Effect of a small harmonic damper vs large on a 350 SBC

Last edited by a moderator:
DorianL said:
I just called a buddy of mine - he may have a used 8-inch damper. If he does, we will try swapping that on to see if it changes anything.
Click to expand...
Make sure the damper does not have a section of "extra weight".
That would be for externally balanced engines and if you put one of those on your internally balanced engine - you WILL HAVE vibrations!

You can temporarily remove the entire clutch fan to test.
Just make sure the bolts going into the water pump hub do not go in so far to hit the housing on the other side. You can use washers or even larger nuts as spacers.
 
My 1987 Corvette with its L98 TPi 350 Chevy engine has a small harmonic balancer.

All Pontiac V8's used a small diameter harmonic balancer. Just under 7 inches.

My 1965 Olds 425 Uses a small Harmonic balancer.

It really depends upon the crankshaft internal counter weights mass & diameter size used with a given crankshaft stroke & Piston -rod rings bob weight determined.

I just know a Huge heavy Mass Balancer is Bad for Drag Racing & Dirt track racing.
Everytime one flies through the hood at 6,000-8,000 rpm its from a Small Block Chevy.
Seen it happen several dozen times now.
The Crankshaft snout snaps right off at the #1 Main journal.
 
I am doubting it is the balancer unless it is an externally balanced model is the engine factory original. You would be amazed how out of balance these things come from factory. I know my internals are balanced to .01 grams on calibrated scale and overbalanced on the crank to smooth high rpm operation. I also run a small ATI harmonic balancer not the larger.
 
And I think you are on the money. See The Force Awakens thread.

I replaced the a completely worn trans mount. This in turn lifted the pipes a good .5 inch if not more One pipe is against the bottom of the vehicle. The other is as good as.

Tomorrow I will tweak a little and if there is a remarkable difference... we’ll know it’s the source of the problem!
 
Loves302Chevy said:
Dorian you can add a plenum divider to your single plane intake.
I'm sure Grumpy will post the picture before I can find it.
It helps by splitting the intake in 2 sections, like a dual plane, but different.
It can even be added to a carb spacer.
View attachment 9656

http://garage.grumpysperformance.com/index.php?threads/old-school-plenum-intake-divider-fix.5022/

http://garage.grumpysperformance.com/index.php?threads/carb-plenum-intake-design.4362/#post-11826
Click to expand...

Added info:
I was going through some old paperwork and found an article in Budget Building Chevy Small Blocks by David Vizard.
On page 118, he talks about single plane intake manifolds and camshafts big enough to kill intake vacuum.
Although it borders on an "X" design, the Weiand 7504 manifold can be made to work quite well. However, it must be used with a
divider as shown here or the results achieved will be disappointing. Without the divider I've seen as much as 60 foot-pounds of torque
and almost a like amount of horsepower disappear.

Dorian, if you are not going to swap to a dual plane intake, you might want to add a divider to your Edelbrock Torker intake.
It can be done without removing it from the engine with a vacuum cleaner and careful use of a dremel.

http://www.stevesnovasite.com/forum...d1241020d956a0c97a9864&p=1183463&postcount=12
 
I think I might well do that or something similar... of the line torque is very poor.

See more shortly on my "Force Awakens" thread...
 
You must log in or register to reply here.
Back
Top