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Noob needs some guidance...

745 views 14 replies 4 participants last post by  70nova327 
#1 ·
just picked up a 70 nova last week with a 327, someone put a lot of time and money into but the kid i bought it off of tweeked something and im at loss right now, im "assuming" i have a timing issue, it was straight piped and backfiring all over the place when i bought, i thru flow masters on it and that helped a bit, but once i hit about 3500 rpms it gets bad on acceleration and deceleration. theres a new edelbrock carb on it and a HEI distributor as well. last night i timed it AGAIN, warmed it up, plugged the dist vacuum line and set it 3 degrees past BTDC, a mile down the road it got bad again, so i checked the timing on the roadside and it was about 4 to 5 inches past TDC, so far that no adjustment to the distributor would bring it back down to the timing marker. what would cause this? possibly the distributor not aligned right? major vacuum leak once its fully warmed up? even if the TDC mark on the balancer isnt right how would it get so far gone once driven? any help would be amazing!
 
#3 ·
Sounds like the distributor is moving. Make sure you have the clamp on right that holds the dizzy down.
Set it at 12*. Test it. If it does the same thing first grab the dizzy and see if it moves. The timing will retard if it's loose causing the backfiring.
 
#11 ·
good point on the suspect balancer, if the balancer is loose will it be noticable still on the engine? like grabbing a hub on a loose wheel bearing? or will it need to come off to see if its bad? but wether i can get it to 12 or even 3 for that matter and tightened it up and found movement on it that would be most likely be the answer wouldnt it? or am i wrong?
 
#14 ·
Also verify that you have the right timing pointer. Older vehicles used a tab (or tube) on the timing cover that pointed straight up, but newer vehicles (early 70's and up) used a tab at the 2 o'clock position. The balancer and pointer need to match. You can also get an adjustable tab that bolts on to the timing cover bolts if the old one is way off.

Bruce
 
#15 ·
i went old school, pulled plug #1 rolled a paper towel like a cigar and put in the cylinder, then bumped it till it launched out on the compresssion stroke which should be TDC, after crawling under the car i found the mark on the balancer at a dead 6 o'clock when then timing plate is at 2'oclock. looks like balancer is shot.
 
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