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MG Midget and Sprite Technical - Crank pulley. (damper).

Is there anything to be gained by fitting a 1275 crankshaft pulley with damper, to a 1098 engine, which normally has just the pressed steel pulley? My engine is already balanced. ie. crank, rods, pistons and flywheel.
Bernie Higginson

Interesting question Bernie. I think you would have to get it balanced with your crank - mine has balance marks on it (drillings) - it was balanced with my complete crank, lightened flywheel and clutch as a unit.

But as to any advantage of a "harmonic balancer" on a 1098 - well hopefully someone else will explain. I have never really understood the "how" of that!
GuyW

Not unless you balance it with the damper.
Otherwise you risk bringing more vibration in the engine due to a possible unbalance in the damper.

But it does not produce more power with it.
It might aid longevity because it reduces crank flex.
But with the milage most midgets do it all is a bit of a stretch.
And should make it run smoothly
Onno K

Onno. Yes, that was my thinking. To balance it with the crank would mean dismantling the engine, so it's probably not going to be worth the hassle for any perceived gain, and as you said, it's not going to produce more power.
Thanks as always for the input, chaps.
Bernie Higginson

Balancing a damper type front pully has always raised questions with me
If it is a precision fully machined unit it shouldn't need balancing
But if it's the normal cast type, balancing it as an assembled unit is questionable in my mind
OK , even if the crank is in the balancer and has been balanced, then the pulley is fitted and balance checked and found to be out----Most pullies I've seen have had the balancing job done by drilling the outer part of the pully---The outer part is usually a fully machined piece and should be ,initself naturally balanced leaving the actual out of balance piece being the inner hub which you hardly ever see drilled for balancing

What do you think

Also, I fitted a Callies crank in my mate's Mustang and he rolled up with a new billet aluminium balancer for it, fully machined and not a balance drilling anywhere
We enquired about the weight of the balancer being quite a bit lighter but were told by the reputable manufacturer that it worked exactly the same--- How can that be when there is a significant weight difference---------------
It's been fine so far but I'm not fully convinced yet
The last crank broke from fatigue and was a clean break
I've had cranks break from harmonic problems before and it's a different break and looks all carrotty/shattered in the break------time will tell

willy
William Revit

This thread was discussed between 05/04/2016 and 06/04/2016

MG Midget and Sprite Technical index

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