How to tell if balancer has slipped
#2326519
06/25/17 05:51 PM
06/25/17 05:51 PM
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Joined: Jun 2013
Posts: 1,521 Tacoma, Washington USA
Adam71Charger
OP
pro stock
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OP
pro stock
Joined: Jun 2013
Posts: 1,521
Tacoma, Washington USA
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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?
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Re: How to tell if balancer has slipped
[Re: Adam71Charger]
#2326541
06/25/17 06:30 PM
06/25/17 06:30 PM
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Joined: Jan 2003
Posts: 10,748 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,748
North Dakota
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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.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: How to tell if balancer has slipped
[Re: 6PakBee]
#2326546
06/25/17 06:37 PM
06/25/17 06:37 PM
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Joined: Jan 2003
Posts: 20,706 Eagle, Idaho
Neil
The Doctor is in.
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The Doctor is in.
Joined: Jan 2003
Posts: 20,706
Eagle, Idaho
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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.
Last edited by Neil; 06/25/17 06:40 PM.
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Re: How to tell if balancer has slipped
[Re: Adam71Charger]
#2326633
06/25/17 10:53 PM
06/25/17 10:53 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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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?
Last edited by RapidRobert; 06/25/17 11:56 PM.
live every 24 hour block of time like it's your last day on earth
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Re: How to tell if balancer has slipped
[Re: 6PakBee]
#2326672
06/25/17 11:55 PM
06/25/17 11:55 PM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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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. 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.
**Photobucket sucks**
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Re: How to tell if balancer has slipped
[Re: 70Cuda383]
#2326835
06/26/17 10:40 AM
06/26/17 10:40 AM
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Joined: Jan 2003
Posts: 10,748 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,748
North Dakota
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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. 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. 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.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: How to tell if balancer has slipped
[Re: 6PakBee]
#2326861
06/26/17 11:14 AM
06/26/17 11:14 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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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.
live every 24 hour block of time like it's your last day on earth
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Re: How to tell if balancer has slipped
[Re: Adam71Charger]
#2326942
06/26/17 01:41 PM
06/26/17 01:41 PM
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Joined: Mar 2011
Posts: 3,089 Michigan
A727Tflite
master
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master
Joined: Mar 2011
Posts: 3,089
Michigan
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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.
Last edited by Transman; 06/26/17 02:47 PM.
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Re: How to tell if balancer has slipped
[Re: Adam71Charger]
#2327041
06/26/17 05:23 PM
06/26/17 05:23 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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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.
live every 24 hour block of time like it's your last day on earth
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Re: How to tell if balancer has slipped
[Re: Adam71Charger]
#2327243
06/26/17 11:19 PM
06/26/17 11:19 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Yes keep it capped till you fix the (vac) leak.
live every 24 hour block of time like it's your last day on earth
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Re: How to tell if balancer has slipped
[Re: Adam71Charger]
#2327368
06/27/17 02:32 AM
06/27/17 02:32 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Maybe it's be because the 750 carb is too big for my 318. I agree, you could trade it to me for my eddy 1406/streetmaster intake!
live every 24 hour block of time like it's your last day on earth
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