Question about bolts from engine to engine stand

   #1  

Frank Sorbello

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Power Trac PT-422
I noticed a vibration coming from my engine. Shut it down. Let it cool off. Shook the engine and noticed it was loose. Checked the four bolts from the engine to the stand and all four were loose. I retighten all four, but am not sure if they are the right bolts. Called Terry at Power Trac. He doesn't know the correct size of the bolts. Not any information of the correct size in his 3 manuals. Said It would be all right with grade 5 bolts from Tractor Supply.

MY questions are: 1 Does anyone know correct size of the four bolts from the engine to the engine stand? 2 Am I better off with using a nut with nylon locking insert or just plain lock washers. 3 I am going to use Loctite this time when I take them out and replace them. Loctite Red (requires heat when removing) or Loctite Blue (just hand tools).
4 Why would all four locknuts come loose with so little time on the engine?
Thanks and as always, I do appreciate your input.
Frank
 
   #2  

ponytug

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Single use nylon lock washers aren't much of an improvement on a lock washer. Locktite can be better, but they don't deal well with impact.
When you really need something to stay on: Nord-lock washers. Your new best friend. Honest.
video (by Nord-Lock)

All the best,

Peter
 
  
  • Thread Starter
#3  
OP
F

Frank Sorbello

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Thanks Peter! I am sold. Have you used them?
 
   #4  

ponytug

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Not on my PT Deutz engine, yet. I used them on my chipper to hold my drive motor on and to hold the motor supports together.

All the best,

Peter
 
   #5  

Farmall140

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So, do you need a pair...one pair for the bolt head and one for the nut?
 
   #6  

Gary Fowler

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I used them on the front wheel axle housing that keep loosening off on my LS. After the second tightening using the factory grade 10 bolts and lock washers, I bought all new grade 10 bolts ($$$$ there) plus Nord-lock washers (about $2 each set for a 13mm bolt) and it hasn't loosened up again. I did also use Loctite Blue on the cap screws when I installed them the last time. Better safe than sorry on those bolts since that could cause some catastrophic damage if the hub came completely off.

As for as putting lockwashers on the bolt head side, I have never seen that done or needed. As long as you keep the nut from backing off, I don't think the bolt is going to try and turn.

By the way, the Nord-lock washers are a two piece unit per washer.
 
   #7  

newbury

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Just a note on on standard lockwashers from a 1990 navy study on Fastener Design
Lockwashers
The typical helical spring washer shown in figure 14 is made
of slightly trapezoidal wire formed into a helix of one coil so
that the free height is approximately twice the thickness of the
washer cross section. They are usually made of hardened
carbon steel, but they are also available in aluminum, silicon,
brome, phosphor-bronze, stainless steel, and K-Monel.
The lockwasher serves as a spring while the bolt is being
tightened. However, the washer is normally flat by the time
the bolt is fully torqued. At this time it is equivalent to a solid
flat washer, and its locking ability is nonexistent. In summary,
a lockwasher of this type is useless for locking.

The pamphlet has lot's of good fastener design points.
 
   #8  

dickfoster

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Thanks, sold American. Now I appreciate the ones on my backhoe and loader all the more. I'd never seen them before.
 
   #9  

CADplans

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We had a vibration issue allowing VERY high current copper bus bars come loose.
This was a LOT of $$$ if the bolts/nuts came loose.

We tested all sorts of fasteners. Some sort of washer/nut was the best, NASA used them on the space shuttle.
It was the best single fastener result.

In the end, we tried a lock nut,,, or in other words, two nuts, on a slightly longer bolt.
THAT system was unbeatable.
Jam those two nuts together,,, it was like the nut was welded to the bolt.
 

CobyRupert

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Just a note on on standard lockwashers from a 1990 navy study on

"..The lockwasher serves as a spring while the bolt is being
tightened. However, the washer is normally flat by the time
the bolt is fully torqued. At this time it is equivalent to a solid
flat washer, and its locking ability is nonexistent."

The pamphlet has lot's of good fastener design points.

Huh? To me that's a non-sequitur. I don't follow.
It's still a spring, no matter if it's flat (while torqued). Thus it is not equivalent to a flat washer.

...though 40+ years of a anecdotal evidence could be wrong...
 

ponytug

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As you know from your own experience, when you have torqued your nut on the bolt and lock washer, the lock washer is effectively flat. The Navy's (and other's) observation is that the standard slightly spiral lock washer has about the same anti-loosening abilities of a flat washer, which the lock washer resembles in use.

Two nuts jammed on each other are pretty good in a high vibration environment, and if it works for you, go for it! The Nord-Lock is better, though.

All the best,

Peter
Huh? To me that's a non-sequitur. I don't follow.
It's still a spring, no matter if it's flat (while torqued). Thus it is not equivalent to a flat washer.

...though 40+ years of a anecdotal evidence could be wrong...
 

elderlyphart

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yacolt wa
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power trac pt425
Learn something new everyday.
Never heard of a Nord-Lock before. Remember seeing one in the washer supply though.
Wonder what I took it off of?
Now I'm in a panic!
What if it's the bolt that keeps my old hot rod from falling apart?
I shant be sleeping well tonight.
 

MossRoad

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South Bend, Indiana (near)
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Power Trac PT425 2001 Model Year
It sounds like a wrestling move..... nord-lock.

Didn't we discuss those before? Sounds familiar. We have a lot of machinery here that use a flat washer, a lock washer, and two nuts. All small stuff, around 1/8".
 
   #14  

ponytug

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It was discussed recently. I used the Nord-locks on the chipper conversion that I did as the chipper seemed to have the potential to be a high vibration environment...

All the best,

Peter
 
 
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