Weber OEs and OM differences

[nobody]

I've been digging out jets and chokes from the DCOEs that I got for use in my DCOMs. I thought I'd share some of what I'm finding now that I have both side by side.

The jets, chokes, tubes and gaskets are all interchangable. However the carriers are different. The OMs on the right in the pic show an O ring for the idle jet carrier and the OE has two sets of threads. For the main assembly the carrier itself is the air corrector and would have to be drilled out to be able to use air correctors from the OE style.

On the pic of the bottom of the carbs you can see the big differance in the OM has a mechanical accelerator pump and the OE has jets for this curcuit. I also noticed that the OM has a lock down for the venturies where the OE uses the air horns to lock it all in place.

The top view shows alot of changes. The OM fuel inlet is on the top and has a filter on the banjo bolt. OE is on the side and has a seperate top mount for the filter all by itself. The OM also has both metered and direct vacuum ports and no accelerator jets.

[nobody]

Ok I was stil digging and wanted to check another Jet and well they don't look interchangable to me.

[tekenaar]

INTERESTING . . . second picture accelerator pump looks like an exact copy of those used on ALL Dell'Orto DHLA carbs. The DHLA's also use venturi locks on all their models. SO, Dell'Orto copies basic DCOE design and improves it and then Weber incorporates Dell'Orto's improvements into their late production sidedrafts.

VERY incestuous business, if you ask me!

[PROPEL]

Some great info...

http://members.ebay.com/ebaymotors/w...serid=alfa1750

[nobody]

Gabriell is a really nice guy too. He has more than is listed on the store to if you ask. I got a 6 pack of OMs from him....so far.

Just looked over that page and he has been busy. If you are even thinking side drafts go check that out.

[nobody]

One other item that doesn't interchange are the venturis. OMs are flanged at the end and have a spot for them to be locked in place. OEs have just a spring clip. OEs are typically undercut for a staight air horn that also won't fit an OM. They aren't as similar as I was led to believe.

[nobody]

I just got an E mail from Gabriele and my 30mm screened air horns and air corrector sets x 2 will ship tomorrow. Not bad for 86 bucks.

[PROPEL]

I just checked with Pierce Manifolds, and the owner does not think the DCOM and DCOE chokes will interchange, according to his books.

But as they say:

"In Theory there is no difference between theory and practice. In Practice, there is."

Does anybody here (other than nobody) have practice in swapping chokes between DCOM and DCOE's without issue?

Thanks!

[GTJIM]

By chokes, I presume you mean venturis ?? see post #6

I have a nice NEW pair of 40mm OMs from a late model twin-spark Alfa and several used ones from 'alfa1750' on EBay ... but no OE's to compare!

Do have some 40mm Dell'Ortos though - must check to see if their venturii fit.

[PROPEL]

Originally Posted by GTJIM By chokes, I presume you mean venturis ?? see post #6.

Hmm, 'venturi' makes me think of 'auxiliary venturis' (first pic). I mean the things (I call them 'chokes') in the second pic...

[GTJIM]

The 'chokes' are the venturii - that is why the 'auxiliary venturii' have that prefix ... they are 'auxiliary' (in addition) to the actual venturii.

I will try to check if Dell'Orto 'chokes' fit into OM's

[wrench459]

Dang I miss Dave..
Not on the carb issue but on personal side

[baz]

Originally Posted by wrench459 Dang I miss Dave.. Not on the carb issue but on personal side

kind of like an itch

you miss it when its gone and you have nothing to scratch

[yellaopelgt]

Originally Posted by wrench459 Dang I miss Dave.. Not on the carb issue but on personal side

Yea...me too.....
But now that I sighted in my rifle I wont miss again!!!
Good ridance.......POS
Joe

[PROPEL]

Still not practice, but from as close to a definitive source as possible...

Hello, DCOM and DCOE chokes are perfectly interchangeable. Kind Regards, Gabriele D.

(Although it would still be worthwhile for future reference to know whether Dell'Ortos also fit.)

[bigjim5551212]

Originally Posted by tekenaar INTERESTING . . . second picture accelerator pump looks like an exact copy of those used on ALL Dell'Orto DHLA carbs. The DHLA's also use venturi locks on all their models. SO, Dell'Orto copies basic DCOE design and improves it and then Weber incorporates Dell'Orto's improvements into their late production sidedrafts. VERY incestuous business, if you ask me!

I would disagree with this. I think Weber was making carburetors to specification for Alfa Romeo.

Dellorto stopped production and Weber could still make product.

If Weber felt that the diaphragm pump design was better, they would have incorporated that design into the DCO 2, DCO/SP designs. They didn't.

The Weber DCOE was designed to be used for alcohol fuels as well. Alcohol attacks some rubber parts. Specially pump diaphragms. The DCOE is designed as a racing carburetor that has nothing that will stop the running. Sure, you can break stuff, and the old brass floats will vibrate apart, but you have to keep up with maintenance and inspection.

We have the repair kits for DCOM in stock if anyone is looking for them. The DCOM is not my choice by a long shot. If you want to have a part like a carburetor, you need to have parts availability and standardization. The DCOM does not have this, where the DCOE does.