Z80 revisited
12-22-2004, 10:17 AM
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Z80 revisited
I am putting a ZDZ 80 back in survice after a long lay off and a bad crash. In the crash the propeller (26-10 Metz S) was destroyed but the spinner and engine were untouched.
I finally got the engine started. It tachs 6250 RPM with a Zinger pro 26-10.
I noticed that the prop is about 1" out of track ( one blade 1" ahead of the other) when the engine is running at low speed. It pulls into track when it is running at full speed. The spinner also seems to wobble at low speed.
The bearings seem to be tight.
Do I have a bent shaft?. I cant see any wobble when I turn it over by hand.
Could it be a bad prop?
I finally got the engine started. It tachs 6250 RPM with a Zinger pro 26-10.
I noticed that the prop is about 1" out of track ( one blade 1" ahead of the other) when the engine is running at low speed. It pulls into track when it is running at full speed. The spinner also seems to wobble at low speed.
The bearings seem to be tight.
Do I have a bent shaft?. I cant see any wobble when I turn it over by hand.
Could it be a bad prop?
12-23-2004, 08:48 AM
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RE: Z80 revisited
Yep, sounds like the main prop stud is bent - easy fix. Order a new one, double nut the old one to remove, double nut the new one to replace, use some blue loctite on the threads into the crank. I doubt you could bend the crank, it is very stout.
12-23-2004, 10:05 AM
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RE: Z80 revisited
I talked to RCS and they said not to use any locktite on the shaft... it could be impossible to get back out. Anyone have a problem with them coming loose without locktite?
12-23-2004, 10:42 AM
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RE: Z80 revisited
Loctite does not make anything impossible to get out..I use the strongest grade, green 680, on all bolts and screws everywhere on the engine..All it takes is heat to soften it...680 Loctite is good to 400 degrees F, easy enough for a propane torch....You don't WANT the screws to come loose.....
ANY crank can be bent, trust me, I have seen what should be unbendable, bent...Don't know how, but it DOES happen..Most can be straightened, but not all....
ANY crank can be bent, trust me, I have seen what should be unbendable, bent...Don't know how, but it DOES happen..Most can be straightened, but not all....
12-23-2004, 10:54 AM
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RE: Z80 revisited
Thanks for the comments everyone. It appears to be the prop. I put a Mentz on there and it tracks OK. The stud was a bit loose and that could have aggravated the situation. I will put locktite on the stud. I have been able to get bolts loose that had blue locktite on it.
12-28-2004, 01:36 AM
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RE: Z80 revisited
Wrong, not talking about some wimpy threadlocker..I use stud and bearing mount on all screws...
Look up Loctite 680 green on their website...4000 psi locking shear strength on steel after 24 hours, good to 400F, fills gaps to .015...........You can twist off a 4-40 brass carb screw or strip out a 3/16 allen bolt head trying to get it loose after a day......Been there.....
Look up Loctite 680 green on their website...4000 psi locking shear strength on steel after 24 hours, good to 400F, fills gaps to .015...........You can twist off a 4-40 brass carb screw or strip out a 3/16 allen bolt head trying to get it loose after a day......Been there.....
