distributor ?

[esty]

my dist's vac advance looks like the one on the left...is it supposed to have 2 vac hoses connected....what's the fitting on the back of the vac module...should it be cap'd or connected someplace?

[Zenon]

my dist's vac advance looks like the one on the left...is it supposed to have 2 vac hoses connected....what's the fitting on the back of the vac module...should it be cap'd or connected someplace?

The dizzy on the right is a common vac advance style. The dizzy on the left is the "vac advance and retard" dizzy found on some '75s. The outer (left most re: pic) nipple is the vac advance function. The inner nipple (closer to the dizzy body) is the retard. The retard and advance were controlled by valves and relays to adjust ignition as part of the emission control strategy. With a Weber carb and the rest of the smog stuff disabled, the retard function becomes useless or even counter productive.

That dizzy is still fine to use (assuming it is not worn out) - you just ignore the retard connection and simply connect the advance nipple on the dizzy to "ported" vacuum from the carb. No need to plug unused vacuum connections on the dizzy.

What is "ported" vacuum? Here's a great description I stole from "jakobsladderz" over on the MS EFI forum:

"Basically when they say ported they mean 'taken from a port in the carby/throttle body'. Essentially, it's a small hole just on the intake side of the throttle plate such that at idle there's no vaccum, but as soon as the throttle is cracked open you get vacuum again. It's better for economy and getting a nice idle, since idling with too much advance can mean on some engines that heaps of fuel is required."

Could not have said it better myself.

Another thing that many don't consider: When you have swapped the carb and disabled the emissions stuff (and let alone any mods to the engine), the original factory timing specs are now only starting points and are very probably not optimal - you'll have to tweak and test-drive to find the optimal base-timing (the only variable you have control over short of replacing or re-curving the dizzy) for your combination of changes. You also don't absolutely have to connect the vacuum advance but in the majority of cases it is beneficial.

Ignition timing is perhaps the most critical variable in engine tuning - very small changes can make a very big difference so it is well worth the effort to make sure you have it right.

regards,

Zenon

[esty]

thanks zenon...on the subject of timing....for weeks now, i've been trying to get my car to run like it did before i pulled the distributor and have so far been unsuccessful....

i was reading chilton's again a few nights ago and noticed it said to set static timing, go past the mark on the crank pulley to the 2nd mark as the starting point....

when i started, i set the marks on the crank, cam sprocket and dist to rotor...ISSUE: there is only one mark on my flywheel pulley, not a 2nd mark and that may be part of my setting the timing...how far past the mark should i go to set static timing?

[Zenon]

thanks zenon...on the subject of timing....for weeks now, i've been trying to get my car to run like it did before i pulled the distributor and have so far been unsuccessful....

i was reading chilton's again a few nights ago and noticed it said to set static timing, go past the mark on the crank pulley to the 2nd mark as the starting point....

when i started, i set the marks on the crank, cam sprocket and dist to rotor...ISSUE: there is only one mark on my flywheel pulley, not a 2nd mark and that may be part of my setting the timing...how far past the mark should i go to set static timing?

But it is running again, right?

Static timing is only for getting the motor started. Once running you have to set the dynamic timing either to the factory specs using a timing light and/or by trial and error as I mention above.

Look up "BigDog timing method" in the archives - he laid it out very well, IIRC.

That second mark they are referring to is on the front crank pulley, not the flywheel. It is called Z! (or Z') and is 3 degrees BTDC. It is a smaller notch close to the larger TDC mark and may not be present on all years. It lets you get a better initial timing but again is not relevant once you get the motor running. The engine will still fire and run enough to work with if you set the initial static timing to the TDC mark.

regards,

Zenon

[esty]

But it is running again, right?

crank pulley..sorry i wasn't paying attention to my words...

yes it is running, it starts instantly but turning the distributor each direction to it's limits isn't helping, even slightly

[c.d.iesel]

VACUUM ADVANCE

& VACUUM RETARD

LOOK AT THE VACUUM HOSE ROUTING STICKER ON YOUR CAR ?

IS IT A CALIF EMISSION MODEL ?

HAVE AN OWNERS MANUAL ? - IT will have an insert

for Calif. Emissions with all the details.

[esty]

VACUUM ADVANCE

& VACUUM RETARD

LOOK AT THE VACUUM HOSE ROUTING STICKER ON YOUR CAR ?

IS IT A CALIF EMISSION MODEL ?

HAVE AN OWNERS MANUAL ? - IT will have an insert

for Calif. Emissions with all the details.

it has no stickers, is a california model and the owners manual has been long gone...but thanks

[c.d.iesel]

[Zenon]

But it is running again, right?

crank pulley..sorry i wasn't paying attention to my words...

yes it is running, it starts instantly but turning the distributor each direction to it's limits isn't helping, even slightly

I doubt re-installing all your emission control stuff would help, even if it were possible at this point.

I'm out of ideas other than I suspect there is something else going wrong beside just the base timing setting. Perhaps a detailed description of exactly why you feel it is not running right and what you have done in terms of valve adjustment, spark plugs, carburettor and pretty much everything else you have done to or know about your engine will provide a clue. Either that, or hold the car closer to your keyboard. ;-)

regards,

Zenon