6.75" Harmonic Balancer (ext) users step inside
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Sorry I misunderstood you original post.
When I have the option, I won't build one with extra balancing weight hanging on the ends of the crank. Add/remove all the needed weight from the butterflies/pork chops/whatever using mallory is the route I take
I choose machine shops, in part, on their ability to do it that way, take everything to them, front to rear, top to bottom for the balancing. I don't trust "factory" balancing or pre-balanced kits.
If I bought or received a create engine or a built short block, I'd tear it down and have it blue-printed, including re-balancing. Mass produced stuff SUCKS, just my view.
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
When I have the option, I won't build one with extra balancing weight hanging on the ends of the crank. Add/remove all the needed weight from the butterflies/pork chops/whatever using mallory is the route I take
I choose machine shops, in part, on their ability to do it that way, take everything to them, front to rear, top to bottom for the balancing. I don't trust "factory" balancing or pre-balanced kits.
If I bought or received a create engine or a built short block, I'd tear it down and have it blue-printed, including re-balancing. Mass produced stuff SUCKS, just my view.
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
O.K....Add'l posters have chimed in with their concern for the PP units. Will (rklessdrvr) emailed me with a suggestion that I hadn't found with my searches.
I'll use the 34266 Pro Stock damper by Pro Race Performance. It's a lot more expensive than the $50 PP unit I picked, but it's necessary to "get it right" on the first try.
I thought about going back and asking my builder to balance the nose, but I was assured that ext/ext motors won't be a problem. Obviously ext rear is necessary unless I want to go grinding on a new $900 DMF, so the front might as well by external too.
And, yes, I'm having everything balanced by the builder. It just won't be internal balance.
I'll use the 34266 Pro Stock damper by Pro Race Performance. It's a lot more expensive than the $50 PP unit I picked, but it's necessary to "get it right" on the first try.
I thought about going back and asking my builder to balance the nose, but I was assured that ext/ext motors won't be a problem. Obviously ext rear is necessary unless I want to go grinding on a new $900 DMF, so the front might as well by external too.
And, yes, I'm having everything balanced by the builder. It just won't be internal balance.
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I thought about going back and asking my builder to balance the nose, but I was assured that ext/ext motors won't be a problem. Obviously ext rear is necessary unless I want to go grinding on a new $900 DMF, so the front might as well by external too.
And, yes, I'm having everything balanced by the builder. It just won't be internal balance.
And, yes, I'm having everything balanced by the builder. It just won't be internal balance.
I called Scat today. I wanted to verify I received the correct crank (since the stamp engraved on the nose ended with "-LR" vs "-L" as listed on the box. After learning the cranks are contracted out and delivered in raw form (-LR means late SBC motor 1pc RMS in RAW form), Scat polishes/finishes them. That means the crank is fine. But....
More importantly, the Scat guy (today) said my crank (9-350-3750-5700-LR) won't balance with a 400ci balancer. (IOW, an unbalanced damper). He said the 400 damper has too much offset weight in it. To get this 383 crank to balance, he said 1-pc of Mallory is required in the nose -- if heavier-than-400g pistons will be used. If lighter pistons are used (i.e., SRP Professionals @ 374g), then the total bobweight will be low enough that Mallory is not required. In either case, a neutral balancer is required.
Gee...I wonder what I'll learn tomorrow!
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Well, I should have known....The answer changed yet again!
I called Scat today. I wanted to verify I received the correct crank (since the stamp engraved on the nose ended with "-LR" vs "-L" as listed on the box. After learning the cranks are contracted out and delivered in raw form (-LR means late SBC motor 1pc RMS in RAW form), Scat polishes/finishes them. That means the crank is fine. But....
More importantly, the Scat guy (today) said my crank (9-350-3750-5700-LR) won't balance with a 400ci balancer. (IOW, an unbalanced damper). He said the 400 damper has too much offset weight in it. To get this 383 crank to balance, he said 1-pc of Mallory is required in the nose -- if heavier-than-400g pistons will be used. If lighter pistons are used (i.e., SRP Professionals @ 374g), then the total bobweight will be low enough that Mallory is not required. In either case, a neutral balancer is required.
Gee...I wonder what I'll learn tomorrow!
I called Scat today. I wanted to verify I received the correct crank (since the stamp engraved on the nose ended with "-LR" vs "-L" as listed on the box. After learning the cranks are contracted out and delivered in raw form (-LR means late SBC motor 1pc RMS in RAW form), Scat polishes/finishes them. That means the crank is fine. But....
More importantly, the Scat guy (today) said my crank (9-350-3750-5700-LR) won't balance with a 400ci balancer. (IOW, an unbalanced damper). He said the 400 damper has too much offset weight in it. To get this 383 crank to balance, he said 1-pc of Mallory is required in the nose -- if heavier-than-400g pistons will be used. If lighter pistons are used (i.e., SRP Professionals @ 374g), then the total bobweight will be low enough that Mallory is not required. In either case, a neutral balancer is required.
Gee...I wonder what I'll learn tomorrow!
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Well....kindof. You said that's the way you'd do it,,,not that it was necessary/unavoidable. Today's the first time I understood the real issue. (Keep the thoughts comin' though! 
)
Another thought....Since the 34266 has a bolt-in weight, I wonder if lighter weights are available?
)Another thought....Since the 34266 has a bolt-in weight, I wonder if lighter weights are available?
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Well Pete,,,here's another one for you -- and my lesson for today.
My builder said I could go to the only guy in town who might do Mallory -- or -- I could do it his way.
When forced to use an external balancer, he removes weight from the counterweights. He prefers doing that vs adding Mallory. That's because he had Mallory come loose in not one,,,but two of his race cars. Cars that revved above 7k rpms for long periods of time.
My builder said I could go to the only guy in town who might do Mallory -- or -- I could do it his way.
When forced to use an external balancer, he removes weight from the counterweights. He prefers doing that vs adding Mallory. That's because he had Mallory come loose in not one,,,but two of his race cars. Cars that revved above 7k rpms for long periods of time.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Well Pete,,,here's another one for you -- and my lesson for today.
My builder said I could go to the only guy in town who might do Mallory -- or -- I could do it his way.
When forced to use an external balancer, he removes weight from the counterweights. He prefers doing that vs adding Mallory. That's because he had Mallory come loose in not one,,,but two of his race cars. Cars that revved above 7k rpms for long periods of time.
My builder said I could go to the only guy in town who might do Mallory -- or -- I could do it his way.
When forced to use an external balancer, he removes weight from the counterweights. He prefers doing that vs adding Mallory. That's because he had Mallory come loose in not one,,,but two of his race cars. Cars that revved above 7k rpms for long periods of time.
You are between a rock and a hard place I guess.
I know what I would do.
My opinion does not matter though.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Take a look at the photo below. It is a pic of a 400 I did recently. Notice mallory in the front counterweight. If installed properly, the only way that the mallory can leave that counterweight, is if the counterweight blows apart.
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Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Talked to him (and his partner) more this afternoon....
It sounds like they don't have the bridgeport necessary to drill sideways into the cranklobes (to do it "the right way"). When they have tried it, sticks were placed into the ends of the lobes (vs across them). With welding of course.
Now,,,instead of adding weight, he uses an external balancer and removes weight [from the counterweights] instead. Of course by drilling holes. He considers a balanced assembly balanced -- regardless whether it's internal or not.
If I want Mallory, there's another guy across town that can do it. And, he's the only one in Kansas City who can add Mallory.
It sounds like they don't have the bridgeport necessary to drill sideways into the cranklobes (to do it "the right way"). When they have tried it, sticks were placed into the ends of the lobes (vs across them). With welding of course.
Now,,,instead of adding weight, he uses an external balancer and removes weight [from the counterweights] instead. Of course by drilling holes. He considers a balanced assembly balanced -- regardless whether it's internal or not.
If I want Mallory, there's another guy across town that can do it. And, he's the only one in Kansas City who can add Mallory.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Talked to him (and his partner) more this afternoon....
It sounds like they don't have the bridgeport necessary to drill sideways into the cranklobes (to do it "the right way"). When they have tried it, sticks were placed into the ends of the lobes (vs across them). With welding of course.
Now,,,instead of adding weight, he uses an external balancer and removes weight [from the counterweights] instead. Of course by drilling holes. He considers a balanced assembly balanced -- regardless whether it's internal or not.
If I want Mallory, there's another guy across town that can do it. And, he's the only one in Kansas City who can add Mallory.
It sounds like they don't have the bridgeport necessary to drill sideways into the cranklobes (to do it "the right way"). When they have tried it, sticks were placed into the ends of the lobes (vs across them). With welding of course.
Now,,,instead of adding weight, he uses an external balancer and removes weight [from the counterweights] instead. Of course by drilling holes. He considers a balanced assembly balanced -- regardless whether it's internal or not.
If I want Mallory, there's another guy across town that can do it. And, he's the only one in Kansas City who can add Mallory.
Placing the mallory inside the crank vs hanging weight on the ends is like comparing bubble balance vs spin balance (of a tire/wheel).
Both work to a point, but an entire industry has determined that 1would be better than the other.
If your guys cannot handle the proper installation of mallory you don't want them doing it.
I just thought they were trying to **** on your leg, and tell you it is rain.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
If you do have them mod the balancer and/or flexplate, be sure to log the info. If you hurt a something in the future, and need to swap parts, you will need the info to re-balance whatever you are changing.
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
No...That's something they won't do. Either they'll use balanced FW/dampers or standard unbalanced pieces. And, it's for the very reason you point out -- in case one needs to be replaced. And, so the assembly will still in balance after said replacement.
I agree they "can't handle proper installation of Mallory", but I've yet to hear an explanation of why their approach is any worse. As mentioned before, I forced to use an external FW (stock DMF) -- which is how the factory did it on millions of cars. So, why is that any worse?
I can understand that you have a preference for internal vs external balancing, but I don't see a reason to avoid that option (or my builder) being stated.
I agree they "can't handle proper installation of Mallory", but I've yet to hear an explanation of why their approach is any worse. As mentioned before, I forced to use an external FW (stock DMF) -- which is how the factory did it on millions of cars. So, why is that any worse?
I can understand that you have a preference for internal vs external balancing, but I don't see a reason to avoid that option (or my builder) being stated.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
No...That's something they won't do. Either they'll use balanced FW/dampers or standard unbalanced pieces. And, it's for the very reason you point out -- in case one needs to be replaced. And, so the assembly will still in balance after said replacement.
I agree they "can't handle proper installation of Mallory", but I've yet to hear an explanation of why their approach is any worse. As mentioned before, I forced to use an external FW (stock DMF) -- which is how the factory did it on millions of cars. So, why is that any worse?
I can understand that you have a preference for internal vs external balancing, but I don't see a reason to avoid that option (or my builder) being stated.
I agree they "can't handle proper installation of Mallory", but I've yet to hear an explanation of why their approach is any worse. As mentioned before, I forced to use an external FW (stock DMF) -- which is how the factory did it on millions of cars. So, why is that any worse?
I can understand that you have a preference for internal vs external balancing, but I don't see a reason to avoid that option (or my builder) being stated.
Greg,
You seem to be reading only parts of my reply's. My intention was to help you only, and offer options. Not to debate, beat the horse to death, or contradict your plan. If it appeared that way, I apologize.
I have repeatedly said that either way works for the low powered stuff we are building.
The automotive industry has decided any 1 way is better than another, not you or I.
Your money, your car, your builder, your decision.
Again, I only intended to educate you with my real world experiences.
Carry on.
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Because I always ask lots of questions and try to understand the issues/options, I usually will press until I'm certain I'm not doing anything wrong. (Or if there's a better way.) This costs way too much to do it wrong.
To be honest, I'm still not sure if/how internally balancing is better than the approach this guy takes. I'm certain my builder doesn't see the difference. Otherwise he probably would have invested in the equipment to install Mallory. That,,,plus the fact he said so.
