New CJ owner- timing question?

New CJ owner- timing question?
K

Kruser

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Location
Wilsonville, Oregon
Vehicle(s)
1977 CJ7, 4.2L, 4 Speed
Hey guys, I just bought my first CJ on Sat. and I couldn't be more excited. Have owned 2 Wranglers in the past, but this is my first round headlight Jeep. It is a 1977 CJ7 , AMC 258 i6 / 4.2l , 4 speed.

I am wanting to get it in shape to be a daily driver. It doesn't run too bad as it is, but there is some hesitation when I rev the engine. I replaced the spark plugs, plug wires, dist cap, and adjusted the timing to factory specs. After adjusting the timing it ran terrible (very sluggish and backfire) then I kept adjusting the timing until it smoothed out and wasn't as sluggish. My concern is that I had to adjust the timing so far that it is right as the last timing mark... Why is this? Can this cause any damage?

Where is a good place to start to get rid of the hesitation?

Thanks.
 
Point-type distributor, right? Did you replace the points? Did you set them correctly? I suspect that they're in need. When they're adjusted right, do the whole timing thing again - I think your timing is advanced much too far and you'll get detonation when you drive it - especially accelerating uphill.

Be sure your idle speed is good & low when you check the timing, and do it with the vacuum hose disconnected from the distributor.

If all that won't correct the hesitation issue, I'm betting it's time to put a kit in the carburetor.
 
if its a carter bbd throw it in the garbage and switch to a webber or motorcraft carb and your problems will probally be solved.
 
dalefan88 said:
if its a carter bbd throw it in the garbage and switch to a webber or motorcraft carb and your problems will probally be solved.
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x2 but i'm not sure what came on that year model i believ its a 1 bbl carb probably still junk though and i wouldn't think a 77 would have points
 
Yeah, they used a point-type distributor through '77, but went all-electronic in '78.

A carburetor issue wouldn't make it run only with very high advance... and some BBDs run just fine (the one in my '85 CJ7 does). When they quit running fine, you can Nutter 'em & they're fine again after that. Saves the $300+ to buy a Weber or Motorcraft...
 
i have about 65 in my motorcraft. 20 for the carb from a friend, 20 for the rebuild kit, and 12 or 15 dont remember for the adaptor. the rest for gaskets and misc other stuff for brackets. fixed all my idle, bogging, ect ect problems i had.
 
OK I'll start with the points. I was thinking a new carb was probably in my near future. What would be the most economical to switch to? My current is the 1bbl with manual choke. would really like to get an electric choke.
 
You can convert that choke to electric if you like - it's not a hard conversion. I like manual chokes better, myself, because electric chokes often have a nasty tendency to close again in cold weather while the engine's still warm. Makes 'em likely to flood.

If you go to a different carburetor altogether, I'm assuming you'll also want to go to a 2-barrel. A Motorcraft/Autolite sells for around $300, and a Weber with electric choke sells for nearly $400. Add to that a 2-barrel intake manifold (without which you'd have to use an adaptor plate, and they seldom work very well). A stock intake sells for a little more than $AMC 150 new.

A junkyard visit may very easily turn up everything you need, though... probably for a lot less money. EBay isn't a bad place to look for stuff like this, or CraigsList.

EDIT: You can sometimes pick up a COMPLETE 6-cylinder motor with intake & carburetor on CraigsList for $100 or so.
 
i bought my mc2100 from a local guy for $50, the adapter plate was $13, the rebuild kit was $12, you can find a 2 barrel intake fairly easy and cheap. as far as the bbd i did the nutter bypass on mine and it still ran like :dung:, on top of running like :dung: it ran really rich, i adjusted the needles every which way i could and it still ran like :dung:. if i had to do it all over again i would ditch the bbd in a heart beat. just my op on the bbd :D
it doesn't have to cost $300+ to do a mc2100 conv. just put an add on craigslist for the parts you need, intake and carb. i got my rebuild kit and adapter from advance auto parts. yeah the adapter feels cheap but it works perfectly fine
 
The two best upgrades you can do to make it run the best is the carb and the ignition, I wouldnt do one without the other. Go to an electronic ignition, either a good hei unit or one from Davis Unified. The systems on these Jeeps werent that good 25 years ago, definately no good today.
 
I don't think you have points but you do have the crappiest distributer that was ever built.
The best upgrade you will ever do to your AMC 258 i6 / 4.2l will be to replace the prestolite distributer you have with a motor craft from a 1978 jeep and do a TFI upgrade. Google TFI upgrade and you will find all the info you need. The TFI is better, cheaper and easier that the HEI.Your hesitation will go away.
The carb upgrades are good but you will have to change out the intake manifold to make it possible and the cam shaft to get the full benifit of the carb. I would save that for phase 2.
 
Awesome info guys, I will definitly look into the different upgrades. The carb and dist. are at the top of my list as soon as the funds get in...
 
Kruser said:
Awesome info guys, I will definitly look into the different upgrades. The carb and dist. are at the top of my list as soon as the funds get in...
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Don't wait for money, just go ahead and use the rent or house payment to buy stuff for the jeep. Things like this give the wife all sorts of amusing stories to tell, at the hearing.:laugh::laugh::laugh:

Seriously; The new distributer is about $75 and the TFI coil is about $50 You will need to upgrade to the motor craft module and do a bit of re wiring but the rest of it is just what you would do for a tune up anyways. You can find these things in a grave yard and save a few bucks, I think there is a ford truck dizzy you can use if you change out the gear but I don't recall where I read that. Your helpful auto parts professional may be able to cross check this for you.:cool:
 
Call me the odd man out, but I'd much rather have a point-type distributor. It's easy to work on in the woods, it's bone simple, and it can be made to last virtually forever.
 
TDHofstetter said:
Call me the odd man out, but I'd much rather have a point-type distributor. It's easy to work on in the woods, it's bone simple, and it can be made to last virtually forever.
Click to expand...

Very valid points. All of which I have considered while changing out the module that gives absolutely no warning before becoming FUBAR. :mad:
 
Here's a good plan - install solid-state, but carry a complete point-type distributor in your toolbox with the points already gapped & ready to go. Whattaya think?
 
I think it takes less room to carry an extra module.:laugh:
which I highly suggest
 
Will it be a good module when you need it? A point-type distributor WILL BE GOOD, guaranteed, if it was good when ya tossed it in the toolbox & didn't drop a four-pound sledge on it. :)

I never count on a module being good until it's actually running.
 
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