sbc harmonic balancer

Ed Wright · 03-02-2013, 11:00 AM

Do your engine a favor and put an ATI dampener on it.

Bob Bender · 03-02-2013, 01:59 PM

Quote:

Originally Posted by Ed Wright

Do your engine a favor and put an ATI dampener on it.

x2

james schaechter · 03-02-2013, 03:14 PM

Back in the 80's we put an aluminum balancer, I guess it was really not a balancer, just a hub that Moroso sold on our 427. It looked nice, it was very light, it was cheap too!
When we put it on the car, it even seemed like it revved up real quick! After it was on the car a few runs, we got tired of picking up all the crap that shook off of the car! It unscrewed almost every meaningful bolt on the car! Even the transmission case cracked!

It made someone a real neat looking ashtray.

Your story made me think of that one we had. Save a little, Spend A Lot! LOL.

Alan Roehrich · 03-02-2013, 04:29 PM

Quote:

Originally Posted by james schaechter

Back in the 80's we put an aluminum balancer, I guess it was really not a balancer, just a hub that Moroso sold on our 427. It looked nice, it was very light, it was cheap too!
When we put it on the car, it even seemed like it revved up real quick! After it was on the car a few runs, we got tired of picking up all the crap that shook off of the car! It unscrewed almost every meaningful bolt on the car! Even the transmission case cracked!

It made someone a real neat looking ashtray.

Your story made me think of that one we had. Save a little, Spend A Lot! LOL.

We took the stock balancers off of our 454 based bracket/.90 Super class engines back when NHRA mandated an SFI balancer for 10 second and faster cars. We bought some of those aluminum balance hubs. A few passes later, all those cranks that had a lot of passes with stock balancers were broken, and the timing sets were worn out. We had a rough season that year. The only engine that didn't break was our "high end" (for the time) "big" engine, that had a forged crank and "dimple" rods, and it broke a lot of valvesprings, killed two timing sets, and beat up a set of bearings. That winter, Jim Beattie, owner of ATI, came to the shop (he's a good friend, and has family here), looked at the cars and engines, and asked me how many cranks we broke that season. After he laughed at my answer he told me we were getting some presents for Christmas. A few days later, 4 new ATI Super Dampers arrived at the shop. Never broke another crank, and timing sets started lasting several seasons. We were, and I still am, an ATI dealer, and Jim has always treated me really well.

Adger Smith · 03-02-2013, 05:18 PM

Bobby,
In your better terms, yes you can use different parts from SBC's to make them "Hybrids". The late mod crank is keyed the same as the early mod crank as far as I know. the cam timing would be different, too. The number of degrees difference in the mark is in the balancer. I thought it was more than 10 degrees, like 26 for one series balancer and 13 for the other. My memory tells me there are actually 3 different timing combos (locations) for a SBC without the LT-1 and LS. As to the use of the balancer. Yes, you can use it, BUT and that is a big But... It might cause some of the symptoms mentioned in some of the other posts. That balancer you are talking about was designed for the harmonics of the 3" stroke 283 crank and was also used on the low RPM (Low PERF) 307/327's. If this is just a "driver" and not a race car that is going to see some 5,000-7,000 RPM blasts it might survive and your other parts might survive as well. If you want a better stock balancer there is a heavier, extra wide 305 balancer that is about the same diameter as the 6 3/4. I think it will match up to your timing mark, too. That timing mark on your cover is straight down from the top, behind the water pump. You do realize you MUST use a long water pump to see that mark? I think It is about 6 7/8" diameter. From Pioneer they are pretty cheap and I think Powerbond makes a better replacement that is a little higher priced. I know we are talking about a balancer that is NOT Aluminum. How did we get to talking about them? I thought everyone knew the aluminum weren't even good paper weights or doorstops. OK, ash trays! :~)

Dave Casey · 03-02-2013, 06:53 PM

I believe that the balancer that I used on my 305 stocker for years is the one you are refering to. It worked fine for me for 20 years, it is a narrow balancer. It would probably still be on my car, but I believe g/s and faster requires an aftermarket balancer and I put one on.

I always assumed that the rear of a one piece seal 305/350 crank is balanced externally, but the front was not. Is that correct ?

Rob Petrie E395 · 03-02-2013, 07:19 PM

Did I screw up when I ordred my Damper? ATI has several available for my engine (Late Model LT1) My thought was the less weight on the crank the better for performance. So instead of getting the 7.53 inch steel one I got the 6.78 inch Aluminum one. The steel one weighs 9.75 Lbs. the one I got weighs 4.5. I figured that much weight had to be worth something in terms of performance. Should send it back and get the steel one? Or is the Alum ATI super damper as good as the heaver steel one they sell? Thanks

Adger Smith · 03-02-2013, 09:22 PM

Correct Dave.
The flywheel on the one piece crank is smaller on the hub and has a smaller bolt circle it also has what is called a "Butterfly weight"
That weight replaces the "Ear" that is on most 2 piece seal cranks out side the seal surface. That ear is usually weight that is in line with the rear counterweight. The ear is cut off on the 1 piece cranks. They are full round in that area.
The balancer end of the crank is neutral balanced.
Rob the small is OK

03-02-2013, 11:00 AM	#1
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: sbc harmonic balancer Do your engine a favor and put an ATI dampener on it. __________________ Ed Wright 4156 SS/JA

03-02-2013, 03:14 PM	#3
james schaechter VIP Member Join Date: Dec 2004 Location: Cumming GA Posts: 1,984 Likes: 1,277 Liked 1,423 Times in 294 Posts	Re: sbc harmonic balancer Back in the 80's we put an aluminum balancer, I guess it was really not a balancer, just a hub that Moroso sold on our 427. It looked nice, it was very light, it was cheap too! When we put it on the car, it even seemed like it revved up real quick! After it was on the car a few runs, we got tired of picking up all the crap that shook off of the car! It unscrewed almost every meaningful bolt on the car! Even the transmission case cracked! It made someone a real neat looking ashtray. Your story made me think of that one we had. Save a little, Spend A Lot! LOL. __________________ James Schaechter 3163 STK

03-02-2013, 05:18 PM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: sbc harmonic balancer Bobby, In your better terms, yes you can use different parts from SBC's to make them "Hybrids". The late mod crank is keyed the same as the early mod crank as far as I know. the cam timing would be different, too. The number of degrees difference in the mark is in the balancer. I thought it was more than 10 degrees, like 26 for one series balancer and 13 for the other. My memory tells me there are actually 3 different timing combos (locations) for a SBC without the LT-1 and LS. As to the use of the balancer. Yes, you can use it, BUT and that is a big But... It might cause some of the symptoms mentioned in some of the other posts. That balancer you are talking about was designed for the harmonics of the 3" stroke 283 crank and was also used on the low RPM (Low PERF) 307/327's. If this is just a "driver" and not a race car that is going to see some 5,000-7,000 RPM blasts it might survive and your other parts might survive as well. If you want a better stock balancer there is a heavier, extra wide 305 balancer that is about the same diameter as the 6 3/4. I think it will match up to your timing mark, too. That timing mark on your cover is straight down from the top, behind the water pump. You do realize you MUST use a long water pump to see that mark? I think It is about 6 7/8" diameter. From Pioneer they are pretty cheap and I think Powerbond makes a better replacement that is a little higher priced. I know we are talking about a balancer that is NOT Aluminum. How did we get to talking about them? I thought everyone knew the aluminum weren't even good paper weights or doorstops. OK, ash trays! :~) __________________ Adger Smith (Former SS) Last edited by Adger Smith; 03-02-2013 at 05:25 PM.

03-02-2013, 06:53 PM	#6
Dave Casey VIP Member Join Date: Dec 2002 Location: Hampden, MA Posts: 1,197 Likes: 233 Liked 769 Times in 162 Posts	Re: sbc harmonic balancer I believe that the balancer that I used on my 305 stocker for years is the one you are refering to. It worked fine for me for 20 years, it is a narrow balancer. It would probably still be on my car, but I believe g/s and faster requires an aftermarket balancer and I put one on. I always assumed that the rear of a one piece seal 305/350 crank is balanced externally, but the front was not. Is that correct ? __________________ Dave Casey 1330 STK

03-02-2013, 07:19 PM	#7
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,092 Likes: 162 Liked 216 Times in 77 Posts	Re: sbc harmonic balancer Did I screw up when I ordred my Damper? ATI has several available for my engine (Late Model LT1) My thought was the less weight on the crank the better for performance. So instead of getting the 7.53 inch steel one I got the 6.78 inch Aluminum one. The steel one weighs 9.75 Lbs. the one I got weighs 4.5. I figured that much weight had to be worth something in terms of performance. Should send it back and get the steel one? Or is the Alum ATI super damper as good as the heaver steel one they sell? Thanks

03-02-2013, 09:22 PM	#8
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: sbc harmonic balancer Correct Dave. The flywheel on the one piece crank is smaller on the hub and has a smaller bolt circle it also has what is called a "Butterfly weight" That weight replaces the "Ear" that is on most 2 piece seal cranks out side the seal surface. That ear is usually weight that is in line with the rear counterweight. The ear is cut off on the 1 piece cranks. They are full round in that area. The balancer end of the crank is neutral balanced. Rob the small is OK __________________ Adger Smith (Former SS)