Dako
Well-Known Member
This is why I come to this site. :eusa_clap:
The dialog is great without all that :violent1:
The dialog is great without all that :violent1:
b motor dist vacum line to?
- Thread starter funnycar
- Start date
If your motor is idling, there should be no ported vacuum, since it is taken above the throttle blades. If you 'wing the throttle' and let it go, you probably still won't see any ported vacuum. However, if you hook up a vacuum gauge with a rubber hose into the driver's compartment so you can see it and then go out on the road and put the motor under load by accelerating hard, you will see ported vacuum. It's how it works. BTW, the info in that article applies to all brands, not just GM. Happy motoring...
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The ported vacuum source is just above the throttle blades, as you state. So at idle, the port doesn't see a vacuum. When you open the throttle blade, the port is exposed to intake vacuum and adjusts the distributor. But under full acceleration and load, there is no more intake vacuum, so therefore no ported vacuum. The distributor relies on mechanical advance under WOT conditions.
67 coronet
Well-Known Member
the conversation is interesting to say the least.both set ups will work.ported vac and full manifold vac work in the oposite directions.both will drop to zero,for a short period of time,at full throttle stomp.both can be made to work.full manifold vac is much more stable and tends to work better for higher performance eng.factory or stock eng will prob work better with the ported setup.the manifold vac takes more creative adjusting to get it right.the ported set ups are almost plug and go,just use factory settings.in the end it just depends on you and what you are running.two ways to achive the same goal.
Meep-Meep
дворянин
I don't agree with using manifold vacuum on the distributor. I use ported only. Set your mechanical advance properly; get your basic engine combo with regards to cam, compression and mixture right and you won't have any problems. Ported is really manifold vacuum just higher up but I don't want to rely on manifold vacuum to hold my initial timing. Also when you open the throttle the manifold vacuum drops instantly retarding the timing, and if the mechanical advance is not loose enough you will have a flat spot. If the mechanical advance is too loose the weights will come in at idle and cause instability problems. For big cam race engines it may be necessary to just lock out the distributor at full advance and run an MSD to retard during starting.
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