<VV> Rod caps and balancing

[RoboMan91324 at aol.com]

Bob (and anyone else)

I didn't know that Chevy balanced the rods only in pairs but thinking about 
the design of our "boxer" engines, I understand why.  Is it possible to do as 
Chevy did when balancing our rods for performance and just pay attention to 
pairs or is there a possible harmonic problem?  ..... or other issue?

Thanks in advance,

Dave
1960 Vette; 1961 Rampside; 1962 Rampside; 1964 Spyder coupe; 1965 Greenbrier; 
1966 Corsa Turbo Coupe; 1967 Nova SS; 1968 Camaro ragtop
~~~~~~~~~~~~~~~~~~
In a message dated 6/11/2008 9:01:05 AM Pacific Daylight Time, 
virtualvairs-request at corvair.org writes:

> Message: 8
> Date: Wed, 11 Jun 2008 11:55:31 EDT
> From: BobHelt at aol.com
> Subject: Re: <VV> Rod caps and balancing
> To: HallGrenn at aol.com, virtualvairs at corvair.org
> Message-ID: <d4a.2fc659a0.35814f73 at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
> 
> In a message dated 6/10/2008 6:19:49 AM US Mountain Standard Time,  
> HallGrenn at aol.com writes:
> 
> Anybody  with experience building performance  engines have any  
> recommendations or guidance as to how much rod caps can be  ground  before 
> they become 
> too weak?
> 
> Bob Hall
> 
> 
> 
> Hi Bob,
> You may already have your answer from Dan. But just in case, I'll add my  
> comments too.
> 
> As you probably know, Chevrolet just balanced the con rods in opposing  
> pairs. Thus there can be a great imbalance from pair to pair. So when you 
> want  to 
> get a set of six balanced there are potential problems because of the great  
> 
> imbalances between pairs. The balance shops just try to work with what you 
> send 
> them so thus often you wind up with an excessive amount of material being  
> removed in an attempt to balance rods that are way out of balance to start 
> with.  There is only one solution to that in my opinion and that is to send 
> at 
> least 18  and better yet 24 rods to the balance shop so that they can pick 
> the 6 
> that  are already closest in balance before they remove any metal.
> 
> Now to your question. If you even have the slighest concern that too much  
> material was removed anywhere on any of the rods, just toss them and have a 
> new  
> set balanced. Rods are highly stressed on the big ends and might fail at 
> high 
> rpms. Of course, if one might fail, it could destroy the engine. So it's 
> better  to be as safe as possible.
> HTH
> Regards,
> Bob Helt


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