Same here, I typically run the regular grade fuel but we got that stupid ethanol blend around here, once I move I can get 93 octane in straight gas which I will go with. But here I can get 87 Octane regular, 89 Octane premium, or 93 Octane super. Ive been putting 87 octane regular in here cause of the low compression and that's what I run in my 302 in my '82 truck that has the same compression ratio along with in my 351W in my '78 Mercury. But this is acting a bit different which could be due to points and the lack of mechanical advance.The ignition system I replaced it completely about 3 or 4 years ago but I haven't drove the car just ran it from time to time while I did other work on the car. The plugs, plug wires, point, condenser, cap, rotor are all new basically with limited use. The dist how ever is original to the car and from all the service records I have in my grandfathers notebook that was in the ash tray there is no mention of replacing the dist as far back as 1963 so I assume this is original from 1956 and has never been pulled.
Timing is bumped up to 12* initial which at idle in neutral it is 16* with the vacuum lines attached. I saw the timing go retard when I hit the throttle fairly hard from an idle when I was checking the dist operation.
I haven't pulled the plugs to read them but the whole ignition system was replaced minus the dist about 4 years ago. But mind you the car hasn't been driven in those 4 years just idling and a few revs here and there just to maintain the battery as I worked on other aspects of the car.
Im wondering if its just bad weak gas that is truly not 87 octane or if its carbon buildup or if its something else. I did turn my idle mixture screws out half a turn at a time and the knocking dieseling feel got better. at 1 turn out from where it was on both screws the engine now doesn't stumble but I can hear a knock for a moment on the initial hit of the throttle. but loading the engine up its running a little rough but no sound of a knock like it does when you first hit the throttle with the brake applied.
Correct, stock as in the engine has never been apart as far as I know. Only work that's been done on it was pulling the intake to put a newer 2V intake and late model 2V carb on it which I pulled off and reinstalled the original 4V intake that came off the carb and a reman holley 4000 along with a NOS dual reservoir vacuum advance.
Im kind of wondering if it was carbon build up I don't think its advance because the engine spins over too easily with the starter to be too far advanced. I currently have timing set at 12* initial which is 16* at full idle with the venturi and manifold vacuum lines attached. Reving the engine I saw it advance smoothly with a rev and when I hit it quite hard to nearly full throttle I saw the TDC mark quickly fall back behind the pointer for a split moment before it went back to around 30* advance at around 2,000 rpm I guestimate.
That is what I am concerned with is if it might be my old dist. I did turn my idle mixture screws out half a turn equally and putting car in drive and stepping on the gas it got better, wasn't shaking as bad and wasn't dieseling as bad. Went another half turn out on both screws and its gotten better it actually tries to pull. I can feel transmission slipping in second gear so that is probably my problem on the transmission falling out of gear, a band that is worn out, needs adjustment, or a leaky servo not applying enough line pressure. But the car pulls now and doesn't shake dieseling but it is still knocking for a split moment when I first hit the throttle. if I load the engine up like checking for a miss it doesn't knock it just knocks on the initial hit of the throttle.
I thought about going another half turn out on the idle screws but I don't know how far out they are now and don't want to have them fall out. Like wise I don't know if another half turn out will remove the initial knock that is there. I did get the stumble out and the roughness out. Guess I had the carb set ideally and not slightly rich like is wanted so with the air filter on it made a change. I know I put my hand over the choke housing to check for a lean condition when I initially set the carb idle mixture and it didn't race up like it was running lean it stayed idled the same with no change indicating an ideal mixture.
I guess what I will need to do is look at getting this dist rebuilt and then go from there. I got just under 3/4 of a tank not sure how quickly I can burn that out to get some 93 octane in there to see if that is the cause that I have now.
1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi