Hey people,
I pulled off my harmonic balancer last night and noticed in two areas,the rubber ring appears to have shifted/moved.Its low and high going around the center part.I can also see it maybe shifted some because the balancer was given a quick coat of black spray paint by the machine shop and since then, where the rubber moved,theres a seen paint edge where it used to sit.

I also wanted to know if anyone knows what/where the timing mark on the stock balancer would normally line up with the keyway slot on it.Im trying to determine if the balancer has slipped a few mm's or inch(es) as well.

Im going to order a Fluidamper instead of using the GM one and not sure of I can compare the FLuidamper to the Old unit as far as the keyway and mark go.

Im going with the "street" damper which is around 159 bucks or so,instead of the more expensive fluidamper that goes for 300 or so.

Anyone use a "street"fluidamper?Do they work and fit good?
Thanks!
:)




[Modified by Bill's86Coupe, 10:30 AM 9/13/2002]

 

Bill, I have a street dampner and it is a great unit. As far as the timming marks with your keyway I can't help you there. :cheers:

 

Thanks for the reply...I will more than likely order one today.Hopefuly,this will solve that vibration problem Ive been having...wasnt severe but noticeable and annoying at times.

Anyone else know any more specifics to the questions I had?
Thanks again.
:)

 

Bill

How goes it? I received a call from LPE about a week after my engine was pulled. They mentioned the harmonic balancer wasn't any good...and they we're going to replace it. It's a regular GM piece...and so far, so good.

Hope you get things solved. How is the body work coming along.

I hope all is well.

JD

 

Hey JD,
Good to hear from ...alls well here in Ky...bodywork is on hold and so is paint...figures eh? Even though im not really driving the car anywhere,except up and down the road at times to keep it healthy,I figured to try and get some of the little pesky bugs fixed that was bugging me.Man the car looks like crap sanded down like that...lol..but I believe paint work may have to wait until xt spring if I cant find someone to do it before the winter comes.

Yeah Ive noticed that LPE uses GM dampers...weird..maybe theyre onto somthing we dont know about...but really want to try a streetdampr this time around.You gonna go with a stock GM piece or something else?

Ill talk to you later man...also hope I get some of my questions here answered...lol..I think I always ask odd techies that only a few actually know or had expereience with it.
:)

 

I'm running the small diameter streetdamper too and I like it a lot.

Dan

 

To find the actual place for the TDC marker you really need to locate TDC for your engine.
It's a lot easier to do with the engine out of the car but you can do it anyway.
You'll have to pull the valvecover on left cylinder bank.
You'll need one of those magnetic base dial indicators.
It's a lot like degreeing in your camshaft.
You'll locate TDC and split the difference then mark the damper to match your degree pointer.

Jegs sells a timing tape you can put on the damper, it's 5 or 6 bux.

Another idea may be to forget about marking the damper and use one of those timing lights that you can use to determine the total static timing.
You may not need to accurately mark the damper this way but I have not tried it.

Good luck with your engine.

 

Thanks for the reply...I wasnt asking how to determine TDC,since I was trying to find out if my stock damper had moved off somewhat but I didnt have another damper to compare it to since it was already out of the car...But thanks for the info anyways.It always comes in handy later.

Also,I went to the auto store and they had a New damper in stock and I compared the two..yep,the rubber ring on mine is sticking out further and the timing mark is a little further off or moved.No wonder I had some problems adjusting the timing the last time I did it..it was off by a few degrees!!This was more or less causing the vibration ive been having.

A forum member,I think apollo or someone sent me an IM or instant message but I could not reply.If youre reading this,sorry about that..for some reason I cannot reply or use the IM with this system.It never has worked for me before.
Just wanted to let you know why I didnt reply back..I also could barely read it.Thanks anyway.
:)

 

Bill, looks like your question has already been taken care of...but I figured I would toss this in.

Taken from Chevrolet Power Catalog, 6th Ed., 1988. Pg. 5-21...

"Due to variations in engine accessories, two different timing marks have been used to indicate Top Dead Center on Chevrolet production torsional dampers. Dampers produced since 1969 have TDC marks which are 8 degrees farther advanced than 1968 and earlier versions". Interestingly enough, back in 1988 it appears that Chevrolet offered Fluidamper brand harmonic balancers.

So as long as they had the right part number listed, then it moved...now if they had the wrong one listed and the mark was about 8 degrees off, well, you gotta keep wondering ;) Good luck, -Matt-

 

Hey Matt,
Always good to hear from ya...thanks for posting that heads up...I had planned to compare the damper marks to keyway after I got the streetdampr from Vibratech.
This post you made was helpful to make me compare the two more closely when I get it.

I also woudnt be suprised to see the mark off a bit on the aftermarket damper or even an OEM style one from GM...will just have to set TDC and make my own mark...shouldnt be too difficult...just hoping the new street damper will fit fine with the stock crank key...really dont feel like changing it out for another one.
Aftermarket parts just never seem to fit right without some tweaking or cussing...
:)

 

Here's a shot of old vs new, new on top, keyways lined up exactly.
http://www.corvetteforum.net/c4/hend...s/balancer.jpg

 

Does anybody have a picture of what a good balancer looks like on the engine with the pulley bolted to it? The reason I'm asking is mine looks like it might be messed up also. It looks like the balancer may have slid back a little and exposed some of the rubber on the front surface.

 

Jim,
Wow,I can see the big difference in the timing mark...thanks for posting that pic.
:)
KYVette,
Its gonna be hard to tell if the balancer is bad in the car if it isnt wobbling or something.Before I pulled mine off,I took the pulley off and looking down there with a flashlight,looking at the balancer and the rubber was difficult to see unless you can see its broken or sticking out a bit in places.It should be a flushed,one continous ring of rubber going around the center.

The rubber on mine was sticking out a little bit higher and lower on some areas but I still wasnt sure what was normal until I seen the new one in the store I checked out for comparison...big difference.

HTH some.
:)

 

Here's a front view of old vs new (old on right). You should be able to see this on the car, now that you know what to look for. The new one is flush in front and rubber ring on the old one is shifted back about 1/2" or more toward the timing cover.
http://www.corvetteforum.net/c4/hend...ncer-front.jpg

 

Jim,Great pic again...thanks for posting that too...wasnt sure if ya had more of those.That should help others to see what to look for better.
:)

 

Bill,

Digicam has saved my butt more than once trying to reassemble all the unbagged and untagged bits and pieces I always end up with. Nowadays everything gets photographed. Good thing when others are able to get some useful information, too - no sense re-inventing the wheel. Good thing the forum provides space to share pics, many of us have little or no public web space to use.

 

Bill, If you do in fact go with the StreetDamper, let me know how the quality is...this, an oil pan, and a new front spring are on my next list of needed replacements/broken parts. :rolleyes:

 

Jim,
I hear ya on the digi-cam...pictures really do help...I was lucky I managed to do everything I took apart/put back together from memory but at times I wish I had pics saved.Thanks again for posting the pics..they go a long way here as always.

Matt,
I made a last minute decision to change my mind AGAIN and decided against the streetdampr and get a new GM unit.
http://www.gmpartsdirect.com has them for 69 bucks for the Vette...I paid more from paceparts.com ...stupid me...shouldve called Jeff Kopp or parts direct but didnt think to do so...Jeff K seems to have the best prices as well..

Anyways,heres my plan...go with a GM piece for now and see if the vibe is gone...if not,then go with a streetdampr.If no fix,then yank the engine for a balance problem a machine shop did.

See,for the past 7 years,just about any/every after-market part needed some work to fit or something done to make it work right...wasnt many but enough to jade me in the long run to stick with the GM stuff nw at first.

With my luck,say I got a streetdampr...the the timing mark would be off,then the damn GM key on the crank would be too wide or something,and then I have to experiment with keyways to make the streetdampr fit and so on...Thats how my luck has been...I really wanted a streetdampr but just felt that if I did,it wouldnt be 100% "bolt on and forget it modification".I also am tight on money so the GM piece was cheaper.Should go straight on the crank there lke the POS stocker did.

I'll keep ya all posted..sorry if I led some people on for me being another test mule for another fluidampr product and didnt come through in the end to post better results.
I woud rather install a aftermarket damper on an engine stand then in the bottom of the car where I cant see anything.

:)

 

I'm kinda talking out my bum here because I don't take harmonics stuff until next semester, but I was under the impression that the harmonic balancer is there just to dampen the oscillation caused by the firing of the cylinders--not the actual balance of the reciprocating assy itself. That is why I kinda assumed that some balancers were taylored to different RPM ranges.

To further go on this point, the 400 uses a different balancer of course, but mainly because the external balance of that engine with the balancer and flexplate/flywheel.

I guess in the end, I kinda figure that if you still have a vibration with the GM unit that you will still have one with a streetdamper. I could be way wrong though...I haven't even been able to ground a wire correctly lately :(

 

Hey Matt,
Thanks for posting that...I totally agree with you about the damper controlling harmonics and not the balance job of the machine shop engine work.Fluidamper has a tech note about this on their web site as well.If the engine has a internal balance problem,these dampers wont fx it.

So anyways,today I decided, "let me try a "cheaper" GM damper" before I buy a streetdampr...one reason is even though I know the dampers wont fix an imbalance problem of the engine,it would be My Luck that I install a streetdampr and it somehow "maskes" a slight imbalance where I dont notice it much anymore and in the long run,I ruin the bearings and kill the engine...see what im getting at?

My faith suxs in car parts nowadays...I never had the luck of the draw when I needed it.Bearings can wear down faster with a engine vibration that isnt corrected.I want a streetdampr Just to have the best stuff,but money talks right now as well.

So,If the GM unit doesnt fix it,Im sending it back and even though ill get a streetdampr,I know Im going to have to pull the motor again to have the balance fixed and when I do,install the streetdampr while its out of the car.By then I should have the extra money for it saved up for the streetdampr.

Im pretty confident now the new GM damper will fix the vibes I got seeing how it is now.But im glad you pointed this subject out,I dont mean to lead anyone to believe a fluidamper set up is going to fix what could be a imbalance problem.I may have made it sound like that in the other posts but need to rethink my words sometimes.
Ill keep ya posted this week when its done.
:)