• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Need to rebalance rotating assembly?

JTGS850GL

JTGS850GL

Forum Sage
Past Site Supporter
I've noticed that almost no one had the rotating assembly rebalanced after replacing pistons with overbore pistons. Is this normal? Do people notice any increase in vibration after the rebuild? A little surprised about this since it was normal on cars to do the rebalancing and I figured it would even more critical since these engines pull more RPMs.
 
balance the pistons and be happy.
if the crank was a part you could balance the rods...that's as much as you can do on a press pin engine.
 
Really? Then there's no way to add/remove weight from the crank based on the static weight of the pistons? I would have thought there would be a way to compensate for more rotating mass. I guess I was wrong.
 
Oh, there is probably a way, but the only way to balance a crank properly is to SPIN it.

Since the rods are one-piece affairs, they will be spinning along with the crank.
eek.gif.pagespeed.ce.LrCKuSadLI.gif


Yeah, you could take the crank apart to take the rods off, then put the crank back together to balance it, then take it apart again to put the rods back on, then HOPE it's still balanced.

There is enough weight in the crank that the slight extra weight of the pistons will not matter all that much.

.
 
So, has anyone noticed any significant increase in engine vibration after installing a big bore kit on their engine?
 
no - but you can weigh each piston if you like and check they're all the same...
 
I am a firm believer in making all the pistons weigh the same. Weigh the pistons on a triple beam scale leave the lightest one alone and make the other three weigh the same. I put the rings and wrist pin with the cir clips on the scale with the pistons when I weigh them.
 
Where and how do you relieve the pistons to reduce the weight to match the lightest one?
 
I take weight from the underside of the pistons when I am balancing. If the weights are WAY off, I have even taken weight out of the pins if needed.
Ray.
 
You must log in or register to reply here.
Back
Top