anyone balanced a stock 360 crank?

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swinger340

swinger340

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Have heard of people having it done. Am thinking about doing it to a 360 im building. Advisable or not? 9.8:1 360 w RHS heads. Didnt want to mess around w balancers and flywheel. Want to eliminate the external balancing.
 
got two internally balanced stock 360 cranks...

talk to your machine shop to get a price....mallory metal is expensive and could add another $200 bucks to the cost of the balancing.
 
I would balance it for sure, but I would not waste the money "converting" it to internal balance. You will have more money into the crank than its worth. Its better off going to a stroker crank or just keep it external.
 
Internally balance it...if you plan on upgrading the motor or converter
 
So great question! i tried to do the same and went to a good local machine shop, and this is what he said.WHY and what are you trying to do? I said maybe 300 to 350 HP maybe a hair more;just a good all around drive-able and fun car for me and the wife.Well you will be surprised that the stock external rotating assembly is well balanced from the factory and i said really; he also said 360s don't like all that unnecessary RPM; He only recommended the basic machine work, cool. So maybe the question is what is best for your needs;personally i would not spend the money on that;maybe a good intake... but whatever you do just have fun doing it...
 
I am building a 1999 360 Magnum. I have a MP 4.0" cast stroker crank, Eagle SIR rods, Probe forged pistons, 727 Transmission.

1. What balancer should I use. I have the one that came off the engine but it has a big *** pulley welded to the front of it. Would like to run a march pulley system.

2. Do I use a B&M Flexplate part # 10242 or do I use the Mopar Weight Package part #P5249842.

This whole balancing thing confuses the crap out of me. Please someone tell me what I need so its balanced.
 
Internally balancing helps crank & bearing life a bit because there's not that extra weight hanging out on the ends, especially in performance & higher rpm applications. It's not necessary, but certainly doesn't hurt. OEM balance can be off anyway and if you changed the rods and/or pistons, it can throw it off even more. Use lighter rods and pistons and you might be able to get by with minimal mallory metal or none at all!

You still should balance it even if you keep the external OEM balancer and converter weights to make sure it's "right".

The B&M flexplates are nice if you keep the external balance weights.

If the balancer/damper has a pulley WELDED on, THROW IT AWAY IMMEDIATELY!
The rubber already deteriorates over time, but welding around it certainly hurt it more.
 
I built my 360 with KB107 pistons and Eagle SIR rods. Both of these are significantly lighter than the stock piston and rod. I had the rotating assembly balanced and they wound up taking almost a pound of metal off the crank. That much out of balance is going to be felt at idle not to mention the extra wear and tear on the engine. If you ate building the engine with Pistons or rods that are not stock replacement pieces i would say balancing is mandatory.

BTW, the don't balance the crank, it's the entire rotating assembly. The shop will need the crank, pistons, rings, rods. Plus if you are staying with the external balance they will need the harmonic balancer and the flex plate/ torque convertor (depending where the balance is) or the flywheel.
 
dgc333 said:
I built my 360 with KB107 pistons and Eagle SIR rods. Both of these are significantly lighter than the stock piston and rod. I had the rotating assembly balanced and they wound up taking almost a pound of metal off the crank. That much out of balance is going to be felt at idle not to mention the extra wear and tear on the engine. If you ate building the engine with Pistons or rods that are not stock replacement pieces i would say balancing is mandatory.

BTW, the don't balance the crank, it's the entire rotating assembly. The shop will need the crank, pistons, rings, rods. Plus if you are staying with the external balance they will need the harmonic balancer and the flex plate/ torque convertor (depending where the balance is) or the flywheel.
Click to expand...
Yes i realize it is the whole assy being balanced. I guess i should have been more clear. If i choose light enough pistons and rods will alot of weight still be needed to to convert to an internaly balanced engine? If malory cost is going to be retarded i might as well just stroke it seeing as i need to get rods and pistons anyways.
 
KB K107 pistons, stock 340 rods, stock crank.
I used a B&M counter weighted flexplate & aftermarket Balancer with a bolt on weight.
I had it balanced externally to keep the cost down. I built the engine to go into a street car & it ended up in a race car.
The engine has 900+ passes on it since 2007, no concerns yet.
It has ran a between 11.20's & 11.50's depending on conditions.
Internally would be the proper way to balance it in my opinion.
 
mikedevore said:
KB K107 pistons, stock 340 rods, stock crank.
I used a B&M counter weighted flexplate & aftermarket Balancer with a bolt on weight.
I had it balanced externally to keep the cost down. I built the engine to go into a street car & it ended up in a race car.
The engine has 900+ passes on it since 2007, no concerns yet.
It has ran a between 11.20's & 11.50's depending on conditions.
Internally would be the proper way to balance it in my opinion.
Click to expand...
Id be more than happy w your combo. I want to try and keep my price down as well. Will spend more on a stroker later.
 
swinger340 said:
Id be more than happy w your combo. I want to try and keep my price down as well. Will spend more on a stroker later.
Click to expand...

Very simple combo.
.020 KB107 pistons @ zero deck
stock reconditioned 340 rods with ARP bolts
stock 360 cast crank R.010/M.010
stock closed chambered Edelbrocks w/Huges valve springs
Hughes solid camshat 579 lift
Huges 1.5 rockers / Crane push rods
Stock oil pump / Moroso pan / stock windage tray
Holley strip dominator intake & ebay 750dp carb.
Mopar race electronic dist. & MSD 6AL box, Taylor wires, Champion plugs
Hooker 1 3/4 headers
904 auto / coan 8" convertor / turbo action man. valve body / 8 3/4 - 4:30 gears
1971 Demon, 3250LBs with driver
 
I own an automotiver machine shop that specializes in Chrysler performance work.
I have built a number of the 360 performance engines and although they are external balance they have all performed very well. A few have been copies of the Chrysler 360 crate motor with some extra enhancements in the valve work area. It is costly to convert to internal balance because of the expense of the mallory metal(tungsten). Balancing the crank as an external with an aftermarket damper or stock unit works out better than going internal due to the cost of the metal and the labor involved.The entire thing boils down to "attention to detail". When we balance we go to "0" for the right and left counter weight correction. Most shops stop at .5 grams which is commercially acceptable and for the most part will work OK. I just feel that I will balance someones motor the same way I would my own.
 
I had my machine shop balance my 360 rotating assembly, I just gave them the stock cast crank, one of those offset-weighted B&M flexplates, pistons (plus rings and bearings), rods, and a weighted Summit SFI damper. Like dgc333 said if you're using lightweight aftermarket pistons and/or rods the factory crank will be way off and rebalancing is pretty necessary. My machinist said it wasn't totally needed for less than 4500 RPM but I'd rather keep things as efficient and smooth as possible and I plan to rev to at least 5000.
 
Welcome to the site!!!!! You're joining an elete proven group of machinists already here. I always enjoy the input you guys have to add to the site.
 
northeast mopar said:
I own an automotiver machine shop that specializes in Chrysler performance work.
I have built a number of the 360 performance engines and although they are external balance they have all performed very well. A few have been copies of the Chrysler 360 crate motor with some extra enhancements in the valve work area. It is costly to convert to internal balance because of the expense of the mallory metal(tungsten). Balancing the crank as an external with an aftermarket damper or stock unit works out better than going internal due to the cost of the metal and the labor involved.The entire thing boils down to "attention to detail". When we balance we go to "0" for the right and left counter weight correction. Most shops stop at .5 grams which is commercially acceptable and for the most part will work OK. I just feel that I will balance someones motor the same way I would my own.
Click to expand...
Where in Maine are you at? Lets make this thing work. Thanks, Kevin
 
My 4.00 cast Eagle crank has a 2250g bobweight (they allowed +-5%, it was right on) . My MP stroker pistons/pins/rings (all balanced to the lightest one) , 360 rods/bearings (again, balanced to the lightest cap and then balanced to the lightest rod hung from the rod bolt at a 90 degree angle on a digital scale, slick!) with the formula for a Mopar V8 came out on paper to be....drum roll..2235g without oil @~7g (?) so that means I take about 7g off the throws? How much to balance when I already did the component balancing, ie. hand him the crank and the bobweight weight? Any less? $175 to tell me its in balance or close enough is not going to make me happy.
 
I have done this exactly ONCE. It cost me $600.00 to balance alone. I can buy a brand new STEEL Eagle for that--I know which way I would go. J.Rob
 
MRL Performance said:
I would balance it for sure, but I would not waste the money "converting" it to internal balance. You will have more money into the crank than its worth. Its better off going to a stroker crank or just keep it external.
Click to expand...
x2 i did mine it $creem$....
 
Have it balanced.
I just had my 360 mag balanced last month.
.010 stock crank, reconditiond stock rods and KB 107 pistons.
New sfi balancer and flywheel so the rotating assembly is matched together.
The price for the balancing was $250.00
 
dgc333 said:
I built my 360 with KB107 pistons and Eagle SIR rods. Both of these are significantly lighter than the stock piston and rod. I had the rotating assembly balanced and they wound up taking almost a pound of metal off the crank. That much out of balance is going to be felt at idle not to mention the extra wear and tear on the engine. If you ate building the engine with Pistons or rods that are not stock replacement pieces i would say balancing is mandatory.

BTW, the don't balance the crank, it's the entire rotating assembly. The shop will need the crank, pistons, rings, rods. Plus if you are staying with the external balance they will need the harmonic balancer and the flex plate/ torque convertor (depending where the balance is) or the flywheel.
Click to expand...
X2, I had mine balanced when they machined the block. You'll need the ENTIRE rotating assembly. Mine is going into my convertible. I changed the pistons and rods (much lighter) and it threw off the factory balance.
 
I just had my 360 assembly balanced... all things considered, I do wonder if buying a new crank and rods would have been a better way too go(everything else is new) But i find it a little confusing, the machine shop wants to re-fresh your old parts(that's how they earn a living) and the parts store wants to sell you new parts(that's how they pay the rent) Anyhow I had my stuff balanced :)
 
I had mine balanced, still external balance though. Going in front of a 4spd so it has to be imo.
 
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