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Join Date: May 2014
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Nuts and Bolts Reuse in Engine Application

05/13/2014 4:14 AM

Hi Experts

I am in remanufacturing business where we try to re use old parts in engines.Recently there is is project going on so I am stuck in decison whether to reuse nuts and bolts or not as it can save lots of money . Pls suggest . If yes what all parameter I shouls check inoder to confirm its integrity

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Anonymous Poster #1
#1

Re: Nuts and bolts reuse in engine application

05/13/2014 5:04 AM

Old part usage is ok up to some xtent. but thorough qc check required before installation. I know one company (company name and place withheld due to copyright issue) which prefer only second hand engines to power their mining equipments. one or two accidents I have witnessed, fortunately there was no loss of human life or animal life on those occasions.I cannot blame or forget that company as it was my beloved training school. I learned a lot from there and the best lesson I learned was how to survive in hostile working environments and how to survive in extreme climatic conditions.

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#2

Re: Nuts and bolts reuse in engine application

05/13/2014 5:54 AM

Diameter and material?

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#4
In reply to #2

Re: Nuts and bolts reuse in engine application

05/13/2014 7:40 AM

M16 bolts and MS material

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#11
In reply to #4

Re: Nuts and bolts reuse in engine application

05/13/2014 8:53 AM

Ok

1./ Clean the bolts and nuts

2./ Dimensional check (remain plastic elongation & height and size of the threads)

3./ PT or MT (Better MT)

That's all

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#17
In reply to #11

Re: Nuts and bolts reuse in engine application

05/14/2014 1:29 AM

What is this BT and MT ??

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#19
In reply to #17

Re: Nuts and bolts reuse in engine application

05/14/2014 4:18 AM

BT I don;t know

PT: Penentrat test (ASME V)

MT: Magnetic Test (ASME V)

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Member

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#25
In reply to #17

Re: Nuts and bolts reuse in engine application

06/02/2014 6:37 PM

British Thread and Metric Thread .

CS is Carbon Steel.

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Location: OHIO, tri-State design and installation, and travel nationally and consults also are international
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#26
In reply to #25

Re: Nuts and bolts reuse in engine application

06/07/2014 10:26 AM

and either way,

or CS or not,

v8 5.7 diesel engine head replaced at 134,000 miles

was again leaking at the water jacket/ in 5,000 more miles...

, with same head bolts installed by Chevy seller of the olds engine 1984-1987 repaired once and sold back to them. a loss-loss; but the 'zone office ' paid the then 900 bucks.

some relief with buying from same, a Chevy Celebrity 2.4 v6 carburated 1985 (in 1987 with 57,000 miles) running to 286,000 , finally popped a timing chain in 1996.

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#24
In reply to #4

Re: Nuts and bolts reuse in engine application

05/20/2014 2:44 AM

Mild steel? Surely you must know the grade/class of the material used in an electricity generator: 8.8; 10.9; 12.9 - what is quantity?

Economy has many facets. Moreover, unless there is something special about the fasteners, M16's are not expensive - unless your in Scotland.

...yes, I am a Scot.

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#3

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 6:49 AM

Most correctly installed bolts and nuts should be capable of re-use. It is rare for a design to overstress a bolt intentionally. A visual inspection rejecting any which show any sign of abuse would suffice in most applications. Maybe in critical area a closer inspection/length measurement? would be prudent.

Del

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#8
In reply to #3

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 8:33 AM

This is true but on some car engines the head bolts are designed to stretch on installation. These should never be re-used. The OP really needs to check with the engine maker if possible.

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#13
In reply to #8

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 10:53 AM

Correct.

Some hardware is a "use once" application.

Typically, the criteria for any form of no-reuse are:

1. Fasteners required to be torqued to near their limits

2. Safety critical components where failure would result in a catastrophic loss of equipment or endangerment or loss of life.

Point #2 is a liability that you carry as a business. If a fastener fails and you or your business is found liable, then you and/or your business could stand to lose significant revenue or even prison time for some employees found negligent.

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#5

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 8:00 AM

Engines for what?

A few years ago there were quite a few postings at CR4 related to what happens when a bolt is properly torqued. Posters described stretching of the bolts when installed with proper torque and lubrication. I was amazed at how complete my lack of understanding was. So, engines for what? Used cars? Industrial equipment? Third world airlines?

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#6
In reply to #5

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 8:06 AM

Actually its a Alternator of 1500 KV used for power generation . It has vibration due to stator and rotor

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#12
In reply to #6

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 9:49 AM

Alternator hardware is probably OK to re-use.

I'd use a thread locking compound, too.

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#18
In reply to #6

Re: Nuts and Bolts Reuse in Engine Application

05/14/2014 2:52 AM

If it is going to be vibration related and other issues or moving parts - I would always use new bolts and from the same box - we newer know the exact weight and diameter tolerances of the old bolts used and this can cause vibrations and unbalancing of the rotating parts. So play it save use new stuff from a single manufacturer.

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#7

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 8:23 AM

i'd measure all the bolts or risk destuction

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#9
In reply to #7

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 8:34 AM

This seems to be informative , can u pls elaborate on this equipment

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#10
In reply to #9

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 8:36 AM

its a bolt stretch gauge

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#20
In reply to #9

Re: Nuts and Bolts Reuse in Engine Application

05/14/2014 5:49 AM

Note coment #8. Never re-use a bolt that has an installation torque value eg cylinder- head bolts (although these do not fall into the bolt-and-nut category).

In my own experience, your stated 16mm bolts should be safe for re-use if the assembly is done by hand-spanners only. When an assembly requires power-wrenches/flogging it may well be that the bolt was over-torqued in the first place and has been compromised for re-use at the required torque. Corroded bolts should be replaced.

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#14

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 10:56 AM

Well I think it depends on how critical the application is....and what might be the consequences of failure....after carefully contemplating these factors, then make a common sense decision....The material composition of the bolts, the environment the equipment was used in, the age of the bolts, operating temperatures, torque specifications, all these contribute to metal fatigue....You might try destructive testing on random selections....

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#15

Re: Nuts and Bolts Reuse in Engine Application

05/13/2014 2:21 PM

According to many tests (some made by myself) a bolt can be reused up to 4 times but: at every assembly friction increases so that for same tightening torque the obtained preload will be smaller and this is a risk in assemblies where the bolt preload plays a major role. Those are connecting rods and head. If normally stretched bolts do not get a permanent deformation and can be reused but the friction has to be monitored and compensated.

So that limit your re-usage of bolts to the NONCRITICAL assemblies.

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#16

Re: Nuts and Bolts Reuse in Engine Application

05/14/2014 12:53 AM

In general re-using fastners with physical and measurements check is OK. but it must always be linked to loss/costing - if it fails. so at important places where damages are more with failures of fastners better have sample checks for elongation and torque it can withstand -- sample size to dependm on economics. For general purposes re-use can be made. In any case they will be cleaned and a good technical person can observe damages while cleaning them and can seggregate.

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#21

Re: Nuts and Bolts Reuse in Engine Application

05/14/2014 7:40 AM

The best on site testing of nuts and bolts was being done by Sisu mfg of Crown Point Indiana. They tested every bolt they used, new and old, to repair/rebuilt aircraft parts. I feel sure they would give you the name of their testing machine which did not look expensive. Rich Byrne

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#23
In reply to #21

Re: Nuts and Bolts Reuse in Engine Application

05/14/2014 10:44 AM

I think aircraft parts are in a different category. You will find the larger airlines do not bother to effect smaller repairs (eg wheel strut assembly), but simply fit a new one.

The used, faulty part is then destroyed, supposedly so that it cannot be re-used/ sold by other interested parties.

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#22

Re: Nuts and Bolts Reuse in Engine Application

05/14/2014 10:16 AM

Many bolts are torque to yield when it comes to head bolts, intake, etc. It wouldn't be a good idea to use these again.

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