Philly Miata

iTrader: (1)

But where else can I use my ONE INCH DRIVE AIR GUN

concealer404

iTrader: (3)

NLA.

aidandj

iTrader: (5)

I've replaced one of those in the dark, without taking the alternator belt off. Just wiggled the ****** on there.

Bolts usually come out pretty easily, sometimes you can get a vice grips on the broken bit.

Replace with high quality M6 bolts.

**** mt.net. Now I have to unsub again.

ridethecliche

iTrader: (2)

Thanks to our feline overlords for the thread title change.

What's the failure mech? One of the bolts backs out and that sends the thing off axis and shoots it out?

Dang. They held on like that for like 8-10k miles :/
I'll make sure to use loctite next time. It kinda looks like one of them might have backed out, but I honestly think sometime got sucked in. No harm doing a better job next time though.

​​​​​​​I know :/ such a bummer...


Was going to replace with grade 8 bolts. Thanks for the input. I'll try to get it done this weekend once I get home. I'm going to see if I can get out of the insurance inspection since I don't expect anything good to come of it.

And c'monnn give me some credit. My posts are so much better nao :(

turbofan

iTrader: (1)

The failure mode is the bolts break from being overtightened, or come out from not being tightened/not using Loctite/bolt fatigue.

One more time: replace them with quality M6 bolts torqued to spec with Loctite and move on.

Edit to add: that post was not better and I also have desires to unsub atm.

aidandj

iTrader: (5)

And there you go. Countering yourself again.

If you use grade 8 you will have to drill and tap.

Metric are rated by class. SAE by grade.

Don't use a grade 8.

bahurd

iTrader: (8)

You sure you don’t mean M8?? Using a different grade doesn’t change the size...

aidandj

iTrader: (5)

SAE:Grade X
Metric:Class X

eddyc49

But a 1/4-28 would probably thread in if you weren't paying attention, so...

ByteVenom

You know what he meant.

turbofan

iTrader: (1)

Is my sarcasm detector broken? I hope this is sarcasm.

Not recommending larger bolts, just ensuring they're high quality bolts.

aidandj

iTrader: (5)

18psi

iTrader: (76)

U W0T M8?!!

lulz

shuiend

iTrader: (24)

I would suggest not listening to any of these guys. What you want to do is get about 4 dozen tooth picks and some JB weld. Make 4 small bundles of tooth picks and cut them to be about 2cm long. Then mix up some JBWeld and smother the 4 bundles in it. Then rub the JB weld along the outside of the crank boss. Insert one bundle of tooth picks into each of the 4 bolt holts. Then push the crank pulley on. Slather some additional JB weld around each hole with the tooth picks coming through. Let it sit over night. The next morning you will have a crank pulley they should not accidentally fall off when hit by road debris.

Steve Dallas

^ This only works with Balsa wood toothpicks. I'm surprised Lars left out that important detail.

18psi

iTrader: (76)

I just re-drilled and tapped for M27 bolts.

ByteVenom

You want Class 10.9 bolts. If those bolts were 10mm heads: https://www.boltdepot.com/Metric_hex...m_x_1.0mm.aspx

bahurd

iTrader: (8)

Nope, no sarcasm...

For some reason, there was a couple threads related to BRP superchargers where people had drilled/retapped for larger M8x1.25 bolts.

One thread not MT.net: Problems with crank pulley bolts snapping?, read the posts by J_Man

So, I thought @aidandj mentioned Grade 8 maybe he meant M8 [as there's no "grade 8 in metric] but whatever...

Anyway, use 12.9 bolts if using the Mazda 109-151 in/lb torque.

You can get them here [allen head 12.9 bolts] M6x1.0: Metric socket cap, Class 12.9 steel black oxide finish, 6mm x 1.0mm and even drive there to pick them up @ridethecliche

ridethecliche

iTrader: (2)

Thank you sir!

bahurd

iTrader: (8)