Author Topic: Potential Breakdown Warning to China Diesel Owners!!!!!  (Read 11627 times)

mobile_bob

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #15 on: December 19, 2007, 06:07:40 AM »
awe shucks guys

you all can loctite, safety wire, or for that matter weld every friggin bolt, nut and cotter pin if you like

i am just glad i don't have to follow up with service on one of your engine's :)

i would bet that with dragonof's 38 years, and my 34 years of diesel hands on experience
he and i have had our grubby mits on a dumptruck load of rocker jamb nuts,,, and the only ones that came lose in operation
were never torqued right to start with.

but what do we know?

one nut fall's off on one engine, and everyone want's to jump on the loctite wagon

knock yourselves out!

you all got my blessing!

lol

i just wonder though,, if one of us has a car wheel come off after having tires put on

are we all going to loctite the lugnuts on?

maybe we should safety wire them?

drill the studs and put in cotter pins?  lock tabs? weld them in place?

or just simply torque them correctly to start with?

don't get me wrong, there is a place for loctite,, i just don't think it is rocker nuts
especially with only one failure of which a determination of cause has not been made.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

trigzy

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #16 on: December 19, 2007, 07:25:45 AM »
Hi,

All I have to say is; I have known the Chinese manufacturers to make/use bolts that are marked to be of a certian grade, but infact be of very low quality.

I have also known them to over/under torque just about every bolt on a given piece of machinery.

So, it's hard to say "the proper torque" on some of these chinese fasteners, because it might be marked grade 8, but if you try and tighten it to a grade 8 spec,you'l end up with more metal filings than a Chrysler transmission.

Good luck with all of your fastening needs!


Steve

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Vendor of AVR's, Small Clones of Yanmar Diesel and Honda Gasoline Engines

draganof

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #17 on: December 27, 2007, 09:00:15 PM »
It's sort of funny that we sit here and squabble about locktite vs proper torque when the tool kit that comes with these engines has a wrench you strike with a hammer for the proper head bolt torque? I wonder how many farmers in Thailand, Vietnam, China etc. have a torque wrench? Probably not very many. I know I have mine. These are some hardy little engines and with third world  farmer style maintenance will last for many years. Now take that same engine and apply the proper northern hemisphere maintenance standards and it will out live you by decades the same as the Listers have done. :P

Draganof
Changfa 195 and ST10
8kw Yanmar/Kohler

okiezeke

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #18 on: December 27, 2007, 10:52:37 PM »
Always figured loctite was invented for any engine that runs over 3000 rpm.  Thats why I like slow speed diesels.  Wonder if pro race cars use loctite?
Zeke


ps.  In the interest of total honesty I did use loctite on the flywheel bolts connecting my direct coupler to the ST 15 on my changfa 1115.  I did this because I thought the bolts seemed kinda loose in the threads in the flywheel.  What the heck, cant hurt.  They havent fallen out yet.
Changfa type 25hp with 15kw ST head
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ZackaryMac

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #19 on: December 28, 2007, 12:52:18 AM »
I used to work in a motorcycle shop, with engines that at the time revved to 14,000rpm (higher now).

No loctite anywhere in the engine. Any valves that were actuated with rocker arms (one model was with 14k rpm redline) only used a nut to lock the adjuster in place.
Many engines use shims to adjust the valves, some use shim-under-bucket, meaning removing a million bolts, many hard to get at, and removing the cams to adjust the valves. You had to know before hand what shim you would need for what valve.

Anyway, Bombardier likes loctite, but not the Japanese.
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All are diesel.

Doug

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #20 on: December 28, 2007, 12:59:01 AM »
Thats because not too many Japs drive the roads around Valcourt.....
It's a Good Life, If You Don't Weaken

draganof

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Re: Potential Breakdown Warning to China Diesel Owners!!!!!
« Reply #21 on: December 28, 2007, 01:04:37 AM »
Just a thought, you senior motorheads.

The old Lycoming aircraft engines (yes I own and fly one) have 32 allen head pipe plugs in the oil galleries. They are prone to loosening over time, even with proper torque. So, guess what? Loctite to the rescue. You might think it is not necessary, but you might end up being dead and wrong at the same time. And, yes, before Loctite, safety wire and/or pipe thread sealant was used.




Yes, it is a "high temp" loctite, good to about 400 deg F.

Also, standard Loctite has little holding power over the boiling point. Exactly what temp might you guess the rocker arms operate at? I would guess about there.

Chris

Oil galley plugs? Without question! Oil galley plugs in crankshafts? Oh hell yes! Some things are designed to have loctite as an additional safety margin. Every moving/adjustable part on an aircraft airframe and engine will have a thread locking device of some type. Well maybe not the rocker arms. There are many things loctite is used for but some parts (main bearing caps, rod bearing caps, rocker arm lock nuts) in a 240 degree oil soaked environment will not benefit from its use. On Caterpillar SR4 generators the PMG is held onto the end of the shaft by 4ea  1/4" grade 8 bolts. You must use locktite on the threads or the PMG will come loose and destroy the generator! Caterpillar tried changing torque values, length of bolts, hard washers and finally the answer was loctite! Never had a repeat failure after that. Bottom line is there are times to use loctite and times to avoid it. We just need to realize it's limitations.

John

Changfa 195 and ST10
8kw Yanmar/Kohler