coated steel bolts into alluminium

[Dave999]

Hello

in a bit of a quandary. bout ten years ago i started a Megajolt ignition set up that uses a 36-1 trigger wheel and then got sidetracked into rebuilding engines and diffs and swapping gearboxes and etc

Trev D made a great hub to mount my crank trigger wheel on, sits in the well of my big fat balancer and holts onto the puller threads with hight tensile cap screws, it won't come off, steel bolt into steel balancer. it is perfect in everyway, with 45 degrees adjusability for the trigger wheel apart from the studs and nuts to hold the trigger wheel onto the hub hit the fan.

i could space fan forward
i could run electric fans

i don't want to do either. leccy fans will involve alternator and wiring upgrade
spacing the fan forward might be an option

so out came the studs to be replaced with button headed bolts. m8 thread

i will have approx 2 cm worth of thread into the ally for each bolt (x4) the trigger wheel will only see rotational forces so the bolts will be in shear.

i.e the bolts need to be tight but not like flywheel tight.

and i'll loctite them once the trigger wheel position is established

helicoil inserts necessary?

or rivnut style inserts from the back of the hub

or

try it and see?

Dave

[Prothed]

Hi Dave,
Not sure if I'm seeing this correctly but I would think that screws straight into ali would be fine. I'm thinking that motorcycle front brake discs are bolted straight onto the ali wheel hub with m8 screws and the shear force there must be astronomical compared to your application...
Dave.

[Dave999]

i'm inclined to think it will be ok and that certainly adds context

the more thread engagement the better its going to be so i might get some 6 cm bolts just in case.

just ally is soft as cheese in comparison with the bolt... studs would be a better solution but i can't fit a decent nut in...

MMm

dave