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Discussion Starter #1
I haven't been on for a while. I am THIS close to having a nice running Caprice.


I have an Ellwein engine that is internally balanced. My mechanic and I didn't realize we needed a neutral balanced flywheel as opposed to the stock external balanced flywheel. With the stock flywheel I had a really bad engine vibration (clutch pushed in sitting still) at about 4000 RPM.


The best way to describe the high frequency vibration is it buzzes the whole interior at 4K rpm.



I explained my situation to Tick Performance. They sent me a Spec SC85S billet steel flywheel. The vibration is still there.



Any ideas?
 

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Well, that part number comes up as a 93-97 f body.
I see no notation about it being neutral balanced.

What does the back of the flywheel look like?
Should be pretty obvious if there is a weight .

edit, found this photo of what is supposed to be your flywheel
http://www.taekwondoplus.org/z28/SPEC04.JPG
 

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Discussion Starter #3
Thank you! To be honest I didn't even open up the package. I just handed it off to my mechanic. I am willing to bet he didn't remove that weight. I mean what else could it be? Do you believe I should have him completely remove it and send it to the machine shop to have it ballenced? Or would removing the weight zero balance it? I am not sure what is typical with these things.

Learning about T56's has been a really long and expensive road. I am seriously considering putting the automatic back in.

Your Googlefoo is way stronger than mine. I have spent a lot of time and couldn't come up with a picture. I appreciate your help. I owe you a drink of your choosing if our paths cross.
 

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Discussion Starter #4
So I put the car on jackstands and got under there. Yes it was 2 am. I removed the oil filter and it gave me pretty good access to remove the weight. The car runs smoothly right up to 6500rpm now.

So when it comes to spec flywheels, leave the weight on for external balence. Remove the weight for internal balence.
 

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So I put the car on jackstands and got under there. Yes it was 2 am. I removed the oil filter and it gave me pretty good access to remove the weight. The car runs smoothly right up to 6500rpm now.

So when it comes to spec flywheels, leave the weight on for external balence. Remove the weight for internal balence.
Excellent news.
Pretty sure that spec says to just remove for zero.
Being the wheel is fully machined, one might think you might be out by the weight missing by the threaded holes.
I have no idea how much or little that is.
If you wanted to experiment , you could measure the depth of the holes, weigh a threaded rod,
calculate, fit a single bolt weighing the total in the center hole.
Maybe ask spec if it is truly zero with the three holes.
The only dealing I have had with a removable weight was when i had a t56 lt1.
My flywheel was not a spec.
I was matching the stock oe flex plate.
The weight postion was not 100% and I had to make a new offset one
 

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Pretty sure that spec says to just remove for zero.
Being the wheel is fully machined, one might think you might be out by the weight missing by the threaded holes.
I have no idea how much or little that is.
Well Gerry IIRC SPEC notes that if using their FW for "internal" balance motors remove the weight....and install 3 of the 4 hold down screws for the weight, use loc-tite

My McLeod Street Twin came with a billet FW. Specific part # for a "neutral" clutch/FW kit....well the FW was the same as a external balance one but just minus the weight BUT the 4 holes were drilled/taped.

Machine shop balanced it and guess what...those 4 holes = 25 grms so they put 25 grms worth of small alan head screws/washers in 3 of the holes

Fortunately the OP was able to remedy his problem by just removing dust cover and accessing the weight....but might want to put a few screws back in
 

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Well Gerry IIRC SPEC notes that if using their FW for "internal" balance motors remove the weight....and install 3 of the 4 hold down screws for the weight, use loc-tite
Rodger, I am bench racing, Googling, posting from the Holiday Inn ;)

Never personally seen a Spec or Mcleod LT1 wheel and was basing my "hole" advice on the three hole photo I found, and others reports of Specs install instructions.


Upshot, we both agree on the fact that the missing weight from the drilled holes should be accounted for.

And then, was the pressure plate checked for balance.

The ONLY way to really know ( hey we agree again) is to actually check the flywheel and pressure plate out of the car .
Gerry
 

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Rodger, I am bench racing, Googling, posting from the Holiday Inn ;)

Never personally seen a Spec or Mcleod LT1 wheel and was basing my "hole" advice on the three hole photo I found, and others reports of Specs install instructions.


Upshot, we both agree on the fact that the missing weight from the drilled holes should be accounted for.

And then, was the pressure plate checked for balance.

The ONLY way to really know ( hey we agree again) is to actually check the flywheel and pressure plate out of the car .
Gerry
ah the glamor of surfing the web from the hotel room....in my biz I live in them but for 20 years it was on a tour bus so the hotel is a cut above...at least when it comes to the bathroom :)

Ever since I went 383 internal balance motor I had every PP & FW neutral balanced, or checked, at a machine shop. Only took one time previously not doing this where the motor vibrated like a dog shiating razor blades

The shop first zero balances the FW then adds the PP to it and zero balances that

Smooth sailing every time...even when the FW is "advertised" as being neutral balanced. To much work to pull it all out if it isn't
 

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