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Re: Small Block Internal and External Balance Questions
[Re: 70AARcuda]
#1524873
10/28/13 10:23 PM
10/28/13 10:23 PM
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Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog
Striving for excellence
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Striving for excellence
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
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Quote:
All 360s are externally balanced...all need weight on the damper/balancer and all need weight on either the converter or the flexplate...
weighted converters from 360s are interchangeable.. as is the dampers.
Well, this is true for the LA series of 360 engines. The Magum 360/5.9 engines use a different balance factor.
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Re: Small Block Internal and External Balance Questions
[Re: 70AARcuda]
#1524875
10/28/13 10:28 PM
10/28/13 10:28 PM
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Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog
Striving for excellence
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Striving for excellence
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
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I read what he wrote. Sometimes these threads apply to more than just the OP and we wouldn't want to lead anyone astray would we?
Last edited by Frankenduster; 10/28/13 11:02 PM.
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Re: Small Block Internal and External Balance Questions
[Re: Kern Dog]
#1524876
10/28/13 11:41 PM
10/28/13 11:41 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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If you answer the question that is asked..then you are not leading the OP a stray....pretty simple...
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: Small Block Internal and External Balance Questions
[Re: Kern Dog]
#1524877
10/28/13 11:43 PM
10/28/13 11:43 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Frankenduster, while you are correct about other people reading this remember one technical detail here. The 360 is an LA motor and the 5.9 is a magnum, technically speaking, though people tend to be flexible about the terminology.
So you are both right.
Also, to address the OP's concerns, early 360's and later 360's have different design balancers, as you have seen. they are interchangeable though.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: Small Block Internal and External Balance Questions
[Re: Badge]
#1524880
10/29/13 08:07 AM
10/29/13 08:07 AM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Look on the back side of the damper, you'll probably have to pull it to see.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: Small Block Internal and External Balance Questions
[Re: Supercuda]
#1524882
10/29/13 09:53 AM
10/29/13 09:53 AM
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Joined: Jan 2006
Posts: 8,162
USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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Does anyone have knowledge of how close to "true balance" the externally weighted 360 LA and Magnum 5.9 V8 typically are from the factory ? Are they within, say 15 grams of zero? Are the internally neutral 318/5.2 V8s typically better balanced from the factory? I know a guess always has to be made about the weight of "residual oil" clinging to the crankshaft of a running engine. It has seemed to me that 318s have less vibration than 360s http://www.ebay.com/gds/Crankshaft-Engine-Stroker-Kit-Balance-Balancing-/10000000013602009/g.htmlsample quote So what does this actually mean in terms of the forces generated inside an engine? An imbalance of only 1/4 oz. (7 grams) located four inches out from the center of the crank on a counterweight will generate a force of about 7 lbs. at 2,000 rpm. At low rpm, you would hardly feel a thing. But at 8,000 rpm, that same force would grow to 114 lbs. with every revolution of the crank. If this same engine had one ounce (28 grams) of imbalance, the forces generated would be multiplied by a factor of four, generating 456 lbs. of unwanted gyrations at 8,000 rpm! That’s enough vibration to rattle your teeth and pound the heck out of the main bearings. It’s also wasted motion that goes into shaking the block instead of spinning the crankshaft. Consequently, imbalance hurts horsepower as well as smoothness and engine longevity. The factory balance of crankshafts can vary a great deal depending on the application and the OEM tolerances. For a low rpm stock engine, plus or minus 8 to 10 grams or more may be close enough for the average Joe. For a street performance engine, those numbers should come down to plus or minus 3 grams or less. And for a high revving NASCAR engine that spends most of its time at 8,500 to 9,500 rpm, plus or minus 1 gram or less is the rule. How much is 1 gram? Not very much. A dollar bill weighs one gram. A penny, by comparison, weighs about 2-1/2 grams. An ordinary sheet of office paper tips the scale at a whopping 5 grams, which is more than the amount of imbalance that’s generally desired in a street engine.
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Re: Small Block Internal and External Balance Questions
[Re: 360view]
#1524883
10/29/13 12:26 PM
10/29/13 12:26 PM
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Joined: Jan 2003
Posts: 1,263
Southwestern Ontario Canada
racealittle
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,263
Southwestern Ontario Canada
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Are the two factory harmonic balancers the same? ('70's vs '80's). The 1974 damper I have has a huge amount of weight cast into it. The 1982 damper that I have has a smoother, lighter design where the weight has been removed (machined away) to balance it. I am not sure that they are completely interchangeable. I'm sure many have done the swap with no known ill effects. I am hesitant. The crankshafts also appear to be machined differently to me (at least the ones that I am comparing).
Too many cars, too many parts, too little coin, too little space to work in, too little time left to make it all happen!
Update: down to one ride, still too many parts, a little more jingle in the pocket, gaining space, and it's going to happen this year!
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Re: Small Block Internal and External Balance Questions
[Re: dogdays]
#1524885
10/29/13 04:05 PM
10/29/13 04:05 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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Look at an Aftermarket balancer...such as Professional Product 90012, it comes with 3 bolt on weights...
one weight for cast crank externally balanced 340
one weight for cast crank externally balanced LA 360s 71-92
one weight for cast crank externally balanced magnum 360
and the balancer can be used with no weights for a internally balanced 318/340...
dont see a different weight for a 70s 360 nor a different weight for a 80s 360...
So Albert Einstein would concluded that one weight would fit all 360s from 71-92...which is weighted the same as OEM balancers from 71-92....
Last edited by 70AARcuda; 10/29/13 04:05 PM.
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: Small Block Internal and External Balance Questions
[Re: 360view]
#1524886
10/29/13 04:12 PM
10/29/13 04:12 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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Quote:
Does anyone have knowledge of how close to
"true balance"
the externally weighted
360 LA and Magnum 5.9 V8
typically are from the factory ?
Are they within, say 15 grams of zero?
Are the internally neutral 318/5.2 V8s
typically better balanced from the factory?
I know a guess always has to be made about the weight of "residual oil" clinging to the crankshaft of a running engine.
It has seemed to me that 318s have less vibration than 360s
http://www.ebay.com/gds/Crankshaft-Engine-Stroker-Kit-Balance-Balancing-/10000000013602009/g.html
sample quote
So what does this actually mean in terms of the forces generated inside an engine? An imbalance of only 1/4 oz. (7 grams) located four inches out from the center of the crank on a counterweight will generate a force of about 7 lbs. at 2,000 rpm. At low rpm, you would hardly feel a thing. But at 8,000 rpm, that same force would grow to 114 lbs. with every revolution of the crank. If this same engine had one ounce (28 grams) of imbalance, the forces generated would be multiplied by a factor of four, generating 456 lbs. of unwanted gyrations at 8,000 rpm!
That’s enough vibration to rattle your teeth and pound the heck out of the main bearings. It’s also wasted motion that goes into shaking the block instead of spinning the crankshaft. Consequently, imbalance hurts horsepower as well as smoothness and engine longevity.
The factory balance of crankshafts can vary a great deal depending on the application and the OEM tolerances.
For a low rpm stock engine, plus or minus 8 to 10 grams or more may be close enough for the average Joe.
For a street performance engine, those numbers should come down to plus or minus 3 grams or less.
And for a high revving NASCAR engine that spends most of its time at 8,500 to 9,500 rpm, plus or minus 1 gram or less is the rule.
How much is 1 gram? Not very much. A dollar bill weighs one gram. A penny, by comparison, weighs about 2-1/2 grams. An ordinary sheet of office paper tips the scale at a whopping 5 grams, which is more than the amount of imbalance that’s generally desired in a street engine.
the balance of a engine whether is it internally or externally is based on the weight of the rods and pistons...
A 360 has a cast crank which material is not as dense as some people heads on the forum...there fore addition weight must be added to balanced the rotating assembly...so from the factory..the cheapest way to do it is to add weight to the balancer and converter...
a 318 is internally balanced with a cast crank because the weight of the rods and pistons..which are smaller in size ...hence dont weight as much allow the cast crank to be internally balanced...
to balance an externally balanced 360...heavy metal (mallory) which is very dense is added to the counterweights...how much is added depends on the weight of the pistons and rods...
get lighter rods and pistons...not as much mallory metal is required to balance a 360...
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: Small Block Internal and External Balance Questions
[Re: 70AARcuda]
#1524887
10/29/13 04:19 PM
10/29/13 04:19 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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Quote:
Quote:
Does anyone have knowledge of how close to
"true balance"
the externally weighted
360 LA and Magnum 5.9 V8
typically are from the factory ?
Are they within, say 15 grams of zero?
Are the internally neutral 318/5.2 V8s
typically better balanced from the factory?
I know a guess always has to be made about the weight of "residual oil" clinging to the crankshaft of a running engine.
It has seemed to me that 318s have less vibration than 360s
http://www.ebay.com/gds/Crankshaft-Engine-Stroker-Kit-Balance-Balancing-/10000000013602009/g.html
sample quote
So what does this actually mean in terms of the forces generated inside an engine? An imbalance of only 1/4 oz. (7 grams) located four inches out from the center of the crank on a counterweight will generate a force of about 7 lbs. at 2,000 rpm. At low rpm, you would hardly feel a thing. But at 8,000 rpm, that same force would grow to 114 lbs. with every revolution of the crank. If this same engine had one ounce (28 grams) of imbalance, the forces generated would be multiplied by a factor of four, generating 456 lbs. of unwanted gyrations at 8,000 rpm!
That’s enough vibration to rattle your teeth and pound the heck out of the main bearings. It’s also wasted motion that goes into shaking the block instead of spinning the crankshaft. Consequently, imbalance hurts horsepower as well as smoothness and engine longevity.
The factory balance of crankshafts can vary a great deal depending on the application and the OEM tolerances.
For a low rpm stock engine, plus or minus 8 to 10 grams or more may be close enough for the average Joe.
For a street performance engine, those numbers should come down to plus or minus 3 grams or less.
And for a high revving NASCAR engine that spends most of its time at 8,500 to 9,500 rpm, plus or minus 1 gram or less is the rule.
How much is 1 gram? Not very much. A dollar bill weighs one gram. A penny, by comparison, weighs about 2-1/2 grams. An ordinary sheet of office paper tips the scale at a whopping 5 grams, which is more than the amount of imbalance that’s generally desired in a street engine.
the balance of a engine whether is it internally or externally is based on the weight of the rods and pistons...
A 360 has a cast crank which material is not as dense as some people heads on the forum...there fore addition weight must be added to balanced the rotating assembly...so from the factory..the cheapest way to do it is to add weight to the balancer and converter...
a 318 is internally balanced with a cast crank because the weight of the rods and pistons..which are smaller in size ...hence dont weight as much allow the cast crank to be internally balanced...
to balance an externally balanced 360...heavy metal (mallory) which is very dense is added to the counterweights...how much is added depends on the weight of the pistons and rods...
get lighter rods and pistons...not as much mallory metal is required to balance a 360...
Speaking of density, 318 and 360 used the exact same rods after about 72 and.... a 318 piston is heavier than a 360 piston.
The 318 has a shorter stroke so the weight has less affect on the imbalance and requires less balance weight and therefor can be internally balanced with a cast crank even though the bob weight is heavier.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Small Block Internal and External Balance Questions
[Re: HotRodDave]
#1524888
10/29/13 04:32 PM
10/29/13 04:32 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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a quick checks of ICON flattop 318 pistons weights in at.....492 grams...
and a ICON flattop 360 weights in at..530 grams..
kinds of throws that 318 pistons are heavier out the window..
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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