pinning crankshaft

[chorty55]

Some may know, i have an odd project, and around that was the discussion of pinning the crank up front in relation to my limited options.

I found a kit here :Pin Kit Crankshaft BB-SB All MOPAR Balancer - to avoid having to Double Keyway the Crankshaft

Really don't want to spend money on something i'll never use again, but anyways can anyone give an idea of how much extra strength this kit actually adds to the rotational torque being transmitted to the pulley?

The better question, how much of an improvement is adding a 1/4"round pin @ the seam compared to the single woodruff OEM?

 

[gzig5]

I would think you could get a machinist to add a keyway or pin for about the same or less. I know I could set it up in 15-20 min and take less than ten to cut on the mill. IMO an additional square key done correctly is stronger, but a pin done like that would take some load off the key.

 

[mygasser]

same principal was when the splines stripped on the kickstarter on motorbikes. we'd drill across the seam, thread the hole and loctite a bolt in rather than a pin.
neil.

 

[chorty55]

that's the other limitation of this current situation.

I'm not in a good option to remove the crank. It's a long story.

another key of something needs to be added on the spot assembled.

I'm pondering if i should just drill 2 or 3 more holes for a quad-pin set to keep it in place.

 

[RAMM]

Some may know, i have an odd project, and around that was the discussion of pinning the crank up front in relation to my limited options.

I found a kit here :Pin Kit Crankshaft BB-SB All MOPAR Balancer - to avoid having to Double Keyway the Crankshaft

Really don't want to spend money on something i'll never use again, but anyways can anyone give an idea of how much extra strength this kit actually adds to the rotational torque being transmitted to the pulley?

The better question, how much of an improvement is adding a 1/4"round pin @ the seam compared to the single woodruff OEM?

Checked the link....that's peanuts...well worth the price and you can resell. J.Rob

 

[chorty55]

besides the headache of matching up a replacement balancer on any half holes i make on the crank snout, are there any drawbacks?
I feel like maybe i should do this to a brand new balancer? It's going to be a headache to try and match any holes that aren't OEM?

Then again, my entire life, i've only had one harmonic balancer that came apart, while still on the crankshaft. I just spot welded it back on center the best i could. It's a wobbler.

 

[middleagecrisis]

The guys that run superchargers do this all the time to keep the blower crank pulley from stripping under high boost. I’d get a new balancer since you’re going to the trouble, but I wouldn’t worry about it being strong enough.

 

[chorty55]

The guys that run superchargers do this all the time to keep the blower crank pulley from stripping under high boost. I’d get a new balancer since you’re going to the trouble, but I wouldn’t worry about it being strong enough.

i'm far beyond the torque needed to turn a blower. Unless one more 1/4" pin will hold back all the torque this little 318LA has to offer.

 

[middleagecrisis]

Understood. The point was that pinning the crankshaft to the balancer is plenty adequate for a blown motor, so you shouldn’t have to worry about your little 318 torque causing any issues with spin the balancer off the crankshaft.

 

[chorty55]

Understood. The point was that pinning the crankshaft to the balancer is plenty adequate for a blown motor, so you shouldn’t have to worry about your little 318 torque causing any issues with spin the balancer off the crankshaft.

i'm attempting to transfer all the engine torque through the pins to turn a high GPM hydraulic pump, and i plan to be brutal with the machine fighting junk cars and scrap iron constantly bumping 2000 psi.

Luckily the mini-shaft is 3/4" round with 3/16" key at each yoke, so hopefully they'll give up the ghost before spoiling the crankshaft. I've been doing alot of math and getting numbers ran, and the pump im using needs easily 180-220ft pounds of torque.

 

[mopowers]

At what power level is it important to pin the balancer?

I've seen a woodruff key shear on the crank causing the crank timing gear to slip and it caused some serious damage - valve kissing pistons, etc. I wonder if pinning the balancer would take the majority of the load off the keyway so it would be less likely to shear where the crank timing gear is located.

 

[chorty55]

At what power level is it important to pin the balancer?

Exactly my wonder and worry. And the reason i'm adding a pin. I'm going blind trying to pump all the torque through the key and not the flywheel, so i don't know what else to do besides pin the crank in addition to the OEM square key, and cross my fingers and tie my you-know-what in a knot and hope for the best.

 

[mygasser]

as you suggested i'd fit more than one pin, belt and braces as it were.
neil.

 

[chorty55]

I have so much doubt in this project

Good thing I stretched and tied down a tarp

I'm dry while working. This is all humidity. And all the tools.

 

[jimjimjimmy]

I found a kit here :Pin Kit Crankshaft BB-SB All MOPAR Balancer - to avoid having to Double Keyway the C

The better question, how much of an improvement is adding a 1/4"round pin @ the seam compared to the single woodruff OEM?

This pin will add consideral shear protection . if you are using a factory balancer i would be more concerned with it breaking before the pinned setup .