[Vwdiesel] OT: response to Risks of Hydraulic Heating?

[Gerry/Joy Wolfe]

If Val thinks my comments are appropriate, then so be it!
Didn't want to respond originally to the list, because content was not 100% 
diesel content.

rgds, g.

ps: Val: Tell me about your compressor... manufacturer, type, what it's 
doing that you think it needs rebuilding.
The ones the company I work for typically run for about 5K hours before 
needing minor overhauls (typically: front-end gear cases and bearings),
excluding stuff like clutches and idlers and tensioners i.e. consumables.

rgds a'gin

----- Original Message ----- 
From: "Val Christian" <val at mongobird.com>
To: "Gerry Wolfe" <gjwolfe at telus.net>
Sent: Wednesday, December 21, 2005 20:43
Subject: Re: [Vwdiesel] Risks of Hydraulic Heating?


> Gerry,
>
> Thanks much.  I respectfully disagree with your not posting.
>
> The info you have presented would be very useful to someone
> managing a fuel system in extreme cold, or even a WVO user in
> moderate cold.  These tangents add depth to our interests.
>
> Besides, you're not talking about Eisenhaurer's policy of handguns
> in non-enforcement governmental service, or some such thing.
>
> Now, how do I tell if my air compressor is getting to the point
> where I should rebuild before it really breaks?
>
> Again, thanks for the email, and it is very helpful.
>
> Val
>
>
>
>
>
>>
>> Hi Val,
>> replying off-list because I'm not adding any diesel content <grin>
>>
>> I work at a company (VMAC - Vehicle Mounted Air Compressors - 
>> www.vmac.ca)
>> that builds underhood and above-deck air compressors.  The above-deck 
>> units
>> are hydraulic driven and, since this is the first cold season they're 
>> being
>> operated in since their summer introduction, users are experiencing
>> cold-weather issues.  Myself and fellow tech-support folks at the company
>> recently had a 2-day intensive course on hydraulics, and this was one of 
>> the
>> topics of discussion.
>>
>> Some comments:
>>
>> The most preferable solution is to install an immersion heater in your
>> hydraulic reservoir.  If you're getting any level of moisture in the
>> hydraulic oil, you wanna install an oil separator in the reservoir.
>>
>> Sluggish operation in the winter is often caused by extra-thick hydraulic
>> oil resulting in very high pressures.  This will result in your relief 
>> valve
>> opening, resulting in not much oil getting to the rest of the system.
>>
>> Forcing use of the relief valve is not really a bad idea.  It will end up
>> generating quite a bit of heat, and the warmed hydraulic oil will be
>> returning to the reservoir and cycling until things warm up enuff for 
>> normal
>> operation.  Don't worry about erosion etc. of the relief valve.  The only
>> real concern would be if the relief valve flutters, which could cause 
>> some
>> mechanical damage.
>>
>>We're offering a "cold
>> weather" kit which consists of a manifold with a temp sensor, solenoid, 
>> and
>> orifice.  If oil is too cold, the solenoid forces all the hydraulic oil 
>> thru
>> an orifice and back to where it came from.  Forcing thru the orifice adds 
>> a
>> bunch of heat to the oil.  When the oil is warm enuff, the solenoid kicks
>> out and the oil does its normal thing.  So, forcing thru an orifice to 
>> heat
>> is an acceptable (and fairly common) procedure.  You would be simulating 
>> the
>> same thing by stalling your system and using the relief valve as a 
>> heater.
>>
>> Hope this helps some.
>>
>> rgds, g
>>
>> ----- Original Message ----- 
>> From: "Val Christian" <val at mongobird.com>
>> To: <vwdiesel at vwfans.com>
>> Sent: Tuesday, December 20, 2005 17:17
>> Subject: [Vwdiesel] Risks of Hydraulic Heating?
>>
>>
>> > Gang,
>> >
>> > On my DIESEL (idi, even) tractor, I have an annual problem with 
>> > hydraulics
>> > jambing up.  What I think happens is that moisture in the hydraulic 
>> > system
>> > (transmission, brakes, loader, etc.) crystalizes at low temps, and as a
>> > solid, clogs the hydraulic filter.
>> >
>> > Heating the filter, with a propane torch frees things up, and after a
>> > period of operation at winter temps, the system seems pretty trouble 
>> > free.
>> >
>> > Here's the problem...how to cook out the oil?
>> >
>> > This year, I'm considering running the tractor at a moderate power
>> > 1800 out of 3000 RPM, and putting the hydraulics into a lock mode, so 
>> > that
>> > the pressure limiter goes into bypass.  I'm a little concerned about
>> > the effects on the bypass valve (erosion, etc.), and local heating of 
>> > the
>> > hydraulic oil as it goes through the bypass.  Can anyone comment?
>> >
>> > Val
>> >
>> > ps: As the battery fails on the tractor, I find that running the block
>> > heater
>> > pays of (timewise, not powerwise) over topping the charge on the 
>> > battery.
>> > Hello summer cylinders.  If my cars were harder starting, I'd be 
>> > popping
>> > frost plugs.
>> >
>> > pps: Extreme cold starting technique...I've seen the gas/kero soaked 
>> > rag
>> > trick used at the quarries.  I did something similar on an old Rabbit,
>> > except that it was in the garage.  I wanted something cleaner.  I 
>> > pulled
>> > off the crankcase vent hose, and used tissue saturated with isopropyl
>> > alcohol.  I reasoned that the tissue wouldn't hurt the engine when
>> > injected
>> > and the alcohol wouldn't be as sooty.  Later refinements had an 
>> > assistant
>> > holding a propane torch in the intake manifold.  Preheating the propane
>> > in extreme cold helps, but the burn is short.  5 or 10 seconds.
>> > The same torch is used to blast misquitoes in the garage in the summer.
>> >
>> >
>> > _______________________________________________
>> > Vwdiesel mailing list
>> > Vwdiesel at vwfans.com
>> > http://www.audifans.com/mailman/listinfo/vwdiesel
>> >
>> > __________ NOD32 1.1331 (20051220) Information __________
>> >
>> > This message was checked by NOD32 antivirus system.
>> > http://www.eset.com
>> >
>> >
>>
>
>
> __________ NOD32 1.1332 (20051221) Information __________
>
> This message was checked by NOD32 antivirus system.
> http://www.eset.com
>
>