283 bakcfires through carb

1. Recheck all ignition timing variables.

2. Make sure rockers are correctly set.

3. Do a compression test.

 

Back to the possible cam problem. If the lobe is worn, it won't let as much air in so that cylinders compression reading will be low or non existant right? Do I need all the plugs out to do each cyl?

 

Yes that way you get a Correct Reading

 

I had the same problem with my 283, (780 vac secondary Holley). It was the accelerator pump. I didn't change the actual pump, but I did change the pump nozzle,(squirter), located down in the primary throttle bores. It took care of the problem.

 

what did you use to break in the motor/cam,er what kind of oil?

 

I'm not making fun of your misfortune. This seems to be a way too common occurence. I hope we can ALL learn from this. I have a fresh rebuild waiting to start myself. Maybe there's something to this zinc thing.

 

Say WHAT!!!

 

If you can ease into the throttle without it poping back ,first thing is not enough fuel from the acc. pump not to much.

 

Use either Delo 400 or Rotella both still have zink compounds. Delta Cams recomend that also.

 

If you want to rule out a wiped cam lobe and are planning on re-adjusting valves anyway, I'd pull the rocker covers, get a set of those oil deflectors (otherwise flying oil will make a mess) and start the engine. Confirm that each valve opens and closes.

Then pull all the plugs and do a compression test. Then adjust valves (cold or hot its up to you... I do them hot) Then do another compression test.

If that hasn't changed anything, confirm the firing order. Make sure you put the dist. in with #1 at TDC, and make sure your plug wires aren't one position off. That can cause the symptom you have.

 

Needs more fuel!!

 

flat cam lobes will make it pop and snort through the carb.
He said he has 500 miles on the motor, that mileage is enough time to flatten a lobe if things were not set correctly.

 

kick

 

Bill, did you ever get it figured out?

 

vac advance n/w

 

Thanks to all. Installed smaller carb. 500 cfm is plenty for a 283. Even a slightly hot one. Also timing was off. Don't trust the marks on after market balancers unless you verify with timing marks before you install timing cover. Also, valves were too tight. Thanks Gerald Meacham for help. The 41 truck is going down the road under it's own power for the first time since 1962. How cool is that?

 

Glad you stuck with it and figured it out. Very cool to be drivin it again.