Anyone using Weber's with Alpina (repo) plenum?

mark99

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Anyone using Weber's with Alpina (repo) plenum?
The wing nut that holds the cover onto the carburetor interferes
Is there a mod to the wing nut?
thanks
 

Markos

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Anyone using Weber's with Alpina (repo) plenum?
The wing nut that holds the cover onto the carburetor interferes
Is there a mod to the wing nut?
thanks
I’ll be mocking mine up this week on the bench with the Korman manifold. Let the fiddling begin!
 

mark99

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Mark, are you using Webers?
The top wing nut comes very close to the bottom of the plenum, but just clears if turned so it is aligned fore and aft, maybe it is fine
What are you doing for linkage?
It looks like we have to shorten the mounts and links
 

Markos

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Mark, are you using Webers?
The top wing nut comes very close to the bottom of the plenum, but just clears if turned so it is aligned fore and aft, maybe it is fine
What are you doing for linkage?
It looks like we have to shorten the mounts and links
Hi Mark,

Yep I will be using webers. I plan to set them up before tearing the car apart. For linkages I will be using two balance levers, one of them with a ball joint on it. I am not using the Korman linkage.

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Markos

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Hi @mark99,

I am indeed getting some very slight interference on my Weber 152’s. So minor that I could just grind the thumb screw down. With that said, I won’t be thumbing them open with the airbox in place. The thumb screw has female threads on the underside.

An alternative would be a “button head sex bolt”. Go ahead and google it at work folks.

I haven’t measured the diameter of the thumb screw but I’ll find something that works.

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And just because the work of @daddywad is just so damn impressive...

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mark99

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Hi @mark99,

I am indeed getting some very slight interference on my Weber 152’s. So minor that I could just grind the thumb screw down. With that said, I won’t be thumbing them open with the airbox in place. The thumb screw has female threads on the underside.

An alternative would be a “button head sex bolt”. Go ahead and google it at work folks.

I haven’t measured the diameter of the thumb screw but I’ll find something that works.

View attachment 71136

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And just because the work of @daddywad is just so damn impressive...

View attachment 71141
exactly the problem, Mark that we bought these from does not have Webers
Were the "Purolator filter" letters in aluminum when you got it?
I thought the ALPINA letters looked garish, so I painted over them, then I decided it looked like I was too lazy to mask them so I polished them off
I also redid the texture
 

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That box is beautiful.

If I remember correctly, the thumb screw is pressed into the cap, with a seal around it. I would recommend grinding off the top half of the mickey mouse ears rather than trying to replace the thumb screw in order to retain the seal.
 

mark99

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I bought this plenum because back in the day I had a 2002 with Webers and I had those foam filters with the wire cages
I hated those
 

daddywad

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Hi guys, I have been watching the thread with interest, I don't believe anyone I have sold the airbox to so far has any major issues in fitting it all together.

Remember that when Alpina released this airbox / carb arrangement on the B2 they used both Weber 45 and Solex 40/45DDH. It must have been tight but they obviously had used both Weber and Solex so they must have fitted OK. Also the manifolds used may affect the overall position of the carb as they are at an angle that sets the carbs up nearer the bottom of the airbox. The ones I sell are copies of the Alpina one and may therefore differ slightly from yours.

The airbox is a very accurate copy and should fit, I'm sure you will overcome the slight interference problems with some trial and error. Please keep the feedback going.

The "PUROLATOR FILTER" was standard and cast into the airbox.

Mark
 

mark99

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On the PUROLATOR FILTER, what I was referring to was sanding them so they are natural metal, not painted black
From the measurements you sent me, I think my manifolds are very close, but we are talking fractions
 

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exactly the problem, Mark that we bought these from does not have Webers
Were the "Purolator filter" letters in aluminum when you got it?
I thought the ALPINA letters looked garish, so I painted over them, then I decided it looked like I was too lazy to mask them so I polished them off
I also redid the texture
Mine came exactly as shown in my poor
quality pic. The whole thing is cast aluminum and is surprisingly heavy/sturdy. The aluminum letters have some visible swirls that I could care less about. The texture looks great IMO. I can’t stress enough how nice it is. A hand file would fix the clearance issue.

Here is the underside of the thumb screw. My calipers weren’t functioning this morning. The stud looks like an M6. I will measure the outer diameter of the hidden portion of the thumb screw, as it matches the opening on the cover plate. The threaded portion is flared on the end so it doesn’t fully disengage from the plate.

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Markos

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@daddywad,

Do you have any recommendations on small trumpets/fillers for the DCOE’s. The trumpets slide
between the choke and the carb body. So when you remove them, you are left with a turbulent transition from the carb to the elbows. I also have a question about the brass inserts but I will take that offline.

I can design inserts for the choke transition but would prefer to just buy something. Given that @mark99 is a professional modeler maybe he can design them. ;) This is all based on the assumption that the elbows weren’t already port matched to the ID of the chokes.

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mark99

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@daddywad,

Do you have any recommendations on small trumpets/fillers for the DCOE’s. The trumpets slide
between the choke and the carb body. So when you remove them, you are left with a turbulent transition from the carb to the elbows. I also have a question about the brass inserts but I will take that offline.

I can design inserts for the choke transition but would prefer to just buy something. Given that @mark99 is a professional modeler maybe he can design them. ;) This is all based on the assumption that the elbows weren’t already port matched to the ID of the chokes.
are you using 40s or 45s?
 

Markos

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@daddywad,

Do you have any recommendations on small trumpets/fillers for the DCOE’s. The trumpets slide
between the choke and the carb body. So when you remove them, you are left with a turbulent transition from the carb to the elbows. I also have a question about the brass inserts but I will take that offline.

I can design inserts for the choke transition but would prefer to just buy something. Given that @mark99 is a professional modeler maybe he can design them. ;) This is all based on the assumption that the elbows weren’t already port matched to the ID of the chokes.
This is what I have been looking for. Something for you to consider offering @daddywad. With that said. I will simply turn off the end of my existing trumpets.


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JamesE30

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Hi guys, I have the original alpina b2 airbox and Solex carburettors.
One thing I don’t see in this thread are the rubber gaskets that mount between the airbox and intake runners which from memory are a couple mm thick.
I will try to snap some pics tonight, but I guess they would give the clearance you need. I am sure that can be easily replicated.
 

mark99

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Hi guys, I have the original alpina b2 airbox and Solex carburettors.
One thing I don’t see in this thread are the rubber gaskets that mount between the airbox and intake runners which from memory are a couple mm thick.
I will try to snap some pics tonight, but I guess they would give the clearance you need. I am sure that can be easily replicated.
Hi, thanks
I was wondering about the gasket, it seems like it should be rather thick and compliant and there are three separate parts (carburetors) mating to one surface and they would therefore not be perfectly planer
 
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