ford 390 engine help

[tgbulger2]

okay guys. this is my first time posting something on here. i have gotten a lot of good help from the forums on here. i have a 1972 ford f250 ranger xlt camper special with a 390 and c6 auto trans. it was running great but real rough. especially in gear. then all of a sudden it started this chirping hick up while the truck is in gear and will not let me give it any gas what so ever. it will die if i do. i took the stock replacement 2 barrel off and put a holley 500 cfm 2 barrel on. runs great until you put it into gear. starts the chirping hick up again and idles really rough. i was thinking ignition timing might be off. i installed the distributor with no. 1 atdc and advancement is a little tough to figure out due to all markings on the balancer are gone. motor also sat for 16 years. it is also running a pertronix electronic ignition. idles great in park until you give it some gas and then back fires thru carb and shuts the choke on the holley 2 barrel. any help would be much appreciated. and thanks a million in advance to everyone.

[BobbyFord]

Sounds like the timing is late, advance it.

[tgbulger2]

just redid the whole timing. it is now set at 10 to 12 btdc. runs okay now but the holley caarb i put on is bad and it wont run for very long. going to try putting the original carb back on. will see how it runs and then see what it does in gear if all goes well with the stock carb.

[ToughOldFord]

Usually that's bad timing or a very bad vacuum leak.

[Thunderfoot]

I agree with the guys.
Check your vacuum advance on the distributor, it could have died and is leaking vacuum = bad timing and vacuum leak for the carb.

[F10YRB12118]

Gentlemen,

I have a simular problem as tgbulger2 does and was following the advice that you all offered him, but with no luck. I was wondering you could offer some help my way too.

BTW this is my first time working on anything below the intake manifold! I'm a newbie!

I have my 360, w/2bbl OE carb (This is the one I want to rebuild into a 390). Had a bad head gasket leak on No. 4 along with an exhaust leak too. Truck ran ok with leaks except for sounding like crap and sluggish power. Pulled carb, distro, intake, on pass, side head and exhaust. after pulling intake I found the lifter and small wire retaining clip from No. 4 sitting in the slug atop of the block! I pt them back.

Man! the intake is darn heavy!

Replaced everything with new gaskets & etc. New plugs, rotor, points, condenser & cap. Didn't disturb the engine.

Now when I start the engine it runs real fast & rough. It will only run at about 15-20 BTDC any closer to 10 and she just dies.

This engine just bucks and runs rough. It sounds like it is missing or firing order is not right. I've checked firing order 3 times. I've put No.1 at TDC, put a screw driver down the spark plug hole to feel that the piston is all the way up, checked the Distro to be sure rotor is under No.1 spark tower. I've set gap on points.

Everything seems to be right according to my Chiltons, but she just won't run right.

Any suggestions?

[convincor]

my 72 got like that. Ditch the points(if you still have them) for a Pertronix.

[ToughOldFord]

What the heck is your breather system hooked into your heater lines for?

[F10YRB12118]

What? No wonder all that coolant is in my motor?!

No, really, the breather is not hooked up to the heater lines.

It just looks like it.

The breather line is just hanging down right on top of the heater line. You can just barely make it it out that there are two hoses there. It was that way when I bought it and the photo was taken on the day I bought the beast.

So, you think I should just ditch the points and go with Pertronix. I sure do want to get a Petronix or MSD system. I really like what I've read about the Mallory HyFire system too, but it seems a little pricey.

What do you think of the Pertronix Ignitor system (PNX-1281 in the Summit Catalog)?

Based or your suggestion, it sounds more like I have a points problem. I'll have to go over them and set the gap again. Hopefully that'll fix it.

Thank you friends for all your help.

[tgbulger2]

F10YRB12118
go with the pertronix. great system. i have been running it on my truck for quite sometime and very easy to install. just make sure to follow the instructions to the dot and everything will work out great for you.

also i think you guys might be right about the vacuum advance. the distributor sat for 16 years too. going to get a new rebuilt distributor from the autoparts store. reason is the vacuum advance is thirty bucks and the distributor is thirty three bucks. might as well get the new distributor for the differ. in money. thanks for all the help. best repair trouble shooting ever....

[F10YRB12118]

tgbulger2


Thanks for the advice, I'm drooling all over my my Summit catalog as I write. The Pertronix looks good for $75.95.

In addition to the points issue, I' was thinking vacuum advance too, so I swapped it with another. I also thinking I need to check the seal of my Intake manifold. I might not have gotten a good seal when I bolted it down. Do any of you think that would account for my problems?

[Thunderfoot]

tgbulger2


Thanks for the advice, I'm drooling all over my my Summit catalog as I write. The Pertronix looks good for $75.95.

In addition to the points issue, I' was thinking vacuum advance too, so I swapped it with another. I also thinking I need to check the seal of my Intake manifold. I might not have gotten a good seal when I bolted it down. Do any of you think that would account for my problems?

Does sound like a possibility to me... Take and spray WD-40 around all the sealing / mating surfaces for the intake and the carb when it is running, and you will be able to tell if you find a leak.

[F10YRB12118]

Convincor

Thank you for the suggestion of Mustangs Unlimited. great site and much better price than Summit. I'll save the site to my favorites.

Thunderfoot,

Thank you more the suggestion on the WD-40. I read that somewhere before, but forgot about tell you mentioned it. I'll get on it tomorrow and see if my problem is indeed vacuum.

Thank you all again.

[willowbilly3]

I have a petronix and highly reccomend that upgrade but it won't cure the drivability problem and I would get that straightened out before I started swapping parts.
First off if you are going to do your own tuning you need to go buy a vacuum pump/guage. Hook it to manifold vacuum and see what the reading is, note any needly movement. Then get the specs for your distributor and hook the vacuum pump up and check it. Bring that information back and some sort of intelligent diagnostics can begin, not just guessing and throwing parts at it. That is a last resort.

Basics:
Vacuum reading should be above 17 for a healthy engine. Incorrect timeing may make it low or internal wear also. If the needly is dipping you probably have a carb problem and if it is vibrating you have a valve problem.
I like to use a legnth of vaccum hose and listen through one end while I move the other end around the carb base or any area suspected of a vacuum leak. You can pinpoint the problem very quickly without flammable aerosols.

[71PA_Highboy]

Vacuum Modulator/hose on the the C6....

Vacuum tree on the the intake, brake booster.

When looking for a vacuum leak make sure you check the hoses VERY carefully. Also pull the booster hose (if so equipped) to ensure the booster isn't creating a leak you may not be able to see or hear because of engine noise.

Also, WD40 doesn't work as well as it used to... they stopped using a flamable propellent. I like to take a MAPP gas nozzle (the one for oxy-Mapp) and use it... you can really pinpoint the leak (if it exists) and not have the spray mess of carb cleaner.

hth,

eric