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Discussion Starter · #1 ·
Hi, I have a carburetor grounding strap and was looking to install it (not the engine/bellhousing strap). A couple questions: Did the cars have these originally and if so where is the typical place it should install?

I imagine it goes under one of the stud nuts but am curious where it would attach to the manifold..also which carb?
 

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Here is a 40DCOE2, 1600 Veloce Spider induction system I restored recently.
 

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Discussion Starter · #3 ·
Thank you Gordon, very clear. ...and a beautiful restoration job. My S1 1750 has the same configuration so this is perfect.

Wish I had installed it during my rebuild. That inside nut is going to be tricky to get at.
 

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It is supposed to be one of the hard-to-find, 12mm hex x 8 mm fine thread. 13mm hex is difficult to R & R. 12mm not too bad.
 

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I have usually found that strap on the rearmost 2 studs on 1750 carbed engines. Once I found it on the forward most studs.

As to the M8 - 12mm flats I have only found those on the back side of the manifold in the nut wells where sockets would not fit unless thin wall. Again on 1750 carbed engines. Sometimes there were M8- 13mm flats in those wells and generally M8- 13 mm flats in the other locations.

Of course it is possible that mechanics did their own thing over the years.

FWIW

Ken
 

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I'm not so sure the intent was to ground the carbs/manifold to each other as in the photo.. I think the strap was used to give a direct dedicated ground to the engine for the purpose of grounding the temp sender if it is in the intake manifold and not rely on nut's and bolts to do the job.. The strap arrangement in the photo would not serve that purpose and the grounded temp sender would have to be through a stud/ nut combination. I don't think the carbs need lightning strike protection.
 

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I'm not so sure the intent was to ground the carbs/manifold to each other as in the photo.. I think the strap was used to give a direct dedicated ground to the engine for the purpose of grounding the temp sender if it is in the intake manifold and not rely on nut's and bolts to do the job.. The strap arrangement in the photo would not serve that purpose and the grounded temp sender would have to be through a stud/ nut combination. I don't think the carbs need lightning strike protection.
My understanding is the strap was to discharge any static electricity that might arise from the fuel/air flowing through the system. Without it the carb would be isolated and subject to discharge spark ignition of the fuel. Although then I wonder if there should have been 2 straps, one for each carb. Or is the ground between carbs via the linkage enough??

Just my understanding.

Ken
 
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I just don't think we are driving Zepplins like the Hindenburg. The DCO3s' have no such strap but there is one on the water tube end where the temp sender is isolated from the rest of the engine and it goes to the head or block. It would seem an unreasonable safety grenade if some unknowing tech or DIYer forgot it resulting in a catastrophe. I think it was attached as I said and migrated to where it is in the photos for lack of being sure where it goes after working on the carbs or manifold. The electric sender is plugged in the block on some cars. like SPICA cars I think. I doubt there is s strap for them. Just my 2 cents
 

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I have been advised to keep the ground strap on the front carby as it has been found to have come loose or broken and fallen on to the high tension connections on the starter and made an awful mess when sparks and petrol mixed. Prevention sounds good and easier to get at.
Mark
 

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.... I wonder if there should have been 2 straps, one for each carb. Or is the ground between carbs via the linkage enough??
Yes, the ground between carbs via the linkage is enough to dissipate a static charge. Sure, if your audio connections were passing through the throttle linkage, your speakers would sound a little crackely. But for just dissipating a static charge, the linkage between the carbs is just fine. In the stock application, the airbox also provided conductivity between the carbs.
 
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I just don't think we are driving Zepplins like the Hindenburg. The DCO3s' have no such strap but there is one on the water tube end where the temp sender is isolated from the rest of the engine and it goes to the head or block. It would seem an unreasonable safety grenade if some unknowing tech or DIYer forgot it resulting in a catastrophe. I think it was attached as I said and migrated to where it is in the photos for lack of being sure where it goes after working on the carbs or manifold. The electric sender is plugged in the block on some cars. like SPICA cars I think. I doubt there is s strap for them. Just my 2 cents
Again in my experience with several 1750 Carbed GTVs and a spider; I have always found that strap bridging the rubber mount. I doubt all previous owners or mechanics were so like minded to move it from a different location to that one.

Moving to the front for the reason mentioned by MarkEd is a good idea as is using a plastic long linkage rod, for the same reason.

I had forgotten about the air box grounding the carbs together as does the support strut. Another reason to use the stock setup vs 2 aftermarket air cleaners

Ken
 

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Discussion Starter · #14 ·
Amazing information in these forums. I had leaned about the insulated throttle linkage in case of breakage and it tangling with the starter. Before I had my linkage sorted there were several occasions when it did come undone. I expect I'll install on the #1 cylinder carb for the reasons given and since it is easier to get to.

There is some logic to following the stock setup - sometimes more than we know.
 

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Amazing information in these forums. I had leaned about the insulated throttle linkage in case of breakage and it tangling with the starter. Before I had my linkage sorted there were several occasions when it did come undone. I expect I'll install on the #1 cylinder carb for the reasons given and since it is easier to get to.

There is some logic to following the stock setup - sometimes more than we know.
As with most changes instituted by the factory, the engineers went back to brainstorming a solution for a disconnected metal linkage fouling in the hot starter connections resulting in a change to a plastic accelerator rod that replaced the metal rod in the 105 cars. This has no relationship to the ground strap unless I am missing something. BTW TAV 153 in the Giulietta parts book does specify one ground strap between the "cylinder head and Carburettor" on the Weber equipped cars in addition to one at the fuel tank for the fuel sender; one at the water pipe to the head as previously mentioned; and fuel pump (electric). So my earlier point of misplacement is shot full of holes.. mea culpa. So the maestro in Chicago has it correct. Still learning.
 

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Don't forget the ONE aluminum washer under the cam cover bolts added in the early Duetto era. Connect the cam cover to the head, or a spark gap exists between the cover bolt stem and the cover to detonate gasoline fumes inside the block. Ka BOOM!!
 

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Yes. This is for PRE-front cover bolt covers. One GTA engine explosion with a magnesium cam cover, front cover and sump (which turn to dust) complete with FLAMING oil from a running engine (often at SPEED) cures you forever of errant spark issues, regardless of source. Particularly if you are standing next to it when this happens.
Just my opinion as usual.
 

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Wouldn't the two 6mm bolts at the front of the cover do that?
Yes, on 1750 and 2L engines. But earlier 1300 - 1600 engines (*) didn't have those two 6mm bolts at the front of the cover.

*) Yes, I know. In Europe, 1300's and 1600's were still made in the era of front cam cover bolts.
 

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Yes. This is for PRE-front cover bolt covers. One GTA engine explosion with a magnesium cam cover, front cover and sump (which turn to dust) complete with FLAMING oil from a running engine (often at SPEED) cures you forever of errant spark issues, regardless of source. Particularly if you are standing next to it when this happens.
Just my opinion as usual.
OK, well stuff happens. Earlier Veloce engines didn't have those conductive washers did they?
 
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