C2 SB Balancer

[Michael H.]

Re: C2 SB Balancer

My point exactly. If all we're talking about is adding a cam, there's no point in going any further with the balancer but if it's going to turn into a major revamp into all Sp H/Per, then by all means, go with the 8". If he just wants it to look and sound like a 365 HP, then buy the aluminum intake instead but if he's going to run it hard, buy the balancer first.

Also... the dampner works the hardest and is the most active in the upper middle of the torque curve, not the max RPM that the engine is now capable of with the new cam/lifters. The amount of C/Shaft twist begins to taper off after the max torque area. The ring and the rubber in the ring are tuned to the level of the power inputs for different engines and that's another reason why the correct unit should be used for the application. Adding just a cam does not a 365 HP make.

[Joe L.]

Re: A couple more things to consider...

Duke-----

Yes, it does. The covers are different for the 6" and 8" balancers due to the timing tab location. However, when one is changing a cam it's pretty easy to replace the timing cover or relocate the timing tab.

[Michael H.]

Now, that reason I will agree with

I would say that there is no longer a debate. Amazing that the 6" is actually more than the 8".

[Joe L.]

Re: C2 SB Balancer

Michael-----

No, adding the GM #3972178 camshaft doesn't make a base engine or HP 327 into an L-76. However, it does make the engine a special high performance engine and it moves the RPM range about 1000 to 1500 RPM higher. If one doesn't intend to use that extra RPM, at all, then why install the cam? And, if one's going to install the cam, then one might as well make as many other improvements as possible to the engine to covert it to SHP configuration. That includes the balancer.

The only other differences in base/HP engines compared to SHP was induction system, pistons, and ignition advance curves. The induction system didn't make a huge difference in performance, the ignition curve should be changed anyway if the cam is changed, and the cast pistons of the base/HP 327s will work just fine in a SHP engine. ALL 283 pistons, including the SHP 1961 315 hp, were conventional cast pistons, and this type piston will work just fine in a SHP 327 engine, too. Also, all base engine Corvette 327s EXCEPT 62-64 250 hp used heads with 1.94/1.50 valve size, the same as 62-63 SHP 340 and 360 hp engines. The 1.94/1.50 valve size easily supports an engine with SHP specifications (perhaps, even better than the later 2.02/1.60 heads).

[Michael H.]

Re: C2 SB Balancer

Joe,

Actually, this whole debate is completely pointless as we have absolutely no idea what the original poster has in mind for the engine.

My original point was, and still is, if the only thing that's to be changed on a base engine is the addition of the solid lifter cam, there's not going to be a major increase in horsepower. In fact, if the 178 cam is installed, the HP difference isn't even worth the price of the gaskets that are needed to make the switch, not to mention the cost of the cam itself. It will rev higher, as you mention, but, as I mentioned, the RPM range of the most severe crankshaft twist isn't happening at 6500 RPM. It's happening at probably 4500 RPM and at that speed, the LT1 cam isn't going to make enough difference in actual torque output to matter. Likely, it would match that of an original 300 HP cam at that RPM. You were kind enough to explain to me what the difference was between a base engine and a Sp H/Per engine so I'll explain to you the function of a torsional damper. It dampens the flex or twist that's introduced at each cylinder firing position. It responds to the inputs and dampens them. It has absolutely nothing to do with engine rotating mass balance. If the amount if energy introduced at the critical speed isn't changed, then the correct factory calibrated damper is highly recommended because it's tuned for that exact frequency. If the amount of energy is changed, then the tuning of the damper should be changed. It's not the RPM, it's the amount of energy in each power stroke that determins the size/weight of the ring and tuning of the elastomer. If the LT1 cam is all that's changed, there has been little change in the amount of energy at 4500 RPM and almost no change in crankshaft flex.

The LT1 cam alone is not going to turn a 300 HP motor into a 350 HP motor. It takes the whole package, as you mentioned, to get any decent results, which brings us back to my original statements. IF the only item changed is the addition of an LT1 cam, there's absolutely no need for the 8" balancer. IF the entire engine is to be completely converted to Sp H/Per., I then agree with your recommendations 100%.

Hopefully, we'll all be surprised to hear that the original poster already has the correct parts to make a complete Sp H/Per engine. Or, has no intentions of ever buzzing the motor and just want's the cool sound. In either case, I'm sure he's had enough of this debate. I know I have.

[Steve D.]

Re: C2 SB Balancer

Gentlemen

Thanks for all of the comments.

I am setting the car up to be driven and although I won't be doing any serious racing, I do plan to visit the red line frequently and smoke the tires every now and then.

Steve