Colin Martin Posted June 30, 2018 Share Posted June 30, 2018 I have two of these engines. They have, generally, performed very well and are incredibly economical. However, both engines have recently had to go back for repair and, in each case, the exhaust valve seat had fallen out of the cylinder head. Had it happened to just one engine, I would have considered myself unlucky but now I wonder whether there is a design/construction fault with these engines. Has anybody else experienced this problem? Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted June 30, 2018 Share Posted June 30, 2018 No but I have had a valve sticking open, leading to loss of compression. Self rectified but I had a close look anyway. Valve gear looked quite dry when I took the rocker cover off. I reckon they need lots of oil in the petrol mix and the occasional few drops of oil down the valve tubes and around the tappets to keep them happy. P.S. "Incredibly economical" is an understatement. I can't believe how little fuel mine uses. Edited By Gary Manuel on 30/06/2018 22:34:50 Quote Link to comment Share on other sites More sharing options...
bert baker Posted June 30, 2018 Share Posted June 30, 2018 Been running a NGH38 for about a year,,has had loads of flights,, No running problems finger cross it will remain that way, First and second runs during running in the silencer manifold kept coming loose, I removed the gasket and used a RTV sealant, that sorted that Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted June 30, 2018 Share Posted June 30, 2018 Somewhere on here there are pics of the camshaft on the one I bought after just two tanks of fuel through it; the lobes were disintegrating. Over 1000rpm down on the spec. as well. Sent it back where it came from and got a no quibble refund. Ah, found one. Quote Link to comment Share on other sites More sharing options...
Paul Hazelgrove Posted July 1, 2018 Share Posted July 1, 2018 Just had the same thing on mine,had numerous flights with it and then wouldn't start . Strip it and found the exhaust valve seat had come out,luckily no damage and have refitted it with loctite . I'm allowing it to cure before giving it a go. Also had a broken inlet manifold which appears to be a common fault. I'm running it on valvoline synpower at 30-1. Despite the faults this engine has been perfect for my 45cc chippy and hope to carry on with it. Quote Link to comment Share on other sites More sharing options...
bert baker Posted July 22, 2018 Share Posted July 22, 2018 Hmm,my NGH 38,,,,,,,,,,, although I hadn't disturbed the exhaust manifold screws. And having many flights with this engine in another model, on completion of maiden flight with engine in its new plane, I noticed the manifold had come loose,, five minutes with some RTV sealant and retorqued screws all is well again., will be keeping a lookout for the problems reported by others, Quote Link to comment Share on other sites More sharing options...
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