Timing problems

[poser]

I have an 84 CJ7 with the AMC 258 i6 / 4.2l . It's all stock it has the T-5 Transmission and in third fourth and fifth gear I have a bad ping when it's under a load I have replaced the distributed wires and plugs I have the timing set at 8 deg and I have played with the vacuum adjustment , where does the vacuum line go from the distributor and any other help or ideas would be great thanks.

 

[73CJ]

where does the vacuum line go from the distributor and any other help or ideas would be great thanks.

Goes to the base of the carb. With out it should run like . It will advance it up to 24 total degrees.

Stock motor I presume?

Story changes with a non-stock cam.

 

[Old Dog]

Pinging means the timing is to far advanced.

 

[jeepy]

Pinging means the timing is to far advanced.

Yep, and cheap gas (too low octane) amplifies the problem.

 

[poser]

Could it be the timing gear set I run 91 octane

 

[73CJ]

http://www.buicks.net/shop/reference/engine_timing.html

Ignition Timing Explained/Timing an Unknown Engine

Check these 2 links out. If someone has put a cam in it, things have changed. One of my friends found he had a mild cam after we changed the points and it ran like at the stock setting.

The AMC 304 timing chain liked to jump. I went through 3.

It's hard to jump a AMC 258 i6 / 4.2l , but you never know.

 

[Cheepjeep85]

remember the stock AMC 258 i6 / 4.2l has a nylon cam gear, when i rebuilt mine the timing chain was so loose it was slapping around, and the gear pretty much fell apart when i took it off. this can also cause your timing to float around. i'm not saying you have the same problem but its possible.

 

[poser]

Thanks for all the help now I have a place to start