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rick · 08-19-2003, 02:54 PM

I just bought a crashed G38 with a bent crank. Any suggestions on how to straighten it? I thought I would center it on a lathe, dial guage the journals then whack it until I got it straight. I would appreciate any advice

Thanks

Rick

:
PS - maybe you have a crank for sale?

JimMoss · 08-19-2003, 10:49 PM

Good friend just straightened one for me, put it in a lathe dialed the crank in on both sides of the connecting rod then to the end of the crank.

Put the crank back in the engine, runs great!

Said if I get another prop strike we may have to split the crank and lock tight it together as it will be prone to twisting now ..... maybe.

Jim Moss

Don Bright · 08-20-2003, 12:06 AM

Hi Rick: What Jim said works. If you have problems straightening it let me know, I have a business and straightening cranks is one thing I do. You can e-mail me at dbright@interbaun.com My business is also listed in MAAC mag under Hobbyshops Canada.

Don Bright/D & D Model Works

rick · 08-20-2003, 07:54 AM

Thanks Guys! I guess I was on the right track about the lathe & dial gauge. But how do you actually straighten it? Do you hit the high side with a plastic hammer until straight?

Guest · 08-20-2003, 09:47 AM

Don't hit anything use a small arbor press. The only place most likely that it is bent is on the prop side after the front bearing. Sometimes cranks that are pressed together at the rod journal will move and be out of alignment. This should be checked as well.

Dennis

rick · 08-20-2003, 03:10 PM

Thanks - Thats what I needed to know!

Cheers

Rick

JimMoss · 08-20-2003, 10:16 PM

My G-38 wasn't actually bent, it was twisted at the rod pin.

We left the crank in the lathe and tapped the heavy masses till everything lined up.

When we had the masses lined up we had to to pry between the masses when the rod pin was at the low point when spun in the lathe.

Jim Moss

Randy Brown · 08-21-2003, 06:07 AM

I am surprised you guys didn;t ask this first before telling him how to

How much is it bent first??

Randy

kersplat · 11-02-2003, 02:22 PM

If it is bent a lot, beware of work hardening of the bent area......

08-19-2003, 02:54 PM	#1
rick RCC Contributor I am: Rick V Join Date: Dec 2002 Location: Guelph Ontario Radio of choice: Spektrum # of RCs: too Feedback: 9 / 100% Posts: 317 Total Props: 2	How do you straighten a bent crank on a Zenoah? Remove this ad - become a site supporter! I just bought a crashed G38 with a bent crank. Any suggestions on how to straighten it? I thought I would center it on a lathe, dial guage the journals then whack it until I got it straight. I would appreciate any advice Thanks Rick : PS - maybe you have a crank for sale?
	.

08-19-2003, 10:49 PM	#2
JimMoss RCC Supreme Contributor I am: Jim M Join Date: Sep 2002 Location: Oshawa, SE Zone Feedback: 4 / 100% Posts: 2,569 Total Props: 1	Good friend just straightened one for me, put it in a lathe dialed the crank in on both sides of the connecting rod then to the end of the crank. Put the crank back in the engine, runs great! Said if I get another prop strike we may have to split the crank and lock tight it together as it will be prone to twisting now ..... maybe. Jim Moss __________________ Jim Moss MAAC 16236 IMAC 3716 My Old Gallery: Straighten Up & Fly Right!
	.

08-20-2003, 12:06 AM	#3
Don Bright RCC Apprentice Join Date: Jan 2003 Location: Morinville, Alberta Feedback: 0 / 0% Posts: 96 Total Props: 0	bent crank Hi Rick: What Jim said works. If you have problems straightening it let me know, I have a business and straightening cranks is one thing I do. You can e-mail me at dbright@interbaun.com My business is also listed in MAAC mag under Hobbyshops Canada. Don Bright/D & D Model Works
	.

08-20-2003, 07:54 AM	#4
rick RCC Contributor I am: Rick V Join Date: Dec 2002 Location: Guelph Ontario Radio of choice: Spektrum # of RCs: too Feedback: 9 / 100% Posts: 317 Total Props: 2	bent crank Thanks Guys! I guess I was on the right track about the lathe & dial gauge. But how do you actually straighten it? Do you hit the high side with a plastic hammer until straight?
	.

08-20-2003, 10:16 PM	#7
JimMoss RCC Supreme Contributor I am: Jim M Join Date: Sep 2002 Location: Oshawa, SE Zone Feedback: 4 / 100% Posts: 2,569 Total Props: 1	My G-38 wasn't actually bent, it was twisted at the rod pin. We left the crank in the lathe and tapped the heavy masses till everything lined up. When we had the masses lined up we had to to pry between the masses when the rod pin was at the low point when spun in the lathe. Jim Moss __________________ Jim Moss MAAC 16236 IMAC 3716 My Old Gallery: Straighten Up & Fly Right!
	.

08-20-2003, 09:47 AM	#5
Guest Guest Join Date: Sep 2002 Feedback: 0 / 0% Posts: 0 Total Props: 57	Don't hit anything use a small arbor press. The only place most likely that it is bent is on the prop side after the front bearing. Sometimes cranks that are pressed together at the rod journal will move and be out of alignment. This should be checked as well. Dennis
	.

08-20-2003, 03:10 PM	#6
rick RCC Contributor I am: Rick V Join Date: Dec 2002 Location: Guelph Ontario Radio of choice: Spektrum # of RCs: too Feedback: 9 / 100% Posts: 317 Total Props: 2	Thanks - Thats what I needed to know! Cheers Rick
	.

08-21-2003, 06:07 AM	#8
Randy Brown RCC Supreme Contributor I am: Randy Brown Join Date: Oct 2002 Location: St thomas Feedback: 2 / 100% Posts: 4,986 Total Props: 4	I am surprised you guys didn;t ask this first before telling him how to How much is it bent first?? Randy __________________ Randy Brown MAAC 45752L
	.

11-02-2003, 02:22 PM	#9
kersplat RCC Contributor Join Date: Mar 2003 Location: Edmonton AB. Feedback: 0 / 0% Posts: 288 Total Props: 0	Bent crank If it is bent a lot, beware of work hardening of the bent area...... __________________ There is no such thing as a landing, it's a controlled crash. Jim West MAAC 22948
	.

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