Poor Performance

[goodnigh]

Mike, on your Ultra 770 the full manifold fitting is on the front, near the base, right next to the PCV fitting.

btw, you did pull/plug the hoses when you put the light on you engine and were moving the dizzy, correct?

The primary vacuum port on my distributor is connected to what

Holley calls "Timed Spark Vacuum Source". It is on the choke side

of the carb just above the PCV port. The other port on the

distributor is connect to the intake manifold by way of a thermal

switch on the water pump. No need to plug the hoses at idle, no

vacuum to dizzy. I Should plug the manifold vacuum port as it serves

no purpose unless the engine over heats, which is unlikely. Even then,

it causes engine RPM to rise to about 1200 at idle until it cools down.

mike

 

[72HCODE]

For now just disconnect all vacuum accessories to weed out the erratic problems.

This includes the brake booster if you have one. Lets assume for a second you have a vacuum leak this would elimate the accessories from the cause and this includes the vaccum advance.

There are 2 check valves In the vaccum system that could be blown or defective causing problems also. But the idea is get the engine working consistently then add function back till the problem returns.

A messed up mechanical advance can cause erratic timing as well, and you want to make sure that is not a problem. Also throw the 8mm wires in the trash and get ford oem carbon filament wires for the engine, those after market wires cause all kinds of delayed spark and erratic timing issues by themselves.

 

[wwhite72]

vac hose diagrams for all 7173 mustangs, including 250ci engines, CA cars, A/C cars, 2v's, 4v's...it's actually kind confusing trying to figure which diagram is correct for your car. you find one that looks right and then think "wait do i have this one, or is it this one? and what was it when i GOT the car? ha ha : http://www.autozone.com/autozone/repairguides/VACUUM-DIAGRAMS/VACUUM-DIAGRAMS/_/P-0900c1528027a09c

 

[goodnigh]

For now just disconnect all vacuum accessories to weed out the erratic problems.

This includes the brake booster if you have one. Lets assume for a second you have a vacuum leak this would elimate the accessories from the cause and this includes the vaccum advance.

There are 2 check valves In the vaccum system that could be blown or defective causing problems also. But the idea is get the engine working consistently then add function back till the problem returns.

A messed up mechanical advance can cause erratic timing as well, and you want to make sure that is not a problem. Also throw the 8mm wires in the trash and get ford oem carbon filament wires for the engine, those after market wires cause all kinds of delayed spark and erratic timing issues by themselves.

Can get oem wire set from NPD, but I need a spool (30 feet). We

need to cut our own wire preferably 8mm because of the way it is

routed. The timing marks are not always steady under the light.

The marks will move around which I think indicates a worn distributor.

mike

This is a great thread, imformative.

 

[wwhite72]

For now just disconnect all vacuum accessories to weed out the erratic problems.

This includes the brake booster if you have one. Lets assume for a second you have a vacuum leak this would elimate the accessories from the cause and this includes the vaccum advance.

There are 2 check valves In the vaccum system that could be blown or defective causing problems also. But the idea is get the engine working consistently then add function back till the problem returns.

A messed up mechanical advance can cause erratic timing as well, and you want to make sure that is not a problem. Also throw the 8mm wires in the trash and get ford oem carbon filament wires for the engine, those after market wires cause all kinds of delayed spark and erratic timing issues by themselves.

Q- I have MSD 8.5mm super conductor wires. I run the 6AL box with magnetic pickup distributor...are you not a fan of these wires, or just not good for lower output ignitions?

 

[goodnigh]

Q- I have MSD 8.5mm super conductor wires. I run the 6AL box with magnetic pickup distributor...are you not a fan of these wires, or just not good for lower output ignitions?

That brings up another interesting issue. The dizzy I ordered is

stock Cleveland rebuild w/points. Is my 40,000 volt coil going

to be too much for the points?

mike

 

[Don C]

I believe this was what I got for mine, there was plenty or wire for various routing, and it came with two different distributor boots and terminals:

http://www.summitracing.com/parts/sum-g826/overview/

 

[wwhite72]

Q- I have MSD 8.5mm super conductor wires. I run the 6AL box with magnetic pickup distributor...are you not a fan of these wires, or just not good for lower output ignitions?

That brings up another interesting issue. The dizzy I ordered is

stock Cleveland rebuild w/points. Is my 40,000 volt coil going

to be too much for the points?

mike

depends on your coil's resistance. http://www.pertronix.com/prod/ig/flame/coils/chart.aspx you need a 1.5ohm coil for points