Timing issues

[ken98k]

I’ve had a couple distributor/timing problems with my new to me 74 CJ5 .
It’s a AMC 304 with a GM HEI distributor.
It seem a little gutless, almost like it was under water so, on the weekend of the 7th I set the timing to 5*BTDC. That seem to do the trick, it ran way mo betta.

Yesterday, while doing some very easy trail riding it stalled on a small incline.
At first I thought I just wasn’t giving it enough gas, so I attempted to jump start as I rolled back but no dice.
After cranking several times I found I was out of gas. L Found out it runs out with gauge showing ¼.
After adding fuel to tank, it would start but not stay running unless I gave it a lot of accelerator.
After checking all the usual things I loosened and moved the distributor and the problem cleared right up.
When I got home I put the timing light on it and it will not run if set at 5*BTDC.

My question is what happened? Did the timing chain jump? Did the distributor jump a tooth?

 

[Old Dog]

Whats the timing set at now, when it's running good.

 

[ken98k]

Whats the timing set at now, when it's running good.

I'm not sure it's off the scale. My chalk mark doesn't even show in the light.

 

[Old Dog]

sounds like something jumped time for sure. I'm surprized it will run.

 

[elwood blues]

Have you pulled the dizzy to look at the gears? The AMC 304 is notorious for eating dizzy gears if they aren't the correct metal.

 

[ken98k]

Have you pulled the dizzy to look at the gears? The AMC 304 is notorious for eating dizzy gears if they aren't the correct metal.

Not yet.
Probably tomorrow afternoon.

 

[ken98k]

I finally got around to pulling the distributor today and the gear is okay.
I guess that means the chain must have jumped a tooth or two.
I was really hoping I just needed to replace the dizzy gear. I'm not looking forward to pulling the timing chain, looks like I'll need to pull the radiator and water pump first.

 

[ken98k]

The fuel and oil pumps appear to be connected to the timing cover.
Do they need to be removed from the cover or can the whole thing be removed as an assembly?

 

[CJ]

Fuel pump - yes. (the lever arm pushes on the cam concentric)
Oil pump - no. (that is because you pulled the dizzy)

 

[ken98k]

I ran into a wall until I get a better puller for the balancer. I picked one up from napa and promptly twisted the the center screw like a pretzel

 

[LongHorn]

I'd be willing to bet the nylon factory cam gear has chipped teeth.
A very common problem. allowing the timing to slip.
I always use all steel double roller timing sets when I do a re-build.
Your timing can also be way off if you attempt a engine re- build without a degree wheel when you set up your cam.

 

[ken98k]

It was the nylon cam gear. Very worn and chipped allowing chain to jump 2 teeth.

I got everything back together what a difference! Maybe it's my imagination but, it seems to have more power than before it jumped time.

I did notice a little smoke I never noticed before but I attribute that to the vaseline I packed in the oil pump. Hoping it will stop soon.

 

[Al Lindner]

I ran into a wall until I get a better puller for the balancer. I picked one up from napa and promptly twisted the the center screw like a pretzel

I have a colection of twisted up gear/pulley pullers! Modern Art? Now when ever I need one I rent one. GOOD LUCK

 

[Old Dog]

Ken, glad to hear you got it fixed.

 

[dpuck]

All too familiar. I had to replace the timing chain and gears on mine this weekend. Replaced the fuel pump and rebuilt the oil pump while I was at it. And it does have more pep.

 

[Rescue Diver]

I got everything back together what a difference! Maybe it's my imagination but, it seems to have more power than before it jumped time.

I would have been surprised if you didn't notice improved performance. Even before your chain skipped teeth, your valve timing would have been a couple degrees retarded from chain stretch and the worn plastic gear. Advancing valve timing with a multi position gear set is an easy way to gain bottom end torque in just about any stock engine. The down side to doing that is you tend to lose a little HP on the top end.

Be glad the problem wasn't with your distributor gears. That would have required you to pull the cam which involves removing the rockers and push rods on top of all the work you already had to do to change the timing chain. Plus, the fact that your distributor gears are ok means you've avoided the problem that most AMC 304 's experience with the HEI swap.

Congrats on getting the problem fixed!

 

[ken98k]

Thanks to all who offered their .02
I think it's been a little over 20 years since I last did any motor type mechanics so it was good to have some support.

Today I put a "for sale" on the rig in question. I figured I better sell it before I break something else while I'm hot roding with the thing!

 

[Rescue Diver]

Thanks to all who offered their .02
I think it's been a little over 20 years since I last did any motor type mechanics so it was good to have some support.

Today I put a "for sale" on the rig in question. I figured I better sell it before I break something else while I'm hot roding with the thing!

Planning to buy another one, or giving up old Jeeps?

 

[ken98k]

Planning to buy another one, or giving up old Jeeps?

I have others
I bought this one with the idea of a quick turn around.