What are these? And other questions..

[GrUmPyBoDgEr]

Bloomin' dipsticks can cause no end of stupid problems!
Ask anyone who has been involved with either the design or development of engine lubrication systems & I'm sure they will agree wholeheartedly that they are a pain in the ar5e!

How nice it is to be retired

Cheers
John

[Craven]

Hi john
Your car should be fitted with 40 DCOE 18 carbs not 2?s will be interested how well the 2?s work.
On subject of carb?s take a look at the air corrector jet size, it?s will be 155 for sprint spec, 200 is a standard engine size.
Ron.

[Johnfm]

Should be 18s?

What is the difference between the 2 and the 18?

I will be checking all the jet and tube sizing tomorrow.

[Craven]

Hi,
Virtually all jets etc. on 40?s can be changed, but the body is true to type, 2?s 18?s 31?s and so on.
Unfortunately an important set of small holes, that control the progression between the slow running system and main jet system, are fixed, their position and size being different on a 2, and 18 and again different to 31. There are other casting changes as well but it?s the progression that will cause problems if not correct.
Well you did ask.
Ron.

[Johnfm]

Cheers Ron

Is the 2 really not recommended with the +2?

If so, I will refurb and sell them and buy 18s.

I was intending to email KIth Franke and order whichever hypo tubes and bits that he recommends - but if the DCOE2 is not the right carb, I should get the right ones.

[Johnfm]

The original workshop manual I have says they should be 40 DCOE31s.

Confused!

[Craven]

Hi john.
Weber parts are quite expensive and remember you have to buy 4 of everything so hold on until you have determined more about the engine, it?s not quite that simple to get hold of 18?s you may be lucky, 2?s however are quite sought after as they are early type, You queried the drilling in one of the butterfly nuts, may be you have a made up pair of carbs! The serial numbers are far apart so probably not a pair, the tops carry the detail and are interchangeable so it?s worth checking the carb's out by comparison. In my opinion the 18 suits the twin cam 1558cc the best. not sure of when change over to 31's.
Ron.

[GrUmPyBoDgEr]

I'm not sure if a list appears anywhere on these forums but questions concerning differences between the various Weber 40 DCOE Carbs that have been fitted or could be fitted to the Twin Cam in all its various guises regularly crop up on these forums.

How about that those "in the know" start a definitive list all variants with a clear description of the feature(s) that make them different from each other; also the pro's & contra's of those variants.

Cheers
John

[rcourtney]

Hi,

Not sure if it makes a whole lot of difference but your Thackeray Washers look very tight? Could cause fuel frothing / stumbling etc

Think you can tighten then unwind 1 whole turn - this shold give you a good approximation of correct spacing without a gauge.

Am still fairly new to all this so might be wrong / am prepared to be corrected.

Ralph

[Chancer]

I think I know what the central hole in the wing nut is, and if the carbs are not a matched pair then its even more likely.

The first ever webers that I rebuilt had a sort of castelated ring between the jet cover and the top cover, the rebuild kits came with gaskets for the jet covers which were not compatible with the castelated pi?ces, if the carbs were inverted fuel flooded out so I threw away the rings whose function I could not fathom.

The vehicle suffered from fuel starvation, it would run on full throttle for 30 yards or so and then become straved and limp, I could not find the problem but decided to try the carbs without the gasket and the original castelated rings, engine ran perfectly.

Further inspection revealed that on the (presumably) earlier carbs the float chambers were vented via this orifice, on later ones there is a hole in the vertical mounting face mating up with a corresponding hole in the airbox or air filters, presumably safer in a roll over accident and for stray sparks etc.

I reckon the hole has been drilled because on that carb you dont have the hole in the inlet face of the carb (compare the two) and the castelated thingy has been lost.

now if anyone can tell me how to spell castelatted I would be gratefull

[Sea Ranch]

Castellated.

http://en.wikipedia.org/wiki/Castellated_nut



And thanks for that great observation about Weber float venting.

Randy