Notices
944 Turbo and Turbo-S Forum 1982-1991
Sponsored by:
Sponsored by: Clore Automotive

who is actually running without balance shafts?

Thread Tools
 
Search this Thread
 
Old 02-10-2004 | 08:17 PM
  #16  
Sam Lin's Avatar
Sam Lin
Addict
Rennlist Member

 
Joined: Jul 2003
Posts: 3,788
Likes: 16
From: Gilbert, AZ, USA
Default

SeaCay, I saw pics posted of a delete kit about 6 months ago and have never found who made them. Can you post or e-mail pics of the Scott Gomes kit? They don't have to be high quality, I just need something to eyeball.

Thanks
Sam
Old 02-10-2004 | 11:18 PM
  #17  
David Floyd's Avatar
David Floyd
Addict
Rennlist Member

 
Joined: May 2001
Posts: 7,109
Likes: 4
From: Tennessee
Default

Originally posted by TonyG
>>>So how do you get smooth as stock and certainly not in another? What are the differences between that would influence it?<<<

Good question.


TonyG
Tony, do you have a stock bottom end ?

Nevermind I reread your 1st post.

My car is smooth, if anything the shifter might viberate just a little more but that is it and nothing has viberated loose in 10 k miles, so I don't know what the difference would be?

Last edited by David Floyd; 02-11-2004 at 12:50 AM.
Old 02-11-2004 | 12:07 AM
  #18  
mochman's Avatar
mochman
Pro
 
Joined: Sep 2003
Posts: 708
Likes: 1
From: PA
Default

I've run with and without. For the street keep 'em. On a dedicated track or de car where evrything is checked reg. you can ditch 'em. As Tony said even with a lightened and bal. recip assbly. he still has some (vibration). These cars def. vibrate a lot more w/out them.
Old 02-11-2004 | 12:51 AM
  #19  
FSAEracer03's Avatar
FSAEracer03
TRB0 GUY
Rennlist Member
 
Joined: Nov 2003
Posts: 3,769
Likes: 0
From: Daphne, AL
Default

just out of curiousity... what is the process to remove them??
Old 02-11-2004 | 04:27 AM
  #20  
Laust Pedersen's Avatar
Laust Pedersen
Addict
Rennlist Member

 
Joined: Sep 2003
Posts: 1,357
Likes: 8
From: Menifee, CA
Default

Balance shafts are there to cancel second order imbalance caused by the fact, that the pistons only perform a true harmonic motion, if the connecting rods are infinitely long. As a rule of thumb if a 4-cylinder engine is larger than 2 liters then they should have balance shafts, something I believe GM forgot (or cheapened out on) in their QUAD-4.

The disadvantage is obviously increased complexity and killing a few horses.

Laust
Old 02-11-2004 | 08:55 AM
  #21  
SeaCay's Avatar
SeaCay
Thefu
Rennlist Member
 
Joined: Sep 2003
Posts: 19,935
Likes: 658
From: 28*09'58.16" N, 82*35'17.07" W
Default

Originally posted by Sam Lin
SeaCay, I saw pics posted of a delete kit about 6 months ago and have never found who made them. Can you post or e-mail pics of the Scott Gomes kit? They don't have to be high quality, I just need something to eyeball.

Thanks
Sam
Ask, and ye shall receive. All the machine work is of top notch quality. A tad pricey, but saved me hours of work.
Attached Images  
Old 02-11-2004 | 11:04 AM
  #22  
Sam Lin's Avatar
Sam Lin
Addict
Rennlist Member

 
Joined: Jul 2003
Posts: 3,788
Likes: 16
From: Gilbert, AZ, USA
Default

That's it! Mind me asking how much it cost?

Sam
Old 02-11-2004 | 11:55 AM
  #23  
TonyG's Avatar
TonyG
Rennlist Junkie Forever
 
Joined: Dec 2001
Posts: 5,978
Likes: 2
From: Los Angeles
Default

I'm not running a kit like that. I have no balance shafts, balance shaft covers, or any of the balance shaft gear.

My block was welded up when the short block was being built.


TonyG
Old 02-11-2004 | 12:17 PM
  #24  
David Floyd's Avatar
David Floyd
Addict
Rennlist Member

 
Joined: May 2001
Posts: 7,109
Likes: 4
From: Tennessee
Default

Originally posted by TonyG
I'm not running a kit like that. I have no balance shafts, balance shaft covers, or any of the balance shaft gear.

My block was welded up when the short block was being built.


TonyG
Mine is welded also, so there is no going back to stock.

Not that I would want too
Old 02-11-2004 | 12:27 PM
  #25  
TonyG's Avatar
TonyG
Rennlist Junkie Forever
 
Joined: Dec 2001
Posts: 5,978
Likes: 2
From: Los Angeles
Default

One-Way Ticket :-)



TonyG
Old 02-11-2004 | 08:40 PM
  #26  
SeaCay's Avatar
SeaCay
Thefu
Rennlist Member
 
Joined: Sep 2003
Posts: 19,935
Likes: 658
From: 28*09'58.16" N, 82*35'17.07" W
Default

Originally posted by Sam Lin
That's it! Mind me asking how much it cost?

Sam
I think it was a buck75.
Old 02-11-2004 | 08:52 PM
  #27  
Sam Lin's Avatar
Sam Lin
Addict
Rennlist Member

 
Joined: Jul 2003
Posts: 3,788
Likes: 16
From: Gilbert, AZ, USA
Default

That's not bad at all actually, the machining time on those costs some money in this quantity. I wish Scott's web site didn't suck so much!

Sam
Old 02-12-2004 | 12:06 AM
  #28  
SehrSchnell's Avatar
SehrSchnell
Intermediate
 
Joined: Feb 2004
Posts: 43
Likes: 0
From: Oklahoma
Default

New to Rennlist...but machined my own bearing block-offs and used flat plates on the front...cost ~$10.00..
Old 02-12-2004 | 02:44 AM
  #29  
Under Pressure Performance's Avatar
Under Pressure Performance
Instructor
 
Joined: Jun 2001
Posts: 185
Likes: 2
From: Assonet, MA
Default

Yeah, my web site (or lack thereof) does suck for now, but I have a new site perpetually in the works...

Now, regarding balance shafts and their removal...

For starters, in a "completely" stock engine, the removal of the balance shafts is "almost" unnoticeable as there is still a lot of rotating mass which acts as a simple damper for small vibrations. That is not to say that the balance shafts do nothing, they do. The primary function of the balance shafts are to counter the secondary harmonics that are inherent in ALL inline four cylinder engines. The job of the balance shaft is relatively simple and it does its job quite well, BUT there is a misconception regarding the balance shafts function, read on...

Balance shafts do not eliminate the secondary harmonics (remember, they are inherent) - The balance shafts simply mask the "effect" of the harmonic which is a tempo vibration which will become more or less apparent at varying engine speeds, BUT keep in mind, they are internally present whether or not you run the balance shafts, only the subtle effect you feel becomes present when they are removed, and ONLY at certain "sustained" speeds.

So, why then do some people have silky smooth running engines, while others have bolts falling out? Well, you have to look at how much internal dampening has been removed from the engine. In a completely stock engine, the difference in feel with or without the shafts is based "mostly" on the factory internal balancing tolerances more than anything else. In a highly modified engine running a lightened crank, light rods, light pistons, lightened flywheel, and so on, the internal balancing becomes MUCH more critical as you are reducing the natural internal dampening of the additional mass. I have built MANY engines without balance shafts and can attest that "excessive" vibration (the type that will loosen bolts) is usually a result of parts that were not balanced together, and balanced to zero grams (or very close)

As a general rule, the lighter the internals, the more critical the balancing becomes.

Keep in mind that factory balancing allows the crank to be out as much as 12 grams!! Now, compound that with the rods, pistons, flywheel, clutch/pressure plate, belt pulleys, and so on, and you can be talking a lot of built-in imbalance right from the factory.

We eliminate the balance shafts in EVERY SINGLE race engine we build - Every one! We do it for several reasons; Lighter weight, less potential for leaks, and the simple fact that the factory balance shafts are virtually useless once you start changing the weight of all the internal and external rotating/reciprocating parts.

Are there circumstances where excessive vibrations are encountered when removing the shafts? Well, the simple answer is yes, BUT in these exceptional circumstances, the problem should not be isolated to the removal of the shafts, the problem lies elsewhere.

We have many folks that have been running our balance shaft delete kit for years (we have been making them since the mid 90's) and to the best of my knowledge none have had pieces fall off their cars from vibration, none have removed the kits to replace the shafts, and none have had any isolated catastrophic failures as a result of the shaft removal.

While we also weld up the blocks when possible, we developed this kit as a solution for those wanting to remove the shafts, but while keeping the engine in the vehicle. Also, they are 100% reversible should you decide to go back to running the balance shafts, which I am 99.94% sure you would not do once removed.

Thanks for those that have endorsed my kit and I appreciate the comments regarding the quality and such.

As stated earlier, the kits are $175.00 which includes everything you need to get the job done; Shaft bobbins/spacers, front covers, factory O-Rings for the covers and rear caps, all stainless hardware, and a bottle of Loctite 574.

Please feel free to ask if you have any questions, and I encourage any comments.

Thanks for reading, and I will do what I can to bring you all a better web site in the near future.

Thanks for your interest!

Hope this helps.
Old 02-12-2004 | 10:45 AM
  #30  
OZ951's Avatar
OZ951
Three Wheelin'
 
Joined: May 2001
Posts: 1,657
Likes: 7
From: Sydney
Default

Scott, thanks for sharing the wisdom that comes from experience.

For whoever was asking the initial question: - I run without balance shafts in my yellow 951 (lots of lightened parts).


Quick Reply: who is actually running without balance shafts?



All times are GMT -3. The time now is 11:12 AM.