L98 Harmonic Balancers
Melting Slicks
Joined: Apr 2002
Posts: 3,019
Likes: 0
From: down that one road next to that big tree
Re: L98 Harmonic Balancers (HWoods)
yes, and they can be bought new from GM, it's listed in the parts performance catalog. just a 6-3/4" damper. i even used one on my new motor.
Racer
Joined: Apr 2002
Posts: 415
Likes: 0
From: loughborough Leics ENGLAND
Re: L98 Harmonic Balancers (gtsyellow)
Be careful :nono: I am sure the 86 on l98's are not the same as the 85 and earlier
I have been looking into dampers a lot latey and one is internally balanced (upto 85 )and one is for externaley balanced (86 and on ) 350's.
The external balance 350's use a different damper to the 400's which are also externally balanced.
:cheers:
I have been looking into dampers a lot latey and one is internally balanced (upto 85 )and one is for externaley balanced (86 and on ) 350's.
The external balance 350's use a different damper to the 400's which are also externally balanced.
:cheers:
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: L98 Harmonic Balancers (BLUE ONE)
Sure, I know that the GM performance parts book specs a different one for 86 and above. Thing is I really don't know why its needed...nor does my machinist...nor does the manager at the local GM parts counter. The reason the flywheel is not neutral balnced on 86+ years is because the one-piece-rear-seal-crank for th 86+ years, lacks the 'balance' flange at the rear of the crank....like the 85 and prior years, had. So to make up for the missing flange, the flywheel for 86+ years, has a weight to compensate. Now the front of the crank is identical between all years. Given: 3.48" stroke. My new block has a one-piece-rear-seal; along with the proper crank; and I have a new 86+ flywheel. So the balancing guy is going to balance everything as follows: PISTONS+RODS+CRANK+FLYWHEEL+BEARINGS the balancer is going to be from an 85 or prior. Hopefully the snout on all these cranks have the same dimensions.
:thumbs:
[Modified by GRX, 2:36 PM 12/28/2002]
:thumbs:
[Modified by GRX, 2:36 PM 12/28/2002]
Burning Brakes
Joined: Nov 2000
Posts: 1,012
Likes: 1
From: Bowie MD
Re: L98 Harmonic Balancers (BLUE ONE)
My 1990 original engine in the garage on a stand being rebuilt is and always was an internally balanced L98, with a one piece rear main seal. the replaced 2001 ZZ4 GM crate motor in the car is also internally balanced. The smaller balancer had to be put on the crate motor and it fit great, with the proper tools. Don't know where blueone is getting his misinformation from. :crazy:
Racer
Joined: Apr 2002
Posts: 415
Likes: 0
From: loughborough Leics ENGLAND
Re: L98 Harmonic Balancers (corvette1990)
I got my info from John Ligenfelter....quote What many Chevy fans may not know is that ALL '86 and later chevy small blocks are externally balanced engines requiring specific flywheels. flexplates AND torsional dampers.
This rarely presents a problem because ALL '86 and later engines require the specific one piece rear main seal crank etc.
this quote is from his book on modifying sbc engines page 32 crank shaft and bearings section.
If he's wrong then i am wrong, i do not claim to be an expert in this area, i was just recalling what i had read recently and have just re read to make sure i was not miss quoting.
the explanation about the rear seal makes sence to me as it would make the crank external balance which could mean the damper would still be the same as an internally balanced pre 86 if all the weight is added to the flexplate/flywheel
I guess anyone can make a mistake even John :lol: If your machinist and chevy dealer are happy go with that or you could just double check by contacting Lingenfelter performance and see if its a typo.
:cheers:
This rarely presents a problem because ALL '86 and later engines require the specific one piece rear main seal crank etc.
this quote is from his book on modifying sbc engines page 32 crank shaft and bearings section.
If he's wrong then i am wrong, i do not claim to be an expert in this area, i was just recalling what i had read recently and have just re read to make sure i was not miss quoting.
the explanation about the rear seal makes sence to me as it would make the crank external balance which could mean the damper would still be the same as an internally balanced pre 86 if all the weight is added to the flexplate/flywheel
I guess anyone can make a mistake even John :lol: If your machinist and chevy dealer are happy go with that or you could just double check by contacting Lingenfelter performance and see if its a typo.
:cheers:
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: L98 Harmonic Balancers (corvette1990)
If you attempt to internally balance your '90 L98, you will find that you need about $35 of Mallory metal to do it. They were/are externally balanced. If you go ahead an internally balance it, you should be able to use a small lightweight race balancer.
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Racer
Joined: Jan 2001
Posts: 253
Likes: 0
From: Bahama NC
Re: L98 Harmonic Balancers (GRX)
I'll go WAAAY out on a limb and offer my humble experience... I was researching a fluidamper for my '86. From info given me by various experts and my own observations - ie. balance weight on the flywheel, I determined that the engine was externally balanced.
I ordered the external SBC damper from summit and found it to be totally wrong. It has a large balancing hump on one side and was considerably larger in diameter. This damper is meant for 383's and 400's that are full external balance.
After more research, I determined that SBC's (non 400 crank based) are both internally and externally balanced. Internal on the front and external on the back.
I returned the damper and ordered the one specified for all 262-350's. It fits and works perfectly! :yesnod:
I ordered the external SBC damper from summit and found it to be totally wrong. It has a large balancing hump on one side and was considerably larger in diameter. This damper is meant for 383's and 400's that are full external balance.
After more research, I determined that SBC's (non 400 crank based) are both internally and externally balanced. Internal on the front and external on the back.
I returned the damper and ordered the one specified for all 262-350's. It fits and works perfectly! :yesnod:
