Ignition/detonation help please
#17
Ok so I got a new remaned distributor today. As I mentioned before its a 73 f250 points 390 application distributor. I opened it up right away to see what I got. This bottom weights are different than my other distributor in motor. the slots are not like this in my other one.
I dont see any marks for the weight #'s ?
Do you guys think I should just swap over my petronix lll and run this setup? Think it will be an improvement or should i get it recurved at a shop for my setup??
The motor is in the truck in my avatar. 44" tires, 5:13 gears, 6200lbs give or take.
The springs in the new distributor are one light one heavier. Also when i suck on the vacuum advance before taking it apart i had to suck really hard but it did advance eventually..
I dont see any marks for the weight #'s ?
Do you guys think I should just swap over my petronix lll and run this setup? Think it will be an improvement or should i get it recurved at a shop for my setup??
The motor is in the truck in my avatar. 44" tires, 5:13 gears, 6200lbs give or take.
The springs in the new distributor are one light one heavier. Also when i suck on the vacuum advance before taking it apart i had to suck really hard but it did advance eventually..
#19
#21
So put a heavy spring on one side and you will be fixed. Then you can hook up the vacuum advance (the the ported vacuum nipple on the carb, please) and get a little better MPG with it.
#22
Yeah I just did that. I had a spring kit kicking around. I went from the one flimsy spring to a medium and the tension now acts like the new reman.
One thing I notice is when I hold bottom gear and spin shaft I get a little more advance turn out of my old distributor than the new one. I'm thinking I limit mine just a tad and I'll save the $100??
One thing I notice is when I hold bottom gear and spin shaft I get a little more advance turn out of my old distributor than the new one. I'm thinking I limit mine just a tad and I'll save the $100??
#23
#24
Full mechanical advance has NOTHING to do with vacuum. The vacuum advance is a mileage improver and when you stomp the throttle it has no effect until you lift. If you have a light truck with at least a 3.91 rearend, then yeah, 38° at 3500 will work, but a heavy truck or with 3.50 gears is gonna need about 4000 to prevent pinging on the street. My '84 F250 Supercab/Superduty with a 460, C6 and 4.11 rear will not tolerate 38° at 3500 so I backed it off to 36° and it is happy. My old 1969 Torino Cobra with a 428CJ, C6 and 4.30 gears loved 38° at 2500 and would tolerate 44° in 1st and 2nd gear but had to be backed off to 38° for high gear. Did this using a neat trick with a dual point dist. and a switch on the shifter.
#26
Holy crap Bear significantly better! I took off the plastic boot limiter and wrapped it with some electrical tape to limit more. I put distributor back in and it had a minor hiccup when turning over. I retarded it a tiny till it turned over smooth and went for a drive. The roads are wet but it had a crisp clean snap off the line and I spun both 44's down the street!
I hit 3rd and pinging went to a very minimal. There was still some when on a slow coast and throttled hard in 3rd.
It had a bit of a high idle and when I shut it off it had a slight cough with some run on.
Now I can turn idle down to make that a littlebetter but it's almost there.
Should I advance or retard distributor now or is it limit more advance.
Thanks for help again it's almost perfect!
It even sounds nicer
I hit 3rd and pinging went to a very minimal. There was still some when on a slow coast and throttled hard in 3rd.
It had a bit of a high idle and when I shut it off it had a slight cough with some run on.
Now I can turn idle down to make that a littlebetter but it's almost there.
Should I advance or retard distributor now or is it limit more advance.
Thanks for help again it's almost perfect!
It even sounds nicer
#27
#28
#29
So I got a chance to go for a drive tonite on dry streets without spinning it like last nite.
Wow I think I gained at least 50 HP! The truck explodes off the line getting squirly in 2. I retarded the initial timing just a tad and the detonation is 95% gone. My only concern now is it still had some engine run on after I shut her off after the hard pulls.
Any other suggestions on this?
The motor sounds awesome though as it explodes off the line I'm pretty impressed!
Wow I think I gained at least 50 HP! The truck explodes off the line getting squirly in 2. I retarded the initial timing just a tad and the detonation is 95% gone. My only concern now is it still had some engine run on after I shut her off after the hard pulls.
Any other suggestions on this?
The motor sounds awesome though as it explodes off the line I'm pretty impressed!
#30
detonation
Without knowing the total specs of the engine; compression, heads and porting, intake, carb, exhaust; the cam specs are a waste of timing for dist. setup.
tater_51, the dist advance curve belong in a Mustang and not a truck unless you are running a minimum of 4.10 gears. Otherwise it is gonna ping the hell out of the motor.
tater_51, the dist advance curve belong in a Mustang and not a truck unless you are running a minimum of 4.10 gears. Otherwise it is gonna ping the hell out of the motor.