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Like any IC gasoline engine give it as much timing as it will handle without detonation or hard starting.
Start out with the OEM spec then increase it until it detonates under load or starts hard then back off in 1° increments. You may need to adjust for different ambient conditions(hot humid day vs other). I keep my dist loose enough to adjust on the fly if needed.
Tune with the same fuel you normally purchase.
Tune with a vacuum gauge to set timing and A/F ratio
Along with proper timing, all the ignition parts involved need to be serviceable(in good working condition).
Same for the fuel system and A/F ratio.
Ignition and fuel settings must harmonize to optimize the engine's full performance potential.
Here's the procedure I was told about by others in the past:
1. Set the dwell to factory spec.
2. Set the initial timing using a timing light. Hit eBay for a "vintage" timing light. mine is a craftsman from the 1980's. its capable of being used with 6v power. I'll attach a pic at the bottom of this post.
3. Using a vacuum gauge (you can tie into the vacuum line that supplies vacuum to your wipers), loosen the distributor hold down nut, and turn the distributor to see what the highest vacuum reading is just before the running engine starts to stumble. Turn the distributor to the other direction to see what the lowest reading is, before the running engine starts to stumble. God back to the highest reading and turn the distributor BACK 1" under the highest reading. Lock down the distributor. Using this method will also set your timing for the altitude you're driving at most of the time. Distributor/Timing adjustment procedure that worked for me:1949 Oldsmobile Rocket 88 (303 V8) 1- begin with new points/condenser inside distributor or ensure they are adjusted to specification.
2-disconnect the distributor vacuum advance from the base of the carb/engine.
3- plug the now open vacuum port on the carb/engine. Failing to do so will affect engine RPM.
4- start engine and allow it to warm up to normal operating temperature.
5- with automatic transmission in neutral, adjust engine RPM to 500 (factory manual states 500 RPM is the ideal idle speed).
6- loosen distributor hold down clamp and align distributor timing mark to zero. Tighten bolt into place.
7- loosen adjustment screws that secure distributor to distributor hold down clamp. These screws allow the distributor to be rotated to advance or retard the timing.
8- using a strobe/timing light tester on cylinder 1, adjust timing by rotating the distributor until the engine timing mark points between the two reference ***** on the harmonic balancer. Once aligned, tighten adjustment screws securing distributor to base plate.
9- remove carburator/engine vacuum plug and re-attach vacuum line to the distributor vacuum advance.
10- check engine RPM and adjust to 500 RPM.
Timing procedure should now be complete. At idle, the engine timing mark should point between the two reference ***** on the harmonic balancer. As RPM's increase, the timing will not appear to remain the same using the timing light, but rest assured, the engine is timed properly. Timing should return as engine slows down returning to idle rpm.
After adjusting the timing this way, it runs strong, accelerates without hesitation or backfire. While it's not mentioned to do so in the official shop/service manual, to set distributor/engine timing, VACUUM MUST BE DISCONNECTED from the distributor before adjustments are made.
Just a question, doesn't wiper vacuum come from the dual action fuel pump and wouldn't that be different and unrelated than manifold vacuum. Maybe there wernt dual action fuel pumps in 49. Just curious..... Tedd
Just a question, doesn't wiper vacuum come from the dual action fuel pump and wouldn't that be different and unrelated than manifold vacuum. Maybe there wernt dual action fuel pumps in 49. Just curious..... Tedd
great point Ted. I believe your correct. If the wipers are powered off fuel pump vacuum, it won’t work for timing adjustment. As I said in my post, I was passing on info that I was told but didn’t do. You picked up on what I missed.
I adjusted my timing using the longer procedure at the bottom of my post. I got my vacuum off the intake manifold/carb base.
October 20th, 2021, 07:21 PM
