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Corroded engine block
https://forums.tipec.net/viewtopic.php?f=25&t=16833		 Page 1 of 1
Author:  Pink piggy [ Wed Jan 15, 2014 1:20 pm ]
Post subject:  Corroded engine block
Hi folks.
A question for all.
"how can you clean a heavily corroded alloy engine block please?"
Author:  Rhett [ Wed Jan 15, 2014 1:43 pm ]
Post subject:  Re: Corroded engine block
Hi, unfortunately I don't think there is an easy way as the oxide that builds up seems to attract crud like a magnet! I had been advised off of using some of the more powerful solvents as they can cause long-term problems. So, all I did was scrub the block with stiff brushes (wire and bristle) while applying 'gunk'. Then washing down (lots of cheap detergent) and repeating until the alloy looked as clean as it could be. Then using wire wool, emery cloth, small wire brushes (lots of them!) and other abrasive material I removed as much oxide as possible.

Believe me, it certainly took a while, but the results are worth it.

I then took the process a stage further (omit this if you are an alloy purist!) - I sprayed the block with a hi-temp engine enamel. This gave a good finish that looks like it will certainly last a good few years, and is easy to clean off and maintain whenever necessary.

Here are before and after shots:

Attachment:
Dirty engine 1.jpg

Attachment:
clean engine 1.jpg


Yes, it is the same engine :D .

Hope that helps.. :wink:

Perhaps someone else has done it a different way and used other products - could be interesting...
Author:  jmgarage [ Wed Jan 15, 2014 2:25 pm ]
Post subject:  Re: Corroded engine block
Are you just wanting to get the outside of the engine looking clean and without oxide all over it?

If so, use an alloy wheel cleaning acid.. yes its an acid, but follow the directions for using it on alloy wheels and it will attack the corrosion and not the aluminium itself.

Once applied, brush it in with a stiff detailing or paint brush, leave it for however long the instructions say, and then flush it away with fresh water.

Once you are happy with the finish, there is a product called corrosion-x which is used in aviation, it soaks into the pours of the aluminium, and forms a thin barrier.. it is not a paint, more of a wd40 type matial, in a spray can, do not spray too much of it because it will just be wasted and run off an pool into puddles.

Its not cheap stuff, but I have built engines which years later are still not oxidising after this stuff being used, but unlike a paint, it will not alter the thermal conductivity of the block, or perhaps I should say the convection of heat from the block, like paint does.

If you are talking about corrosion in te waterways of the block, then I would be tempted to say you could do with a citric acid based coolant flush, but beware, it may remove corrosion which is currently sealing things up.. but my attitude is it is better that those deposits are removed while you are trying to remove them rather than them removing themselves at 70mph on a motorway when you are 100 miles from home.

Or, if you are talking about bore corrosion, obviously that is a bit more of an issue and potions will not help.

Just as a side note, of course when I say corrosion, being aluminium, the block oxidises, not corrodes, but you know what I mean.
Author:  Rhett [ Wed Jan 15, 2014 3:46 pm ]
Post subject:  Re: Corroded engine block
Very interesting process Jon, I hadn't thought about using alloy wheel cleaner - doh! Could have saved myself some elbow grease... :wink:

This corrosion-x stuff sounds good, I found this website:

http://www.corrosion-x.co.uk/

I guess this is it?

If I had known about that product, I might not have painted the block, etc. However, I have to say that I haven't experienced any heat issues as the temp stays spot-on, but I made sure not too much was applied. Got to admit there is something nice about clean, unfinished alloy... :D.

I have got another transmission that I want to clean up at sometime this year, might just give the acid treatment a go. Thanks for the tip.

** If you do use acid-based products, rubber gloves, goggles and even perhaps a mask are always a very good idea! **
Author:  frenchy [ Wed Jan 15, 2014 8:18 pm ]
Post subject:  Re: Corroded engine block
Rhett, looks good though !
Author:  Pink piggy [ Thu Jan 16, 2014 11:20 pm ]
Post subject:  Re: Corroded engine block
Thank you gents. It has certainly made me think, I will digest and decide what to do because the engine in question will be raced and it just has to look reasonably good and certainly wants to cool as much as possible.
That paint does look good though!

By the way the 944 family of engines surprised me by having straight alloy bores and the pistons sprayed with steel to ensure no seizure. The fact that these engines can pack a lot of miles before they need work says heaps. I think the Boxster is similar too.
Before I bought mine I assumed it was a wet liner.
Conclusion is that oil change even more important and an overheat can kill quickly.
Does any other maker use this method or is Porsche unique.
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