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Author Topic:   Engine Balancing
ZR1RACER
Dirt Roller

Total posts: 10
posted April 12, 2005 05:41 PM  
I've run several unbalanced engines (factory balanced) all season @ 6500 rpm without problems. these engines were at about 350-400 HP. I think if you tried to run unbalanced engines at higher horsepowers/ RPM's it would cause much grief.

chapa73
Dirt Maniac

Total posts: 169
posted April 15, 2005 07:26 AM  
Im no engine expert,But I believe a Balance is a must,If you drop $1,000 in an engine,why not spend the extra $125-200 in a balance job.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 15, 2005 07:31 AM  
The thing is even stock stuff is somewhat balanced. Maybe not as fine as a spin balance but the rod weight, piston weight and crank weight is somewhat standard for the application. If you are running all stock 350 stuff then you are still somewhat balanced. But keep in mind most stock stuff was designed for 4000 or less rpm. Start mixing and matching some aftermarket stuff and turning up the rpms then you either need to keep an eye on the weight of the pieces or have it balanced. To me the extra 150$ is worth it even on 1500$ engine. The other side of it is if you are trying to run stock stuff balanceing will help it last longer, so you can get by without as many failures.

There is no doubt in my mind balancing is better for an engine. Will it live? prob, how long? thats the mystery.

[This message has been edited by dirtbuster (edited April 15, 2005).]

petordragon
Dirt Maniac

Total posts: 167
posted April 19, 2005 12:58 PM  
balancing will help the motor last longer. we run a claim rule also but no one has used it so far and more and more money is bieng spent. basicly you need to decide what's the chances mine will get claimed and can I live with the loss.

zeroracing
Dirt Forum Champ
Total posts: 1876
posted April 19, 2005 09:01 PM  
My little motor is unblanced, it is a 355 flat top, eagle i beam rods, stock crank, 4 bolt main .030 overbore. i run it in a modified, on 1/3 to 1/2 mile tracks, hook it up hard on a four bar hiked up, and turn it about 6800-7200 nightly but for a recent big show turned it about 7800. The motor will be going on its 4th season i think it is, been apart one time for bearings, hold oil pressure great, and runs strong.
this motor has never been balanced, just bought the stuff and stuck it in there.
I ran a friends balanced motor that was similar to this one, only turned it about 6600 it broke the 2nd night out in my car about 6th overall, was a rod bolt failure, but it had major wear on everything already. no i did not build that granade.

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