383 Balancing ?'s inside...DON'T WANT MALLORY! Please advise...already searched
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From: AACO, MD
383 Balancing ?'s inside...DON'T WANT MALLORY! Please advise...already searched
OK, I think my crank is hosed, so I'm going 383. I know there's plenty of 383 threads, but I couldn't find my answer.
Here is what I know.
1. The balancer isn't a balancer, it's just a dampener.
Off corvetteforum, this is how balancing is done:
Now, I've seen cranks for sale that are already balanced. How does this affect what I need to do? From what I see, Mallory is some expensive stuff, and I'd rather not have to add that to my crank. I want to retain my current flywheel as well (stock).
I can get this one real cheap:
I guess I'm just totally lost. Please advise on the best route to buy a crank. I'm assuming w/ a new rotating assy, I can't avoid getting it balanced? I just don't know how they come "already balanced" if I need my flywheel to balance it....
Here is what I know.
1. The balancer isn't a balancer, it's just a dampener.
Off corvetteforum, this is how balancing is done:
The pistons and rods are paired and weighed then the lightest one is found. The balance pads on the rods are then ground on the heavier rod/piston assemblies so that all assemblies weight the same as the lightest assembly.
They assemble an unbalanced crank with a flex plate or flywheel and neutral balancer. Bob weights equal to the weight of the piston/rod assemblies are then attached to the rod journals and the assembly is spun in a balancing machine.
The machine indicates where weight has to be added or removed from the crank counterbalance weights. Many of these machines have a drill press built in and the operator just drills the crank counterweights without removing the crank assembly from the machine.
Tungsten(mallory metal or heavy metal...weighs about twice as much as steel) can be added by press fitting it into holes drilled in the crank counterweights then permanently welded in place if wieght has to be added to your crank.
The assembly is then spun again to check to see if it is properly balanced.
Usually this is done a minimum of two times to come up with a perfect balance.
They assemble an unbalanced crank with a flex plate or flywheel and neutral balancer. Bob weights equal to the weight of the piston/rod assemblies are then attached to the rod journals and the assembly is spun in a balancing machine.
The machine indicates where weight has to be added or removed from the crank counterbalance weights. Many of these machines have a drill press built in and the operator just drills the crank counterweights without removing the crank assembly from the machine.
Tungsten(mallory metal or heavy metal...weighs about twice as much as steel) can be added by press fitting it into holes drilled in the crank counterweights then permanently welded in place if wieght has to be added to your crank.
The assembly is then spun again to check to see if it is properly balanced.
Usually this is done a minimum of two times to come up with a perfect balance.
I can get this one real cheap:
You are bidding on a new Scat 9000 series cast steel 3.75 stroke 383 crankshaft for a 1 piece rear main seal 87-up block (this means you too LT1 guys). Box only opened to take picture. This crankshaft will require 6.00 length rods and the corresponding pistons. Crankshaft is properly counterweighted for internal balance.
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Joined: Feb 2003
Posts: 270
All one piece rear main seal cranks where designed to be externally balanced. In doing this, you usually have to remove material instead of adding. This is what you want since that is a lot cheaper than adding.If that is the way you want to go, you provide the machine shop with the balancer and the flywheel/flexplate as well as the rest of the rotating assy.
If you think (like I did cause I was stupid) that you want to go internal, There are some cranks that have enough bob weight so you can internal balance by sutracting weight but it depends on the weight of the rods pistons and so on. Some can only be balanced by adding mallory.
My suggestion is to get a prebalanced rotating assy from a good source. Scoggin-Dicky has them, PAW, Jegs and several aftermarket tuners have them as well. Consider some crate engines as well. Golen has a kick gas unit
Last, talk it over with some tuners like Nu-tek or TPIS. They can give you some tips and pit falls with out spending money.
Good luck
If you think (like I did cause I was stupid) that you want to go internal, There are some cranks that have enough bob weight so you can internal balance by sutracting weight but it depends on the weight of the rods pistons and so on. Some can only be balanced by adding mallory.
My suggestion is to get a prebalanced rotating assy from a good source. Scoggin-Dicky has them, PAW, Jegs and several aftermarket tuners have them as well. Consider some crate engines as well. Golen has a kick gas unit
Last, talk it over with some tuners like Nu-tek or TPIS. They can give you some tips and pit falls with out spending money.
Good luck
Thread Starter
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Joined: Oct 2002
Posts: 2,168
From: AACO, MD
Yes removal is much better than adding 
I believe he told me $125 to balance...I'd have to recheck. I'll talk to him on Tuesday.
If I get a pre-balanced rotating assy, it will still need to be balanced with my flywheel correct?
I appreciate your advice, but a crate motor etc. isn't an option, This is my daily, so I'm trying ot get away as cheap as possible. I race Mustangs
I believe he told me $125 to balance...I'd have to recheck. I'll talk to him on Tuesday.
If I get a pre-balanced rotating assy, it will still need to be balanced with my flywheel correct?
I appreciate your advice, but a crate motor etc. isn't an option, This is my daily, so I'm trying ot get away as cheap as possible. I race Mustangs
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Joined: Oct 2001
Posts: 1,462
From: smog zone adjacent to a great lake
Originally posted by badass383
All one piece rear main seal cranks where designed to be externally balanced.
All one piece rear main seal cranks where designed to be externally balanced.
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Joined: Jan 2002
Posts: 360
From: Montpelier, VA USA
Yea def get something thats already internally balenced.. I bought a rotating assembly that came externally (thought it was external b/c of the flywheel, didn't pay attention to the damper) and well I had to get mallory metal put it.. it was a pretty expensive balencing job haha. Not to mention in the kit i bought they left machine marks in the crank where you wouldn't normally check and well I had to pull the crank again b/c it ground a bearing down and got shavings everywhere ..
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