Are aftermarket Harmonic Dampeners worth the investment for a street car that won't see over 6000 rpm? Are there any performance gains?

 

For your application-no. BUT just be sure to buy a brand new one since the seals/rubber in your current factory unit have seen better days and you dont want to take a chance of the damper letting go.

 

im with this guy... a new stock one is cheaper than a hole in a fender/hood

 

One convenient feature of aftermarket dampeners is getting one with a degreed face- really helps when you're checking your ignition timing at different RPM points, etc.

Summit has one for about the same as a parts store replacement that's got marks on it from TDC up to 60*. This is not an SFI-approved piece. Basically just a factory dampener with degree marks.

 

when installing a new dampener will my timing marks be the same or will i have to make new marks.

tried seeing where the timing was and theres no mark even close.
a dampener only goes on one way on the crank so are the marks on a new dampener my new timing marks??? did my old balencer slip???

sorry for hi jacking the tread

 

GM put the timing marks in one of 2 places. The common or "typical" location is over at about the 1:30 position. L-98 TPIs, for instance had it in that location. This location is typical for both 8" and 6-3/4" balancers over many years and models. The timing tab is typically held on using two of the timing chain cover bolts (but not always- some are welded in place).

The other location is straight-up at 12:00 behind the water pump. This was used on many 305 engines throughout the 80s. Like carbureted 305 LG-4 and L-69 motors. Also 305 TBI engines in Camaros/Firebirds. All these units were the smaller 6-3/4" diameter balancer. The timing tab was welded right onto the front of the timing chain cover.

If you re-use a 12:00 balancer with a 1:30 position timing tab you'll be way off. Vice versa and you'll be way off. A typical "gotcha" is when you reuse an old 12:00 position balancer off your old stock 305 on a new crate motor or other aftermarket engine that almost always uses the more common 1:30 position timing tab. It'll be off by a mile every time.

The balancers are completely interchangable, it's just that the TDC line is scribed onto the outside shell in a different location.

All this assumes you just have a simple mismatch and that you balacer's outter ring hasn't slipped.

 

yes its the L-98 tpi and the timeing tab is at the 1:30 position. but the top dead center marker on the balancer is like at 6:30.

with the advance disconneced and the connector on #1 cylinder plug wire "first cylinder on the right side standing in front of the car".
and pointing timing light in the gap at the timing tab i belive i can see the marker at about 6:30 position. am i doing this right or has the balancer slipped???
thanks for the help

 

Put the engine at #1 TDC firing and find out.