Questions about tuning and timing dual carb 1.8 Options

[Slick914]

I'm going to attempt a tune-up on my car and have many questions. I know most of these are basic questions, so please bear with me. Your help will be greatly appreciated!

My engine... 1974 1.8 Has dual Weber carbs. Not positive which ones. Distributor appears to be original? I'm assuming that the cam is original, really have no idea. I attached a couple pics that may help identify what I have. Sorry, it's raining outside and the car is covered, can't get better pics at the moment.

Many questions, so I'll just ask them as they pop into my head, no specific order...

1. .016 gap correct for points?
2. At what rpm should I set timing? 3000, 3200, 3500?
3. What's a safe timing setting? 27, 28, 30, more?
4. Is it true if my point gap is set right, the dwell should be fine?
5. How do I sync my carbs? I have a synchrometer from previous owner.
6. Is my distributor supposed to have a vacuum line?


Hmmm, I know there were some other ?'s but can't think of them right now. The car runs ok now, but I know I can get her to run a little smoother. When cold, it backfires through the carbs especially upon acceleration. Even when at running temp, it can be hesitant during acceleration at times. Once the rpms get up there some the hesitation goes away. These symptoms could be a common thing with the set-up I have for all I know, but I still need to give her a tune-up regardless.

[Cap'n Krusty]

Set the dwell at 47 +/- 3 degrees, which is around .016". The timing should be set 28-30 degrees BTDC at 3000 RPM. Valves are set at .006", cold, inlet and exhaust. You have what appears to be the infamous 009 distributor, not stock, and it has a VERY short advance curve, meaning it'll be around 10 degrees BTDC at idle. Works, but you have to back off on the idle stop adjustment on the carbs to get the idle down. Might wanna look for an 050 or some other distributor with a full curve.

Synching the carbs is more an art than a science. Once the other stuff is right, make sure there's no preload at the throttle cable and disconnect one end of one linkage rod, balance them at idle with the throttle stop screws and get the idle speed right Some carbs have individual air bleed screws to get all barrels synched, some don't. Once that's done, reattach the rod making sure there's no preload. Raise the engine RPM to 1500 or so, hold it VERY steady, and adjust the rods until both sides have identical airflow. Recheck the idle balance, and readjust it as necessary, then redo the part load balance. Then you adjust the mixture screws, generally a little to the lean side of fastest idle. Once that's done, you may have to reset the idle stop screws and recheck the idle balance. You should be done with the part load stuff. Oh, be sure you have fairly hot plugs in it, 'cause Webers run fat and a cold plug will foul easily.

As you can see, adjustment is a round-and-round procedure, requiring you to continually fine tune the settings until they all work together.

Best of luck! Stick with it and you'll be fine. The Cap'n