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

Fri Dec 23 02:15:55 EST 2005

Gerry, you might want to consider synthetic hydraulic oil in the compressor
drive also. That makes a tremendous difference, as it is then fine to use a
10W weight oil that is easily flowable at most temps, and the oil will not
break down like a mineral oil.  Guys that feed cattle in winter usually use
this in their loader tractors if the tractor is parked outside- it usually
has to run at least every second day, no exceptions.
These are the compressors that the industrial tire service guys run I
assume? The ones I've seen are pretty nice units.

As with any immersion heater, you have to be very careful not to cook the
oil.  That is the main problem associated with exposed element immersion
heaters- they subject the oil to excesive temperatures before convection can
carry the hot oil away.  Better are the stick on heaters that warm the tank,
and indirectly the oil- the oil does not see such an extreme heat.
-James

-----Original Message-----
From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com]On
Behalf Of Gerry/Joy Wolfe
Sent: Thursday, December 22, 2005 12:23 AM
To: vwdiesel at vwfans.com
Subject: [Vwdiesel] OT: response to Risks of Hydraulic Heating?

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
>> >
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>
>
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