Balancing the crank? Worth it?

[cawcislo]

I'm building up a 2.5 t2 and I want this motor to run really nice. Any tips? Is it worth balancing the crank. I've heard from some that it isn't worth it for out little 4s? Any other things I should get done while getting the block bored and getting my forged pistons installed and ARP hardware.

[eef mcglikn]

from all ive seen and heard ma mopar has enough balance built in forget blueprinting etc. good luck

eef

[turbovanman]

3 words

BALANCE IT NOW!!!!!!!!! I balanced mine and the machinist said it was out quite a bit, no wonder they use balance shafts!!!!!!!!!

[Turbolag87]

So was mine. A while back i balanced my first 2.2 and i felt a difference.

Danny

[boostaholic]

when i balance my rods one was out 6 grams.. so at like a certain rpm i cannot recall now thats like 60 grams.. so i'd say do it.. even though ur talkin bout crank.. and what not.. balance it!

[Shelby VNT]

Depends how serious of a motor your building up. It can't hurt, but it might not be worth it money-wise if your only going to make around 200hp.

[turbovanman]

Quote:

Originally posted by Shelby VNT Depends how serious of a motor your building up. It can't hurt, but it might not be worth it money-wise if your only going to make around 200hp.

You don't do it to make power, you do it to make your engine live. Balancing involves, crank, pistons, rods and clutch if you have one. It makes the engine run smoother and the engine lives longer. Your bearings don't take quite a beating and its cheap. Cost me $175, thats cheap insurance!!!!!!
It doesn't matter what type of buildup, big or little, every bit helps.:big grin:

[glhsken]

Quote:

Originally posted by Shelby VNT Depends how serious of a motor your building up. It can't hurt, but it might not be worth it money-wise if your only going to make around 200hp.

You make a good point. And I agree.

However, as long as you are building one, why not just do it. How many of us simply "stop" at 200 hp??? I hate addictions

[Shelby VNT]

I know you don't balance a crank to make more horsepower, but the point I was getting at was this. If the crank is not in balance from the factory then you'll probably be fine at lower horsepower levels. Now as your horsepower goes up, your multipling the stress on your bearings with an unbalanced crank. In which case it wise to get it balanced.

Ken's right, very true, once you get a taste of 200hp, you'll want more.

I was also going to ask, but I assume you guys are talking about just balanciing the crank alone and not the entire rotating assembly. My above comment was pointed more at entire balance and blueprint jobs, including rods and pistons. I plan to do just that with my engine. Many say it's not needed, but it's my money, and I'll do what I want with it.

[glhsken]

You need to balance the entire rotating assembly or nothing at all...

[macncheese]

so the rotating assembly would include crank, rods, pistons,.....?
tony

[glhsken]

And flywheel.

[GLHS0658]

If you are going to do the flywheel, you might as well bolt the clutch to it and have it balanced with it.

These are internally balanced motors meaning there are no weights on the flywheel or crank pully/harmonic balancer.
That is not to say that the flywheel shoouldn't be balanced. It is a cast piece of metal and like a crankshaft, it has variances. I had my flywheel balanced after I had it resurfaced and lightened.
Yes there was a noticeable difference lightened (5lbs removed).
It is not as light as an aluminum flywheel and I was still able to launch.

The cranks are self balancing from the factory by design. The 4 cylinder cranks are cast/forged with 2 rod journals up and 2 down.
It is good to balance within 1 gram.
My 87 GLHS (T1) stock crank was 1.5 grams

Pistons are usually close, within a few grams of each other
Aftermarket pistons bought in sets are usually within 1 gram if not exact. Depends on the manufacturer

Connecting rods are what is most off. Casting/forging variances
require them to be balanced.

Yes balancing does help in a lot of ways
Idle quality/ High rpm/ longevity

[eef mcglikn]

<sobbing>

ok ok maybe ma mopar isnt perfect...........

i love her balance just the way she is......go ahead...go ahead.....change her....<sobbing>

maybe its that im only pushing 183 hp at the crank......

.......i just never thought bigger....we were so in love...



loves ma mopar......

eef

Was the engine knocking bad when you took it apart? If it wasn't making a sound, it's not worth your time or your money as long as you use parts that weigh the same amount as oem specifications. If the pistons sounded like they were trying to bang a hole thru the block to escape, then it would be a good idea. Even a moderate noise could have just been the pins in your connecting rods. You probably have pressed in pins. If the car was making noise I recommend getting them replaced along with the balancing. You should also see about getting a full floating setup.