What would be the best way to set the timing with a bad harmonic balance. At idle I’m showing 60 degrees of timing. With mark on the balancer at TDC the rotor is pointing to the number 8 cylinder. Engine runs pretty good especially under hard acceleration. Misses a little when not under a load. Maybe a vacuum leak somewhere. Doesn’t make a difference with the vacuum line capped off. The car starts like the timing is a little advance.
thanks for any info.

 

I think I would be more concerned about replacing the bad balancer than I would about how to set the timing with it. Those things can do some serious damage when they let go.

 

Dan1495 is 100% spot on: Priority #1 is to change the balancer. There are pics here of balancers that have come apart and it's not pretty. The fact that your timing mark is so far off indicates the outer ring has broken free of the rubber joining it with the hub. I'd say your ability to keep going is on borrowed time.

 

Good point I was hoping to milk it to the winter. Can you buy an aftermarket/original looking balancer?
thanks

 

https://www.summitracing.com/search/...yword=Balancer

 

You can also have yours rebuilt, if original. DamperDoctor is one source but no direct experience with them myself.

 

Operating the engine with a slipped/damaged balancer is extremely dangerous. Don't do it, and don't try to set the timing with your body and face anywhere close to the front of the engine. When it fails, it will come apart like a hand grenade. A good friend got his foot almost fully cut off by a "slipped" balancer when it suddeny and instantly came apart. Another friend with a slipped balancer on a '65 Vette had it come apart within minutes of me setting the timing to compensate for the slipped outer ring: When it came apart at freeway speed, it broke the hood in half, sheared the water pump off the front of the engine, broke all accessory brackets, sheared the exhaust manifolds off at the collectors, and the parts hitting the pavement and boucing back up broke the bellhousing. It's no joke. Park the car.

ProForm makes some nice SFI-rated balancers that are the right size with degree markings on them at a very affordable price.

See my complete write-up on the process here:
https://www.corvetteforum.com/forums...blem-post.html

Lars

 

Slipped balancer you say?


Don't do anything to that car until you replace that part.

It's not that hard with the correct tool, you just need to get the fan and shroud out of the way (or, in my case, do nothing to my electric fan setup). Here's my saga:

https://www.corvetteforum.com/forums...nd-videos.html

 

Thanks for the info took the balance off today. Like you said not a big deal. Couldn’t see anything terribly wrong in appearance. I do see like a crack in the rubber. The key way doesn’t line up with the timing line. Not sure if that is correct.
thank you everyone for your advice.

 

Thank you.

 

See the crack in the rubber

Timing line doesn’t match up to the key way.

 

The timing line never aligns with the keyway. Do a TDC check - it sounds like you don't know if it's slipped or not, and it appears you didn't bother reading the info in the link I sent you. Good luck with the project.

 

will check TDC reinstall balancer mark and recheck. Don’t think the balancer is bad just surprised the line is so far off. Will carefully read your article. Thanks

 

your last picture is so dark I can only see the white line on the outer edge. Can not see the keyway. Also how about a picture of where the timing tab is attached to the cover?

 

Mel -
He just needs to start with the basics and do an accurate TDC check. This will immediately determine if there is an issue with timing marks or not and will determine path forward to correct the issue. His balancer doesn't look as bad as some I've seen that have slipped and shifted, but that doesn't mean it hasn't happened. Trying to guess if the timng tab is the correct one in the correct place based on a photo is not going to gain much: Just get the facts with a good TDC check.

Steve - E-mail me if you need a copy of my "How to check TDC" tech paper.

Lars
V8FastCars@msn.com

 

Thanks, I understand your point. Just figured with his statement of 60 degrees something with the balancer or the tab would be obvious. Hopefully he will follow your advice.

 

My reasoning is as follows:

If the balancer has slipped 60 degrees, there would be obvious visual indication of the outer ring having moved. If it rotates 60 degrees, the outer ring is also going to have some fore/aft movement and will not be aligned with the inner hub. The rubber will be in sorry shape, and usually will "extrude" forward to form "bulges" of rubber coming out from between the inner hub and the outer ring. His balancer does not show any of these symptoms, and it would be unusual to have an outer ring (which will usually only slip about 10 degrees-or-so before total failure...) move 60 degrees without any of the other failure symptoms. I'm leaning towards his balancer not being bad, but I could be wrong...

For the timng tab to be mis-located by 60 degrees, it would almost have to be installed on the wrong side of the timing cover. I'm guessing this is not the case.

That said, I have a funny feeling that he does not have a timing line/tab problem, but may have other diagnosis issues giving an incorrect indication of the over-advanced condition. Only way to determine and verify that is with a good TDC check with the right tools: Visual inspection alone won't provide usable factual data.

Lars

 

Maybe the timing chain jumped, but it would run like crap, if at all. 60° off is a huge change. RU sure your pick-up for the timing light is on #1?
The pic of the balancer doesn't look like it's off by 60°. No way it can rotate that much without major distortion. Something else wrong here.

 

Has the timing light connected to the wrong plug wire?

 

My bet is on something along those lines.... The TDC test will verify...

Also, to comment on Steve's opening post observations: The indication that the distributor rotor is pointing to #8 at TDC is not a reliable troubleshooting indication, since #8 is right after #1 in the firing order. The distributor has moved way past the #1 tower position by the time the engine is at TDC since the ignition fires roughly 10-15 degrees before TDC. So at TDC, the rotor is on its way to #8, which is normal.

Highly unlikely that the t-chain has jumped a tooth. The engine generally won't run with the chain off by a tooth, or it will run extremely poorly with severe symptoms.

Lars