2300 on a 1978 304 4 speed, hesitation and timing problems!

K

Kyle Dillehay

New member
Hey guys,
so I have read and re-read these threads and my manual many times trying to solve these issues and have had no success, hopefully someone here can help.
I am the original owner of this 78 SSII and it has always been a pretty dependable vehicle, as long as the gold box functioned properly. About 10 years ago I swapped out the Holley dist. And gold box for a points style dist. And a pertronix ignitor. This worked great for several years until I stopped driving it so much, and over the past 5 years or so it started developing the notorious stumble and hesitation issues. It had the Holley 2245 carb on it that I rebuilt last week using all of the proper gaskets and parts, this made no difference with the hesitation issues even though I had 18hgs of vacuum at 8 to 10* timing at 800rpms. After reading so many success stories about the 2300 carb, I installed a new 2300 from IH parts today. The Scout idles well but still has the hesitation and bogs down when going into 3rd.
The timing is all over the place with the engine barely chugging along at 5*btdc, have to advance the timing to around 15 to 20* btdc to keep the engine smooth at idle but still doesn't help when out driving it. The timing actually changes too after I adjust it. The rotor lines up with the #8 cylinder at the proper time, the dist. Vacuum advance holds a vacuum with the mityvac, and when I suck on the vacuum hose I create about 5* of movement. I spoke with pertronixs today to make sure I have the right ignitor. The accelerator pump produces a strong jet of fuel. I removed the erg valve and sealed it up with the plate and gasket from IH parts. Not sure what to do about the other left over vacuum hoses that go to the high and low temp sensors. Unless I can find a major vacuum leak somewhere, I am out of ideas. Any advice or suggestions on what could be effecting my timing and causing power loss and hesitation, from those more knowledgable than I, would be greatly appreciated! Thanks,
kyle
 
Sounds like you could have a loose point cam. The pertronix relies on the gap between the module and the point cam on some models to determine dwell and switching of the coil on and off. If things are wobbling due to and loose distributor shaft the dwell and timing will shift around.
 
How do you check for that? Everything feels solid and secure when I apply hand pressure to the shaft. Is this something that needs to be checked on a machine of some kind? Thanks for the suggestion.
 
You would be able to feel it and see it while loading it back and forth by hand. Pay close attention to the pertronix to cam gap. Which part number pertronix do you have?

I take it the only thing that happened before it started to run bad was sitting? For how long?

Verify fuel pressure while driving and at the point where it likes to hesitate and bog.

Verify a stable voltage on the + post of the coil and where the pertronix gets it's power. Are you running the resistor wire still?
 
Shouldn't have been a resistor wire or aftermarket ceramic ballast resistor present on a '78 with gb system. Had you retained the breaker points when you swapped in the points dizz, you would have also needed to supply additional resistance to preserve the points and coil. But, since you went immediately to a pertronics module in lieu of the points, no additional resistance is required, provided the coil has approximately 1.5 ohms across the pos/neg terminals. Since you report those components functioned well for several years, it is probably safe to assume there was proper agreement between the coil and the module during that time frame.
I'm with Robert in thinking there must be some wear induced slop somewhere within the distributor to make the timing jump around as you've described.
 
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