Hi all,

Putting together an engine from a complete mish-mash of parts and I've come to setting endplay, however, the e shaft bolt bottoms out in the shaft before it touches the front hub. If I lift the hub up to the bolt, it's about a 1/2" gap. I'm using an RX8 e shaft and rotors in an FC block, so maybe there's some combination of front hub and bolt that works here?

For clarity, here's the full list of front stack parts I'm using:

RX8 E Shaft and Front Bolt
FD Chamfer Washer
FD Torrington Bearings
FD Endplay Spacer
RX8 Counterweight
FD Oil Pump Drive Gear
12A Dizzy Gear (engine is going in 1st gen and will be using 1st gen dizzy)
RX8 Front Hub

Does anyone know what the problem here is? I've read a lot of posts from people who've used RX8 shafts in their engines and have never come across something like this.

(Pictures show where the bolt bottoms out, the e shaft protruding past the front hub, and the gap when the hub is lifted)

 

do you have one of the older front hubs to try? also, which front stationary gear did you use?

 

Using RX8 hi power stat gears. Just tried a 12A hub, the gap is significantly reduced, now its maybe 1-2mm, but the bolt is still bottoming out before it touches the hub. I'm using a brand new RX8 bolt straight from Mazda, could that be the problem, maybe I need an FD bolt?

Edit: just measured with the 12A hub. Hub protrudes 3.4mm over the e shaft now, isn't that over the spec? I'm 100% certain the bearings aren't crushed

 

i don't know if it has to be an FD bolt, but i would certainly try an older one.

if the bearings are not crushed and endplay is within spec, then use this hub. if not, then maybe try an older 13B hub and see if that gets you in the sweet spot.

that said, i don't think i've ever come across this problem before, but i find it fascinating.

 

Haha, literally 5 minutes before you posted this, the FD bolt was delivered. Success. It was the bolt all along.

I assume there's some some of taper on the unthreaded part of the RX8 bolt that jams it before it goes all the way down. I even sacrificed that RX8 bolt and cut it down until there were maybe 5 threads left, still got stuck in the same place.

Unfortunately, in all the excitement of going back and forth trying to figure out what was wrong, I did manage to crush one of the bearings right on the very edge. I get a good endplay measuremeny and it still fits around the spacer, but it does contact the spacer a bit. So hey ho, guess I'm gonna have to wait until next week to finish the build