Wierd timing issue

[S-Car-Go]

Hi All, Last week I bought a 68 convertible. It’s got a 289 (or 302) /C4 with a 4.11 trac-lok. I’m planning on swapping in a 351/T5 this winter, but I’d like to keep this motor running in the mean time. Anyway, last night I changed the plugs, but when I checked the timing, I found it at about 20* AFTER TDC. I had to jump a tooth to get it anywhere near TDC and then it wouldn’t start (popped back through the intake). When I put it back to 20* ATDC, the car starts and idles fine, plenty of power down low, but runs out of power quickly as RPM’s go up. I’m going to be looking at it later today but so far I think
1) jumped a tooth on the timing chain
2) Harmonic balancer scale is sliding.
Any other ideas to check out would be appreciated. Oh yeah, It’s got a Petronix ignition. Could something on that cause this?

 

[iskwezm]

check the elastomer ring on the balancer like you guessed.I think jumping a tooth on the timing chain is unlikely.

 

[StephenMarsh]

This may sound stupid but - you did get the firing order correct right? 289's and 351's are different if memory serves. I have NO idea if that would even cause the problem your describing but thought I'd throw it out there.

 

[grego37]

did you check your timing at idle "initial timing" with the vacuum advance dis-connected and hose plugged?

Sounds like your advance may not be working properly in your dist.

to check your timing to make sure its advancing .
hook the vacuum advance hose back on the dist.
With your car in park, using a timing light, have a buddy slowly bring up the RPMs while you read the timing. It should stop climbing at approx 3000rpm, when it stops climbing read your timing. This reading is your total timing.

If you can use a timing light with a 'zero' dial its much easier, all you need to do is use the TDC mark on the balancer and read the back of the 'zero' dial for your "total timing"

Dont forget when ever you change/adjust your timing, to go back and adjust the carb.

 

[S-Car-Go]

Thanks all! I think I got it. Balancer was fine and timing chain was fine. Combination of things. Pulled #1 plug and brought the motor up on compression. Pretty close to TDC. Good! Pulled the distributor moved it a couple of teeth and static timed it at 10*BTDC. Confirmed firing order and she fired right up. Bumped inital timing to 14*. Down side is that even at 14* initial, I still only have 30* total (with dial-back timing light). I'd like to see ~36 total. Grego, good call. I think I'll pull petronix out this weekend and a junkyard dura-spark is going in.

Now I have a bunch of really noisy lifters Motor has prolly been revved pretty hard due to the 4.11 gears...