Supersprint Weber linkage and anti-vibration spacers

[Tony]

Two questions.

My '93 Supersprint engine with two 40 DCOE 151s, each with a metal spacer between carb & manifold. They look to be 1/4" thick with very small spacing on both sides of the spacer. Can't seem to find any reference to exactly what type of gaskets go there. Are these anti-vibration spacers? Regular gaskets?

 

Q#2: Again, can't find photos or detailed info on the throttle cable to carb linkage. Throttle cable comes over the top of the valve cover to the top of the throttle plate. The outside of the cable ends there in a barrel, the inside cable continues straight down to a round slot in a V-shaped bracket under the carbs. The inner cable, when exiting the barrel goes straight down, at a sharp angle which is on the verge of binding. The bracket is mounted to one screw on each of the carb's bottom bowl covers, screws closest to the block. I might be able to move the bracket to the two bowl cover screws farthest from the block, but I believe that will cause the bracket to interfere with one to the frame tubes. I greased the inner cable and it works OK, but the geometry just doesn't seem correct. Anyone dealt with this?

 

Thanks much.

 

Tony

[Kitcat]

Tony:

 

A photo would help. On my 2nd long blat (to the USA7's event in '07 on the Dragon), in my original X-flow Cat, the little barrel you reference fell out. No barrel=no go. I ultimately "fixed" it w/electrical tape wrapped around the throttle cable and the throttle lever on the carbs. Drove it (gently) another 400 miles that way. Always kept a spare barrel (and spare elec tape) in the boot after that.

[xflow7]

The spacers you see are the sealing part of the soft mount system for the carburetors. As you surmised, the purpose of the soft mount arrangement is to provide a degree of vibration isolation to avoid frothing the fuel in the bowls. So, there is generally some type of compliant washer used to attach to the studs along with a compliant seal between carb body and manifold. There are a variety of types out there, but they seem to fall into one of two categories.

 

a) A stamping with molded elastomeric sealing rings like this:

 

http://www.piercemanifolds.com/product_p/99005.146.htm

 

b) Spacers with discrete elastomeric o-rings either side (which is what it sounds like you have:

 

http://www.opelgtsource.com/store/9000/9065.html

 

As far as I know, there's nothing magical about the o-rings used in style (b) other than they must obviously tolerate heat and fuel.

 

As for Q2, I have the same arrangement on my Supersprint. While I've always been a bit leery of it (for the reasons you describe) it's yet to cause me any real grief. But I check it periodically.

 

There are some other linkage solutions out there, but one must be careful that they clear the hood. RD Enterprises has a low profile linkage that looks promising (click on Carburetor->Linkage over on the left):

 

http://www.rdent.com/

 

Dave

[Tony]

Dave,

Thanks for those links.

 

b) seems as you say to be what I have which are approx. .200" thick.

 

a) differs in that they are connected and come with captive washer and hour glass rubber washer for each stud.

 

Both seem applicable, either one preferred?

 

Curious about my current install, but each stud has two of those cuplike captive washers, face to face (cupped areas facing each other) with no visible hourglass rubber washer, all held down on the stud by the self locking nut. Seems like that would cancel any flex offered by the hourglass washer. I'm going to dig through my books again to see if I can find a correct picture of how it goes together. I will be ordering once the carbs are off......

 

As for the sharp bend in the throttle cable, I'll leave it be (well greased though) and keep a sharp eye out for the barrel working free.

 

Tony

[xflow7]

Hi Tony,

 

I think the picture for (a) is incomplete. There should be a pair of the cupped washers and the rubber bushing for each stud. The correct installation of these is to have the nut tightening up against the pair of cupped washers capturing the rubber bushing, but you don't tighten them down until they're metal-to-metal for the reason you state. You're supposed to tighten them down to where there's ~1/16" gap between the cupped washers. This allows the compliance. If yours are missing the rubber hourglass bushings, you'll want to address that.

 

The alternative solution which appears to be shown in (b) are called Thackery washers. They're basically small, thick springs. Here's a better picture:

 

http://jhps.com/mm5/merchant.mvc?Screen=PROD&Store_Code=jhps&Product_Code=93558

 

Same idea, you tighten them down part way so that they compress the gasket and form a seal, but retain some give.

 

As far as I know, either type of gasket can be used with either type of retaining washer. As for preference, I don't really know. My car has the cupped washers/rubber bushings and started life with the gaskets like in (b). Then when I stripped and rebuilt the carbs, I decided to replace the gaskets and what I found easily was the type in (a), so I used that. Both seem to have worked fine.

 

My impression is that the critical thing is that the retaining hardware is in good condition and properly tightened.

 

Dave