Ideally, the strobe timing light is the most accurate way to set ignition timing. Static timing should only be for getting the engine started. If 7.5BTDC seems too advanced, dial back to 5BTDC and see how that works. This should be where you have the 7.5BTDC mark. Add 50% to that length and measure CW from the TDC mark to the right. Use a wire and measure the distance from TDC to the center of the 5ATDC notch. Just check that your 7.5BTDC mark is about 1.5x the distance between the TDC mark and the 5ATDC mark. If you remove the distributor cap center wire and it cranks easier you know you have too much advance. It almost seems like the battery is weak and cannot turn the engine, but it is actually the engine fighting against the starter. When you try to crank and engine with this much initial timing you actually see the starter struggle to crank the engine. When you advance the ignition timing "way too much" the spark fires while the piston is still on its way up to TDC and the peak pressure tries to push it back down before it can get over the top of the arc. 7.5BTDC is no problem for a healthy engine to start. What exactly do you mean by the "car does not want to start"? If the engine cranks smoothly but does not start it may not be the timing. Posted: Mon 8:24 pm Post subject: Re: Timing, Pulley, and Notches Running that distributor at the 5ATDC timing would have been terrible Whew! Good thing Cusser had you check your distributor model. Should I set this back to where the car was starting ok or just wait til I have time to go through a full tune-up and timing with the timing light? We tried going 7.5 BTDC as in my pic and the car does not want to start. Was very hard to start.Īfter that we went to 7.5 from the white mark thinking it was TDC. Initially we set the timing (test light) at TDC. Posted: Mon 11:45 am Post subject: Re: Timing, Pulley, and Notches Posted: Sun 6:28 pm Post subject: Re: Timing, Pulley, and Notches i am 100% new to all of this! Terrible how? Thanks! So, I should be good at this 7.5 right? Posted: Sun 6:09 pm Post subject: Re: Timing, Pulley, and Notches Most find 30BTDC or even 28BTDC a better max setting. retard the timing so it comes down to 32BTDC or less. This makes sure the mechanical advance does not push the engine into detonation.Įven if your idle timing is 7.5BTDC but the mechanical advance takes you above 32BTDC. This test is done with the vacuum advance disabled as it is ONLY checking the mechanical advance. You do not want to read more than 28-32BTDC once the mechanical advance has fully added timing on top of the initial timing setting. You should also do as Cusser suggested and confirm the distributor is not over advancing. Running that distributor at the 5ATDC timing would have been terrible! Posted: Sun 5:51 pm Post subject: Re: Timing, Pulley, and Notches Posted: Sun 5:28 pm Post subject: Re: Timing, Pulley, and Notches No, Tim this time you missed (no pun intended) Posted: Sun 4:24 pm Post subject: Re: Timing, Pulley, and Notches So, the V notch on the other side of the pulley is your timing mark. The dimple on the other edge of the pulley is TDC. Posted: Sun 4:12 pm Post subject: Re: Timing, Pulley, and Notches All manual transmission except for the Yukon. The '71 now has the 1835 engine, swapped from the '70. But the question is: what distributor are you using, and do you plan to use a timing light at full advance as well ?ġ970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. You'd measure 7.5° clockwise from that point if you really want to static-time at 7.5° BTDC. The dimple on the rear part of the pulley is TDC for #1 or TDC for #3. The white mark on the forward part of the pulley is 5° after top dead center, that's what the 1973 distributor used for its timing. Posted: Sun 4:11 pm Post subject: Re: Timing, Pulley, and Notches
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