SBC Harmonic Balancer Questions

[fine69]

Hello All,

It's been a slow process (been out just about every weekend enjoying the Camaro!), but I'm putting my engine back together again.

I'm using an engine rotator tool connected to the pulley bolt holes in the front of the harmonic balancer to turn the engine for valve adjustments, etc. I found out that when rotating the motor the balancer "slips" by a few tick marks (on the timing tab), before catching and turning the motor.

Is this normal?

The balancer is approx 6 3/4" in diameter. It was a replacement, so it's relatively new (less than 50 miles on it). Could it be possible that the balancer is not the correct size?

Thanks.

Ralph

 

[geekinavette]

Argggggg there's that word "harmonic" again!!! (sorry that's a bit of a beef with me :L)

Anyway....

No it's NOT normal for it to slip like that...and will cause major problems when you attempt to set the ignition timing. I can't recall if the holes for the pulley bolts are inside or outside of the elastomer ring...if they're outside then turning the engine by using those holes is a BAD idea. If that outer ring has slipped at all relative to the inner half...then I would toss it and get a new one. I used a large nut that has a slot cut in it that slips over the crankshaft snout with the half-moon key installed for turning the engine.

VERIFY that the timing mark lines up with TDC #1 compression stroke!

Bill

 

[bossvette]

for a HP small block you should have an 8" balancer, there should be no slippage when turning and as Bill said verify TDC it will make timing much easier.

 

[Jack]

Hello All,

It's been a slow process (been out just about every weekend enjoying the Camaro!), but I'm putting my engine back together again.

I'm using an engine rotator tool connected to the pulley bolt holes in the front of the harmonic balancer to turn the engine for valve adjustments, etc. I found out that when rotating the motor the balancer "slips" by a few tick marks (on the timing tab), before catching and turning the motor.

Is this normal?

The balancer is approx 6 3/4" in diameter. It was a replacement, so it's relatively new (less than 50 miles on it). Could it be possible that the balancer is not the correct size?

Thanks.

Ralph

Are you sure that "slippage" isn't simply slack in timing chain causing this? Even newly installed chains will get slack in them soon after run for a bit. Or ... maybe the rotator tool's holes are a bit larger than pulley bolts and the tool is slipping at the bolts?

6.75" will work fine ... you don't need 8" ... we run a 4.5 pound 6" 327 balancer (yikes, correction ... torsional damper) on 355" circle track motors. BTW ... your 6.75" probably weighs 8-9 pounds ... 8" about 10-11 pounds.

 

[geekinavette]

(yikes, correction ... torsional damper)

THANK YOU! :L

Bill

 

[Jack]

THANK YOU! :L

Bill

You'd pull your hair out if you were to spend a weekend in our pits ... alotta guys call that thing a "pulley" ... my best buddy who's a VERY experienced mechanic calls it a "harmonical balancer" ... he's my best bud so I don't say squat.

 

[Rmodeler]

Can they slip with normal usage and time. My '82' has two sets of marks- original and secondary. For it to run right, you have to use the second set of marks. I thought maybe someone had changed it and had put the incorrect one on, the car has less then 40k miles on it.

 

[warp8]

Put a mark across the front of the balancer so you can see if it is slipping.

 

[GerryLP]

Hello All,

It's been a slow process (been out just about every weekend enjoying the Camaro!), but I'm putting my engine back together again.

I'm using an engine rotator tool connected to the pulley bolt holes in the front of the harmonic balancer to turn the engine for valve adjustments, etc. I found out that when rotating the motor the balancer "slips" by a few tick marks (on the timing tab), before catching and turning the motor.

Is this normal?

The balancer is approx 6 3/4" in diameter. It was a replacement, so it's relatively new (less than 50 miles on it). Could it be possible that the balancer is not the correct size?

Thanks.

Ralph

I looked at my "pulley" and mine is steel center-with rubber in between the center and the outter ring which is steel as well. But if the rotator bolts to the metal center, then how would affect the otter ring? Can you look at the keyway and dowel key (right now I can't recall the correct term for it :ugh )? does it have the wrong dowel [term].

GerryLP:cool

 

[fine69]

Thank you for all the replies.

After looking closely, the engine rotating tool connects to the innermost part of the TORSION/VIBRATION damper. The slack is from the timing chain as Jack surmised.

I'll attack the reassembly of pulleys, alternator, and radiator later in the week.

Thanks again....

Ralph

 

[fine69]

I looked at my "pulley" and mine is steel center-with rubber in between the center and the outter ring which is steel as well. But if the rotator bolts to the metal center, then how would affect the otter ring? Can you look at the keyway and dowel key (right now I can't recall the correct term for it :ugh )? does it have the wrong dowel [term].

GerryLP:cool

Hi Gerry,

You are exactly right. The tool connects to the center of the damper and the outer ring is unaffected.

-R

 

[fine69]

Argggggg there's that word "harmonic" again!!! (sorry that's a bit of a beef with me :L)

Anyway....

No it's NOT normal for it to slip like that...and will cause major problems when you attempt to set the ignition timing. I can't recall if the holes for the pulley bolts are inside or outside of the elastomer ring...if they're outside then turning the engine by using those holes is a BAD idea. If that outer ring has slipped at all relative to the inner half...then I would toss it and get a new one. I used a large nut that has a slot cut in it that slips over the crankshaft snout with the half-moon key installed for turning the engine.

VERIFY that the timing mark lines up with TDC #1 compression stroke!

Bill

Thanks Bill,

I stand corrected.... "torsional damper" .