350 Running rough for no reason

[Lunatic]

This will be the second time in 4 years that this has happened. The first time I "knew" it was the timing chain (but wasn't) and installed a direct drive gear set. Re-timed and has been running fine since.

Just the other day, I was driving through a neighborhood, almost idling. I turned onto a street, gave a bit of gas. and the engine stuttered - And just like that, it is now running like poo.

I can testify that everything is operating smoothly (bearings, push rods, etc) by using an automotive stethoscope all over the top and bottom of the engine. I just cant reason "how" the timing jumped, nor can I find where it jumped to. All I can achieve at this point is a very rough idle and a QJ that backfires under heavy pedal with no load.

A bit of info for the engine: 350 with stock internals, SMI QJ, Edelbrock 3701 intake, Accel Correction 8141R dizzy cap, new AC Delco plain jane spark plugs, Proform noisey direct drive, vacuum lines less than a year old.


I can only come with 2 ideas, both ignition related. Either my timing mysteriously jumped somehow, or my stock dizzy went south.

So before I tear down my engine, I thought I'd come through and present the case to the brotherhood. Hopefully, someone can point out something I haven't thought of or considered looking at.


I hate asking for help, but here I am. Ask any questions and I'll respond quickly. Comments and suggestions are appreciated also.




Troy B
Ft Hood, TX

 

[imiceman44]

DId you try to retime it?
I suspect the dizzy is not as tight as it should be and might have moved.
The gear drive jumping a tooth is most unlikely so I think you could skip that.

This will be the second time in 4 years that this has happened. The first time I "knew" it was the timing chain (but wasn't) and installed a direct drive gear set. Re-timed and has been running fine since.

Just the other day, I was driving through a neighborhood, almost idling. I turned onto a street, gave a bit of gas. and the engine stuttered - And just like that, it is now running like poo.

I can testify that everything is operating smoothly (bearings, push rods, etc) by using an automotive stethoscope all over the top and bottom of the engine. I just cant reason "how" the timing jumped, nor can I find where it jumped to. All I can achieve at this point is a very rough idle and a QJ that backfires under heavy pedal with no load.

A bit of info for the engine: 350 with stock internals, SMI QJ, Edelbrock 3701 intake, Accel Correction 8141R dizzy cap, new Accel plain jane spark plugs, Proform noisey direct drive, vacuum lines less than a year old.


I can only come with 2 ideas, both ignition related. Either my timing mysteriously jumped somehow, or my stock dizzy went south.

So before I tear down my engine, I thought I'd come through and present the case to the brotherhood. Hopefully, someone can point out something I haven't thought of or considered looking at.


I hate asking for help, but here I am. Ask any questions and I'll respond quickly. Comments and suggestions are appreciated also.




Troy B
Ft Hood, TX

 

[Lunatic]

I've re-stabbed the dizzy quite a few times, yes. While I haven't tightened it in a final manner as of yet, the day this happened it was indeed tight.

And yup - Thats exactly why I installed the gear drive - Just saying "gear drive" rules it out. And if you ever were to question a gear drive, it would have to be the reason..... Because the water pump would be in pieces and the timing cover shredded !


I'll be checking my rotor and dizzy a bit closer tomorrow. Thanks for the response.



Troy B
Ft Hood, TX

 

[Lunatic]

Re-Direct

Please add any additional responses to the current thread in the Garage.

I "moved" this thread to the Garage due to higher traffic.


Thanks !



Troy B
Ft Hood, TX