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Old 02-23-2005, 09:37 AM   #1
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Default Crankshaft Balance

How do you balance the crankshaft? And how do one knows that it is balanced?
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Old 02-23-2005, 11:52 AM   #2
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Default Re: Crankshaft Balance

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Originally posted by dameetz
How do you balance the crankshaft? And how do one knows that it is balanced?
I suggest to use 52-58 % balancing-so far it was the best ### for me ( we tryed form way underbalanced to way overbalanced)
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Old 02-23-2005, 11:53 AM   #3
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what does that mean?
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Old 02-23-2005, 11:59 AM   #4
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Quote:
Originally posted by finbone
what does that mean?
You take 52-58 % of weight of P/C assembly and ballance crancshaft with that weight-it should stay in the middle-horisontal position ( cranckpin).
Edward
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Last edited by Top Gun 777; 02-24-2005 at 04:38 PM.
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Old 02-23-2005, 06:09 PM   #5
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I don't fully understand it. Can you explain it in details and make an example? And how do you actually balance it ie: do you put on flat table and see whether the crank pin stays at upright position or is there any other better method?
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Old 02-23-2005, 06:33 PM   #6
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Quote:
Originally posted by dameetz
I don't fully understand it. Can you explain it in details and make an example? And how do you actually balance it ie: do you put on flat table and see whether the crank pin stays at upright position or is there any other better method?
What Edward measn by 52 - 58% balance is as follows.

If the Piston/Conrod and pin weigh say 100g then the ideal weight for the crankshaft is between 52 and 58g.

To get that ideal weight you either remove or add material to the rear section of the crankshaft (the counter-weight). To balance the crank properly the crank should always stay perfectly still when the pin is sitting at Top Dead Center postion. To get this you need a special jig made up that holds the crank at both ends on its center line (similar to a propellor or wheel balancing tool).

if you have to add weight you need to select a heavy material like brass and insert it into the weight (like drilling a hole and squeezing a piece of brass bar into the hole). The process is not easy and I would suggest experimenting with old engines.

It will take time to learn where to take the material off/add material too any given crankshaft to get the ideal weight while achieving the desired balance without weakening the crank at any point.

Last edited by teammpp; 01-12-2007 at 07:52 PM.
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Old 02-23-2005, 09:15 PM   #7
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Quote:
Originally posted by Palmaris Europe
What Edward measn by 52 - 58% balance is as follows.

If the Piston/Conrod and Sleeve weigh say 100g then the ideal weight for the crankshaft is between 52 and 58g.

To get that ideal weight you either remove or add material to the rear section of the crankshaft (the counter-weight). To balance the crank properly the crank should always stay perfectly still when the pin is sitting at Top Dead Center postion. To get this you need a special jig made up that holds the crank at both ends on its center line (similar to a propellor or wheel balancing tool).

if you have to add weight you need to select a heavy material like brass and insert it into the weight (like drilling a hole and squeezing a piece of brass bar into the hole). The process is not easy and I would suggest experimenting with old engines.

It will take time to learn where to take the material off/add material too any given crankshaft to get the ideal weight while achieving the desired balance without weakening the crank at any point.
Thanks for the info.
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Old 02-23-2005, 09:21 PM   #8
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Edward: I thought I understood crank balancing. I have had it done and done it on gas engines also balancing the flywheel and throwing that weight into the equation too. Why is the piston sleeve weight added into the equation??? Theres no motion there.

Bob
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Old 02-23-2005, 11:13 PM   #9
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Quote:
Originally posted by bbntc3
Edward: I thought I understood crank balancing. I have had it done and done it on gas engines also balancing the flywheel and throwing that weight into the equation too. Why is the piston sleeve weight added into the equation??? Theres no motion there.

Bob
Hi there, I think the Sleeve was not meant to be part of the equation!

Just the Piston and Conrod

We shall call it Super balancing , right Edward.....
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Old 02-23-2005, 11:18 PM   #10
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Quote:
Originally posted by dameetz
Thanks for the info.
Hey dameetz, whats uppp

Don't worry about trying the balancing. Next time I make one for you and you will see what we meant.

Bottom end torque ....amazing

Just make sure your car can handle it

Last edited by kitracer; 02-25-2005 at 12:52 AM.
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Old 02-24-2005, 06:41 AM   #11
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Why would sleeve weight be apart of the balancing?
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Old 02-24-2005, 10:48 AM   #12
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Ok, here is my answer. I am not going to go if there is perfect ballance for single cylinder 2 strok engines-it is been talking about it for years, so no need to BS about it.
My procedure is-
I am weihging P/conrod assembly and then calculate what is 52-58% of it weight is ( for example 100 gr is total weight and I take 52-58 gramms). Then I am taking piece of weight with center hole the same as cranck pin and make it by the eight of 52-58 gr. Next step is-I took on of the old crancases and cut off almost everything out of it, just left motor mounts and and front of crancase where the bearings are mounted-so I have easy access to cranckshaft. I put new bearings and wash them with alchogol. No lubricant is use there-just dry bearings. Then I install cranckshaft and make sure it is turning absolutly free. Next step is put prepared earlier weight on pin and see which position is cranck pin located ( swing cranck little bit left and right). Then according position I alter the weight arround the web-sometimes it is on conter weight, some times on the pin area-needs to be looked.
Everybody can choose their own way to do it, I just answer the question. I will not discuse 52-58 % numbers, I just share my expirience. It is slightly overbalanced and this is what I want to achive.
I don't use blades-first of all you have to level them in 2 dementions and watch they sta leveled. Second reason is-blades are too short and ones you move cranck on them-it will always have tendency fall down-tired of it. It is worth it to cut one case and use it as balancing tool. To use that case, just install it in table vase firmly on one of motor mounts. Don't use any lubricants, keep bearings dry during the balancing. For storage use oil to proteck from rust.
Edward
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Last edited by Top Gun 777; 02-24-2005 at 04:38 PM.
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Old 02-24-2005, 12:11 PM   #13
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Default Re: happy girl

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Originally posted by HELLION
If your distribution figures add the weight of the sleeve then your best girl is going to be verry happy because you just built a gas powered vibrator!!! And if you saw my post I said scrapper razor blades they are about 3 inches long and they work great.Also don't be in a hurry to chop a bunch of weight off your crank and do a little at a time . get it to hot and it can warp ,cut to much off it could weaken it.
Everybody has there own way of doing things and all I can say is that TG's seems to work very well. The extra power advantage he has given us whether running his own engine or his P/S sets etc in other brand engines is awesome. A couple of my colleagues are really hard to please when it comes to engines and after trying TG's stuff they are hooked and wont look at anything else.
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Old 02-24-2005, 03:56 PM   #14
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Default Re: oooo nooooo

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Don't tell me I hurt Top guns feelings again


On the contrary, the more people have a pop at him the more power he goes and produces from his products. Please keep it up
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Old 02-24-2005, 04:29 PM   #15
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Nobody hurt my feelings; I really donít care if somebody pop on me, I pass this period of my life.
I donít add weight of sleeve, just piston, wrist pin, conrod and G-clips. If I wrote by mistake piston/sleeve assembly, it is pretty clear that it was mistake and I really feel sorry to make this mistake.
Hellion you can use ice scating blades or 2 swords, whatever it will come to your mind. I do my way, you do your way, somebody else does his own way. I can dsicuse with you about motors only after I will see that you are realy quialify to do so, so far I didn't seen it and it is waist of my time. You are good on vibrators-it is fact, the rest is really questionable.
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Last edited by Top Gun 777; 02-24-2005 at 04:52 PM.
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