Crank Balancing Question

rancheroo · 02-15-2004, 02:51 PM

I just got by Scat forged stroker crank back from the machine shop & the sucker looks like a piece of Swiss cheese. The machinist drilled 10 deep holes in the front counter weight & 9 deep holes in the back counter weight - there are a couple of shallow holes in some of the others. I sent him my crank, Pioneer damper (28 oz.) flywheel & pressure plate. He said that he had to take all of that metal out to get it to balance. He also said that it may have been easier to balance if I had a 'neutral balance' damper. He felt that the damper threw everything out of balance & looking at the back of it, it has a big weight on one side of it. I have 3 questions. Does it sound like the machinist did right? Should I have gotten a 'neutral balance damper (I didn't know there was such a thing). Do other Scat owners have balancing issues?

Rick

rancheroo · 02-15-2004, 09:06 PM

Where's Mike Burch at? He'll answer both of my questions. When Mike speaks, people listen.

Rick

302 LX Eric · 02-16-2004, 09:05 AM

A few questions:

1) Did you ask SCAT what they recommend as far as balancing goes? When I purchased my rotating assembly, DSS recommended an imbalance of 28oz. They said that a 50oz imbalance would make the crank look like swiss cheese. So, I went with a Fluidampr 28oz imbalance damper, and Fidanza aluminum flywheel with the 28oz plate and ended up with very little drilling required.

2) Speaking of the flywheel...are you sure you provided your machinist with the 28oz counter weight and not the 50oz? This would throw things out of whack for sure.

3) Yes, there are neutral balance dampers.

E

jonnyk · 02-19-2004, 03:10 PM

If you have a very light piston/rod combo, most likely you might have been better off with neutral balance. I had mine done to 28 oz. but it would probably have been easy to go to 0.

DirtKing · 02-24-2004, 12:30 PM

i had my scat 351 crank balanced for my 50 oz fluidamper (off my 302)....they did drill out a considerable amount of metal, but nothing that would weaken the crank...nor does it look like swiss cheese. Actually, i consider it a bonus (less rotating mass). HOWEVER, what concerns me is the machinist stating that the "damper is throwing the balance out of whack". Cranks are available in zero balance, 28 oz and 50 oz.. What damper you pick will affect how much work goes into the balance, but any COMPETANT shop should have no problem balancing any of these combinations. (My shop charged me 200 bucks. They also used some heavy metal.) By the way, they also balanced my pressure plate after balancing the crank.

84GT350-1 · 02-25-2004, 12:07 AM

I had my eagle crank and rod 514 kit balanced with a zero balance balancer and hardly had to touch the crank. I think he should have mentioned it to you that a zero balance would benefit you. just my 2 cents..

Jeff Chambers · 02-25-2004, 07:43 AM

All depends on what your bobweight is. Your situation is pretty normal. I just zero balanced my 302 forged Scat crank and it took 14 pieces of 1" mallory metal. That's pretty typical for a ford crank with a bobweight like mine. I know, the crank doesn't look very pretty when its done, but looks don't get you down the track.

84GT350-1 · 02-25-2004, 08:04 AM

hey Jeff
We are almost neighbors..

02-15-2004, 02:51 PM	#1
rancheroo Registered Member Join Date: Dec 2003 Location: Midland, Ga Posts: 8	Crank Balancing Question I just got by Scat forged stroker crank back from the machine shop & the sucker looks like a piece of Swiss cheese. The machinist drilled 10 deep holes in the front counter weight & 9 deep holes in the back counter weight - there are a couple of shallow holes in some of the others. I sent him my crank, Pioneer damper (28 oz.) flywheel & pressure plate. He said that he had to take all of that metal out to get it to balance. He also said that it may have been easier to balance if I had a 'neutral balance' damper. He felt that the damper threw everything out of balance & looking at the back of it, it has a big weight on one side of it. I have 3 questions. Does it sound like the machinist did right? Should I have gotten a 'neutral balance damper (I didn't know there was such a thing). Do other Scat owners have balancing issues? Rick __________________ Building an all forged Scat stroker for my 66 Ranchero

02-15-2004, 09:06 PM	#2
rancheroo Registered Member Join Date: Dec 2003 Location: Midland, Ga Posts: 8	Mike B. Where are you Where's Mike Burch at? He'll answer both of my questions. When Mike speaks, people listen. Rick __________________ Building an all forged Scat stroker for my 66 Ranchero

02-16-2004, 09:05 AM	#3
302 LX Eric or '331 LX Eric' Join Date: Jan 1999 Location: Columbus, Ohio Posts: 2,142	A few questions: 1) Did you ask SCAT what they recommend as far as balancing goes? When I purchased my rotating assembly, DSS recommended an imbalance of 28oz. They said that a 50oz imbalance would make the crank look like swiss cheese. So, I went with a Fluidampr 28oz imbalance damper, and Fidanza aluminum flywheel with the 28oz plate and ended up with very little drilling required. 2) Speaking of the flywheel...are you sure you provided your machinist with the 28oz counter weight and not the 50oz? This would throw things out of whack for sure. 3) Yes, there are neutral balance dampers. E __________________ 1991 5.0 LX Coupe - 40,750 miles 331 cu. in. / Tremec 3550 / BFG Drag Radials 12.22 @ 114.31 mph - w/1.89 60'

02-19-2004, 03:10 PM	#4
jonnyk Being stroked is great Join Date: Oct 1998 Location: Alberta, Canada Posts: 772	If you have a very light piston/rod combo, most likely you might have been better off with neutral balance. I had mine done to 28 oz. but it would probably have been easy to go to 0. __________________ Novi 2000 now spinning off the snout of the 331... Mods Pics

02-24-2004, 12:30 PM	#5
DirtKing Registered Member Join Date: Feb 1999 Location: brooklyn center,mn,USA Posts: 169	i had my scat 351 crank balanced for my 50 oz fluidamper (off my 302)....they did drill out a considerable amount of metal, but nothing that would weaken the crank...nor does it look like swiss cheese. Actually, i consider it a bonus (less rotating mass). HOWEVER, what concerns me is the machinist stating that the "damper is throwing the balance out of whack". Cranks are available in zero balance, 28 oz and 50 oz.. What damper you pick will affect how much work goes into the balance, but any COMPETANT shop should have no problem balancing any of these combinations. (My shop charged me 200 bucks. They also used some heavy metal.) By the way, they also balanced my pressure plate after balancing the crank. __________________ 88LX notch, Speedpro EFI 358windsor 11.2 to 1 compression, 5 lug baer claws all around..g force t5 and 3.55 gears. rwhp soon to come. Oh yeah...92 octane NO detonation.

02-25-2004, 12:07 AM	#6
84GT350-1 Registered Member Join Date: Nov 1999 Location: Willard Ohio Posts: 60	I had my eagle crank and rod 514 kit balanced with a zero balance balancer and hardly had to touch the crank. I think he should have mentioned it to you that a zero balance would benefit you. just my 2 cents.. __________________ 1967 mustang fastback drag car. tube chassis. 468 BBF.. 1989 LX notch 1982 GT 2003 F350 6.0

02-25-2004, 07:43 AM	#7
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	All depends on what your bobweight is. Your situation is pretty normal. I just zero balanced my 302 forged Scat crank and it took 14 pieces of 1" mallory metal. That's pretty typical for a ford crank with a bobweight like mine. I know, the crank doesn't look very pretty when its done, but looks don't get you down the track. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

02-25-2004, 08:04 AM	#8
84GT350-1 Registered Member Join Date: Nov 1999 Location: Willard Ohio Posts: 60	hey Jeff We are almost neighbors.. __________________ 1967 mustang fastback drag car. tube chassis. 468 BBF.. 1989 LX notch 1982 GT 2003 F350 6.0

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