteriorate and will be even worse with modern fuel. If your breaking 'em your tightening them too tight, as for any correct measurement. Where would you measure it, plus 0.0025" wouldn't allow the carb to move. Which is the whole idea of the mounts.

It's 0.025"= 25 thou. not 2.5 thou. DOH Simply put a feeler guage between the coils of the washer and tighten up till the gap is correct.

[Smiffy]

In my experience yes they are the rubbers deteriorate and will be even worse with modern fuel. If your breaking 'em your tightening them too tight, as for any correct measurement. Where would you measure it, plus 0.0025" wouldn't allow the carb to move. Which is the whole idea of the mounts.

It's 0.025"= 25 thou. not 2.5 thou. DOH Simply put a feeler guage between the coils of the washer and tighten up till the gap is correct.

LOL slip of the keyboard, 25 thou would still be too tight, meaning the carb will be virtually mounted solid to the manifold. Too tight and you'll also squash the O rings most likely splitting them.

[ivor badger 2]

In my experience yes they are the rubbers deteriorate and will be even worse with modern fuel. If your breaking 'em your tightening them too tight, as for any correct measurement. Where would you measure it, plus 0.0025" wouldn't allow the carb to move. Which is the whole idea of the mounts.

It's 0.025"= 25 thou. not 2.5 thou. DOH Simply put a feeler guage between the coils of the washer and tighten up till the gap is correct.

LOL slip of the keyboard, 25 thou would still be too tight, meaning the carb will be virtually mounted solid to the manifold. Too tight and you'll also squash the O rings most likely splitting them.

Oh well, John Passini must be wrong and I bow to your superior knowledge.

[Smiffy]

Oh well, John Passini must be wrong and I bow to your superior knowledge.

just talking from personal experience rather than what others have written or told me. But if your having more success with the other type, on your competition cars. I see no reason for you to change, just use what works best for you. But then again I've never broken a Thackery washer.

[LMM76C]

The rubber in the cups is not in contact with fuel. Any rubber item detreriorates with time. In competition use Thackery washers are subjected to flexing. Actually, if you do tighten them way too far they will not break, for obvious reasons - but please do not presume to tell me how much I tighten them! Metal deteriorates with time too - especially when it is having bending forces exerted on it, as with Thackery washers at the correct clearance....

[Smiffy]

Not telling you how to do FA, but there actually made from sprung steel so designed to bend