agmerlin Posted August 18, 2014 Share Posted August 18, 2014 Hello All, has as anyone every painted the inside of their gearbox? A friend of mine is restoring a truck and mentioned he had done this with a special paint inside the gearbox and wondered if it was any good on a motorcycle gearbox? any views? all the best Andy Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted August 18, 2014 Share Posted August 18, 2014 Hello All, has as anyone every painted the inside of their gearbox? A friend of mine is restoring a truck and mentioned he had done this with a special paint inside the gearbox and wondered if it was any good on a motorcycle gearbox? any views? all the best Andy Andy, Gearbox casings that are usually painted inside are cast iron, as most motorcycle gearbox casings are alloy, I see no reason why it would need painting. regards, Richard Quote Link to comment Share on other sites More sharing options...
agmerlin Posted August 18, 2014 Author Share Posted August 18, 2014 Andy,Gearbox casings that are usually painted inside are cast iron, as most motorcycle gearbox casings are alloy, I see no reason why it would need painting. regards, Richard Hi Richard, thanks for for the reply, I sort of thought that might be the case but nice to get that confirmed by someone else. cheers andy Quote Link to comment Share on other sites More sharing options...
Scivo18 Posted August 19, 2014 Share Posted August 19, 2014 On some of our race bikes we have actually polished the inside of the engine cases and covers to make the oil circulate more quickly, and dissipate the heat easily I have never seen the inside of a motor cycle engine painted Tim Quote Link to comment Share on other sites More sharing options...
Griffo Posted August 28, 2014 Share Posted August 28, 2014 The inside of my Harley Davidson wla crankcase, cam case and gearbox had traces of red paint, when is rebuilt them I applied glyptol paint which is supposed to prevent any leaks from any porosity in the aluminium castings. i used to work for Toyota and they used to dip their aluminium blocks in a liquid adhesive for the same reasons!! Dave Quote Link to comment Share on other sites More sharing options...
fesm_ndt Posted August 29, 2014 Share Posted August 29, 2014 A lot of the avid Pinzgauer restorers paint the inside of all the boxes. I cannot recall the reasoning behind it but I know it is very popular and a special paint (I'll have to ask) [ATTACH=CONFIG]96030[/ATTACH] Quote Link to comment Share on other sites More sharing options...
Ron Posted August 29, 2014 Share Posted August 29, 2014 I can't say I've ever seen it. But Griffo's reasoning makes sense. I know sand cast cases can be porous. Ron Quote Link to comment Share on other sites More sharing options...
GeePig Posted August 29, 2014 Share Posted August 29, 2014 On some of our race bikes we have actually polished the inside of the engine cases and covers to make the oil circulate more quickly, and dissipate the heat easily Tim I have never seen that done, though it is worth bearing in mind that a rough surface can allow things to flow faster and will have a greater surface area to absorb heat from a hot fluid. As to painting gearbox interiors, I could see that as being very useful for old, porous castings, especially if you didn't want to paint the exterior surface for originality's sake. Does anyone know what Toyota uses to dip the castings in? trevor Quote Link to comment Share on other sites More sharing options...
rubbatiti Posted August 29, 2014 Share Posted August 29, 2014 A friend of mine builds a lot of engines for racing Jaguar XKs and E Types and he paints the inside of the crankcases and sump pans for the reasons already stated. I've also been told that painting the casting helps ensure that any residue sand from the casting process is sealed in and can't find its way into the lubricant... Quote Link to comment Share on other sites More sharing options...
Griffo Posted August 29, 2014 Share Posted August 29, 2014 Here's what Toyota use http://www.ultraseal.co.uk/porosity/what-is-impregnation/ Quote Link to comment Share on other sites More sharing options...
Griffo Posted August 29, 2014 Share Posted August 29, 2014 Here's what I used http://www.frost.co.uk/glyptal-red-enamel-946ml-us-quart.html Quote Link to comment Share on other sites More sharing options...
welbike Posted August 30, 2014 Share Posted August 30, 2014 I believe older Indian cases were painted red inside for same reasons, do not know when they stopped doing it, maybe mid 20's ?? Cheers, Lex Quote Link to comment Share on other sites More sharing options...
Redherring Posted August 31, 2014 Share Posted August 31, 2014 Might glyptal work on the inside of Al water jackets? Quote Link to comment Share on other sites More sharing options...
Griffo Posted August 31, 2014 Share Posted August 31, 2014 I'm not too sure about water jackets as it may block important water ways within the water jacket area? Dave Quote Link to comment Share on other sites More sharing options...
Redherring Posted August 31, 2014 Share Posted August 31, 2014 Some time ago there was some discussion on another thread about the effects of galvanic action on aluminium top and bottom radiator tanks. I was wondering whether a paint might protect the internal surfaces from severe pitting. Quote Link to comment Share on other sites More sharing options...
GeePig Posted September 1, 2014 Share Posted September 1, 2014 Some time ago there was some discussion on another thread about the effects of galvanic action on aluminium top and bottom radiator tanks. I was wondering whether a paint might protect the internal surfaces from severe pitting. Kind of like what you do to protect the inside of a fuel tank? trevor Quote Link to comment Share on other sites More sharing options...
Chris Hall Posted September 1, 2014 Share Posted September 1, 2014 Some Post war Royal Enfields are painted yellow inside the crank case due to porosity. Quote Link to comment Share on other sites More sharing options...
fesm_ndt Posted September 2, 2014 Share Posted September 2, 2014 One of the Pinzgauer experts came back with this response. "As regards your question re painting the inside of the housings, below are the reasons; Stops weeping/permeating through the castings. Helps with oil drainage. Seals any stray material/media after blasting etc." Some time ago there was some discussion on another thread about the effects of galvanic action on aluminium top and bottom radiator tanks. I was wondering whether a paint might protect the internal surfaces from severe pitting. You have to be very careful with this concept. Logic would say to paint the aluminium as it is the anodic part......... But it would be a great deal more effective if you coat the surfaces of the cathode i.e. the brass or copper bits. Ok basic corrosion we know the anode corrodes..... so my method appears odd. The bit most, even industry forget about is size matters. The bigger the cathode to a smaller anode the faster the corrosion. If you coat the aluminium and there is one tiny pinhole then you have a massive cathode and a ting anode, so corrosion will be extremely fast. If you coat the copper brass and there is a pinhole you have a tiny cathode and a massive anode so corrosion will be almost negligible. Quote Link to comment Share on other sites More sharing options...
Redherring Posted September 2, 2014 Share Posted September 2, 2014 It would be difficult to coat the cathode in the radiator case. However, suppose you wanted to reuse an original but very heavily pitted aluminium bottom tank. Could you clean it up, fill, and paint, and then place a small slab of zinc inside the the tank connecting it to the copper base plate. Robert Quote Link to comment Share on other sites More sharing options...
fesm_ndt Posted September 2, 2014 Share Posted September 2, 2014 It would be difficult to coat the cathode in the radiator case. However, suppose you wanted to reuse an original but very heavily pitted aluminium bottom tank. Could you clean it up, fill, and paint, and then place a small slab of zinc inside the the tank connecting it to the copper base plate. Robert Coating is never perfect, but I guess a pinhole is better than the whole thing corroding. If it has a drain plug in it you could attach a bit of zinc to it and take it out every now and again and look for wastage. It has had me intrigued since this topic came up in another thread a while back as aluminium and brass/copper is a really bad combo but who would have thought of the lifespans we are talking about. You can get some very fancy types of coatings they use offshore which they check using holiday testers. But unless you got a mate in a oil and gas paint shop its expensive. I can find out what the coatings were this guy used on his Pinz as he is based in Melbourne? Quote Link to comment Share on other sites More sharing options...
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