I recently purchased a new old stock mooneyham 10:71. I have a drive setup of a different blower, BDS to be exact, I thought couplers and snouts were universal when it came to roots setups, but I guess I was mistaken.

I need help identifying which parts I need to complete the drive/snout setup for this unit. It appears that the main nut holding the front gear on to the rotor, a large arp 12 point, is too long to accommodate the shaft in my coupler. The shaft within the coupler bottoms out on this nut before the flanges meet. The bolt on the blower goes past the flange face almost a half an inch, whereas the shaft in the snout is pretty much flush with the flange face. I have attached a few pictures for reference.

Any help on what I need to get the blower drive setup correctly would be greatly appreciated!!

i dont see a picture of the coupler thst bolts on the blower gear.do you have one? if yes can you post a picture.

Is there any reason you cannot replace the ARP style 12 point bolt, and what looks to be a washer/spacer under it, with a normal hex bolt of proper length? A pic of the coupler like mike said would be helpful.

il bet the mooneyham snout has a shorter shaft and uses a longer coupler than the bds.like mild said,if you use a bolt with a standard head and the correct coupler it will probibally work.

I dont have a shot of the coupler, its in another shop right now with some other parts of mine. Its a standard looking coupler.

I guess thats really my question, has anyone heard of a specific coupler/snout for mooneyham blowers? I've called and emailed them with no luck, not sure they are in business anymore. And as for the bolt, I too had thought about pulling it to replave with a standard hex, something not as long, but was told that if I replace it I risk messing up the timing on the rotors. Anyone know if/how to keep the rotors and gears timed they way they currently are?

changing the bolt will not change the gear/rotor timing.that is set by shims behind the gear
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I'm thinking as stated above it is definitely the ARP bolt. I have the exact set up you are talking about, Mooneyham blowers with BDS snouts. Thankfully I had no such issues. At the time I just bolted the snouts on there never giving it a second thought.