harmonic balancer

**Mr. CarelessAndImprudent** · 11-03-2005, 08:46 PM

What's the benefit of an 8 inch balancer over a 6 inch? I'm guessing it's the added rotating mass? I'm thinking of getting a rattler so I was just wondering what the difference and benefit is.

**needmorepwr** · 11-03-2005, 08:53 PM

That added weight of the 8" help dampen more of the crankshafts tortional loads. Usually the larger cubic inch motors have the larger dampners. Look at the old 283 and 327 motors, they had tiny dampners compared to later 350 or 454 models. If you are going to go with a aftermarket dampner then get a ATI. They are the best ones made. I have balanced engines for 18 years and they work the best. Are you getting one because you are gonna build a blower motor and need a SFI approved dampner?

**Mr. CarelessAndImprudent** · 11-03-2005, 08:56 PM

No, just wanting to keep it alive when during high revs

**needmorepwr** · 11-03-2005, 08:58 PM

How high of RPM's? Unless you are gonna go higher than 6500 you really don't need it if the motor is balanced right. You can spend the money elseware.

**91Z28** · 11-03-2005, 08:59 PM

Originally Posted by needmorepwr

How high of RPM's? Unless you are gonna go higher than 6500 you really don't need it if the motor is balanced right. You can spend the money elseware.

You seem pretty knowledgeable about sbcs, about how much would it cost to put together a valvetrain that can take 7k rpms?

**needmorepwr** · 11-03-2005, 09:06 PM

7000 is no problem with good springs and retainers. You can run modern hydraulic cams that far without trouble. Lighter valvetrain parts will always help with durability and RPM's, but the valvesprings are whats gonna keep everything together. You don't have to spend a ton of money unless you are running a super high lift cam that is probably a race only grind.

**91Z28** · 11-03-2005, 09:13 PM

http://www.sallee-chevrolet.com/fram...s/safrzz4.html

That gave me the idea for what I want to do. Don't know how my intake manifold compares to a big single plane like that, but I definitely want Competition ported AFR 195s and a cam at least as big as that. I'd run a 230/230 if it would be very streetable with no vaccuum issues. I'd get a 70psi windage nut too just to be safe. Probably do forged 6" rods and a .030 overbore but not set on pistons yet, I hear KB hypers can be pretty strong and I won't be running FI so forged isn't necessary.

**needmorepwr** · 11-03-2005, 09:22 PM

Thats a nice motor. I have a ZZ4 with the GM "hot cam" which is about .550 lift and crane roller rockers. I stuck with the dual plane manifold it came with and that motor runs awesome. Tons of torque out of the hole and it pulls to 6500+ I have heard mixed reviews on the KB hyperutectics. I have used them with a blower at 7psi and never hurt it. The big thing with those pistons is detonation. They can't handle it. Keep your air/fuel ratio on the rich side and don't get to aggresive with the timing and they are fine.

**91Z28** · 11-03-2005, 09:26 PM

I didn't think a cam swap would be wise in a ZZ4 since the heads suck ass, so until I have the $$$ for all that other stuff I'm staying like this. I have my rev limiter set at 5900 since "max recommended rpm is 5800". It may pull farther since I have the stealth ram but I don't want to push it since this isn't a high rpm cam anyway.

**needmorepwr** · 11-03-2005, 09:33 PM

The heads aren't great, but the motor dynoed at 410hp with the cam swap and other changes so I was plenty happy. I have turned the thing to 7000, but the power fades after 6500. You will never hurt it going to 5900, it will run there for a long time.

**91Z28** · 11-03-2005, 09:38 PM

That would be about 350rwhp wouldn't it? Not bad at all. I asked around what a hotcam would do for me and people told me nothing, the less than 200cfm heads can't do anything with it.

**needmorepwr** · 11-04-2005, 04:15 PM

They are wrong. I still have the stock heads and I didn't do anything except match port the intake with the heads and that cam picked the motor up 34HP. Thats worth it in my book.

**91Z28** · 11-04-2005, 06:33 PM

Shit, you've almost got me sold. I'm seeking someone who can tune anyway, might as well throw a cam in real quick.

This'll be after I get a 12 bolt though, might as well switch fuel pumps in the process. DOH! Gonna need bigger injectors too.........................

**91Z28** · 11-04-2005, 07:43 PM

http://www.cis.udel.edu/~davis/z28/buildup/cam/

Looks like you're right. Sallee Chevrolet sells them like that and GUARANTEES 395hp. This'll work great while I'm saving up for the AFRs.

**needmorepwr** · 11-05-2005, 04:41 PM

You will be happy with that combo! Instant throttle responce and torque! You are right about getting that 12 bolt first, no reason to take a chance on having to walk home.

**91Z28** · 11-06-2005, 08:22 AM

Still hard to believe 40hp with a cam swap, that is impressive. Maybe I'll get another 50hp from competition ported AFR 195s. I'm about to start making more money and am already planning its departure from my wallet.