Timing or Carb.? 1968 360

Engine, ignition, fuel, cooling, exhaust

Moderators: Ranchero50, DuckRyder

Post Reply
Adach47
New Member
New Member
Posts: 3
Joined: Tue Oct 31, 2017 12:23 pm

Timing or Carb.? 1968 360

Post by Adach47 »

I am new to the antique truck world. Recently purchased a 1968 F100 with a 360. Everything ran well then it didn't. Looking for any help diagnosing what is going on. I was driving the truck and it was running smoothly then it started to backfire(through carb) and miss. I limped it home, about 5 miles, and it had periods of running normally - maybe 1/4 mile at a time. Got it home and have done the following and it has not improved anything:

1. replaced plugs and wires
2. replaced distributor cap, rotor and coil
3. replaced vacuum line
4. replaced seals in accelerator pump (was leaking just a bit)

I have not replaced vacuum diaphragm or points yet. I am baffled to what could be the problem. Currently, difficult to start and seems like it is missing badly. Any thoughts out there?
JHof44
New Member
New Member
Posts: 31
Joined: Mon Dec 19, 2016 1:36 pm
Location: Vista, CA

Re: Timing or Carb.? 1968 360

Post by JHof44 »

Have you pulled the carb and checked the base and spacer gasket? Mine was torn and causing me to lose vacuum.
1967 Ford F100 Custom Cab longbed
User avatar
sargentrs
100% FORDified!
100% FORDified!
Posts: 9866
Joined: Fri Jun 22, 2007 9:30 am
Location: Georgia, Jasper

Re: Timing or Carb.? 1968 360

Post by sargentrs »

:yt: is where I'd start. Go to your local parts store and get a spray can of carb cleaner/starting fluid (50% ether). Get it running and spray around the base of the carb/spacer, the intake manifold, brake booster if you have one. If it chokes down or revs up when you spray an area, that's the source of your vacuum leak. If it happens to be around the accelerator pump cover, that's a common problem. Over time the cover gets warped and won't seal. Take a piece of 120G sandpaper and tape it to a hard flat surface or wrap it around a 2x4. Remove the acelerator pump cover and place the gasket surface on the sandpaper. Stroke the cover back and forth smoothly and gently across the sandpaper. You'll immediately see the high spots getting shiny. Keep at it till you have a good, flat sealing edge all around the cover then reinstall with a good gasket. Just snug the screws, don't torque them down too tight. Since you still have points, try replacing the condenser and resetting your points. Condensers these days are pretty poor quality.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
cep62
100% FORDified!
100% FORDified!
Posts: 2034
Joined: Sun Oct 26, 2008 8:06 pm
Location: West Michigan

Re: Timing or Carb.? 1968 360

Post by cep62 »

Maybe the resistor wire from ign switch to the coil??
Try hooking a temporary wire to the coil POS , but beware it'll start in gear and you'll have to remove the jumper to stop it.
That bypasses the ign switch.
User avatar
farmallmta
New Member
New Member
Posts: 143
Joined: Sat Nov 16, 2013 2:00 pm

Re: Timing or Carb.? 1968 360

Post by farmallmta »

sargentrs wrote: Since you still have points, try replacing the condenser and resetting your points. Condensers these days are pretty poor quality.
:yt: Motorcraft points and condensers is what you want. Don't buy the cheap chinese crap at autozone, advance, or o'reilly!

Points: https://www.summitracing.com/parts/mof- ... lications/
Condenser: https://www.summitracing.com/parts/mof- ... lications/
Adach47
New Member
New Member
Posts: 3
Joined: Tue Oct 31, 2017 12:23 pm

Re: Timing or Carb.? 1968 360

Post by Adach47 »

Thank you for the tips. Will try these and report my results soon.
User avatar
Manny
Blue Oval Guru
Blue Oval Guru
Posts: 1190
Joined: Wed Oct 04, 2006 7:15 pm
Location: Georgia, Lake City
Contact:

Re: Timing or Carb.? 1968 360

Post by Manny »

You got the right stuff going for you here welcome to the page. Two things have already been mentioned on my list, that is cause we got some sharp tacks around here on the old iron. Whats the points dwell and timing look like. Replace the points or maybe upgrade to petronix system (Mixed success for me here love hate). Second is the vacuum leak by you a cheap gauge and check the vacuum at idle see what you go. Fluid or a propane torch Not lit just the gas flowing will make her sweeten up when you find the leak. Don't forget possible brake booster as well leaking if power brakes. One thing maybe is if the engine is very original like bone stock it could have a nylon timing chain gear and is chipped jumped a tooth. That would be a last resort thing retarding the cam timing causing bad issues. Keep us posted and welcome one again. :fr:
Just another Ford fool named Dan.
The Junk that hangs around
67' F-250 highboy Camper special cross breed currently under way
http://www.fordification.com/forum/view ... 22&t=86706
1974 Bronco 302 3 speed
1984 bronco 302 c6 35's
1994 F350 7.3 5spd dually.
woods wrote: The rust holes in my truck were a factory install (very rare).
Adach47
New Member
New Member
Posts: 3
Joined: Tue Oct 31, 2017 12:23 pm

Re: Timing or Carb.? 1968 360

Post by Adach47 »

I tightened the screws on the accelerator pump. Presto!! Started right up and runs smoothly again. It always seems that is the simplest thing that is the problem. Thank you for all the tips.
User avatar
Manny
Blue Oval Guru
Blue Oval Guru
Posts: 1190
Joined: Wed Oct 04, 2006 7:15 pm
Location: Georgia, Lake City
Contact:

Re: Timing or Carb.? 1968 360

Post by Manny »

Adach47 wrote:I tightened the screws on the accelerator pump. Presto!! Started right up and runs smoothly again. It always seems that is the simplest thing that is the problem. Thank you for all the tips.
Save the tips for the next time. Sadly there will be a next time...... :lol:
Just another Ford fool named Dan.
The Junk that hangs around
67' F-250 highboy Camper special cross breed currently under way
http://www.fordification.com/forum/view ... 22&t=86706
1974 Bronco 302 3 speed
1984 bronco 302 c6 35's
1994 F350 7.3 5spd dually.
woods wrote: The rust holes in my truck were a factory install (very rare).
User avatar
bluef250
Blue Oval Fanatic
Blue Oval Fanatic
Posts: 924
Joined: Fri Oct 29, 2004 8:49 pm
Location: Arizona

Re: Timing or Carb.? 1968 360

Post by bluef250 »

Most likely timing, beside previous suggestions, check the play (side to side) on the distributor shaft.
billdoggy734
New Member
New Member
Posts: 5
Joined: Wed Nov 16, 2016 11:45 am

Re: Timing or Carb.? 1968 360

Post by billdoggy734 »

bluef250 wrote:Most likely timing, beside previous suggestions, check the play (side to side) on the distributor shaft.
I was kind of curious about this. I assume little or no play is acceptable on the distributor rotor? I have no axial play but a few degrees of rotational play. Do people just replace the gear on the dstributor or more?

Thanks!
Billy
User avatar
bluef250
Blue Oval Fanatic
Blue Oval Fanatic
Posts: 924
Joined: Fri Oct 29, 2004 8:49 pm
Location: Arizona

Re: Timing or Carb.? 1968 360

Post by bluef250 »

In my case, the bushings were shot. The shaft was so loose that I could not keep points gaped properly. I updated ignition to a Duraspark II (1975/76) rather than mess around with points.
User avatar
colnago
100% FORDified!
100% FORDified!
Posts: 1882
Joined: Tue Jun 14, 2011 8:48 pm
Location: Ridgecrest, CA

Re: Timing or Carb.? 1968 360

Post by colnago »

I also replaced everything with Duraspark, but I ran with Pertronix II for years with no problems. If you're going to replace the distributor gear, just replace the entire distributor. They're pretty cheap, and it's probably not worth it to tap out the pin holding the gear to the shaft, then tap it in with the new gear, unless you want to (I didn't, so I bought a rebuilt distributor from Rock Auto).

:2cents:

Joseph
"Sugar", my 1967 Ford F250 2WD Camper Special, 352FE, Ford iron "T" Intake with 1405 Edelbrock, Duraspark II Ignition, C6 transmission, front disc brake conversion.
Post Reply