I just thought I'd throw this out there since I didn't see anything about it in search.
I bought a basketcase 86 GT about 8 months ago that needed a new block. I got a known good block from an '88 which I knew was internally balanced vs. the 86's externally balanced. So, I got an 88 flywheel to go with the 88 block and I thought all was good as nobody said anything about needing a different damper in any threads I posted during my build.
Fast forward to now where I'm looking at getting a new damper from http://www.damperdoctor.com where they list two dampers for the 2.8. I thought all the dampers were the same so I emailed them and here is their reply:
"YES WE CAN SEND EITHER ONE. THERE IS A DIFFRENCE
INTERNALLY BALANCED DOES NOT HAVE A LUMP OF WEIGHT ON THE BACK OF THE BALANCER
EXTERNALLY BALANCED HAS A LUMP OF WEIGHT ON ONE OF THE FOUR PRONGS. IN THE BACK OF BALANCER. BOTH ARE SAME PRICE."
So... that means I've been running my 88 motor with an 86 damper and when I replace it, I need to get the 88 balancer to match the motor and the flywheel. Would this mismatch of balancers have caused me any drivability issues? My fuel economy sucks at the moment but I had attributed that to possibly having the timing off due to the rubber on the damper going bad.
On a side note, does anyone have a link to a good thread that shows how to replace the damper while still in the car?
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03:45 PM
PFF
System Bot
TopNotch Member
Posts: 3537 From: Lawrenceville, GA USA Registered: Feb 2009
The wrong damper will cause excessive vibration, which you should be able to feel. And it could damage your crank bearings. If you drop the rear of your cradle, you should be able to change it with the engine in the car.
Its weird, eh? When I was looking into getting parts for the 88 motor all I ever heard was to swap the flywheel and everything else would bolt up fine. Seems there is a discrepancy in dampers though so I figure I'll go ahead and order the 88 damper just to be on the safe side.
Its weird, eh? When I was looking into getting parts for the 88 motor all I ever heard was to swap the flywheel and everything else would bolt up fine. Seems there is a discrepancy in dampers though so I figure I'll go ahead and order the 88 damper just to be on the safe side.
I went out to the shed and looked at my original 86 balancer and there is no sign of any weight. Now the holes might be drilled different but that could be true just to get a balancer balanced.
I have a 3.1L D engine so I am using the 88 flywheel and the balancer listed for 88.
I know some people on here dug into this before and maybe they can shed some light on all of these numbers. I would assume the old Fiero numbers are out of production so these Am parts will be different numbers.
Terry
[This message has been edited by TK (edited 11-10-2009).]
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05:17 PM
fierogt28 Member
Posts: 2960 From: New-Brunswick, Canada. Registered: Feb 2005
Guys, beware that the fiero store's listed balancer is a GM balancer, but not a fiero specific part. It will fit and work the same as the original fiero balancer, the only difference is you need to punch a groove for timing at exactly the same spot of your old balancer. The balancer they sell works / installs the same, just isn't fiero original unit. Matter of fact is the fiero balancer is discontinued, and no longer available...
The DamperDoctor part is a rebuilt Fiero damper that has the correct orientation of the timing marks. That and the fact that its cheaper than the FieroStore damper is why I'm getting one from DD.
FS wants $97 plus shipping where DD wants $70 plus shipping.
I've done a bit more reading through searching old posts and it seems that some people say they are all the same and other says that 88 is different.
From what I'm reading, a 3.4 is internally balanced and would need an 88 balancer from an internally balanced 2.8.
Here is a picture of the externally balanced damper carried by DD that they sent me when I first asked them what the difference is. The lump above the keyway is not present on dampers for internally balanced dampers.
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06:55 PM
katatak Member
Posts: 7136 From: Omaha, NE USA Registered: Apr 2008
I have used the Damper Doctor's rebuilt dampers before - quality product. Sorry - I can't shed any light on the difference between internally and externally balanced motors. I would think that there should be a difference given the internal balance should require a neutrally balanced flexplate/flywheel and damper.
I had to replace a front seal on my 86 after I installed the new motor. I just pulled the two rear cradle bolts and the inner fender well and lowered the cradle about 2 or 3 inches. It was easy after that.
Here's the old next to the rebuilt damper: Note the difference in timing marks. The old one had spun!
[This message has been edited by katatak (edited 11-10-2009).]
Thanks for the pictures! I'm afraid that the two portions on mine has slipped as well and as such the timing isn't adjusted right. It takes a bit to start it and once it runs the idle seems to hunt a little and the car runs rich.
What did you do to get the balancer back on? The original bolt for mine broke in the crank and I had to have it millled out. The shop that did it put in a helicoil, which I doubt is a good place to use to pull the balancer back on with.
Has your 86 ever been worked on though? Maybe its not the original part?
In any case, I don't think there is a clear answer to this but from what I've gathered, I think its good to stay on the safe side and use different dampers for the difference in the way the engines are balanced. I just find it weird that there is just so much discrepancy on this.
Anyway, I clipped a piece of a page out that talks about harmonic balancers and externally vs internally balanced flywheels (I made it big so its readable ) Note the paragrpah in the right column:
This explains the discrpeancies we've been discussing. It doesn't matter whether the harmonic balancer is neutral or not. The quote is "ALL V6/60 torsional dampers are neutral balanced and may be used with either internally or externally balanced crankshafts." Note also in the left picture the damper has the little extra square of metal, but the writer refers to it as "neutral balanced torsional damper".
How 'bout them apples?
[This message has been edited by fyrebird68 (edited 11-18-2009).]
The extra metal on the shaft (the woodruff key) would make up the slot cut into the damper so that little extra blob of metal doesn't do anything to the key.
Um.... yeah. Confusing issue. I still haven't recieved my new damper yet but I imagine it should be in soon. I'd like to get it swaped out this weekend if I go down to Tulsa to steal my dad's garage.
