On which condition does the vacuum advance mechanism shift the ignition point?
9. On which condition does the vacuum advance mechanism shift the ignition point? Explanation: The vacuum advance mechanism shifts the ignition point under part-load operation. The adjustment system is designed so that its operation results in the part-load advance curve.
What’s the correct timing for a vacuum advance?
Make sure the vacuum advance connection is removed, and now rev the engine up to around 2,500 to 2,800 rpm. Ideally, the timing now should be somewhere around 34 to 36 degrees to total advance. With 34 degrees of total mechanical advance and 14 degrees initial timing, you have 20 degrees of mechanical advance—14 + 20 = 34.
What is the idle timing for a vacuum distributor?
Both idle timing and static timing of 7.5 degrees BTDC is correct for the 009 centrifugal-advance distributor and most single-vacuum distributors (e.g., SVDA) on aircooled VW engines (vacuum hose disconnected and plugged on the single-vacuum distributor).
When to set timing on a VW vacuum?
Set timing at high revs (3000+ rpm) at 28-30 degrees BTDC, and hope that the idle will come in about right. Until you get the car to idle at about 900 rpm, you are going to find it difficult to set the timing the ‘normal’ way for that distibutor/carburetor set up.
What does 10 degrees BTDC and 10 ATDC mean?
BTDC means Before Top Dead Centre and ATDC means After Top Dead Centre. So 10 degrees BTDC refers to the spark plug firing 10 degrees before the piston reaches the top of its stroke and 10 ATDC would mean the sparking plug would fire 10 degrees after the piston had passed TDC (Top Dead Centre). Got it? Good.
How to set base timing on a vacuum advance distributor?
BEFORE doing any base timing settings, MAKE SURE where the point dwell reading is, as changing that after the base timing is set WILL affect the base timing. IF it’s still a points distributor. Look at the FSM distributor advance specs. Then add the base timing to that number.
What should the timing be on a Bosch 009?
For a Bosch 009, you will want to set timing to 30 degrees BTDC at 3,000 RPMs. Connect the tachometer and timing light. Disconnect and plug the distributor’s vacuum lines. Start your VW. Use your 10mm wrench to slightly loosen the distributor clamp. You will want to rotate your distributor, but not have it rotate on its own.
What’s the right way to time a vacume?
Dropped the engine in, dropped the distributor in, turned a half of crank fired right up. I set the initial timing with vacume off to 12 degrees, then up to 32 degrees at 3000rpm. It’s sometimes a pain in the ass because of the different timing methods. WELL??????????
What does 38 degrees mean on a vacuum advance distributor?
At part-throttle, higher vacuum levels, it’s a “thinner” mixture, which is a bit harder to ignite, because it’s not as rich. The 38 degrees relates to the time, in crankshaft degrees, from the time that the mixture is initi9ally ignited until it is fully ignited/”boomed” at TDC.