How tight should the impeller nut be?

[tornreality]

I just rebuilt my g pump and I don't know how tight the impeller nut should be. Just hand tight or super tight. Just tightening the nut as tight as I can with my hand makes the shaft and impeller impossible to turn by hand. Any imput?
Also when putting the pump together should I have put silicone on the gaskets. Because I didn't and now my neighbor tells me it might leak. I thought the gaskets should be installed dry? Any input???

[TRG]

ide say that you'd want the imp nut just a bit tighter than "HAND TIGHT" but as for tq. spec's, im definitly not the one to ask!

[tornreality]

Thank you very much I appreciate your input.

[Oldsquirt]

The correct torque is 75 ft-lbs.
If hand tight cause the shaft to stop turning, STOP!!!!! You have created an interference, likely between the impeller and housing or impeller and wear ring. You must remove the impeller and find the cause of the problem. You should be able to turn the impeller and shaft with the only drag being caused by the shaft packing.
Silicone sealer on gaskets is NOT necessary.

[tornreality]

Thanks oldsquirt. One last question, is there a keeper or something that keeps the nut from backing off or does the bowl set close enough to keep the nut from backing off? Thanks again you guys, I really appreciate your help.

[NELSON#109]

i believe you should be adding spacer washers in front of the impelor until you have reached the desired clearance. i believe these spacers/washers are availible in many differant sizes (thikness). talk to some one who is more familliar w/ these things first. good luck.

[Cs19]

Your clearances aernt right, better double check them.
Where are your clearances at right now?

[HoffmanEagleMarine]

Tornreality, 75-80 ft lbs is correct. You can find a nylon lock nut for your shaft.They are about $13 each and they stay on! I would clay everything and measure before you bolt back together......my .03, Doug :rollside:

[sdba069]

You know, for years the correct torque was supposed to be 135 lbs./ft. Now, I tighten them all I can and then take them another half turn, with anti-seize.

[anger management]

You know, for years the correct torque was supposed to be 135 lbs./ft. Now, I tighten them all I can and then take them another half turn, with anti-seize.
Thats what i was thinking .Tight as you can get than a little tighter.Sorry you had to expect those kind of answers

[HammerDown]

Thats what i was thinking .Tight as you can get than a little tighter.Sorry you had to expect those kind of answers
Well not necessarily true..the Impeller is driven by the key-way and not a overly tightened nut. 80 lbs is fine, use some anti-seize between the shaft and Impeller and ya could use a little (blue) loctite on the nut...done deal.

[Heatseeker]

You might want to use the aluminium impeller nut(with a little blue loctite as mentioned above) available at the boat shops(Rex, CP). It will make it easier to get the nut off next time. Anti-sieze or not, I've almost always had to cut those steel nuts off. You can get the impeller shims from those same boat shops too. Sounds like you're going to need them!

[fkeys]

So I need to put enough shims onto the shaft so the impeller/wear ring clearance allows free spinning at 80 lb-ft torque? Excellent info - thanks!!

[steelcomp]

German torque specs call for gutentight. :D Ya, mit den lockentight. :D

[sdba069]

I'm not saying that any of you guys are wrong, whatever works for you is okay with me, but if you have ever been at the track trying to remove a nut that's got Loctite on it, trust me, you'd never let anyone put Loctite on it again. No argument on the impeller being driven by the key, and 80# may be enough, but I'll stick with my method. And by the way, I didn't just pull the 135# out of the air, when Dominator was still around, we used to do a lot of their warranty work in our area, here and back in Oklahoma, and their tightening spec was 135#. Since 99% of the pump manufacturers out there use pretty much the same stuff, I've used that number on all our pump work. I've never had to a cut off a nut that I installed using antiseize, might have had to get a bigger impact, but it came off. Also, a pump with a ratchet is prone to cause the nut to back off, not a common occurrence, but it happens. Hey SC..... gutentight, that's German for virgin. And FlKeys, I recommend .020 to .025 front clearance between the front edge of your impeller and the wear ring shoulder. A lot of builders will tell you to go tighter than that, but I've seen too many problems come from trying to run the clearance too tight in a lake boat.

[jdf]

slowsnow can i still be you head impeller changer tech......haul ass

[steelcomp]

I have an aluminum nut, and my shaft has been turned so my impeller will slide off and on with a good tug. I use anti sieze, no locktite, and have my pump apart frequently enough to know it's never been loose. I don't use a torque wrench on it, but I'd say I tighten it a good 100 ft/lbs.
German virgin. HA! Good one. :D :coffeycup

[HammerDown]

but if you have ever been at the track trying to remove a nut that's got Loctite on it, trust me, you'd never let anyone put Loctite on it again.
This is why I suggested (blue) Loctite...and thats for those that feel they want to use it for a little insurance.
Personally, after 8 years of Jetting I've never had a nut even think of backing off at 80lbs torque.
Not saying it can't happen...anything's possable.

[Heatseeker]

If you have trouble removing a loctited fastener, a little heat will soften it up. Makes it a snap to remove then.

[tornreality]

Thanks again to everyone for the info. I am on my way to rex. now to get some shims. I just want to know why they didn't include shims in their rebuild kit? :hammerhea

[sdba069]

The problem with applying heat to a nylon lock nut is that it melts the nylon and is no longer a locknut.

[Heatseeker]

Why would you put loctite on a nylock nut?
I was refering to lotite on the aluminum nut.