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The demineralised water should not be acidic. The engines concerned are either cast iron with some aluminium or are aluminium with iron elements like water pump impellers, so all have dissimilar metals.Quote:
Originally Posted by 123rover50
Did you know that the air conditioning heat exchangers in the Sydney Opera House use sea water (or at least harbour water) and the steel ducting is protected by only large sacrificial anodes on the sea water intake.
No. In the presence of any electrolyte, where several different metals are electrically connected, the one lowest in the galvanic series will be the only one attacked. It is specifically effective against rusting, but it only works when both the sacrificial anode and the metal to be protected are in the same body of electrolyte. (which is why impressed current galvanic protection for cars is a scam, unless you keep your car submerged!)Quote:
Originally Posted by 123rover50
John
Slightly off topic but still the same principle, I change the sacrificial anode in our electric mains hot water cylinder every five years (as recommended) and so far the cylinder has survived twenty four years with twenty of that on water straight from the Murray River. The last four it has been changed across to
rainwater. The anodes start off approx. 20 mil diameter and 750 mil long after five years there is just the threaded bung left, so I am convinced they work.
Wasn't the reason that cars were changed from positive to negative earth, to reduce electrolysis?
Cheers, Mick.
G'day, Been researching this topic for awhile.
Follow this link for the facts. http://www.google.com.au/url?url=htt...WbrGXog7REJ-mQ
Suggest use Glycol based (to Lubricate water pump seal) with inhibitor not type B inhibitor only. Chris
Sacrificial anodes certainly work when both metals are in the same electrolyte, in the HWS case in the water supply.Quote:
Originally Posted by mick88
I have not heard the suggestion of changing polarity having anything to do with electrolysis. The polarity was pretty much random until the 1930s, when positive earth became pretty much standard, based on a slight (mainly theoretical) advantage in spark plug performance with Kettering ignition, which was then replacing magneto ignition.
The change to negative earth was, as far as I know, purely because early solid state devices, mainly car radios, were simpler and cheaper when the power supply was negative earth. As solid state devices other than car radios became more common in the 1960s, almost all manufacturers changed.
John
G'day all
Finished my research on coolant for Series Landrovers.
I am going to use Tectaloy xtra cool concentrate 500 mls treats 10 ltrs of water. It is a type B fluid. It is available at Supercheap and Repco for a few dollars.
Reasons are:
It has 369g/litre of Glycol and a rust inhibitor.(sent an email to Tectaloy asking what type of rust inhibitor they use.No reply. Probably Boron.).
The glycol level provides minimal or nil anti freeze or anti boil properties. I will use it for anti corrosion properties only. (Live in Sydney). Have been using a similar Castrol Concentrate for 40 years which is no longer available and have had no issues with it. The machine shop commented on how clean the water jacket in the head is after 50 years. (Note the comments about crystalisation of type A fluids with long term use).
The glycol will lubricate the water pump seal.
Regards Chris
I can add my 20 cents worth.
No engine is advantaged by being operated without a coolant additive, and an overflow tank. The overflow tanks stops the air being drawn in each time the car cools down.
Every oxygen molecule will find an iron or aluminium part of your engine to join with.
I fitted these on my old iron engine falcons. There's some rule of thumb .1 mm of corrosion/scale is the same resistance to heat flow as 10 times that amount of metal.
Most old engines are predominately "iron", cylinders blocks & heads etc.
Even iron industrial and marine engines always used additives for long trouble free service life.
The transition engines ( alloy heads ) are vulnerable because the cylinder head is the anode for the engine block if coolant additive is not used.
Both of these engine types i would just use the traditional coolants that have been tried and tested over the years. Even the old "all alloy" volvo V 6 and Renault 4 cycl engines I used the common techtil etc for 20 years with no ill effects.
New all alloy engines I can't advise, best to follow strictly the makers recommendations even use their coolant if you have to.
I like glycol based about 30%, because i don't want to change the water each time I go somewhere its cold. Plus when we talk water temperature your talking average after the water has mixed, one of the advantages of the coolant additives is they help maintain surface contact & avoid gas evolution at the surfaces, either by temperature or cavitation. Gas evolution reduces heat transfer, cavitation can damage the liners etc.
For the cost of 20 -30 % Glycol based corrosion inhibitor I'm happy to pay, and change it every two years, i usually have a job to do in that time and drain some out anyhow. :)
Both ethylene glycol and propylene glycol have specific heats significantly below that of water, and even 30% will reduce cooling by 10-15% compared to water. This is likely to be a much greater effect than that caused by scale.
Glycol is also much better at finding leaks than is water. A corrosion inhibitor, however, without the glycol, is not going to be a problem. Of course, if the cooling system is in reasonable condition, the capacity is sufficient to withstand full power operation at low speeds in desert conditions, so most of us do not have to worry about reductions in capacity.
Most Australians do not need to worry about antifreeze (if you need to where you live you will know), but there are some places you may visit, where it could be needed - mainly alpine areas in winter.
John
G'day,
I agree John with your post. The tectaloy concentrate when mixed with 10 Ltrs of water has a Glycol ratio of approx 1.845% and as the manufacturers info states has little or nil effect on anti boil/ anti freeze characteristics. Glycol there to lubricate the water pump seal. The green dye is also a good indicator if you have a leak somewhere.
I say "If you can't take disappointment don't drive an old Landrover!!!"
Chris
My Series 3 (81 model) has an original sticker which advises to use a quality glycol coolant, so I always have.
I have just had the motor apart for a paint job and tidy up and the coolant galleries are excellent, no rust or crud.