hello i just bought a truck and haven a few puzzlers the guy said its the carb needing rebuilding but idk, its lopes extremly hard at idle barly idles, then when ur giveing it gas it sputters and backfies, pops but if u open it full throtle it clears up and purs for a sec then goes back to same thing. i thought maybe it was in the timeing so i was going to adjust it but found out i couldnt i loosein the dist. but u cant budge it at all vise grips wont even turn it is this normal? any suggestings? Thanks!

 

The obvious question .....is the lock-down bolt & keeper completely free? If so try some good penetrant like PB Blaster or Deep Creep around the base and let it soak several hours, then tap it lightly at the base with small ballpeen hammer (carefully!). It should turn unless badly rusted or somehow jammed in. Are the plug wires good?...properly installed?

Lots of issues can cause the symptoms you describe including points, distributor plate shorting, distributor cap arcing, plug wires, carb, timing, coil etc.

Good luck, check all of the above & let us know.

 

okay thanks and yes i took the hold down all the way off, im puting new cap and wires on it later, i jus replaced the points and plugs, i guess its the carb the guy told me it ran perfect intell this and said it was the carb, i just didnt know if a carb could cause problems like that or not. i also have a carb rebuild kit but have no clue on rebuilding it lol

 

The carb rebuild kit should come with instructions. Follow'em and you should be fine. It's a 2bbl Autolite, right? Them are super easy... even a caveman can do it.

Here are some tips:
1. Get a gallon of carb cleaner. I use Chem-Tool.
2. Wear rubber gloves and safety glasses... Carb cleaner is mildy caustic.. makes me itch and the smell doesn't go away easily although I like how it makes my garage smell... real manly!!
3. Set up a work table with good lighting.
4. Stay organized.
5. Take lots of digital pictures so you know how things are supposed to be oriented or reassembled.
5. Be patient.
6. Some consumables - paper towels, old toothbrushes, rags, and maybe a can of compressed air.
7. Have fun with it!!

 

I think it's had to much unleaded gas put through it and has now burned the exh. valve seats. I'd first do a compression test and make sure what you're dealing with first before doing a bunch of work lost time that's not going to fix it..Like when you go to a doctor they check your blood psi and temp first thing they do. This is the first think any mechanic does doing a tuneup..my 2cent
orich

 

thx for the info i got the dist shaft loose and retarded the timeing a bit, now it purs like a kitten till i went to swap the alternator from the one on my 71 when done now the truck wont even turn over the solenod clicks and give power to starter but doesnt try to turnover i dont know what would cause this, im going to try pullstarting it today to c if its really the starter or somthin else any ideas?

 

Check your ground, terminals and cables first.

 

ive checked them all the solenod was clicking really fast then i found the ground was a little loose so i tightend it up now the solenod clicks once and makes a roaring sound till u let off the key

 

Sounds like your starter is turning over but not engaging.

 

I've talked quite a bit with orich seems to have a good head with Ford stuff - i've got this ongoing issue with popping and backfiring.Edelbrock Performer aluminum manifold,rebuilt Motorcraft 600,headers,MSD disto & 6A box,Taylor wires,2 different sets of new plugs Autolite Platinums and now NGK with some crap called " v " where they've cut a v shaped groove in the center conductor of the plug what this is suppossed to do only the Japs have got a clue.New gas tank fresh 89 gas,all new lines - completely new all the way to the fuel pump which is also new and to the carb- Starts right up and once its warmed up idles great no muss no fuss sometimes when you blip the throttle a little you'll get a little fart right at first but clears out - thru the exhaust - seems to run good up until about 1/3 to 1/2 throttle and if you hold it there all kinds of backfiring popping out the exhaust.In retiming with the new disto i tried to determine in holding the body of the disto without the cap with the attachment points for clips for the cap as parallel as possible with the front of the truck turning the shaft until it pointed to where # 1 would be on the cap marking that point on the valve cover and trying to get the disto dropped down with the rotor pointed in that direction - the disto will actually do 1 of 3 things - it won't engage at all,or in turning the shaft a little bit at a time it will drop down - but not all the way so i'm assuming its not engaging the oil pump shaft,or it drops all the way down in its happy home - looking at it and then using a screwdriver as a straight line with the cap on i drew an imaginary line thru the rotor thru # 1 plug wire to the valve cover and it was a little advanced from my original mark in thinking this was probably more accurate i tired to get the disto down with the rotor pointing exactly the second mark - could'nt do it the disto would engage the drive gear but not seat any further the closest i could get it was where the first mark was.In using a timing light if i time it @ 8 btdc it backfires out the carb - and not idle well if i advance to i'd say 10-12 degrees it smooths out real well idles great but then its got this crap going on at 1/3 - 1/2 throttle i've fiddled with the disto alot trying to feel individual teeth and you can't really and it only seems to engage completely in a few spots - Any ideas? id turned the engine over by hand and set the disto first @ 8b on the damper and then today retimed and set the engine at TDC for # 1 and yes i took the valve cover off to verify i was on # 1 both valves completely closed.Compression as of a couple of weeks ago was 145 in 5, 140 in 2,and 135 in the last 1 not bad for a 42 year old truck! So has anyone got any suggestions i'm all ears - and i've also thought of the timing chain numerous times but before i get into that i want to be sure.

 

Popping thru the carb could be caused by a lean miss, a burnt exhaust valve or possibly incorrect timing. An easy way to check the timing chain is to pull the cap off the dizzy and turn the engine over by hand. Turn the engine over in the other direction and keep an eye on the rotor. If the engine turns over but the rotor takes awhile to move you could have too much play in your chain. Stock gears had nylon or plastic teeth and there is a good chance they are all gone. However that may not be your only problem. You may also be starving for fuel. If you run with the choke partially closed and your backfire goes away then it is probably a lean miss. Good luck!

 

Hmm gee here, I though you were at last a happy camper with a fe.. While using a high energy out put ign box & coils use a non dielectric lube grease should always be used to help stop spark jump. The ring groves in the upper part of a spark plug is suppose to do this. But with added voltage they some times leak an arc and ground to the plug base. Adding some lube in the plug boots helps stop this. Put some in both boot ends and pinch the boot together with your fingers to get it around the insides evenly before pushing on. Also aids for installing or removing them when needed with out breaking the boot off. Well I'd say your having a timing problem. While having the motor running at about 600 - 550 rpm vacuum line off and plugged so it won't suck any air in. Now if your watching the timing marks on the damper pulley and they seem to float around as it's idling you may have to much slack in the timing chain or a bad distributor or bushing. A slipped damper timing ring since it won't time right. Try not having your vacuum- advance line hooked up but plugged on carb end so not to suck air and see how it runs.
A vacuum gauge hooked up do aid in figuring out some problems also for late timing leaking valves, carb adjusting. Yep old school stuff still applies for some hard to figure out problems. This truck had this problem so you not have fixed that yet. The msd dists may have to high of advance curve for your timing to run smooth at higher rpms.. You'll need to try to fine tune what you've done so far... It's like always double check what your doing until you find the problem. we can only throw ideas at you and for you to check what's been all said here.. good luck and don't give up until she's huming the way you want it. orich

 

Its not thru the carb thats only until i retime it and get it advanced to about 12 degrees then it idles and runs fairly good until 1/3 - 1/2 throttle and in holding it there it starts backfiring and popping out the exhaust.It did have the choke partially closed still did it a friend suggested to open it all the way as he'd had a similar issue - still does it.. No in turning it over it seems to move right along but its one more thing to look into thanks -

 

also compression is like i said 145 in 5,140 in 2,135 in 1 - not exactly an indicator of a bad valve i know i'd thought of that one too

 

Yeah orich its been a headache - the msd is all mechanical no vacuum i installed it straight outa the box and it is tunable in regards to advance different springs and weights and such but i'm having enough trouble as it is without headin' off in a new direction i know nothing about - one other has talked along those lines and seems to be pretty knowledgeable with msd's also with wiring the ignition box so i'm going to try some of his suggestions and just take it one step - no i won't give up on it thats not the way we work on this stuff right?