i'm new here and would appreciate ALL help. here goes...just bought 1985 F150 302/5.0L AOT with EEC IV feedback 2bbl. no smog test here so someone's removed smog pump, cat, and PCM. Still, seems to run very well, good compression, all plugs burn right, starts good etc, BUT seems like timing is always leading or lagging slightly except at idle. I've reset timing go 10BTDC. The distributor has the ICM on it and everything is original with carb.
Questions: what distrib / coil set up would work with vacume advance? Centrifical advance? Would the PCV input to the carb work to advance the vacumme advance if I put a T fitting in it?
thanks and sorry this is so long.
Jan2

 

I'm not sure what you're asking, but it looks like you're looking for a new ignition setup. If that's the case, I would highly recommend going with MSD. First, they make a distributor with a vacuum advance either a drop in and connect to your system or one that works with their MSD ignition box. You can adjust the centrifugal advance, total advance, and how fast your total advance comes in. But, I would also recommend replacing your ignition box with an MSD 6A or above (depending on what you are trying to do with your truck). The MSD is capacitive discharge ignition that will send multiple sparks to the plugs at idle over a fairly long duration. It gives you quicker starts and less misfires at the higher rpms. You will need to also change your coil to a high cap coil such as the MSD Blaster. Then top it off with MSD 8.5 plug wires. The distributors are expensive, but the workmanship is 10 times better than the stock Motorcraft distributor and gives you more adjustability. As far as running a T off your PCV intake: it is my understanding that the PCV port is to recirculate an unspent crankcase gases back to the base of the carb to get burned in a second cycle of ignition, so you probably don't want to use the PCV circuit. I would suggest coming off a timed port on your carb. The timed port usually will not open until 900-1000 rpm and will give you true idle timing. If you take the vacuum off a full time port, you will see your idle advance increase to 20 degrees BTDC with the vacuum hooked up. That makes the truck idle a little rougher and a little harder to start.

'82 F150 2WD w/351W (orig 300 I6)
Slik

 

i think you should go with the dui from davis ignition or the above mentioned setup.

 

Thanks TONS! I will most likely do as you suggest. Will I need to replace my carb with a 'non-feedback' carb? This carb has many vacumme lines on it, but none of them appear to be timed to the function of the carb since the distrib didn't need a 'timed' vacumme source. If I replace the carb what one would you suggest please?

Also, today, in total frustration, I disconnect the PIP lead at the distributor AND THE PCM under the dash.....I reversed the cover on the carb breather AND THE TRUCK RUNS MUCH MUCH BETTER....NO STALLING, SPUTTERING...but I think my gas mileage prob went into the pot....still needs the new dist and carb I think...right?..
THX,
JAN2

 

Thanks very much for your interest and reply..
Jan2

 

i would use the dui set up from davis it is a gm hei style cap but its one wire hook up is just to clean and cant be beat for performance, also i would just slap on a 83 or older carb and remove the egr spacer from between the carb and intake, amazing how many wires you can cut and that carbed eec iv still runs tho, makes you wonder just what all those wires do when you cut them and it still runs exactly the same what a waste of wire

 

I checked on the DUI Ford web page and it looks like something I could handle....will it work (somewhat less efficient of course) if the vacumme advance isn't hooked up because thats the way I may have to use it for awhile until I change the carb...
jan2

 

Most distributors will work with a timed or non-timed port. If you can use a timed port off the carb then your idle and startup is a little easier. You can study the vacuum feedback circuits and eliminate those circuits that you can get by without. The carb itself doesn't care. You've just got different smog type switches and pots working off the carb vacuum with the exception of the PCV hose that dumps crankcase gases back into the carb for reburning. The carb is your vacuum source, not the recipient of feedback from other sources. Just eliminate the stuff you don't want and cap the vacuum source. If you want a new carb, get a 4 bbl Edelbrock intake and slap an Edelbrock 600-650 cfm carb with an electric choke. It's a fairly simple swap and the Edelbrocks do not require hardly any setup. Just put them on and go. the trickiest part is to get the Ford linkage adapter and get your linkage to work with the carb.

Good luck,

'82 F150 2WD w/351W (orig 300 I6)
Slik