Harmonic Balancer - How To Check

[tridentt150v]

I searched and searched and couldn't find what I was looking for. Spun bearings, vibrating balancers, Ross balancers, how to remove etc but no check!!!

How can you tell if your harmonic balancer has spun??? I want to check if my harmonic balancer rubber has moved [not collapsed but is on the way out] and need a way to check? My tuner has asked me to check before I get it on the dyno. I know my timing marks line up Ok but this may not be the best way.

Or if somebody has a link to it then much appreciated.

[tridentt150v]

Found this [after much trawling], but there are challenges cos my motor is in one piece. So i can't set up piston stops. I might be able to use a TDC dial and maybe it will be accurate enough to check for slippage - not accurate enough to set the timing, but if there is no slip then my original timing marks are good enough for checking purposes?

http://www.mye28.com/viewtopic.php?t=29605

[Ben C34]

You can use a piston stop easily while engine is together .

The type that goes in a spark plug hole, can make them easy enough from an old spark plug.

[jiffo]

As Ben said, all you need is some means of stopping the piston from reaching TDC, an old spark plug with an extension welded on the end or similar.

(Just ensure it's not some rubbish that will drop into the cylinder)

Blow any dirt/dust from the area and remove No1 spark plug, then screw the device into No1 plug hole.

Hand rotate the crank clockwise until the piston touches the stopper, thus stopping the crank from turning.

Mark the balancer across from the fixed timing pointer.

Rotate the crank anticlockwise until the piston stopper again stops the crank from turning.

Mark the balancer as previously.

TDC will be half way between those marks.

Remove the device, install spark plug etc.

[tridentt150v]

Thanks guys will try it and see.

[tridentt150v]

Just to close out this thread, made up a piston stop using an old spark plug tapped out to 3/8 and a 3" bolt through it. I also rounded the bolt end off to remove any sharp edges Took out my sparkplugs, screwed the stop into No.1, removed the rad fan [for top access] and wound the motor backwards and forwards marking the balancer with a paint pen. I then put the vernier caliper across the pen marks back to the '0' mark on the balancer and it was exactly the same both ways. So my balancer hasn't slipped at all.

Thanks all for the help.