We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Where do I put the new rods?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Lizardracing
Pro
Pro
Posts: 261
Joined: Fri Sep 10, 2010 2:38 am
Location:

Re: Where do I put the new rods?

Post by Lizardracing » Mon Nov 04, 2019 10:12 am

BillK

I fully realize it's not really gonna make much difference. Many overbalance at 1% or even 2% so with a 1800g target bobweight, were talking about less than .02 percent.

mag2555,

This rods had 10 shows on it before it blew up. A valve broke, then the piston broke, the free end of the rod broke everything else on it way out of the block on it's way to low orbit. I use a stretch guage and have already made sure the big ends are still round.

Mark O'Neal
Guru
Guru
Posts: 1366
Joined: Tue Mar 06, 2007 7:23 pm
Location: Torrance, CA
Contact:

Re: Where do I put the new rods?

Post by Mark O'Neal » Tue Nov 05, 2019 12:01 am

Overbalance = LUDICROUS POWER.... :notworthy: :notworthy:

User avatar
BOOT
Guru
Guru
Posts: 1649
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Where do I put the new rods?

Post by BOOT » Tue Nov 05, 2019 12:50 am

Ok I have no clue on balancing or w/e but lets say it might make sense to put them in the middle to not uneven either end of the crank or one rod on either end to even things out BUT on the other hand maybe both on the flexplate/flywheel side since that is the heavy end and may dampen better OR if you wanna just say by weight then both the nose/harmonic damper end to even things out LOL

I understand wanting the best possible position and I'd prob be asking the same question but I'm just gonna say do what makes you most comfortable unless a real balance expert chimes in.
Channel about my projects https://www.youtube.com/user/BOOT350V

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!

Lizardracing
Pro
Pro
Posts: 261
Joined: Fri Sep 10, 2010 2:38 am
Location:

Re: Where do I put the new rods?

Post by Lizardracing » Tue Nov 05, 2019 8:26 pm

I’m pretty sure the real professionals are eating popcorn and taking chit about me for being anal over nothing lmao.
It’s okay though. I can take it. Lol

This is Dirt modified with a falcon transmission so the flywheel is only 5” amd doesn’t serve much of a damper so I think I’ll match them up to the 2 and 7 between the counter weights. If it comes apart again imma cry in a fetal position in the corner of the shop.

gruntguru
Pro
Pro
Posts: 431
Joined: Fri Apr 10, 2015 7:56 pm
Location:

Re: Where do I put the new rods?

Post by gruntguru » Wed Nov 06, 2019 12:01 am

File the small ends to the same weight as the rest of the rods and put the 2 rods anywhere - not on the same crankpin though.

tresi
Pro
Pro
Posts: 341
Joined: Sun Mar 24, 2013 10:10 pm
Location:

Re: Where do I put the new rods?

Post by tresi » Wed Nov 06, 2019 12:56 am

Lizardracing wrote:
Sun Nov 03, 2019 6:40 pm
SBC
4.155"x3.75"
406ci
Scat crank 3.75"
Scat rods 6.00"
JE pistons and rings.
Brodix T1x heads
Brodix Intake
Mike Jones SFT cam
Dirt Modified.
7200 rpm chip

I had a blow up. A bad one. All I saved was the crank and 6 rods. I replaced the rods with 2 new ones from Scat. They are 5g heavier total weight. They are lighter on the big end, a little heavier on the small end. I;m going to mix and match as needed to get the pistons/pins and rods as close as possible to the same. The original rods are all identical small/big end and total weight.
The new pistons are 46g lighter. I hadn't planned for a another balance job if I can get it close enough.
Is there a better position to put the new rods? On the ends of the crank? Middle? Same Journal? Trash can? Does it really matter?
A current pro drag racer told me about a time before he turned pro struggling to make a race with what he had put a motor together with 6 dome and 2 flat top pistons. He claimed he didn't feel it shake

turbo camino
Member
Member
Posts: 136
Joined: Sun Aug 10, 2008 11:51 am
Location:

Re: Where do I put the new rods?

Post by turbo camino » Wed Nov 06, 2019 3:27 am

I knew a guy who built a 350 with a 76cc head head and domed pistons on one side, and a 64cc & flat tops on the other. Ran it like that for many years.
DON'T PANIC

Post Reply