HELP...sbc , I want to skip harmonic balancer

No one seemed to point it out, so here's my $.02..

Internally balanced engines use a DAMPENER, not a balancer. Externally balanced engines use a BALANCER. They are the same thing, except that the balancer has an offset weight to match the rest of the rotating assembly. Their prime function is to counter harmonics created by the twisting of the rotating assembly, sudden reversal of mass on the rod journals when the pistons change direction, variable stresses of imbalanced bangs in each hole, etc.
If you have an internally balanced engine, the dampener can be reduced to a mere sleeve for the oil seal. You pay the penalty in that less mass means less protection from harmonics. As pointed out, in a dedicated drag car, no big deal, especially if you have a precision balance job done on your rotating assembly. I've seen OE imbalance vary from 40 to 140 grams, but a precision job will get you down to 1 gram or less. Winston Cup engines are said to be down to under .1 grams.

If you have an externally balanced engine, you can only shrink the balancer down to the hub for oil seal PLUS the counter weight. This would be the amount of imbalance that the balancer has built in. Turning the ring down could be catastrophic because the weight has a certain effect on overall balance based on weight and radius from centerline. That means 50 grams at the edge of a 6" balancer has more impact than 50 grams right next to the snout.

 

Maybe a little late ..... But why not run a pump extension? Enderle makes them in all lengths starting at 2"... I assume, this Water Pump is driven by a 3/8" hex shaft?

 

DON'T use a cut down stock balancer it's cast iron, and it will come apart (no track in their right mind would even let you pass tech with that). Bite the bullet, and get a blower drive hub, or better yet get an extension for the water pump so you can run an SFI approved balancer.

 

Hi,

I checked the damper, it has no offset weight, so I guess its a engine witch you can just seal the "hole". Its a 010 block with stock crank.

The guy who is going to balance "the stuff" , is using a realy nice machine to messure single grams =)




Yeah, an extension could work, but Im trying to get it compact, and if I dont need a crank pulley, Im happy =) (it´s a 3/8 hex)
The water pump even has a fuelpump connection in the same axle.

 

A little hub is interesting, I have to check that out too.

Im gonna get some pics of my hub, and some other relevant =)

 

Drive hub.
http://www.goodvibesracing.com/BDS_CrankHubs.htm

 

I have been getting the parts together to build a real killer 400SBC and did a lot of research on crankshafts and balancers.

Engines that run from idle to whatever RPMs have a point that they generate enough torsional vibrations that they will literally tear an engine apart if run at that particular RPM for any length of time. Drag racers that typically run wide open for a short time don't need the balancer, Bonneville engines that stay at a given RPM need the best balancer they can get.

I got my info from the tech people at Crower, Manley, Eagle and Scat.

 

I went through hell trying to get a cam driving fuel pump for Hilborn Injection to work with a externaly balanced 383 sbc. I had dampner clearance problems that included finned timing chain covers. So, I gave up on an Injected motor and built a blown and injected motor.

But, I did find here through the HAMB a Jegs balancer that was super thin that cleared the timing chain cover and had decent room between the back of the balance and the cover.

How far off is and where is the clearance issue?

 

It is hard to see, but I just run the hub from a 283, not balancer ring.

 

The solid crankpulley

 

you can use the flywheel/flex plate to do the timing the big dia gives you a more precise timing you just degree it like the frt hub and you don't need a dampener but like most moving in a motor harmonics are a fact of life if they can lessened or eliminated it better but it's not vital