How to tell if balancer has slipped

So I got my 81 318 converted to electronic ignition with the orange box and proform distributor/cap/rotor,a mechanical fuel pump, new gr4 spark plugs, and a summit m2008 carb, 1/2 wooden spacer, and performer intake.

I got it running, but had to bump up the idle because it shakes around 850rpm.

My timing light shows rpm and advance, and at 850 rpm, the lowest I can get the advance before the backfires through carb is about 30 btdc. and it runs like garbage. My spark plug wires are routed correctly, #1 and #8 generally point towards radiator with advance can (which works correctly) points toward passenger side of car. No vacuum leaks detected.

Now, at 1000 rpm idle and an advance of about about 41-ish btdc, the car runs fairly smooth, but slams into gear. Unless Im missing something Im pretty sure my balancer has slipped, or my timing chain is stretched, but could a stretched chain add 20+ degrees to a reading?

Correct me Im wrong, but putting #1 to tdc and drawing the mark on the balancer would give me a correct mark to get an actual timing reading right?

Use a cylinder stop in the #1 cylinder. With the battery disconnected, rotate the engine one direction until you hit the stop. Mark the balancer at the TDC mark on the timing tab. Rotate the engine the other direction until you hit the stop again. Mark the balancer at the TDC mark on the timing tab a second time. True TDC will be halfway between your two marks. If the balancer has not slipped, this will be at the TDC mark on the balancer. If it has slipped, you can use the TDC you found to time the engine but once a balancer slips it usually continues to do so. 340's were notorious for balancer problems and I timed more than one 340 using this exact procedure.

If you pull the cap off the distributor you can watch the rotor turn around when the balancer moves. If you rotate the balancer one direction and then back it up and the rotor takes a long time to catch up then the chain has excess slack in it. Be careful not to accidentally loosen the balancer bolt turning it back and forth.

If the rubber on the balancer is dry rotted and hard as a rock it may be time for a new one even if it hasn't started to slip yet.

For a quick(er) start I would hand bump the crank with a 1&1/4 socket/breaker bar till the dist tooth is dead even with the magnet with the rotor under or near under the #1 plug wire & see what the dampener reads. First confirm that the springs are retracted (twist the rotor slightly CCW), they should be but never hurts to check. EDIT is the can on ported? plugs/plug wires are OK?

This works great... if you did the same procedure to verify TDC when the engine was fresh. Or at any point before your concern, so that you have a baseline to compare to. I've checked brand new engines with all new parts and the timing mark on balancer doesn't line up with the timing tab on the front cover.

Well something is definitely off, and I need to make a Mark so i can get this engine running right. I'll have to verify but im pretty sure this engine has never been rebuilt, and the most work that's been done to it would be timing chain replacement.

If you follow the procedure and the TDC mark on the balancer matches the timing tab, then the balancer is accurate. If it doesn't, you know where TDC is so you can remark the balancer. When I've done this and found a mismatch, I always told the owner that it should be done again at a later date to check if the balancer is indeed slipping or it is off due to a stackup of tolerances. I will give you the fact that if the marks do not match, that does not guarantee that the balancer has slipped. Your point is well taken.

put the dampener at 15BTDC & screw in the stop till it contacts the piston then back up the dampener CCW & see if it hits the stop at 15 ATDC. Updates us when you find out something.

Do what 6PakBee said. Then put a dot on the outer ring and one next to it on the hub.
If in the future the dots don't line up you know the outer ring moved again. And how much. Using the distributor is not even close to being accurate. Building an engine without checking TDC on the damper is as bad as not centerlining the cam. Answering your question - no you can't just mark the damper without knowing if the piston is at true TDC.

There is another possibility and that is, you have the pickup on the distributor wired backwards to the ignition box.

I'd say that is more likely than the outer ring on the damper has slipped. But it needs to be checked right away before you go and do anything that takes more effort or money.

R.

The 2 wires coming out of the distributor end in a connector. The 2 wires coming from the orange box to the distributor end in a connector. These 2 connectors are shaped in a way that they can only be out together 1 way. I didn't look at those wires closely because they were set up to obviously plug together with those connectors. I'll look them.

With the rest of the orange box wires I put black to negative terminal on coil, and blue to to blue ignition 1, and didn't use green wire because there was no pin for it and the kit also came with a 2 terminal ballast resistor

with the blue or blue/yellow main hot ECU terminal at 9 0'clock, the 11 0'clock tan/black wire should go to the male terminal on that end of the ECU zigzag pickup connector & I agree using the dist to check the dampener ain't near dead on but I think it will be good enough (& easy to do which is why I suggested it) to see if the dampener has slipped & I think the prob is elsewhere.

Ok so my brown/white ecu wire is going to the orange distributor wire and the grey/black ecu wire is going to the black distributor wire.

I used a piston stop and my balancer is dead on tdc, it has not slipped. I popped the dizzy cap off just cause and the #1 terminal is about 20 degrees advanced, rough visual estimate.

I'm wondering if my timing light is messed up or if it has an option for # of cylinders. I'll check that, and I'll try a different light if it's not working

If you don't know if the timing set has ever been replaced, now is the time to do it. The old "silent" factory set has been the death of many a motor.

Ok, looks like it was the idk adjustment screws on the carb. I don't think I've ever had a carb that needed the idle adjustment screws so far out! Maybe it's be because the 750 carb is too big for my 318.

I've got it down to 14 btdc at 970rpm with 23 inches of vacuum. Gonna see if I can get it down to 800rpm and 12btdc

Another thing throwing me off a bit is one of the vacuum lines going into the cabin is broke or the vacuum pod it goes to is broke, as attaching it to manifold vacuum on the carb increases rpm. I capped magnified vacuum port for now

Yes keep it capped till you fix the (vac) leak.

I agree, you could trade it to me for my eddy 1406/streetmaster intake!

I need to play around with this combo some more before I make that big of a change. Right now, it runs really smooth with a slight stumble at part throttle if I slam the pedal down. Does fine if I do it gradually. When it was running a bunch of advance, there was no stumble. Tomorrow Im going to check the position of the link at the accelerator pump and re-check my plugs. Before I got the timing and idle down to where it is now (about 840rpm at 13 btdc with 19 inches vacuum) the plugs were crossing the fence from tan to white-ish. Will too much carb cause lean running?

Robert do you subscribe to the all the threads you post on?

What do you mean? (I don't understand the question).

Forums give an option to subscribe (email notifications) when a thread has a new post. I was just thinking about how many emails you must get a day lol

Where's that option, would be useful

I'm not 100% sure on this forum, but it should be in your user options. I think you can turn of certain threads in the topic options button next to the new reply button

I've noticed a lot of forums are set up very similar. On xs11.com and hotrodders.com it's an option and they are set up like moparts. Also the for a bodies, for b bodies, and for c bodies only. Steve's nova site as well

Oh OK I grasp it now. yeah if we had that I would be busy.