# Weber Sidedraft Mounting Interference Problem



## vlksdragon (Jul 28, 2000)

I went to test fit a set of 45 DCOE13s on a two piece TWM long manifold, and I ran into a 
problem with the ends of the throttle shafts interfering with each other, preventing the two 
carbs from mounting. 

It's almost a centimeter of interference, but before I go crazy and trim the shaft ends, is 
there something about this that I'm missing? 

Lousy pic, but you can kinda see the shaft ends in between the two carbs interfering, preventing 
the carb on the right from mounting on the manifold:


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## Rheinland Technik (Apr 2, 2010)

Are the carbs on the correct side?


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## vlksdragon (Jul 28, 2000)

Rheinland Technik said:


> Are the carbs on the correct side?


 I'm not sure what you're asking?


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## Rheinland Technik (Apr 2, 2010)

There is a left carb and a right carb. The linkage for the carbs when connecting duals is specific to a dual set, rather than a single carb. IE: if you are running carbs not origianlly configured for dual carb use, then you will have an issue such as this, or the other cause of interference is you have the wrong carb on the wrong manifold mounting point.


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## vlksdragon (Jul 28, 2000)

Interesting, I had no idea the matched pairs were any different than singles. These were 
from two different sources, so they are not matched. How are the throttle shaft ends 
different on the matched pairs? Does anyone have a closeup pic?


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## Rheinland Technik (Apr 2, 2010)




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## candm (Apr 27, 2003)

vlksdragon said:


> I went to test fit a set of 45 DCOE13s on a two piece TWM long manifold, and I ran into a
> problem with the ends of the throttle shafts interfering with each other, preventing the two
> carbs from mounting.
> 
> ...


 you are going to have to grind each of the throttle shaft ends slightly. i have the same setup


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## VdubyaVR6 (Mar 8, 2004)

> you are going to have to grind each of the throttle shaft ends slightly. i have the same setup


 x2 I have the same setup I'm working on and I just figured that out this week as well. Pic with the linkage installed.


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## Rheinland Technik (Apr 2, 2010)

candm said:


> you are going to have to grind each of the throttle shaft ends slightly. i have the same setup


 That won't help him without having the correct interfacing linkage to tie the two carbs together.


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## candm (Apr 27, 2003)

Rheinland Technik said:


> That won't help him without having the correct interfacing linkage to tie the two carbs together.


 you are correct.:beer:


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## vlksdragon (Jul 28, 2000)

Thanks for the info everyone. Do linkage kits typically come with the interfacing pieces, or 
do I need to find those separately?


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## candm (Apr 27, 2003)

i dont remember if they were included when i bought my linkage setup, but if they are new carbs, they usually are included. you can get them at www.piercemanifolds.com as well as a number of other places


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## vlksdragon (Jul 28, 2000)

Resurrecting an old thread (my own), but I'm finally getting around to my dual weber 16v build, and I'm still running into this same problem with the interfering throttle shafts when using the TWM/Pierce long runner manifolds.

In mocking them up, I'm finding I need to trim more (~3-4mm) from the shafts than I have available. For those of you that ran into this same issue, did you go to lower profile nuts to be able to trim enough?


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## betterfood (Oct 4, 2018)

Looks like your original picture is gone? Can you post another one?

I am in the process of installing the 60mm Pierce manifold. I'm not overly happy with the quality of their fitment. In fact it's pretty ****. A full half of the screws into the head cannot be installed even when using shorter screws as they hit the casting. I have to grind out my brand new manifold just to mount it...

When I installed the carbs to the manifold they they were well clear of each other. When I swapped out the throttle shaft washer on the carb with the throttle cable for the linkage coupler, the throttle lever on the other carb was interfering with the linkage so I hard to grind that down. I will try and get a picture later today.

This is how a shortened head screw fits in their 60mm manifold.


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## DbilasTDI (Nov 5, 2017)

you have to use studs to mount the intake.
get aircooled 8mm nuts these will minimize the clearancing required: https://www.cbperformance.com/product-p/3332.htm
I used a dremel and sanding drums to clearance top of cyl 1 and 2
put the intake on and start those problem nuts with the intake just exposing the end of the stud. 
"push" the intake to the head by tightening the 2 problem nuts a bit at a time. It has to come off in similar fashion. The other nuts should not be an issue
the nut becomes "captured" between the intake runner and the stud if you put the end of the intake up against the head and try to start the nut.
I quit using the standard o ring mounts or the borg warner either. I use a phenolic spacer for the heat and 2 gaskets
I used 8mm Thackery washers (ebay.co.uk) to allow for "soft mounting"
I took a 10mm wrench and ground off the sides to allow closer fitment for final tightening of the intake nuts. I keep this wrench in the truck but it has never come loose. I drilled and tapped 2 6mm flanged nuts to 8mm so 10mm wrench. you cannot use a box end wrench: it will not fit.

Yes, its all a bit of pita and expense considering you could have bought an intake for a V8 muscle car and it fit perfect for less. This happens with "tuner ish" sometimes. Still in the end it is for the best as the carbs are real close to the valves and you have the most room left over in front of the carbs.

also install a 90° fitting into runner #4 before you install the intake cause after it is on all you can do is a straight fitting.


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## betterfood (Oct 4, 2018)

DbilasTDI said:


> you have to use studs to mount the intake.
> get aircooled 8mm nuts these will minimize the clearancing required:
> I used a dremel and sanding drums to clearance top of cyl 1 and 2
> ...
> ...


I had written off studs because I figured the nuts would be too big. But those nuts look like they will help immensely. Even still you can see in my image the fillet on the machined surface is right there the flange will go. Sloppy.

The whole experience and kit is really sloppy. I expected better for the price I paid, but maybe I'm just cheap. They didn't bother telling me I needed studs and special nuts. When I emailed them about this issue they told me to call them, instead of replying with the very simple answer you just gave me. Why should I, the paying customer, have to call you long distance when you could just look at the pictures I sent and say "oh, you need small nuts...". Communication prior to ordering was really spotty as well, questions were just ignored or an email with multiple questions got a single "yes" response. When I called and ordered I explicitly asked them if I needed the cast water outlet piece with the 60mm manifold, they said no, yet when installed the Carb body pushes into the water hose. It's probably fine but, WTF, I would have happily bought the water outlet if I had know they would interfere. I'm not going to order it now because shipping is ridiculous and I don't particularly feel like giving them any more money. I get that this is bit of a custom setup but don't call it a "kit" if half the parts aren't there or don't work with stock parts. At least stock some necessary items and I'll buy them separately. They told me it was going to cost $50 extra to get the carbs jetted the way I want, which was fine. They didn't end up charging me the $50 and just threw the air correctors I wanted in the bag with the rest of the accessories. Which is great, free jets, but I had to take the carbs apart to check the rest of the jets were what I asked for as they originally told me the standard jetting was vastly different than what I wanted. They were all correct except the air corrector, so I have no idea what happened there. It's all just so damn unprofessional. If I treated my clients like that I would be out of work very quickly. I cannot recommend Pierce Manifold to anyone, unfortunately there's not much of an alternative as Redline also was trash to deal with, which is why I went with Pierce in the first place. Anyways, I'm done ranting now.

My manifold doesn't have the port on cyl 4 like the dbilas one. There is a boss for it but it's not drilled out. I don't know who actually makes this manifold. There are no markings on it other than "VW" and "16V". The "Manifold" in Pierce Manifold would indicate they make it but they could just be a reseller, I have no idea.

Also, is your filter box held together with an extension cord?


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## DbilasTDI (Nov 5, 2017)

My intake is the same as yours. Weber makes them. You will need to drill the bung into the boss on #4

Sorry but Weber stuff, Italian stuff, can be a little chintzy by nature. I mean is a Fiat really ever "good?" Is a Ferrari "reliable?" Luckily when dialed in or close, DCOEs are great and when not dialed in they aren't too bad.

Compare a Weber to a Mikuni, basically the same but the Mukini is so much nicer, better material, better fit and finish

I had to get some new o-rings for the DBilas air plenum.

Dude this is all part of the fun. Hang in there. You will hit no problem someone else has not discovered. you need a cheep electric pump, a Facet or other small pump. I think the little Edelbrock $50-60 one is popular


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## betterfood (Oct 4, 2018)

DbilasTDI said:


> You will need to drill the bung into the boss on #4
> 
> Dude this is all part of the fun. Hang in there. You will hit no problem someone else has not discovered. you need a cheep electric pump, a Facet or other small pump. I think the little Edelbrock $50-60 one is popular


What is the purpose of your #4 bung? Brake booster? Does it generate enough vacuum to be of any use?

I am aware of all the "fun". This is not my first time. Just disappointed and needed a rant.


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## DbilasTDI (Nov 5, 2017)

yes the brakes get plenty of vacuum, 2117cc, 276 cams, 21mm master, 11.3" fronts, rear disk


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## vlksdragon (Jul 28, 2000)

Sorry, realized I never came back to this thread with a pic:










Note that I don't have the other connecting linkage piece on the right carb. If I trim the shaft down for clearance, I don't think there's enough room for that piece and the nut.


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## betterfood (Oct 4, 2018)

What's with the gap between the bearing and the lock washer on the left? Optical illusion or is there a spacer in there or something.

That's really tight. Mine on the 60mm manifold were not that close. I cut town the tab that is between the flanges in your picture but I did not have any shaft interference issues. Looks like the shafts are going to need to be cut down regardless. Those are just standard sizes nuts, right? Should be able to find some thinner jam nuts to put on the shafts.


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## DbilasTDI (Nov 5, 2017)

Highly recommend you take carbs, manifolds, head and both sides of the "balancer" linkage that fits between the carbs. You have 1/2 of it in the pic. The other 1/2 has some little spring things and an adjusting screw. Take it all to a machine shop. find the old guy.

Your manifold flanges are ever so slightly out of hork with each other.Those 2 shafts need to match center to center with some space 15mm ish? between for the balancer linkage to mate.

Your manifolds must move apart from each other, just a few more degrees so the shafts line up correctly.
This will require they cut at least 1 surface of 1 intake flange, probably 2.
Expect $250 ish, maybe less, maybe more.
Yea it blows but intakes not viable if they dont fit.
plenty of go faster stuff is tweek to fit.


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## betterfood (Oct 4, 2018)

He doesn't have the "spring thing" part on because it won't fit.

What do you expect a machine shop to do about this particular problem? The left manifold flange looks a little higher than the right, but that may be a trick of the camera. They could mill one down and get them parallel but they are still way too close. Bore out the holes to spread them apart? Then the ports won't line up. Unless the castings are total garbage and they currently don't line up.

I have a little over 6mm of space between my throttle shaft nuts. They are out of alignment in the picture because the carbs are not fastened down fully. In Mr. Dragon's picture, he has a gap on the left shaft, Presumably this will be taken up by the spring thing part. At that point the throttle shafts are still interfering with each other.

Either the manifolds need to separate, which I think will be problematic, or that throttle shaft needs to be cut down. Maybe the shaft's are not symmetrical and it's in backwards? With how low quality these carb kits seem to be it would not surprise me.


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## vlksdragon (Jul 28, 2000)

better is correct, the other part of the linkage is not on because it won't fit as it currently sits. In doing some research, it looks like I wasn't the only one that experienced this with the twm manifolds, so it looks like I'll just trim the shafts and use jam nuts.

On a side note, I also have the redline short manifold, and that thing is terrible in so many other ways.


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## betterfood (Oct 4, 2018)

vlksdragon said:


> On a side note, I also have the redline short manifold, and that thing is terrible in so many other ways.


How so? Bigger issues than my fastener fitment? Post some pictures?


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## DbilasTDI (Nov 5, 2017)

What do you expect a machine shop to do about this particular problem?

Assuming the front of the head is flat:
machine the flange surfaces as required to alter the angle of the manifold runners with respect to the front of the head so the runners are not straight 90°, or whatever they are now, but biased slightly towards the ends of the head, thus slightly spreading the centers

You could mock it up with shims between the inner flanges and the head, figure out how much to slice off. then you use a mill, something and cut a thin wedge from the flange. You remove a piece that would be .100 +/- thick on the outside end of the manifold flange, tapering to a point on the inside end of the flange. Or multiple operations as required to get the flange surfaces parallel

The extent of the job would depend on how far out of whack it is.
a common issue with these?





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## betterfood (Oct 4, 2018)

DbilasTDI said:


> machine the flange surfaces as required to alter the angle of the manifold runners with respect to the front of the head so the runners are not straight 90°, or whatever they are now, but biased slightly towards the ends of the head, thus slightly spreading the centers


That would work but I think we would end up cutting way to much off the manifolds and creating too steep of a misalignment angle. Assuming these manifolds are rough dimensions of 150mm x 100mm, if one wanted to gain an extra +10mm clearance between the two they would have to mill the head flange at ~3°. Over the 150mm of the flange that's ~7.5mm gone from the flange on the outside. How thick are these flanges? Not to mention all the fasteners are now at a ~3° angle. The design quality of these are clearly poor, I can't imagine the manufacturing quality is any good either, I would keep the flanges thick as possible. I don't think 7.5mm difference in the intake runners matter much. But I do not like that ~6° misalignment angle on the throttle shafts.



TheSamba Link said:


> throttle shafts interfere so mount holes will need to be elongated and ports matched or could be suitable for other brand carbs.


This is a better idea assuming there is material to play with. Now this is a big assumption, but assuming everything is straight and the ports line up favorably I would not mess with the manifolds and take my clearance from the throttle shafts. Shafts are cheaper than manifolds if you screw it up. If the manifolds are nowhere close to the ports, then by all means take out material, match them up, and shift them over if possible. The flanges are the parts that are easiest to measure, I hope, but am probably wrong, they did a half decent job lining them up.

The "other brand carbs" comment from The Samba is interesting too. Weber vs Chinese may not have exactly the same throttle shaft. Different varieties of "Weber" may not either. If we look at the 3 different carbs (mine, Dbilas, Dragon) there is clearly more shaft sticking out of Dragon's than the other two.


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## DbilasTDI (Nov 5, 2017)

Actually with a mounting boss on each runner you could do a crossbar linkage to the outside ends. Maybe that was the original design.


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## B1-16V (Aug 5, 2002)

Bringing it back from the dead. Again. 
vlksdragon, what did you come up with for this issue?

I am using the short runner intake, and did not have the shaft interference.
Other issues, but not that.


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## vlksdragon (Jul 28, 2000)

B1-16V said:


> Bringing it back from the dead. Again.
> vlksdragon, what did you come up with for this issue?
> 
> I am using the short runner intake, and did not have the shaft interference.
> Other issues, but not that.


I ended up grinding down the throttle shaft and used a jam nut as others have done. I did a test fit and all seems good.


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