MudmotorTalk.com
http://mudmotortalk.com/mmt_v2/

Balanced crank
http://mudmotortalk.com/mmt_v2/viewtopic.php?f=3&t=70070		 Page 1 of 1
Author:  Marsh Runner [ Thu Mar 16, 2017 6:41 pm ]
Post subject:  Balanced crank
I had my crank out of my 35gtr balanced because it cracked my block. Was told it was out 14 grams. For those that had their cranks balanced, how much were they out? After balanced were they running a lot smoother?
Author:  Wilson [ Sat Mar 18, 2017 11:48 pm ]
Post subject:  Re: Balanced crank
Great question.
Author:  riverrat00 [ Sun Mar 19, 2017 12:34 am ]
Post subject:  Re: Balanced crank
Mine was 21 and yes runs a lot smoother.
Author:  Marsh Runner [ Mon Mar 20, 2017 10:11 am ]
Post subject:  Re: Balanced crank
I guess no one has had their crank balanced. I thought there was talk a while back about some doing this? Just looking to see how much most cranks are out.
Author:  flint87 [ Mon Mar 20, 2017 5:10 pm ]
Post subject:  Re: Balanced crank
Author:  banded-mallard [ Tue Mar 21, 2017 4:26 am ]
Post subject:  Re: Balanced crank
Damn, 14 and 21 grams is a lot. It doesn't seem like much, but when spun up to 5000 rpms, it magnifies significantly. I do this for a living for dow. Also, given the "placement" of the "heavy spot" that causes the vibration is also significant. If the heavy spot is located near the shaft centerline, then as speed increases, the magnitude won't be as significant. But, if the known heavy spot is located further away from the centerline, as speed increases, the forces applied outward increase significantly, thus the vibration you are feeling. By balancing the crank, you will also extend the life of the bearings, seals and the block itself, even if its a lawnmower engine.
Author:  ibfishinb [ Tue Mar 21, 2017 5:20 am ]
Post subject:  Re: Balanced crank
Wish I had been patient enough to send mine off to be Balance when I had the motor apart.

Sent from my SM-G920V using Tapatalk
Author:  pokey79 [ Tue Mar 21, 2017 9:13 am ]
Post subject:  Re: Balanced crank
To be honest balancing the whole rotating assembly is the way to go. But just doing the crank helps too.
Author:  Will C [ Tue Mar 21, 2017 9:21 am ]
Post subject:  Re: Balanced crank
How can a crank be balanced without knowing the bobweight?
Author:  cb5331 [ Tue Mar 21, 2017 9:38 am ]
Post subject:  Re: Balanced crank
Who is Bob?
Author:  pokey79 [ Tue Mar 21, 2017 9:40 am ]
Post subject:  Re: Balanced crank
only thing I can think of is the person that did the crank balance has done a complete rotating assembly and used a known weight. With saying that im not saying its right by any means.
Author:  Russ [ Tue Mar 21, 2017 9:59 am ]
Post subject:  Re: Balanced crank
Author:  pokey79 [ Tue Mar 21, 2017 10:00 am ]
Post subject:  Re: Balanced crank
Here’s the complete list for determining your bobweights for zero-balancing a crank.

Rotating Weight
* Big end of rod (including fastening hardware)
* Bearing
* Oil (normally estimated at four grams)

Reciprocating Weight
* Piston
* Wristpin
* Pin locks (if used)
* Small end of rod
* Piston rings

Bob weight = Rotating Weight + (Reciprocating Weight x .50)

This is just a insight for those that want know , before the question is asked. :shock:
Author:  cb5331 [ Tue Mar 21, 2017 10:01 am ]
Post subject:  Re: Balanced crank
I think he's the cause of all the cracked blocks. Fucking Bob. :roll:
Author:  pokey79 [ Tue Mar 21, 2017 10:01 am ]
Post subject:  Re: Balanced crank
^^^^^ and as I see this was posted to late!!!! :lol: :lol:
Author:  cb5331 [ Tue Mar 21, 2017 10:05 am ]
Post subject:  Re: Balanced crank
And on topic....the only person I've known to actually have their's balanced, I'm pretty sure they did the entire rotating assembly. They also continued to have issues with the motor(s). IIRC, a stretched rod, broken rod, and at least one, maybe two more cracked blocks. There was an issue with the flywheel that caused some of those issues though.
Author:  cb5331 [ Tue Mar 21, 2017 10:06 am ]
Post subject:  Re: Balanced crank
Author:  Will C [ Tue Mar 21, 2017 10:23 am ]
Post subject:  Re: Balanced crank
:lol:
Author:  pokey79 [ Tue Mar 21, 2017 10:28 am ]
Post subject:  Re: Balanced crank
Author:  MaXXis85 [ Tue Mar 21, 2017 10:31 am ]
Post subject:  Re: Balanced crank
Also balancing the flywheel seems to help some. The whole thing helps.... But is it really worth it in the end? Its all up in the air.
Author:  Marsh Runner [ Tue Mar 21, 2017 10:33 am ]
Post subject:  Re: Balanced crank
So they did measure out the weight of piston and rods to put Bob weight. And balanced as rotating assembly. Flywheel wouldn't fit in machine on crank so had it balanced separate and it was out 1 gram
Author:  Will C [ Tue Mar 21, 2017 1:43 pm ]
Post subject:  Re: Balanced crank
Good. They did it right! Care to share who did the work? There arent many places that balance these and this thread has good info..
Author:  cb5331 [ Tue Mar 21, 2017 1:44 pm ]
Post subject:  Re: Balanced crank
Author:  MaXXis85 [ Tue Mar 21, 2017 2:04 pm ]
Post subject:  Re: Balanced crank
On our end Tim's Engines in Denham springs had done it.
Author:  Marsh Runner [ Tue Mar 21, 2017 2:16 pm ]
Post subject:  Re: Balanced crank
It's a local auto engine machine shop, have to find name. But he used an automotive balance machine, he said it was tight to fit but it worked. So I'm sure any automotive machine shop could do it.
Author:  riverrat00 [ Thu Mar 30, 2017 6:03 am ]
Post subject:  Re: Balanced crank
Tim's engines in denham springs did mine too. Really nice people.
Author:  pokey79 [ Thu Mar 30, 2017 8:29 am ]
Post subject:  Re: Balanced crank
what was Tim's price if u don't mind me asking? or u can pm it to me
Author:  riverrat00 [ Sun Apr 02, 2017 2:23 pm ]
Post subject:  Re: Balanced crank
Dont quote me but I remember 175 . Wasnt more than 200
Page 1 of 1 All times are UTC - 6 hours
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/