What are the pros and cons for internal and external balance? What is the typical cost difference? Is it worth the cost for a street motor(432 stock rod and stroke)? Starting from scratch no flywheel(stick shift) or balancer. Thank you!

 

Internal balance is supposed to be better. I paid a fortune, 5 slugs! What are your goals and planned rpm for the motor?

 

I have BOTH in BBc's. Internals like to rev more and theoretically easier on crank/main bearings. Look at it this was, 396 and 427 Chevs were internal, 454 were external balanced when these come from GM.

I much prefer internal over external, but if it's more then $200 or $300 on a stock motor, I WOULD NOT DO IT. My alum block 515 BBc is external and should be around 840Hp and my 522 is external and should make 780Hp. In those it wasn't worth the cost/effort to swap to internal balanced. Now for me, that means I HAVE to stock internal AND external flex places and balancers seeing as I have multiple engine.

 

My unrealistic goal is to make 550hp and run 1-11.80 pass. But I’d be happy with a motor that could run low 12s and just be fun to drive.

 

I did, and I like it. I was originally going 496, but the Eagle crank needed too much Mallory for internal balancing. Given the controversy over crank flex, I like having the counterweight closer to the centerline.
I got a neutral balance flywheel in an early (64-67) pattern from Science Friction. I think they are/were affiliated with American Powertrain.

 

Yea my main thing is durability cause I do hammer on it often. Crank flex I would think would be more on a stick shift application??

 

Internal makes it easier to swap balancers etc.
And even though they’re bringing it INTO balance, it never seemed logical to me to hang the weights out at the ends.
And if your dealing with less than stout parts, like virtually ALL Olds blocks, potentially less flex can only be a good thing. I do more and more internal stuff.

 

The only con is the price.

 

If you don't have a damper and flywheel the price of those will be the same either way, or pretty close. I have never done an Olds internal but if it takes 4 slugs of heavy metal you would be looking at about $790 for the balance job if I did it. That's $350 for the basic balance job and an additional $440 for the heavy metal and installing it.

Is it worth it for a street engine with an occasional romp ? Not sure. There are literally millions of 454 Chevy engines running around that are external balance. All of the Mercruiser Big Blocks are external balance and they run at 4500 rpm under full load for hours at a time ?

The only unknown for me is how the Olds cranks hold up under crazy stress because I have not built enough of them that are really getting beat on. I am betting that there are plenty of them driving around and down the drag strip that it really is not a problem

 

How much did it cost?

 

I believe $1500 CAD😱! I should have heaved the old 330 crank in the scrap metal pile and bought the billet 4" stroke crank from Mark. I have another 330 crank already offset ground. It sounds like it will need similar Mallory for internal balancing 🤔.

 

@ that much, these MILD low rpm Olds engine fo NOT need internal baanced cranks. Since I'm actuually going to be building a Olds, my thoughts are IF YOUR NOT reving over 6500 or not making 650Hp, you don't need internal balance.

You might get a bit extra life but really not like your only getting 20000 mile on external and 320000 with internal.

Is internal better, YES for sure. Just the cost outweighs the benefits in a street motor of these tyoes.

 

So you’re going to use a solid roller in it, which is waaaay more beneficial at higher rpms, but you’re not going to internally balance it, because that’s for higher rpm engines. Hmmmm, interesting.
Just sayin, that’s all.

 

You're entitled to an opinion, but I don't agree with it. ANYTHING you can do helps.

 

Yes because we don't like what we see in flat tappets anymore? I have had some good running hyd rollers in the past with SBs, but these larger engines seem to be hit and miss. So i bought BAM lifters today for this project. Less then $150 difference between BAM solid roller and Morel hyd rollers. So that's a no-brainer for piece of mind as well as better performance.

But $1500 as mntioned above, and no difference in performance doesn't equate well to me. I also run conical springs on all my stuff as we ave seen a performance advantage there as well.

 

Thanks, yes it is my opinion that on this STOCK motor the original poster mentioned, it isn't warranted. We have successfully run cast ext BBc cranks to 7800 rpm, nodular Cleveland ford to 93 to 9700 rpm depending on track conditions. Seen it all to often how easy it is to spend others $$$ when not needed.

40 yrs in this "hobby" and being involved with many many different types of cars, you get to learn a thing or two. Having 6 cars and 10 engines, you learn where you can cut corners and where you shouldn't.

I gave the OP and idea when he should look at going internal with an Olds. What perameters do you have to justify spending the extra to go internal?

 

then forget about the internal balance. Put your money into aftermarket rods or a light piston with the stock rods.

i would say about 100% of the Olds’ out there running low 12’s or 11.80’s are external balanced…it’s not an issue at that power and RPM potential . Your stock rods could be though

what piston are you using?

 

I have a set of Molnar rods in order and have a set of the mahle 4.155 pistons I got from mark (cutlassefi)

 

Thanks for the reply
Is Mark's stroker crank internal balanced?

 

I can't say for sure. I thought Mark said minimal Mallory is needed, like 2 slugs. I could be wrong. I'm sure he will correct me😁.

 

Typically 2 slugs in each end on a stock crank.

 

Couple videos on the process of internal balancing a crank.

 

I have running through drive no shifting 11.60 engine that is internal balanced Chevy big block eagle rods. So 99 % olds are running external balance.

 

NO your wrong. Your running 11.60's. Dale said 12.00 or 11 EIGHTYS not SIXTIES!!! Reading comprehension isn't your friend is it.

 

Yes. They come configured for an approx bobweight of 1900gr. Typical bobweight is mid 1700’s so you’ll be drilling, not adding.

 

🙄🙄🙄🙄🙄I was pointing out I am faster than his numbers . You are using next to nothing of your brain ! Admit it.😂😂😂😂 And my external balanced engine is 11.20. go sit down you are embarrassing yourself.

 

Nice
Another reason to run one of your stroker cranks.
Do you offer a big block crank with stock stroke and journal size that is internally balanced?

 

No sorry. Scat did but they didn’t sell very well, hence why they’re now discontinued.

 

Man your an ignorant person! I can see why people have PM'ed me to get away from this site................... WOW 11.20's way to go there Big Daddy!!! John Force better watch out????

The funny part is you just PROVED what Dale stated! YOUR very own engine run 11.20 and is external. You have such a warped view on things you as straight as a dogs hind leg!!!!

You have made it to the ignore list....... So say whatever you choose to.

 

Good blow fly the door is open for you to leave!! You sure are a dim bulb on this site. The 11.60 was non shift dim bulb. Only used drive in the turbo 400. Yes it could go much faster but no need to. I also proved many have internal balanced engine's I am one that go faster than the numbers Dale mentioned. Actually my engine isn't even a 455 ci. It's a 450 ci going 11.60 in drive. And your claim to fame with a Oldsmobile Motor? I know nothing! Trying to live off what someone else does. 😂😂😂😂

 

Scat dropped the ball when they made it a 2.200 BBC journal. They should have made it accept off the shelf 455 pistons and 6.735 rods.

 

Yep, kiss of death right there.

 

why would you want to limit yourself in bearing and rod selections with a high end internally balanced crank?

Rocket racing’s internal crank is 2.2”.

getting away from the huge 2.5” journal is a good thing

 

Valid point. But apparently not enough shared that same sentiment.

 

I would tend to agree. Hell even BBc usually use SB 2.100 journals to get away from the 2.200 standard BBc stuff. I would think going from standard OLDS 2.500" down to standard BBc 2.200" would be a good thing and even open up to more BBC off-the-shelf parts like rods and pistons. I know Wiseco told me I could move the pin height on any standard piston for $100/set 3 yrs ago???? Now going to the SB 2.100" stuff would get to be some oddball custom rods I would think.

 

Yes all of us know that the 2.200 rod journal is better. I'm talking from a strictly sales perspective. Most guys just want to be able to buy "shelf" parts from Summit listed for that particular engine family.

 

Thank you, you hit the nail on the head Chad!! Some moron on Facebook actually asked why I didn’t suggest changing the port locations on the new Edelbrock heads. I pointed out that then Edelbrock would have to re-cast all of their intakes, AND all of their other intakes would be useless. People don’t get it, 80% of the people on here and other sites just want to do what you mentioned, just bolt on and go. The reverse is true on my small block Stroker crank. That’s the reason why I made the rod journals small block Chevy, and common dimensions for Pistons as well. The counter weight and piston configuration would’ve had to be totally different had I utilized the stock small block Oldsmobile rod. Again Chad, thank you for seeing the bigger picture.

 

Agree on the 2.2 pin being a perceived barrier. Really, all Scat had to do was have someone produce a "shelf" piston for that combo, since 6.8 or 7.1 Chevy rods are common. And all that shelf piston would be is a pin height/diameter change from what exists now.

Oh, and I get everything internally balanced. Anytime the counterweight is closer to the weight its offsetting, it's a good thing. The only downside is cost.

 

I’ll bet it was because there already was an internal balance crank available from an Olds supplier.

there isn’t enough market for tow of them.

 

Molnar makes a 6.750” There’s your close to zero deck already. Its also important to have a wide variety of bearings.