Need holley help...

[Psychopete]

Hey.....what about me......I told him everything he SHOULDN'T have done........... !!!!!!

When your truck is better than everyone else's, you can't be wrong!

 

[kimcrwbr1]

Hook the vacuum advance to the vacuum tree (manifold vacuum) Try retarding the timing to 15 dbtdc with the vacuum advance hooked up or 5 dbtdc without vacuum to the dizzy. plug the advance in and tune the idle air jets for the highest rpm or vacuum in hg. You need to find the sweet spot between fuel delivery and timing so try different timing marks and adjust the carb in that order until you find the sweet spot. I wouldnt go any larger on the jets there is not enough displacement on a stock 2.8 is only 171 cubes. I have been trying to find a new harmonic balancer for my 2.8 right now im at 5 dbtdc and it runs the best it ever has. I want to put a new damper on to see if my theory the damper lies is true.

 

[The_Dealer]

im gonna leave it alone for the time being, i seem to have everything working pretty good together. besides the a4ld. gonna ditch that soon

 

[kimcrwbr1]

If your running your advance on the ported nipple on the carb switch it to manifold and plug the ported nipple on the carb you will be glad you did. and you always need to adjust the idle air needles when you mess with the timing to the highest vacuum or rpm.

 

[The_Dealer]

so how do i adjust my kickdown? i dont have the cable mine has a metal rod Z type deal that goes from the tranny to the carb's kickdown lever. is the screw supposed to be touching the kickdown lever on the cab at idle position or is it adjust to how u like the shifts? on the interstate at about 65 it feels like when it shifts it might be kinda between gears slips a little, give it more or less gas and it shifts right. also drops to like 2nd at 55+ with more then 1.2 throttle. right now the screw is about 1/2" from touching the rod at idle position. it moves to about 1/4 throttle before the kickdown rod starts to move. i gotta get one more road trip outa this trans and i would like to have the kickdown set right so i dont have any surprises

 

[gwaii]

If your running your advance on the ported nipple on the carb switch it to manifold and plug the ported nipple on the carb you will be glad you did. and you always need to adjust the idle air needles when you mess with the timing to the highest vacuum or rpm.

i'm rather curious as to the rationale behind this arguement.

the way i see it(and the engineers at ford and holley see it)is that when the throttle plates are closed,there is little need for advanced timing.this is also when the vacuum in the manifold is highest,and the venturi is lowest.

the advance mechanism is operated by the vacuum signal in a way that increases the amount of ignition advance as the vacuum is increased.

so if the vacuum line is hooked to manifold vacuum the advance will be highest when the throttle is closed,and when the throttle is openned the vacuum will decrease as the throttle is openned,retarding the timing as the engine is trying to accellerate.

the venturi vacuum is lowest when the throttle plates are closed,so if the advance is hooked to this port the advance will be at it's minimum at this point.as the throttle is openned the venturi vacuum increases as airflow through the carb increases,sending this signal to the advance mechanism in the distributer,advancing the timing as the engine rpm increases-which is what any engineer will tell you is needed to get the power needed to accellerate the vehicle being powered by the engine.

anyone that doubts that this is how the vacuum signal responds to throttle position can test it by hooking a vacuum guage to the appropriate ports and observe the results.
they can also apply a vacuum to the distributer and observe the effect with a timing light.

it would take more space than i feel like taking up to explain why advancing the timing rather than retarding it is benificial to accellerating the engine.

 

[Mark_88]

If your running your advance on the ported nipple on the carb switch it to manifold and plug the ported nipple on the carb you will be glad you did. and you always need to adjust the idle air needles when you mess with the timing to the highest vacuum or rpm.

all carbs will have one-on the holley it should be on the right hand side behind the float bowl just above the idle mix screw.

Not to heat up the debate, but I tried this yesterday with mixed results. The engine seemed to have more pep at the top end, but would stall every time I had to stop and started making some pinging noises that may be related to this or the mailbox I ran over (just kidding, it was a female box)...

The carb port may be wonky on mine or I may need to adjust the idle or something else...just thought I'd try it...maybe this works better on a complete carb (mine is missing several parts) or on Holley carbs (simpler???)...

I swapped it back to the manifold and it smoothed right out...

 

[gwaii]

Not to heat up the debate, but I tried this yesterday with mixed results. The engine seemed to have more pep at the top end, but would stall every time I had to stop and started making some pinging noises that may be related to this or the mailbox I ran over (just kidding, it was a female box)...

The carb port may be wonky on mine or I may need to adjust the idle or something else...just thought I'd try it...maybe this works better on a complete carb (mine is missing several parts) or on Holley carbs (simpler???)...

I swapped it back to the manifold and it smoothed right out...

check the advance mechanism on the distributer....i had a similar problem,and it turned out the vacuum diaphragm had a small leak.the venturi vacuum isn't as strong as the manifold vacuum so any leak will prevent proper advance.

also,keep in mind that the timing needs to be set with the vacuum line disconnected,so if it was set connected to manifold vacuum it will be way retarded when that is changed to venturi vacuum,which would lead to the symptoms you've described.

 

[The_Dealer]

i moved the disty vacuum to the port on the carb and it ran worse. i adjusted the idle air mixture afterwards and it didnt do anything. i seem to have lost alot of low end torque, although i too did gain a little somethin on the high end up i dont spend any time at the higher rpms, gas mileage got worse. moved it back to the vacuum t and readjusted the idle air mixture and its way better then on the port on the carb

 

[Mark_88]

check the advance mechanism on the distributer....i had a similar problem,and it turned out the vacuum diaphragm had a small leak.the venturi vacuum isn't as strong as the manifold vacuum so any leak will prevent proper advance.

also,keep in mind that the timing needs to be set with the vacuum line disconnected,so if it was set connected to manifold vacuum it will be way retarded when that is changed to venturi vacuum,which would lead to the symptoms you've described.

I did set the timing with the disty dico'd and found it was right on (after scratching my head as to why it was 30* off...then I saw the step to disconnect the dist vac...)

It is the original distributor from the 2.0 that has been rebuilt, but the diaphram has never been checked...the stator works either way so I know there is suction and it is responding...if a small leak is going to make that kind of difference it will have to wait till I'm gainfully employed, win a lottery, or find a rich girlfriend...

And the odds of finding a distributor in the junkyard are way higher than any of the other three options above...

 

[gwaii]

the fact that it was 30* off with the vac connected tells you there's a problem....you've got full advance at idle,when it should be zero.you'd said that the engine died at idle,i'm wondering how it ran while checking the timing with the vac hose disconnected.the thing is,if an engine has been tweaked to run with manifold vacuum hooked to the advance,just changing that line to venturi vac won't help unless everything else is changed back too(idle mix,idle speed,base timing)

another thing to check is the centrifical advance....to do this,put the timing light on,vac disconnected,and increase engine speed.the timing should advance with engine speed,if it doesnt the weights in the dist are siezed(this happens quite often,especially on a vehicle that's sat for a while).

all ford distributers that use a vacuum advance are designed to use venturi vacuum,regardless of what motor they are on or vehicle they are in,so if it's working better on manifold vacuum there's something else wrong that's throwing it off.

as for replacing the vac pot,i've had a bitch of a time finding replacements.i can buy complete distributers,but have found no source for the pot alone.i ended up getting a universal unit from malory that i was able to modify to use on my b2 distributer,but it's no bolt on.

 

[Mark_88]

With the dist vac disconnected, it was running at about 6-8* BTDC...which is recommended for a manual tranny...I didn't check it on higher rpm because I figured it was correct...

I probably should have another go at it because there were some other variables...like the timing mark wasn't exact...meaning the cover was loose and I didn't tighten it at the time...so there was a couple of degree possible play in that alone...

Right now it is running...getting fairly decent gas mileage...and responds fairly well...unfortunately, without a garage and with the current weather situation it may be months before I can actually do anything with it...we may get a warm spell though...so I will consider checking more closely then...

If you're in the neighborhood, it would probably be better to have someone like you do it...most mechanics around here look at me kinda funny when I ask them to have a look at it...either it means they're cha~chinging me all the way to the poor house or they're afraid I might know more than them...lol

 

[gwaii]

chances of me making it over there are pretty slim......i've never been east of alberta in my life.

but once it warms up i'll be happy to walk you through the process.

while there's always been some confusion over vac source for advance,i think it's even worse now as it hasn't been used in 25 years(which also makes finding good stuff at the wreckers near impossible-it's all 25+ years old too)so most mechanics aren't familliar with it unless they're old farts like me.

all this computer gobeldeygook is great for making engines run nice,but there's a certain satisfaction dealing with stuff where you can actually see what's doing what.

 

[The_Dealer]

but on mine the disty is new and i also set the timing with the advance unplugged, so with the ported vac hooked changing the timing would be useless right?

 

[gwaii]

but on mine the disty is new and i also set the timing with the advance unplugged, so with the ported vac hooked changing the timing would be useless right?

that would stand to reason,but something must be up.if you hook up the vac line at idle and pick up a bunch of advance,it's not right.at idle there should be no vacuum advance-that is to come into play as the engine load(detected by the increase in venturi vacuum)and engine speed(taken care of by the advance weights)are increased.

without being there,i can't tell you exactly what's happenning with your engine-but i do know something isn't right.
if you are happy with how it's working,then let it be,i guess.