[C2] New damper needed
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
New damper needed
I need a new 8" damper for my built 406sbc that's internally balanced. I see many variations for sale on Summitt, Jegs & ebay so is there something in particular to look for or anything to avoid?
Last edited by 65air_coupe; Jul 8, 2022 at 07:33 PM.
Race Director
Joined: Jan 2002
Posts: 15,359
Likes: 2,728
From: Close to DC
C2 of the Year Finalist - Modified 2020
FWIW..... Did a reputable shop build the engine? If so, talk with them. An important part such as this, I would never buy it off Ebay unless it is a WELL know performance supplier. 
Dennis
Dennis
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
I'm not sure you could call me a 'reputable shop', but I built it. And I'd never claim to be an expert at anything, much less building performance motors but I do have some experience.
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
Race Director
Joined: Mar 2018
Posts: 10,774
Likes: 2,206
From: Golden Colorado
Quality for dampers is all over the board now. Lots of cheap inferior stuff out there. Pay a bit more and get an SFI one even if it’s “not a race car”.
The quality control is worth it.
The quality control is worth it.
Drifting
Joined: Jul 2014
Posts: 1,556
Likes: 791
From: Massachusetts
If the only problem is that the rubber isolator has deteriorated, one option would be to have your existing balancer rebuilt by a specialist service such as Damper Doctor.
Also, are you looking for the "big" small block balancer that is 8" in diameter and approximately 1-11/16" thick? The 1962-1968 versions had the timing mark almost lined up with the keyway, but the starting in 1969, the timing mark was moved several degrees.
The service replacement GM part number has gone through about eight changes, but I believe the most recent part number is 19260269 and is still available from GM. I'm not sure what it has in terms of the timing mark.
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Racer
Joined: Feb 2014
Posts: 373
Likes: 93
I had my Camaro at the truck earlier this year for the first time in 25 years. And it showed… I spun the balancer and it pushed off about 1/2” as well. I ordered an SFI balancer which is what I would recommend. No more spun balancers. I think the ProBond was the one I got?
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
You don't mention why you need a new balancer. Can you clarify what the problem is?
If the only problem is that the rubber isolator has deteriorated, one option would be to have your existing balancer rebuilt by a specialist service such as Damper Doctor.
Also, are you looking for the "big" small block balancer that is 8" in diameter and approximately 1-11/16" thick? The 1962-1968 versions had the timing mark almost lined up with the keyway, but the starting in 1969, the timing mark was moved several degrees.
The service replacement GM part number has gone through about eight changes, but I believe the most recent part number is 19260269 and is still available from GM. I'm not sure what it has in terms of the timing mark.
If the only problem is that the rubber isolator has deteriorated, one option would be to have your existing balancer rebuilt by a specialist service such as Damper Doctor.
Also, are you looking for the "big" small block balancer that is 8" in diameter and approximately 1-11/16" thick? The 1962-1968 versions had the timing mark almost lined up with the keyway, but the starting in 1969, the timing mark was moved several degrees.
The service replacement GM part number has gone through about eight changes, but I believe the most recent part number is 19260269 and is still available from GM. I'm not sure what it has in terms of the timing mark.
Mark, it's an internally balanced rotating assembly and the damper can't be repaired according to Damper Dudes.
Le Mans Master
Joined: Feb 2008
Posts: 6,528
Likes: 1,939
From: Folsom CA
Wow, that certainly looks like a failure. You will need new parts. I wish my 400 was internally balanced but I used the parts I had and I am running the original 400 crank turned .010 under so mine will be externally balanced. I like your set up better as you can run the same parts as the original 327 for balancer and flywheel.
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
Wow, that certainly looks like a failure. You will need new parts. I wish my 400 was internally balanced but I used the parts I had and I am running the original 400 crank turned .010 under so mine will be externally balanced. I like your set up better as you can run the same parts as the original 327 for balancer and flywheel.
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
Le Mans Master
Joined: Feb 2008
Posts: 6,528
Likes: 1,939
From: Folsom CA
You might put a mic on your snout and see how large it measures. Sincei it is internally balanced I am guessing Scat or Eagle? It would be important to know the size before installing a new balancer.
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
Update: A new damper arrived today and using calipers, it appears to measure 1.2425". I don't have inside mics that size so I'm going to a friend's machine shop to re-measure but if that's close to accurate, I'll have sufficient interference for a good press fit. That's a big relief!
Last edited by 65air_coupe; Jul 14, 2022 at 03:23 PM.
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 2,965
Likes: 419
From: Melbourne FL
It's 1.245...too small for most balancers I'm finding that are nominally that size as well. In all the reading I'm doing...and it's a lot so far, I find that Scat is known for undersize noses. They actually make dampers as well so I'm trying to get the specs for theirs.
Update: A new damper arrived today and using calipers, it appears to measure 1.2425". I don't have inside mics that size so I'm going to a friend's machine shop to re-measure but if that's close to accurate, I'll have sufficient interference for a good press fit. That's a big relief!
Update: A new damper arrived today and using calipers, it appears to measure 1.2425". I don't have inside mics that size so I'm going to a friend's machine shop to re-measure but if that's close to accurate, I'll have sufficient interference for a good press fit. That's a big relief!
Le Mans Master
Joined: Feb 2008
Posts: 6,528
Likes: 1,939
From: Folsom CA
I see you have about .003 extra clearance. When you slide it on how does it feel? Is there any movement or walk when you try to move it side to side or up and down. If it feels tight, no detectable movement, I think I would bolt it and move on. I am thinking your broken damper went on very tight?
Edit, sorry I read the measurements wrong. Both damper and snout are 1.245. I think I would run it.
Edit, sorry I read the measurements wrong. Both damper and snout are 1.245. I think I would run it.
Last edited by Westlotorn; Jul 23, 2022 at 06:03 PM.
Safety Car
Joined: Oct 2016
Posts: 4,617
Likes: 1,547
From: Olive branch Ms
Did you mic the crank with a micrometer or calipers. This is where everything needs to be measured with a mic. As I told you earlier ATI makes an undersized hub you have to fit to size. You can buy a new damper from them pricey or buy a used one on eBay and change the hub. There are occasionally dampers listed with a bad hub.
Mark I’m reading the crank and damper are both 1.245. So he doesn’t really have clearance or press.
Mark I’m reading the crank and damper are both 1.245. So he doesn’t really have clearance or press.