OzVMX Forum
Marque Remarks => Husqvarna => Topic started by: PEZBerq on January 21, 2012, 11:55:03 am
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I am restoring my first water cooled Husky and would like some learned advice from forum members who are versed in the ways of the magnesium water pump casing ;D ;D. What should I do (if anything ???) with my magnesium clutch covers corrosion at the water pump. The photos show each side of the water pump. The corrosion does not seem to have penetrated the cover ...yet. It looks like a previous owner has applied some resin material to the back of the casing in the pump area. Apart from this pitting the cover is perfect and I am loath to replace it or attempt any weld repairs. The bike is a 87 Husky 510 TE and has a magnesium barrel also - with has some water gallery corrosion also but nothing that will cause me grief during my likely usage of the bike.
I dont know if it leaks or if the seal leaks - I'll find out when I first run the bike I guess ;D
As it will be used occasionally for pre 90 VMX/Vinduro and stored with coolant drained out (best idea ??? ???) I am leaning towards simply leaving everything as it is. What do people think of this strategy? Also what is the best coolant to use in these engines with magnesium components - also assuming it gets drained after every race weekend.
(http://i619.photobucket.com/albums/tt272/berquist01/Husky%20510%20TE%20Restoration/IMG_0004.jpg)
(http://i619.photobucket.com/albums/tt272/berquist01/Husky%20510%20TE%20Restoration/IMG_0003.jpg)
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There is a guy in the uk who makes billet alloy covers to replace the old mag ones, but yours doesn't look that bad, might be best to just clean up any corrosion and coat it with something to prevent any more corrosion. The barrel on the other hand is a whole other ball game.
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do they have mag cast Barells evo?
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There is a guy in the uk who makes billet alloy covers to replace the old mag ones, but yours doesn't look that bad, might be best to just clean up any corrosion and coat it with something to prevent any more corrosion. The barrel on the other hand is a whole other ball game.
Who is that please.
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do they have mag cast Barells evo?
Dunno, pez mentioned it in his first post.
The billet covers where shown on a thread in here somewhere.
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I think it is www.hva-factory.com
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hva-factory.com
Check their site , it has been recently updated and is really quite good.
Great people and great parts with prompt delivery , I have a number of their components , including the engine side covers and they are very functional , fit up great and look quite factory
Be aware that shipping from UK is a little more xxee than it is from the USA.
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You do not want a magnesium water cooled barrel. Nothing but trouble - that's why they are always alloy nowdays. Now an air cooled Mag barrel is another thing!
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I agree ,the mag. WC barrels can be a little bit of a problem. We had a number of issues with them in the mid to late 80's.
One good thing with them , is that they readily available in new or used condition.
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Tidy up the corrosion [ with a wire brush ] and paint it with something because it,s not too bad.
I think the type of paint has been mentioned on this forum before but can't remember where.
I think even enamel would do.
The back is from the factory , they are all like that.
I use Motul coolant in mine and have not had a problem.
I would not drain it out as the air/moisture could cause a problem.
Cheers
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KTM 350s used to be also brutal for corroding out .... I have had a lot of success with Devcon pump repair putty, it dries hard as glass, you need to lightly blast the area so it can key in.... then press in and smooth out. Its designed to do repair corroded water pump, not cheap but the good stuff.
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You guys do know that you can weld these cases ???
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and if you use devcon type materials makes the welding job later (as it doesn't last forever) that much more difficult?
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I have used Devcon on an 86 KTM and the coolant got behind it making the problem worse and hidden.
I thought I had cleaned the base metal all up and was disappointed next time I looked.
This one that Pez has posted a photo of has hardly started and really doesn't need anything done to it.
A coat of paint would settle any worries down tho. :)
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I have used Devcon on an 86 KTM and the coolant got behind it making the problem worse and hidden.
I thought I had cleaned the base metal all up and was disappointed next time I looked.
thats why I mentioned the surface preparation has to be spotless, oil old coolant etc and it will not take. Plus you need the pump repair putty not any old Devcon product.
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Thanks for the suggestions and comments. I think it is the chlorides in the coolant water that rots the magnesium. Oxygen from the air is not the problem if I recall correctly. Then again I could be completely wrong ::)
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Isn't coolant a rust inhibiter aswell?A person i know that services Elvis (the firefighting helicopter)recommended to leave coolant in while storing as the bike could be prone to rust damage without anything in there.He has a few bikes himself aswell and is in the same situation as he works away from home alot.
cheers Dale.
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Did some research on this the other day after getting an '84 KTM with Mag alloy cases. I found a Paper written by a Uni Prof. from South Oz on the use of magnesium alloy in engine castings. It was as dry as a .............. to read but the guy new his stuff. I can not find it again :-[ unfortunately. The magnesium sits much lower on the scale than any other metal common in cooling systems so basically it sacrifices itself as a cathode in a galvanic circuit. I found that the top level Motul Factory line coolant contains the correct chemical mix to at least limit damage to the Mag alloy. There are others. Below is the critical extract from that paper. Yes I know I need to get a life if I end up reading Uni papers on corrosion of metals. Just remember the mag alloy does not rust.
A number of magnesium alloys show promise as engine block materials. However, a critical issue for the automotive industry is corrosion of the engine block by the coolant and this could limit the use of magnesium engine blocks. This work assesses the corrosion performance of conventional magnesium alloy AZ91D and a recently developed engine block magnesium alloy AM-SC1 in several commercial coolants. Immersion testing, hydrogen evolution measurement, galvanic current monitoring and the standard ASTM D1384 test were employed to reveal the corrosion performance of the magnesium alloys subjected to the coolants. The results show that the tested commercial coolants are corrosive to the magnesium alloys in terms of general and galvanic corrosion. The two magnesium alloys exhibited slightly different corrosion resistance to the coolants with AZ91D being more corrosion resistant than AM-SC1. The corrosivity varied from coolant to coolant. Generally speaking. an oraganic-acid based long life coolant was less corrosive to the magnesium alloys than a traditional coolant. Among the studied commercial coolants. Toyota long, life coolant appeared to be the most promising one. In addition. it was found that potassium fluoride effectively inhibited corrosion of the magnesium alloys in the studied commercial coolants. Both general and galvanic corrosion rates were significantly decreased by addition of KF, and there were no evident side effects on the other engine block materials, such as copper, solder. brass. steel and aluminium alloys, in terms of their corrosion performance. The ASTM D 1384 test further confirmed these results and suggested that Toyota long life coolant with 1%wt KF addition is a promising coolant for magnesium engine blocks.