balencing a type iv, is it necessary to use a harmonic balencing technique or is old school triple beam good enough? |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
balencing a type iv, is it necessary to use a harmonic balencing technique or is old school triple beam good enough? |
funk |
Jan 16 2015, 01:07 AM
Post
#1
|
Member Group: Members Posts: 100 Joined: 23-June 14 From: sandpoint idaho Member No.: 17,531 Region Association: Pacific Northwest |
I have a mech who says I should put the internals on a balancing machine. It costs 225$ I have read books saying you can use a small grinder to grind the heaviest rods, pistons ect.. then weigh on a scale for balancing to within a 1/2 gram this mech thinks a balancing machine is far superior and well worth 225$ Any advice? and if I did use a dremel on the rods and internals how do you balance a fan??I couldn't find any literature?thanks just for kicks I also spoke with a retailer/mechanic who states that type four motors don't need to balanced??
|
funk |
Jan 16 2015, 01:07 AM
Post
#2
|
Member Group: Members Posts: 100 Joined: 23-June 14 From: sandpoint idaho Member No.: 17,531 Region Association: Pacific Northwest |
I have a mech who says I should put the internals on a balancing machine. It costs 225$ I have read books saying you can use a small grinder to grind the heaviest rods, pistons ect.. then weigh on a scale for balancing to within a 1/2 gram this mech thinks a balancing machine is far superior and well worth 225$ Any advice? and if I did use a dremel on the rods and internals how do you balance a fan??I couldn't find any literature?thanks just for kicks I also spoke with a retailer/mechanic who states that type four motors don't need to balanced??
|
JoeSharp |
Jan 16 2015, 03:40 AM
Post
#3
|
In Irvine, Ca. May 15-18 Group: Members Posts: 3,947 Joined: 9-July 03 From: DeLand, Florida Member No.: 898 Region Association: South East States |
I balance the pistons to the 1 tenth of a gram on my triple beam and have a fixture for the rods. I have no way to do the crank, fan, flywheel and the clutch. $225 seems OK too me. All this is fine but you still don't want to rev past 6K because of the valve springs.
|
Bulldog9 |
Jan 16 2015, 06:23 AM
Post
#4
|
Senior Member Group: Members Posts: 705 Joined: 21-August 13 From: United States Member No.: 16,283 Region Association: MidAtlantic Region |
You can balance the pistons and c rod assemblies by weight, but the crankshaft fan and flywheel must be spun. The engineers did a decent job, but it doesnt hurt to add a little extra effort in this area.
I balanced my pistons/rings/bearings/rods on a digital scale. Used a small grinding stone on my dremel to lighten the connecting rods to balance. Got everything to within .25 grams I sent the crank, fan and flywheel out to be balanced. They did the crank first, then added fan to the assembly then the crank and balanced. They did not want the flywheel or clutch. The fan was spot on but the crank and flywheel needed to be I also had them mic and polish the crank, total was $375, but I am in Northern Virginia where everything is more expensive. |
Mark Henry |
Jan 16 2015, 07:28 AM
Post
#5
|
that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I sent the crank, fan and flywheel out to be balanced. They did the crank first, then added fan to the assembly then the crank and balanced. They did not want the flywheel or clutch. What??? Fan, crank, flywheel and pressure plate (plus rods and pistons) they all must be balanced. If what you said is true you got ripped off. |
Tbrown4x4 |
Jan 16 2015, 07:36 AM
Post
#6
|
Senior Member Group: Members Posts: 703 Joined: 13-May 14 From: Port Orchard, WA Member No.: 17,338 Region Association: None |
^^^ Agreed. All rotating parts should be attached when balancing. But......all I have ever had balanced was an inline or V-motor.
|
stugray |
Jan 16 2015, 08:24 AM
Post
#7
|
Advanced Member Group: Members Posts: 3,824 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
My local machinist did my entire rotating assembly for $200.
Fan, crank, rods, pistons, FW, pressure plate. He even wanted the rings for exact weights. I didnt watch, but I dont believe that you need to attach the "BOB weights" when balancing a boxer. Probably doesnt hurt though. |
rick 918-S |
Jan 16 2015, 09:32 AM
Post
#8
|
Hey nice rack! -Celette Group: Members Posts: 20,460 Joined: 30-December 02 From: Now in Superior WI Member No.: 43 Region Association: Northstar Region |
Balancing machine? I'm old school. There is more to balancing the just grinding metal off the big end and or small end of the rods. Improper execution can result in weakening the rods. Have it done or read, read, read before you start. Besides, the parts are balanced at the factory and should be close enough for a stock rebuilds. It's when you are pushing for more performance that you start blue printing the parts. There are formulas to what a rotating mass and it's assemblies should weight for max HP and longevity.
The fan is balanced. sometimes there are little weight clips on it. (I think) If you want to check it bring it to someone that has the equipment to balance a flywheel. |
McMark |
Jan 16 2015, 10:23 AM
Post
#9
|
914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
There's a big difference between balancing rod total weights and balancing rods end for end. The latter is superior and requires more than a grinder and a scale.
|
Mike Bellis |
Jan 16 2015, 10:26 AM
Post
#10
|
Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None |
I would suggest dynamic balancing with the crank assembly spinning. This is far better than only making the pieces weigh the same.
|
Lo-Fi Version | Time is now: 17th May 2024 - 08:05 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |