Another BBC Motor??? Dampers - The 1947 - Present Chevrolet & GMC Truck Message Board Network

6600DURAMAX · 04-08-2009, 08:13 AM

Have another engine question – Not to make this to long of post but the motor I have appears to be a 468 with an aftermarket forged crank and H-Beam rods. When I started to tear the truck down and I removed the flywheel I noticed it had no external weight on it like a normal 454, once I found out that it had a aftermarket crank I assumed this was OK it was just an internally balanced assembly (I am only assuming this as I really don’t know how to tell???? The front damper looked weird to me also, but I just figured it was a smaller aftermarket damper BUT a buddy was over the other night and started looking at it and said it was just a stock damper that someone took the outer portion off of. The damper has no timing marks on the outside and also has no external weight?? He stated I need to get a new damper. Would I get a damper for an externally balanced motor? Or does it even matter???

I will post pics of the damper tonight when I get back to my home computer but any additional help before then would be great

Thanks guys

6600DURAMAX · 04-09-2009, 07:51 AM

No one??

**regan wilson** · 04-09-2009, 01:42 PM

Sounds like it would be internaly balanced . If it were mine I would find a damper without a weight to try . I had the same problem one time and had the wrong flexplate so it shook like hell . The motor should tell you if its right or not .

6600DURAMAX · 04-09-2009, 01:54 PM

Has anyone used a Professional Products damper??

Ont67shortbox · 04-09-2009, 11:28 PM

The PP dampers are crap,if your looking for a reasonably priced SFI damper try Pioneer or Probond or Summit

dragula · 04-10-2009, 01:25 AM

If it's in your budget I would get an ATI external, and if your motor is internal you can unbolt the weight. It's like havin two balancer's in one. Look on racin junk.com It's full of good used ones. It's hard to go wrong buying a used balancer!

6600DURAMAX · 04-19-2009, 07:27 PM

Was talking to a guy the other day and when he looked at my motor he said the aftermarket crank has the weight on the back of it, so I am still confused if I have an externally balanced motor or if it is internally. Is there any way I can tell for sure before I put the wrong damper on. I will try and find a pic of the damper that came off it, but it looks like a stock one without the outside rubber part. I can get a ATI blem damper for $200 straight from ATI (only has sractches nothing structurally wrong) jsut need to know which one.

6600DURAMAX · 04-19-2009, 07:31 PM

Heres a pic of the damper that was on the motor

6600DURAMAX · 04-19-2009, 07:34 PM

Back of Crank

6600DURAMAX · 04-20-2009, 09:21 PM

No help guys??

Talked to ATI and they told me while you can remove the weight on their external balancer to turn it into a internal balancer that do not recommend it. He told me I need to figure out what I have then order the proper balancer?????????

HELP

Marv D · 04-20-2009, 10:07 PM

Quote:

Originally Posted by 6600DURAMAX

No help guys??

He told me I need to figure out what I have then order the proper balancer?????????

HELP

While I can't help a bit with making a ID on what you have there, I will agree with the phone jocky at ATI. You better haul the thing down to your local machinist and have them check the balance. Guess wrong and your going to be wasting $'s. The ATI balancers are made 'tight' and have to be honed to a perfect press fit for YOUR crank. Which means your going to own it even if it is the wrong one.

6600DURAMAX · 04-21-2009, 07:54 AM

Wow Marv, so since teh motor just got put back in the truck how in the world am I going to hone the balancer to get it to fit perfectly?? Isn't thte crank snout the same on all bbc cranks. Why would they make it so difficult. Do all aftermarket balancers have to have this done to them?

Marv D · 04-21-2009, 10:32 AM

Because all cranks have a 'slight' variation. I have a ATI superdamper that was honed and fit to a Cola crank. I have a Eagle sbc crank that you can push 'that' balancer on by hand,,, literally BY HAND! ATI leaves them tight so they can be honed to the exact press fit for THAT crank. (off the top of my head) they want a 0.0002 to 0.0007 press fit to properly absorb harmonics from the crank. Too tight and you can't get it on the snout, too loose and it doesn't do it's job,,, absorb harmonics. And No, not all aftermarket dampers need to be honed to fit,,, just the good ones.

In all honesty, if you have a GM crank you will probably be just fine having it honed to /normal/ GM crank size. But if you have some imported POS crank final machined anywhere else other than the US,, it's a crap shoot. If you have a 'good' mic and know how to use it, you can just tell your machinist what the diameter is, and what the press-fit needs to be (will be in the instructions with the damper)

04-08-2009, 08:13 AM	#1
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Another BBC Motor??? Dampers Have another engine question – Not to make this to long of post but the motor I have appears to be a 468 with an aftermarket forged crank and H-Beam rods. When I started to tear the truck down and I removed the flywheel I noticed it had no external weight on it like a normal 454, once I found out that it had a aftermarket crank I assumed this was OK it was just an internally balanced assembly (I am only assuming this as I really don’t know how to tell???? The front damper looked weird to me also, but I just figured it was a smaller aftermarket damper BUT a buddy was over the other night and started looking at it and said it was just a stock damper that someone took the outer portion off of. The damper has no timing marks on the outside and also has no external weight?? He stated I need to get a new damper. Would I get a damper for an externally balanced motor? Or does it even matter??? I will post pics of the damper tonight when I get back to my home computer but any additional help before then would be great Thanks guys __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-09-2009, 07:51 AM	#2
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers No one?? __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-09-2009, 01:42 PM	#3
regan wilson Senior Member Join Date: Mar 2008 Location: tyler texas Posts: 1,532	Re: Another BBC Motor??? Dampers Sounds like it would be internaly balanced . If it were mine I would find a damper without a weight to try . I had the same problem one time and had the wrong flexplate so it shook like hell . The motor should tell you if its right or not . __________________ NHRA Super Street 469C It only runs 10.90 at 156 mph

04-09-2009, 01:54 PM	#4
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers Has anyone used a Professional Products damper?? __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-09-2009, 11:28 PM	#5
Ont67shortbox Registered User Join Date: May 2003 Location: Ontario Posts: 279	Re: Another BBC Motor??? Dampers The PP dampers are crap,if your looking for a reasonably priced SFI damper try Pioneer or Probond or Summit

04-10-2009, 01:25 AM	#6
dragula Registered User Join Date: Jan 2009 Location: ky Posts: 23	Re: Another BBC Motor??? Dampers If it's in your budget I would get an ATI external, and if your motor is internal you can unbolt the weight. It's like havin two balancer's in one. Look on racin junk.com It's full of good used ones. It's hard to go wrong buying a used balancer!

04-19-2009, 07:27 PM	#7
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers Was talking to a guy the other day and when he looked at my motor he said the aftermarket crank has the weight on the back of it, so I am still confused if I have an externally balanced motor or if it is internally. Is there any way I can tell for sure before I put the wrong damper on. I will try and find a pic of the damper that came off it, but it looks like a stock one without the outside rubber part. I can get a ATI blem damper for $200 straight from ATI (only has sractches nothing structurally wrong) jsut need to know which one. __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-19-2009, 07:31 PM	#8
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers Heres a pic of the damper that was on the motor Attached Images __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-19-2009, 07:34 PM	#9
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers Back of Crank Attached Images __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-20-2009, 09:21 PM	#10
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers No help guys?? Talked to ATI and they told me while you can remove the weight on their external balancer to turn it into a internal balancer that do not recommend it. He told me I need to figure out what I have then order the proper balancer????????? HELP __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-21-2009, 07:54 AM	#12
6600DURAMAX Registered User Join Date: Nov 2000 Location: Wheatfield IN, USA Posts: 1,107	Re: Another BBC Motor??? Dampers Wow Marv, so since teh motor just got put back in the truck how in the world am I going to hone the balancer to get it to fit perfectly?? Isn't thte crank snout the same on all bbc cranks. Why would they make it so difficult. Do all aftermarket balancers have to have this done to them? __________________ 1972 K5 Build - plans - LS3-6L80e-One Tons..... 1971 CREWMAX Build.....at body shop for couple more years

04-21-2009, 10:32 AM	#13
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	Re: Another BBC Motor??? Dampers Because all cranks have a 'slight' variation. I have a ATI superdamper that was honed and fit to a Cola crank. I have a Eagle sbc crank that you can push 'that' balancer on by hand,,, literally BY HAND! ATI leaves them tight so they can be honed to the exact press fit for THAT crank. (off the top of my head) they want a 0.0002 to 0.0007 press fit to properly absorb harmonics from the crank. Too tight and you can't get it on the snout, too loose and it doesn't do it's job,,, absorb harmonics. And No, not all aftermarket dampers need to be honed to fit,,, just the good ones. In all honesty, if you have a GM crank you will probably be just fine having it honed to /normal/ GM crank size. But if you have some imported POS crank final machined anywhere else other than the US,, it's a crap shoot. If you have a 'good' mic and know how to use it, you can just tell your machinist what the diameter is, and what the press-fit needs to be (will be in the instructions with the damper) __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. Last edited by Marv D; 04-21-2009 at 10:36 AM.



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