I'm debating whether to balance the crank, pistons, and rods or just the crankshaft alone. I don't remember which post, but I remember a few people saying for Honda's there is no need to balance the pistons/rods, etc. since they are balanced at the factory or something like that. Though I still hear people balancing all of them as a whole. Would it be efficient enough to just do the crankshaft alone?

 

I've been told that honda motors only need to have the crankshaft balanced. Especially if you're buying pistons and rods, they come pre-balanced from the factory.

 

I would balance the whole thing. It's true that the majority of aftermarket parts come pre-balanced, but the only way to be 100% sure of the balance is to have it done as a complete assembly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">I would balance the whole thing. It's true that the majority of aftermarket parts come pre-balanced, but the only way to be 100% sure of the balance is to have it done as a complete assembly.</TD></TR></TABLE>

especially if you are running LS/V's.....

 

or anything that revs for that matter..

 

LOL, how can you balance a crank without the rods and pistons? The counterweights are on the crank to offset the weight of the pistons and rods.

 

people do it all the time... the pistons and rods should be balanced by themselves to a certain extent.

 

i reccomend having crankshaft, flywheel, crank pulley(dampener), pressure plate, rods, and pistons all check for balance. usually, the stock honda stuff are balance from the factory or is only 1 to 2 grams off. using an aftermarket pressure plate(clutch) will definatly throw the balance off the whole crank assembly. inline engine crankshafts do no need the wieght of the piston/rod assembly to be balanced. its only on v6's,v8's, etc. that needs bob-wieghts to be attached to offset the counter-wieghts

 

How do they check the flywheel, clutch & pressure plate for balance. Is it all bolted to the crank and then spun up?

 

first the crank is spun up and balance. then you bolt up the flywheel spin that up, get it balance...proccess repeats for the other stuff. you can also balance the flywheel and pressure plate seperately from the crank if you use the mandrel tool. the clutch disc is not used in the balancing proccess though, because its not always in the same spot.

 

Do not confuse balancing V-8's as compared to 4 cylinder engines. It is a completely different method. Since 2 cylinders are directly opposed to the other 2 cylinders, putting bob weights on the crank does not make any difference in the balance measurement as the added weights just cancel each other out when spinning the crank. Aftermarket pistons and rods come balanced to within a gram. (That is very close when you consider there is 453.6 grams in a pound.) Clutches and flywheels also come spun balanced from the manufacturer. This is necessary in order to have their SFI certification. Same with aftermarket balancers.
The crank is balanced by itself. It does not make sense to add a clutch and flywheel to the crank when you balance because then you are stuck with the same flywheel and clutch forever unless you want to throw your engine out of balance or rebalance the internals after each clutch change.
As to adding the balancer to the crank when balancing, I believe this is not done because you would rather read the out of balance condition on the crank itself and correct it rather than having the balancer mask the condition.

 

i think you have mistaken the proccess of balancing an internal balance engine vs. an external balance engine. its almost the same, but a little different. with an internal balnce engine(example: honda). at first, the crank is balanced by itself. once that is done, you then add the flywheel, balance that with the crank, etc. etc...even though your adding the flywheel, pressure plate, crank pulley(dampener), you are not stuck with same assembly, you can change any one of those things at any time without affecting the balance, unless the thing your adding is not balanced. even though flywheels, pressure plates, etc. are balanced from the factory, it dose not mean it will be good when you just bolt it up to your already balanced crank. i have spun up a lot of stuff at work, and it throws the whole assembly off balance.
with an external balanced engine. the front dampener and flywheel needs to be bolted to the crank when its spun up, because they have external weights. either on the flywheel or dampener or both. this is the engine where your pretty much stuck with the same flywheel and front dampener. unless you switch with an aftermarket one with the same positon/amount of wieght(or close to).
yes, balancing a V engine is different from an inline, flat/oppose engine. but when it comes to internal or external, its the same in both worlds

 

What you are saying just does not make sense to me. First you balance the crank and then you bolt on the flywheel and rebalance? What and where do you rebalance now that you have the flywheel on. You jump from internal to external doing that. That stops you from switching from a heavy flywheel to a light flywheel which also makes no sense as it is done all the time.

 

You balance crank by itself, then balance everything sperately.

wtf?

 

sorry if i was clear enough. let say the crank is perfectly balanced. you then add the flywheel. you, then change the settings on the balancer to where it will read the balance to the flywheel side by changing the offset and radius settings on the machine. when you spin up the crank and flywheel, it will then tell you where to remove or add weight if needed. usually the readings will be zero at the front of the crank and whatever on the flywheel side, lets say about 2 grams need to be removed. this 2 grams will taken away from the flywheel by drilling X amounts of hole(s) that equals 2 grams. the readings should be zero zero when you spin it back up after you have made the change. even if you take the flywheel off(or anything that was added to the crank) and spin it back up, the crank itself will still be perfectly balanced. the crank is no longer touched. its basically like a tool to hold the flywheel, pressure plate, etc..so when you add the crank pulley(dampener), flywheel, pressure plate, the settings have to be changed on the balancer machine to where it will take the readings. any wieght that needs to be removed or added, need to be made to whatever you just added to the crank, and not on the crankshaft. so therefore, if you ever decide to change to a different/new flywheel, pressure plate, etc. it should not effect the balance, unless the part you have now changed is off balance.
the proccess is almost like balancing an external engine except that your basically balancing each thing one at a time as you add it to the crank. instead of having to bolt on the dampener and flywheel to the crank the first time you go to spin up the crank.
from experience, new flywheel, etc. dont always have a perfect balance from the manufacture. especially pressure plates. hope this all makes sense now......

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Suprdave &raquo;</TD></TR><TR><TD CLASS="quote">You balance crank by itself, then balance everything sperately.

wtf?</TD></TR></TABLE>Well how do you do it, Dave?
We do this every day.

 

I've read and understand everything you are saying but still not sinking in. What you are saying is that when you bolt a perfectly balanced flywheel to a perfectly balanced crank, the whole unit becomes out of balance and the flywheel needs to be rebalanced? With this logic, every flywheel/clutch change would throw things out of balance. There would be no need to ever factory balance flywheels. I've had the complete tour of ACT and I know they are balanced for a reason.

 

Well, I don't claim to own or run a shop or nuthin'... but I've been thru 4 built/rebuilt engines... Each time I've had them balanced, including: Crank, Pulley, Flywheel, Pressure Plate, Rods, Pistons. I know the aftermarket pistons and rods were pre-balanced from the factory, also the honda crank is pre-balanced, but it didn't cost much more to do all the parts at one time. I mean, since all the oil splashing around in the pan will be throwing off the balance some in the end... it's good to know, at least your parts are all done up properly. All of my engines ran like budda.

** Have your pistons prepped before you send to balance....

 

I just installed some ctr pistons and used the stock rods on my b16 and actually just had them shaved down to fit the pistons. I had the pistons and rods balanced..now when I drive my car at high rpm's only in vtec i will hear/feel vibratinos..would this be becuase they aren't in balance with the crank?

if so I'm fucked cuase I have no money to get this done...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicSi2000 &raquo;</TD></TR><TR><TD CLASS="quote">I just installed some ctr pistons and used the stock rods on my b16 and actually just had them shaved down to fit the pistons. I had the pistons and rods balanced..now when I drive my car at high rpm's only in vtec i will hear/feel vibratinos..would this be becuase they aren't in balance with the crank?

if so I'm fucked cuase I have no money to get this done...</TD></TR></TABLE>You said you got your ctr pistons and stock rods balanced.....does this mean it was actually out of balance when they checked? So, they do need balancing?

 

Has anyone even had a honda crank that was out of balance? I sure haven't.

When I had my crank, rods and pistons balanced, the machine shop told me that the crank and pistons(ITR) couldn't get anymore balanced, and the rods were just slightly off.

 

I had one that was perfect also. I have found 50% to be pretty close and 50% to be off. Pretty good results for OEM

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">I had one that was perfect also. I have found 50% to be pretty close and 50% to be off. Pretty good results for OEM</TD></TR></TABLE>


Right, My ITR crank was dead on. My B16 and GSR cranks were off but not by much. And I too only balance the crank and then the Flywheel by itself.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 3rdGteg &raquo;</TD></TR><TR><TD CLASS="quote">You said you got your ctr pistons and stock rods balanced.....does this mean it was actually out of balance when they checked? So, they do need balancing?</TD></TR></TABLE>

well they shaved the rods which means the rods had to of weighed less after they were shaved...so the machine shop just made sure they were balanced..

the crank was never taken out of my engine so is it possible the crank and pistons/rods are out of balance causing this vibration feeling/noise?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">Well how do you do it, Dave?
We do this every day.</TD></TR></TABLE>

I'm agreeing with you earl