Tightening Dellorto,s

[Steve Brooks]

Good morning chaps,confirmation needed here.just taken off the carbs from the car,question is when I re-tighten them with the 50 thou gap,do I measure between the double coil spring washers.Regards Steve
Thanks for the confirmation.

[512BB]

Yes you do, but I wouldn't be overly anal about the size gap. If the carbs and therefore O rings have been fitted in place for anything more than a few days, you will of course be fiiting new O rings. I say that because I overhauled some carbs recently and refitted, only to find that the new fuel pump that I replaced at the time was duff, so off came the carbs again to replace it, but I did not replace the 0 rings this time, as they would not have taken a set in a week.

LS

[elans3]

As above, I've always found 50 thou a wee bit too slack, and have always tightened mine to a 25 thou gap. It still leaves enough "give" in the mounting to prevent frothing of the fuel. Its more important to make sure that whatever gap you use, that all eight are the same, and that you have good O rings, be they the two-per-port old type with an aluminium or Nylex spacer between them, or the Misab plates.
If you use the better Cosworth mounts (rubber bobbin between two cupped washers, then treat the gap between the two cupwashers the same as a thackeray washer.
.
That's what I've been dong for 45 +years, including nearly 18 years of competition, almost always with either Weber or Dellorto carbs fitted.

[Esprit2]

The soft mount gap is supposed to be 0.040" / 1mm on either side of the sandwich plate.

Note that the original Thackeray washers had a ziz-zag bend in the center coil where it passed through the gap between the ends of the top & bottom coils. Plus the end coils were partially flattened. Not fully closed & ground, but enough that the ends are approximately parallel and the coil tends to sit square between the carb flange and nut faces.

For those 'proper' Thackeray washers, the gap between the coils should end up at approximately 0.35 - 0.50 inch (0.89 – 1.27 mm). Never tighten them until they go solid.

The cheap clone mounting springs now sold by many suppliers do not have those features. They just look like a short section cut out of a coil spring would with flat wire. Without the zig-zag through the gap, the spring will go coil-bound before the gap in the soft mounts is correct. And without the partially closed ends, they tend to sit a little cocked to one side on the stud.

Regards,
Tim Engel