props - Nord-Lock washers?

[9D280]

OK, In summary, I found the prop that came with my engine is either too low a pitch or diameter.

I had been looking for a Merc one at 14", but having had way too many ventilating moments at Easdale where I came to a grinding halt & had to come back to idle & wait a copuple of seconds to get going again, I decided that instead of up -pitching, I would up -diameter instead.


Cutting long stories short, it would appear the Merc props with the "stud hubs" only come in one diameter (well, in the 13 spline version, not sure about the bigger ones) Now, I have what I think might be a suitable Yam prop lying in my garage, (Certainly WRT pitch & diameter), BUT of course it relies on a split pin & castelated nut to stop the nut unwinding, which of course the Merc shaft isn't drilled for as it uses a tab washer.

So,
Option 1 - Drill & tap a couple of holes & put studs on the Yam hub.
Option 2 - Use a "Nord-Lock" washer.

Nord-Lock wedge-locking washers


Anyone used one on a prop? If so how did it fare?

[Nos4r2]

Option 3. Use a nyloc?

[SPR]

Originally Posted by Nos4r2

Option 3. Use a nyloc?

+1 for option 3 - believe some manufacturers use them as standard - down side they are one shot ... and prop need tool to get them off the full way and on...

[jyasaki]

Originally Posted by SPR

+1 for option 3 - believe some manufacturers use them as standard - down side they are one shot ... and prop need tool to get them off the full way and on...

Deep socket won't do it?

jky

[SPR]

Originally Posted by jyasaki

Deep socket won't do it?

jky

should do he trick ! just pointing out potential issue!

[9D280]

Originally Posted by Nos4r2

Option 3. Use a nyloc?

I did toy with that, but as the exhaust is exiting round there when at WOT I'd be curious to know how hot the shaft / nut combo gets, as there should be next to no cooling round them (the cooling water exiting down the leg I would imagine will get thrown out to the perifery like a centrifuge, leaving the shaft & nut in the exhaust that could be at a few hundred C.

I assume the Nylocks used by the manufacturers are high temp rated?


I guess option 4 is Nord Lock with a Nylock on the end of the shft just in case. (TBH if the yam doesn't improve the setup It'll be back to the merc prop anyway!)

[Nos4r2]

I doubt it actually gets that hot.Rubber prop hubs wouldn't survive long like that.

[9D280]

True..... but there are numerous grades of rubber out there........

Exhaust gas at the port is going to be around the 8-900 C mark.
Most Nylocks seem to be rated to around 120 Deg C "max". (a few are rated to 175C, but that is likely to add risk to a repair!) Now add vibration etc into the mix, how much further down in temp would you come to feel "safe"?


I've not found any "max continuous temp " data for Nylocks yet.... Watch this space.

[Nos4r2]

Originally Posted by 9D280

True..... but there are numerous grades of rubber out there........

Exhaust gas at the port is going to be around the 8-900 C mark.
Most Nylocks seem to be rated to around 120 Deg C "max". (a few are rated to 175C, but that is likely to add risk to a repair!) Now add vibration etc into the mix, how much further down in temp would you come to feel "safe"?


I've not found any "max continuous temp " data for Nylocks yet.... Watch this space.

Exhaust gas won't be that hot-it's got cooling water being dumped into it. It'd come out as superheated steam if that was the case.

[9D280]

Computer failure here - I meant to edit to say "but won't be that hot at the prop"... But tech got in the way.

I do get steam out the idle port, both on the Merc & the old Johnson, but that is mobility closer to the exhaust port.

It max be fine, but at full chat there is approx. 600cc x 5800 of got has being expelled per minute . The cooling water that joins it has already been round the head & warmed up... I am genuinely curios to know how hot it gets round there.

What engines use a single nylok?


Sent from a postage stamp on a 1G connection

[PeterM]

My 25 merc has a a plastic prop nut..it cant be that hot down there or it would have melted !

[bedajim]

Any good ?

Binx Locking Nuts Nottingham stainless steel & brass

[9D280]

Originally Posted by 9D280

but that is mobility closer to the exhaust port.
Sent from a postage stamp on a 1G connection

***** predictive text! Should have read "notably"

Originally Posted by PeterM

My 25 merc has a a plastic prop nut..it cant be that hot down there or it would have melted !

Plastics.
There's plastic on your car engine. There's plastic in Christmas cracker toys....

Granted it does give me a warmer feelng that the nylock might survive. (excuse the pun!)

Originally Posted by bedajim

Any good ?

Binx Locking Nuts Nottingham stainless steel & brass

Very possibly......

[jyasaki]

Could always hit the thread with some Loctite to be sure.

jky