modmanwill Posted November 13, 2013 Share Posted November 13, 2013 Anyone got any ideas why my Kyosho neo ST keeps going through Engines? Here are so me pics of the latest engine, it has plenty of wear marks, hopefully someone can identify what causing this. Thank You an http://www.msuk-forum.co.uk/gallery/image/25566-s1090003/ http://www.msuk-forum.co.uk/gallery/image/25565-s1090002/ http://www.msuk-forum.co.uk/gallery/image/25564-s1090001/ http://www.msuk-forum.co.uk/gallery/image/25563-dsc-0168/ http://www.msuk-forum.co.uk/gallery/image/25562-dsc-0167/ http://www.msuk-forum.co.uk/gallery/image/25557-dsc-0162/ http://www.msuk-forum.co.uk/gallery/image/25558-dsc-0163/ http://www.msuk-forum.co.uk/gallery/image/25559-dsc-0164/ http://www.msuk-forum.co.uk/gallery/image/25560-dsc-0165/ http://www.msuk-forum.co.uk/gallery/image/25561-dsc-0166/ http://www.msuk-forum.co.uk/gallery/image/25556-dsc-0161/ Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted November 13, 2013 Share Posted November 13, 2013 Can see plenty of damage ( bust conrod, bent crank.... ) but do you know what actually caused the failure? Did the thing sieze, or is it simple failure of the components? What sort of runtime have the engines had before they failed? What sort of running are you doing with the truck...racing...casual usage down the park.. It can all have a bearing on engine life ( and death! ) Usually, premature engine failures come in 2 types... 1) User error. Poor tune, resulting in lean running..or poor fuel, all those sorts of reasons. 2) Manufacturer error. Poorly built or poorly QCd parts, bearings failing, poorly fitting parts or just cheap materials used. Now, you are a new member, so I won't judge your skills or tuning ability, but the complete engine strip and layout of parts does indicate a certain level of knowledge...but if I had 3 identical engines fail....I wouldn't keep buying the same motor! Have you contacted Kyosho about the failures? Could be a bad batch of engines Quote Link to comment Share on other sites More sharing options...
atom3624 Posted November 13, 2013 Share Posted November 13, 2013 Was the engine 'tight' - the 'pinch' very good? Were you stopping it at top dead centre - on the pinch, or did you turn it to where there was no pinch? Amazing that damage - not super experienced, but had some time with nitros and never saw that with mine. Al. Quote Link to comment Share on other sites More sharing options...
modmanwill Posted November 13, 2013 Author Share Posted November 13, 2013 Thank you for the fast replies, I would say its had no more than 5 hours run time. I keep my engine and car very clean ie, after run oil and clean the car after every run and i always use quality fuel. This time i was out on the street, i have never raced or thrashed the engine. The piston is now very tight in the sleeve. I spoke to Kyosho and they say it is from over revving. All the bearings seem to be ok. Im now at the stage where im thinking of buying another engine such as Hpi or novarossi etc. Quote Link to comment Share on other sites More sharing options...
mini-z-awd Posted November 13, 2013 Share Posted November 13, 2013 (edited) how can over revving bend a crankshaft like that i can understand the conrod but not the crank but like nitroholic has said it looks like poor tuning has broke the con-rod as its just got too hot so it just broke Edited November 13, 2013 by mini-z-awd Quote Link to comment Share on other sites More sharing options...
modmanwill Posted November 13, 2013 Author Share Posted November 13, 2013 how can over revving bend a crankshaft like that i can understand the conrod but not the crank but like nitroholic has said it looks like poor tuning has broke the con-rod as its just got too hot so it just broke It is far from running lean so im not sure if its heat, also it was running less than 5 minutes before it cut out. Quote Link to comment Share on other sites More sharing options...
mini-z-awd Posted November 13, 2013 Share Posted November 13, 2013 It is far from running lean so im not sure if its heat, also it was running less than 5 minutes before it cut out. one of my mates had the same thing happen and modelsport said that was the problem with his motor and he done the same thing to his con-rod thats why i said the overheating thing Quote Link to comment Share on other sites More sharing options...
nitrocal Posted November 14, 2013 Share Posted November 14, 2013 EXACT SAME HAPPENED TO MINE YESTERDAY! 20 mins of running, same damage... Quote Link to comment Share on other sites More sharing options...
brit_bulldog Posted November 14, 2013 Share Posted November 14, 2013 Difficult to be sure on these. When the conrod is dog legged like that the engine must have been revving very high which can cause it to throw like that. Full size engines used to do that in same circumstances till they was de-tuned. Looking at first pictures the cranck shaft looks very marked and also the piston looks very grey. you would hope to see a dark brown burnt oil look on top of piston. If not is could be that dirt has been acting like an abrasive. What is your airfilter regime? Bent Crankshaft is unusual, did the spur gear and clutch look damaged? maybe a stone wedged in there? To be fair also the Kyosho engines are very high revving and give great performance, But you can not hold them on full throttle for too long like a basic slower engine (like the ones based on aero blocks) as it will keep revving till it blows itself up. They are designed for the purpose of short bursts of high speed and acceleration. If you return the engines you have to Kyosho they will asses them and likely fix very cheap and also advise on what may have caused the failure. Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted November 14, 2013 Share Posted November 14, 2013 What gets me though, is the nature of both failures. The conrod has snapped....but there isn't a lot of evidence of siezure. Bust conrod as a result of the motor nipping up would be understandable...but this looks like simple failure of the component. Could be due to revving...could be due to a poor batch of rods. Nitro motors rev high, and any manufacturer developing an engine would be revving them to and beyond the norm to ensure they are reliable enough for mass market use. Or maybe not... I'd definitely contact Kyosho about the failures. Maybe they have changed something in the engine that they shouldn't....or need to change something! Perhaps they need a lighter piston. The failures in both cases are snapped rods..with the rest of the damage following Quote Link to comment Share on other sites More sharing options...
atom3624 Posted November 14, 2013 Share Posted November 14, 2013 Trying to visualise, it seems like they were very hot, and revving very highly, softening the conrod, with the higher momentum of the piston coming down, smashing against the conrod, bending it, then the crankshaft momentum still trying to turn, but the piston unable to go up again, if you see what I mean ...!! Nitro engines are made to rev high, so its worth trying a complaint to see what they say. Al. Quote Link to comment Share on other sites More sharing options...
modmanwill Posted November 14, 2013 Author Share Posted November 14, 2013 thank you guys for all the messages, im going to send the pictures of to kyosho and see what they say. I am very keen about clean air filters and fuel filters etc. the only thing i have started doing is using a couple of drops of after run oil after each run, could this cause anywhere? Quote Link to comment Share on other sites More sharing options...
nitrocal Posted November 14, 2013 Share Posted November 14, 2013 ive had my mate make me a new cnc conrod, out of some 7075 aluminium, to make it stronger, seems to be running alot better now, had a spare piston that fitted too, i didnt have any other damage to mine which was lucky Quote Link to comment Share on other sites More sharing options...
R46 Posted November 14, 2013 Share Posted November 14, 2013 these engine are weak conrod & crankshaft shows this, kyosho needs to fix up an use quality materials in their engines... 1 Quote Link to comment Share on other sites More sharing options...
brit_bulldog Posted November 15, 2013 Share Posted November 15, 2013 After run can cause more problems than it fixes.Put some drops of it into some fuel and you will see it does not mix in facts it globulates. I have yet to see any afterrun dissolve. I think if you run engine completely dry and use just couple of drops and spin engine dry then it wont cause too many issues. But if you pump it into engine especially with fuel in it you will cause the blobs that will block oilways. It seems especially bad with the cheaper fuels. I think this could be as they are fully synthetic and the after run seem to be mostly organic oil.The best solution is to use a good quality Semi-Synthetic Like Byron as it will leave your engine coated after use. Quote Link to comment Share on other sites More sharing options...
mugen mark Posted November 15, 2013 Share Posted November 15, 2013 there just cheap weak engines,made to be cheap,so simply save up and buy a decent engine.kosyho make cars,not engines,these are desinged to get the rtr package made as cheap as possible Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted November 15, 2013 Share Posted November 15, 2013 After run can cause more problems than it fixes. Put some drops of it into some fuel and you will see it does not mix in facts it globulates. I have yet to see any afterrun dissolve. I think if you run engine completely dry and use just couple of drops and spin engine dry then it wont cause too many issues. But if you pump it into engine especially with fuel in it you will cause the blobs that will block oilways. It seems especially bad with the cheaper fuels. I think this could be as they are fully synthetic and the after run seem to be mostly organic oil. The best solution is to use a good quality Semi-Synthetic Like Byron as it will leave your engine coated after use. Block oilways? There are no oilways. The oil is in the fuel vapour, and gets distributed with it. You are only supposed to put a few drops of after-run oil in anyway, which would get washed out with unburnt fuel anyway when you prime the motor. The purpose of after-run oil is to prevent corrosion if the motor is left unused for any length of time. Nitro fuel naturally absorbs moisture, which will condense out when the volatile fuel content evaporates leaving just the oil behind. This oil residue will be sitting in the bottom of the engine, not on the piston/liner, so a coating of oil there will prevent corrosion. Additionally...if after run oil is mineral/ caster based...then it will mix fine with any semi-synthetic oil...but will not play nicely with fully synthetic in some cases. Most decent fuels use semi-synthetic. 1 Quote Link to comment Share on other sites More sharing options...
nitrocal Posted November 15, 2013 Share Posted November 15, 2013 Block oilways? There are no oilways. The oil is in the fuel vapour, and gets distributed with it. You are only supposed to put a few drops of after-run oil in anyway, which would get washed out with unburnt fuel anyway when you prime the motor. The purpose of after-run oil is to prevent corrosion if the motor is left unused for any length of time. Nitro fuel naturally absorbs moisture, which will condense out when the volatile fuel content evaporates leaving just the oil behind. This oil residue will be sitting in the bottom of the engine, not on the piston/liner, so a coating of oil there will prevent corrosion. Additionally...if after run oil is mineral/ caster based...then it will mix fine with any semi-synthetic oil...but will not play nicely with fully synthetic in some cases. Most decent fuels use semi-synthetic. well said! Quote Link to comment Share on other sites More sharing options...
PurcyP Posted November 15, 2013 Share Posted November 15, 2013 the KE25's are known to eat through conrod's like a beast. Quote Link to comment Share on other sites More sharing options...
brit_bulldog Posted November 15, 2013 Share Posted November 15, 2013 Sorry maybe I did not explain clearly. The oilways I mean are mostly the lubrication holes on the conrod. On a real car engine it would be considered an oilway. These holes are very small and can get blocked if any dirt or Oil blobs get into the engine. they are not there for fuel reason but to get lubrication to the top and Bottom end. I have seen the mess made by using after run as a starting oil to get a tight engine turned over. Quote Link to comment Share on other sites More sharing options...
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