[Roadsters] Differences in carb damper - Figured out

[kendelmccarley at cox.net]

Okay, answering my own questions here.  After posting, I had a few ideas on how to debug things.  First, I figured out that if I don't thread the longer rod all the way in so that it's effectively the same length as the original, the carb pistons rise and fall the same way.  With that in place, the car started and idled, but would stumble on acceleration.

Hmmmm..... why the stumble?  Well, in an attempt to find out why, I then screwed the longer damper all the way in.  The piston with the shorter damper was opening much quicker on acceleration, so I stuck a finger in that carb against the piston to slow it down.  Aha!  Now, the engine accelerates nicely.  Take my finger off so that the piston opens quickly again and it goes back to stumbling.

Conclusion?  The one damper that came with the car is wrong.  Man, oh man.  These old carbs are so cool.  I've messed with SUs on British cars, but these, while similar, are different and fun to play with.  

Joe, do you have another one of those dampers and caps in your stash?


 



---- kendelmccarley at cox.net wrote: 

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I've been working on getting a '70 1600 running that was missing a damper and cap from one of the carbs.  Joe Russo was kind enough to fish one out of his stash to sent me but, after installing it, the car still runs poorly.  I pulled the air cleaner to check the rise and fall of the carb pistons.  Sure enough, one of them was much more resistant to movement than the other.  When I switched the dampers from carb to carb, the one with Joe's part was harder to move.  

The only difference I can see between the two is that the one Joe sent me is around a sixteenth of an inch longer, putting the damper part farther down into the carb.  How does this make a difference?  If I mod the new part to be a bit shorter (pull it out of the cap, cut it down, and re-insert into cap) will that cure this problem?
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kendelmccarley at cox.net

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