Hi people,I am looking for some help with noisy engine.Its a v8 3.9 disco 1993 fitted with new cylinder block less than 15000 miles ago its been built with, new cam and followers new rings new oil pump new shells new timing chain and gears, the crank was unmarked and well within limits and the pistons were all ok.The heads were stripped and nothing found wrong other than valve lap.Its been fine until about a month back I noticed a feint knocking coming from the engine after a fairly fast run It started at about 2000rpm and went at 2500.I have since towed 1.5ton caravan through derbyshire and its getting worse.Its more noticible under loading and when engine is hot Now for the bit that throws me If I drop into 3rd and let the engine rev the noise goes and its not there for some while after changing up again,then it gradually comes back.Its definately not big end Ive just had the sump off everything was fine I have replaced the shells though as I dont like putting back used ones for what they cost.Its not piston slap or little end. I can now get the engine to make the noise when its hot on about 1000rpm sounds like something is loose or broken possibly on the nearside bank.I think it could be a sticky/faulty tappet but I have never heard one thats failed so I dont Know for sure Someone has suggested a broken valve spring again I have never had one so I dont know what that would be like. The engine doesnt lack power and has good oil pressure.I have checked all of the obvious like loose exhausts,broken mouts etc.Given the wealth of V8 knowledge thats out there I was hoping somebody may have had something similar and could point me in the right direction any help would be appreciated Thanks for taking the time to read Alan
- posted
15 years ago