While cleaning prior to rebuild, I dropped my Quadrajet off the work bench. The damage that concerns me is the two locating pins on the carburetor body, on either side of the secondary area. The pins broke off about flush with the body surface.


Are these pins crucial in the proper operation/assembly of the carburetor? Will the screws hold everything aligned and together without the pins?


I can create a jig for the drill press and get those holes pretty straight for either press fit or epoxy-set replacement pins. I would rather not mess with it (or mess it up) if I don't have to, as it took me a while to find this carburetor. Thanks for your time.
Mick

 

I would try to drill and tap for a screw that is smaller than the pins. Perhaps you can use a screw, washers and use a plate to jackscrew the pins out.

 

Bummer, that sounds like my luck. I think you would be ok leaving them as is. As long as you get the gasket aligned properly which should still be aligned with the screws. I am not a expert but that's what I would do, I think those pins are just there to ease assembly by helping align the 2 pieces and gasket. As I said the way my luck is, if I tried to drill those out I would end up ruining the carb for sure!

 

The pins are a tight tolerance fit that locates the parts properly. The screws have clearance in the holes that allows too much slop if you don't have the pins.

 

IMO those pins aren't strictly necessary. Assemble the gasket and air horn slowly and carefully and you'll be fine. Trying to replace them with a screw or rod won't be particularly helpful since it's the interference that makes them useful.

 

Actually, they are. The real problem is that if the gasket between the throttle body and main body isn't located exactly right or moves around at all, the secondary throttle plates can bind on the edge of the gasket and be held open, causing the engine to race. I've had this happen with aftermarket carb kits where the gasket wasn't cut exactly correctly. Even if you align it perfectly the first time, the head/cool cycles can cause it to walk.

 

Thank you all for your responses. I will update when I come up with a plan of action.

 

I would still try to remove the pins without damaging the original holes. They are alignment pins and serve a purpose, as Joe points out. I am not sure what size the pins are, but would guess they are a nominal size. With new pins installed, life would be good.

 

Oh, hey, I read too quickly the first time and assumed we were talking about the air horn pins.


I'll stand by my answer. I've run qjets without the base plate pins several times before. As Joe said, things can go wrong, but I think it's a little harder for that gasket to wander around.



I doubt trying to replace the pins will go well. The next step is replacing the carb.

 

Locate a parts carb and just replace it.

 

If you need a carb for a core I have a friend that has a big stack of 4 Barrel GM Carbs . Let me know exactly what you need and I will see what I can do! Larry