[Bkirk]

1993 mazda Miata na6, lately I’ve noticed that my boss pulley is wobbly, and only the boss pulley. The main crankshaft pulley up front of that one turns true and balanced but the boss pulley seems like it’s wobbling and knocking back and forth on the block and crank pulley. My question is if I buy this will it fix my issue. When I first bought the car I figured out that the rubber ring seal is bad giving me a wrong timing reading. And I’m thinking that has something to do with the wobble it sometimes has at idle.

[Bkirk]

Originally Posted by Bkirk

1993 mazda Miata na6, lately I’ve noticed that my boss pulley is wobbly, and only the boss pulley. The main crankshaft pulley up front of that one turns true and balanced but the boss pulley seems like it’s wobbling and knocking back and forth on the block and crank pulley. My question is if I buy this will it fix my issue. When I first bought the car I figured out that the rubber ring seal is bad giving me a wrong timing reading. And I’m thinking that has something to do with the wobble it sometimes has at idle.

https://www.partsgeek.com/gbproducts...QaAiIkEALw_wcB That’s what I am wondering will fix the issue. Does the boss pulley come with the crank pulley as one piece or a kit assembly? What could otherwise cause my boss wobble. Thanks

[hobie237]

Could you maybe post a picture of the part you're having an issue with? I'm having trouble understanding what is, and what is not, moving, and whether this may be a SNC issue, harmonic balancer issue, or something else. The link is for a Chrysler Town & Country door wiring harness.

[toolinalong]

The link shows me a crankshaft pulley , 91 to 93 .
Op , you are going to have to take it apart to see what is what .

[STO962]

Sounds like you're describing the harmonic damper. The accessory belt pulleys bolt to the front of it. Yes, the harmonic damper can come apart and wobble, and also cause the timing marks to slip out of place.

Your posted link sent me to a Dodge Challenger bumper part.

[no rotors]

The OP's link shows me a "1991-1993 Mazda Miata crankshaft pulley," the harmonic damper.
I wonder why others are seeing a Chrysler part?

[gtxhawaii]

POOR net skills, I've found the same part for under $60. I was about to buy one (Ebay.com) for my '92 Miata, but a lucky trip Monday by the local salvage yard turned up only one Miata, a '93 auto, now minus it's Harmonic Balancer. Which has quieted the noise I couldn't pin down. My old one failed totally, the outer rim spinning (or not spinning) out of sync with the hub/crank, and failing to drive the WP and Alt. I drilled and pinned the gap where the failed rubber membrane used to live, refitted the HB, and the belts started powering their accessories properly. On removal yesterday, the rim had walked a little less than 10º from where it was pinned, but held. Seems this was the noise maker. Takeaway is 10-24 machine screws are Not dependable for pinning this part. All irrelevant to this thread, other than that the same part is for sale at just over a third the cost.
As above, knowing IF this is the problem, requires some disassembly. Maybe only 4 new Class 10.9 M6x1.0x12(?) flange head screws? If any of the 4 present screws are busted, loose or Not present, the fasteners are the first suspect.
Correct name for the part the Harmonic Balancer screws to is the "Pulley Boss", in Mazdese.

[STO962]

This is the crank pulley boss:


This is the harmonic damper / pulley assembly:


The damper bolts to the pulley boss. There could be a problem with the boss fitment to the crankshaft having worked loose and worn the key slot in the crank and boss causing wear on those parts as well as the crank timing gear. The would cause the entire assembly to wobble. This a somewhat common problem on early 1.6 engines with the short nose crank.

Or the problem could be the harmonic damper has begun to separate at the rubber part between it's two pieces. This can cause the pulleys to wobble and the timing marks to slip out of place.

Closer inspection needs to be done to determine which part(s) have failed. The bolt in the end of the crank should be checked to be sure it is still tight. When this bolt loosens, it causes the damaged pulley boss and crankshaft key slot.