AdamQ Posted June 18, 2008 Share Posted June 18, 2008 Morning all, I have a rattle and any ideas as to the cause would be appreciated. I'd describe it as a medium-frequency metallic rattle - a classic rattle to my mind. The car is a recent 2.0 l Duratec conversion with a new (well, reconditioned) gearbox. The rattle occurs in all forward gears (I haven't checked reverse) at 2800 rpm and then disappears fairly soon after that (difficult to tell how quickly as the engine noise obviously increases). The rattle does not occur if one sits in the car and revs it to 2800 rpm whether in neutral with foot off the clutch or in gear with foot on the clutch (I've also dipped the clutch whilst in motion at the point the rattle arises and it goes away (though this is slightly vague as obviously the engine speed increases quite rapidly when the clutch is dipped). The rattle hasn't been there since the completion of the conversion - it cropped up after the car had completed a rolling road session and about another 100 or so miles. Specifically, it came on after a short blast down a straight section of dual carriageway. As I say, any thoughts would be gratefully received. Cheers, Adam Link to comment Share on other sites More sharing options...
Markiebabes Posted June 18, 2008 Share Posted June 18, 2008 Adam may be worth doing a spanner check to make sure nothing worked loose on R/R session ? Mark R400 MW 203 bhp of pure fun( more so with Aero fitted ) Link to comment Share on other sites More sharing options...
TomB Posted June 18, 2008 Share Posted June 18, 2008 Ive had similar at 3500-4000 rpm and think Ive narrowed it down to a rattley silencer. Unfortunately, it 10 years old not repackable and very loud - I think its probably had its day! Link to comment Share on other sites More sharing options...
AdamQ Posted June 18, 2008 Author Share Posted June 18, 2008 Thanks Mark. I've had a good poke around and have done a bit of pushing and pulling of various components, but I'll do as you suggest as I can't claim to have made a completely thorough and methodical check. (203 is a good number - that's what mine is!) Thanks Tom. Sorry to hear about your silencer. Hopefully mine is OK as it's new, though stranger things have happened I guess ... I'll get my stethoscope out! Adam Link to comment Share on other sites More sharing options...
Dickie Normuss Posted June 18, 2008 Share Posted June 18, 2008 Past experience on mine says check: Alternator isn't loose Fan shroud is secure Bonnet isn't vibrating Spark plug cover if the Duratec has one? VX HPC - Loud and proud here Watch out, whatever hits the fan will not be distributed evenly Link to comment Share on other sites More sharing options...
MTH Posted June 18, 2008 Share Posted June 18, 2008 I had something similar. Turned out that at certain revs the bonnet would resonate and rattle against a jubilee clip attached to one of the heating hoses. I only found it because of tell-tale marks on the underside of the bonnet. Mark Mark -----Waitin' on a sunny day Gonna chase the clouds away Link to comment Share on other sites More sharing options...
AdamQ Posted June 18, 2008 Author Share Posted June 18, 2008 Thanks Ric and Mark. The fan shroud is a good suggestion - hadn't thought of that. The alternator seems secure when wiggled by hand, but I'll take a spanner to it. The rattle happens without the bonnet in place and there is no spark plug cover on the Duratec (well, not on mine anyway - sort of wish there was as a search of the archives suggested that was favourite to be the cause!). Adam Edited by - AdamQ on 18 Jun 2008 11:28:18 Link to comment Share on other sites More sharing options...
Miura Posted June 18, 2008 Share Posted June 18, 2008 throttle cable? I had a resonance at a set RPM value and it was the cable rubbing the bonnet ... Link to comment Share on other sites More sharing options...
AdamQ Posted June 18, 2008 Author Share Posted June 18, 2008 Thomas, thanks for the suggestion, but the rattle's there when the bonnet is removed and the throttle cable doesn't really come into contact with anything else. Adam Link to comment Share on other sites More sharing options...
Graham King Posted June 18, 2008 Share Posted June 18, 2008 Adam, hi, I hope the Duratec conversion has worked out as well as you hoped. Is this in all gears or just in top, if only in one gear presumably you can rule out the drive train. Have you checked all the dzus as presumably the nosecone would have been removed during the rolling road session. Was anything else removed during the RR session, air filter, air box. You could try putting the rear end on axle stands and running it in gear at correct revs (carefully) to see if you can reproduce it whilst the car is stationary, you will probably have more chance of finding it then. Good luck. Graham. R7 GPK Superlight #85 Link to comment Share on other sites More sharing options...
AdamQ Posted June 18, 2008 Author Share Posted June 18, 2008 Hi Graham, good to hear from you - I hope all's well. The rattle occurs in all forward gears (I haven't checked reverse yet!) at the same RPM so I don't think the drivetrain can be ruled out yet. The only things removed for the RR session were the nosecone and the bonnet (and a heater hose was removed during the session by the car itself resulting in a lot of steam and a small heart attack for the loving owner!). Both bonnet and nosecone have been off and back on many times since the RR and I hope I'd have got the dzus secured correctly at least once, but I will check! TBH, I'd have said that it was a stronger rattle that one would expect from something like a dzus or the throttle cable. I appreciate that there's a difference between what's going on in and around the engine when a stationary engine is revved and when things are under load, but I have a nagging feeling that you might have a point about the drivetrain. The noise seems (I find it desperately difficult to tell precisely) to come from around the bulkhead area which doesn't rule out the fore section of the drivetrain. Your suggestion about axle stands has lit a big - I'd got as far as thinking of talking nicely to Steve at the RR, but it hadn't occurred to me that I could do as you suggest - I'll give it a go. The conversion has definitely worked out well. The work was done over at John Howe's and it was a lot of fun (most of the time!) and the result is well worth it - a comprehensive write up is in the pipeline ... Cheers, Adam Link to comment Share on other sites More sharing options...
Graham King Posted June 18, 2008 Share Posted June 18, 2008 Adam, what I meant by saying the drivetrain is out the equation is that if it happens in all gears the drivetrain is turning at different speeds in each gear so is less likely to be the cause, if it happens at a fixed RPM range then the only thing that is constant is engine and asociated ancilliaries vibration and the effect they have on their surroundings. Would be good to hear how it all went and what you feel the effect over the K-Series is. Graham. R7 GPK Superlight #85 Link to comment Share on other sites More sharing options...
AdamQ Posted June 18, 2008 Author Share Posted June 18, 2008 Graham, thanks again - Apologies, I seem to have muddled things up nicely so I'll clarify the facts. The rattle happens in all five forward gears at the same RPM (about 2800). With the car at a standstill, there's no rattle if one simply revs the engine to 2800 RPM either with the car in neutral and foot off the clutch or with the car in gear and foot on the clutch. This suggests to me that the rattle is not directly related to the engine and the ancilliaries (though I don't think it rules them out completely because of the differences there must be between a loaded and an unloaded engine). To me (and this is perhaps how I've muddled things) the drivetrain sort of starts from the back face of the flywheel and so the speed of some elements of the (my!) drivetrain matches the speed of the engine rather than the speed of the wheels. Those elements would be the clutch and gearbox input shaft I guess? Anything else? I've run out of mud to stir into this particular pool of water, so I'll have to stop ... Adam Link to comment Share on other sites More sharing options...
akakubi Posted September 18, 2008 Share Posted September 18, 2008 Adam, have you had any luck with the rattle? Mine has developed a similar one (R400 Duratec). It seems to be coming from the passenger side somewhere, but I cannot pinpoint where exactly. The rattle, which sounds more like a loose nut bouncing around, happens in all forward gears at around 2500RPM to about 3500RPM (maybe more, but I can't hear it over the noise). I checked all of the components (by hand) and nothing is loose. The rattles is not there when the car is stationary (i.e. revving in neutral). I did find the plug cover loose (all bolts were out, I have no idea how it still held in place 😳), but after fixing it back, the rattle is still there. It drives me nuts, to be honest. ☹️ On a side note, I have an "old couch" squeak from the passenger rear side as well on bumpy roads. I re-lubed the sway bar and it went away for a while, but it is back again. Is there a fix for it or do I have to grease the bushings after each track day. 😬 cheers Link to comment Share on other sites More sharing options...
AdamQ Posted September 18, 2008 Author Share Posted September 18, 2008 akakubi, The short answer is no, I haven't had any luck - the rattle is still there. Your symptoms do indeed sound very similar to mine. A number of expert ears have listened to the rattle and we're homing in the clutch/gearbox. In an effort to reduce footwell temperatures, I cut the gear stick and handbrake gaiters out of an old tunnel top and replaced them with some perforated material (actually the lining out of a cheap pair of tracksuit bottoms - the material is ideal). Having done that and effectively removed some sound insulation, I'm beginning to think that the rattle is coming from the gearbox. This weekend I'm planning to remove the tunnel top and get a passenger to have a listen to the gearbox with a stethoscope (obviously taking great care that nothing gets near the propshaft). If that doesn't get me any further forward, I think I might get one of these and give it a try. I'll keep you posted - let me know if you find the cause of yours. Cheers, Adam Link to comment Share on other sites More sharing options...
akakubi Posted September 18, 2008 Share Posted September 18, 2008 Cheers! If it is inside the gearbox, then it may be serious. I hope it is rather (fingers crossed) something like a loose gear lever fitment or a fault in the rubber bushing holding the gearbox in place... Looking forward to seeing how you progress with it. Val Link to comment Share on other sites More sharing options...
Richard Ryland Posted September 18, 2008 Share Posted September 18, 2008 Sounds silly but my (what sounded like) serious rattle turned out to be a pound coin under the passenger tillet. Good Luck. Richard Link to comment Share on other sites More sharing options...
akakubi Posted September 18, 2008 Share Posted September 18, 2008 That would be great indeed Now I need to check under the seat more carfully. 😬 Link to comment Share on other sites More sharing options...
AdamQ Posted September 25, 2008 Author Share Posted September 25, 2008 Val, apologies - I promised an update after the weekend. I'm afraid the truth is that I'm no further forward. Beyond just driving the car I didn't get a chance to investigate further. No. 1 suspect by a nose is still the gearbox and I did take the tunnel top off yesterday in the hope that I might just be able to remove the cover plate and have a look - no chance though - the cover plate is much further forward than I envisaged/remembered. So I'm afraid it's another "I'll keep you posted". Adam Link to comment Share on other sites More sharing options...
Andy Whittle Posted September 25, 2008 Share Posted September 25, 2008 What about the electronic speed sensors on the driver's side of the gearbox, it could be in contact with something or the "top hat" connector is loose? I am Leg End... Link to comment Share on other sites More sharing options...
Pete-B Posted September 25, 2008 Share Posted September 25, 2008 Hi Adam, I had a rattle that drove me mad for nearly a year. I could never place where it was coming from, sometimes it seemed from under the bonnet and sometimes from the cabin, lets face it a car can act like a sound box at times. I put cable ties on everything that could possibly move or vibrate inside, outside and under all to no avail. By accident, one day, I bounced back in the seat and there was that noise. To cut a long story short I took the seat out, put two strengthing brackets under the car so the four seat retaining bolts passed through them and hey presto absolute heaven. Peter Link to comment Share on other sites More sharing options...
mav Posted September 25, 2008 Share Posted September 25, 2008 Do you carry a spare? Check the big nut on the inside of the rear skin that holds the boss that the bar fixes to that holds the spare on... Link to comment Share on other sites More sharing options...
AdamQ Posted September 25, 2008 Author Share Posted September 25, 2008 Thanks Andy, thanks Peter, and thanks Mav. All most useful suggestions and I'll be checking them tomorrow evening. I do remember a nut or a washer or something being missing when I put the seat back in and having to use an inferior substitute so maybe something has worked loose there. I don't carry a spare, but the big nut inside the rear skin is still there so ... Thanks again, Adam Link to comment Share on other sites More sharing options...
Anton Posted September 25, 2008 Share Posted September 25, 2008 AdamQ - LE0 has developed a rattle similar to yours, but at lower revs (1500-2000) and in all gears including reverse and neutral, whether the car is moving or not. Like you, I've taken the bonnet off and it still rattles. My wife thinks it's the exhaust - but that's solidly in place (unless, as suggested, it's something loose inside) - so I'll be following your thread with interest to see if it offers me any clues. By the way. LE0's a K, and hasn't had any mods to engine/gearbox/drivetrain. LEO 3eggs Another Slightly Vider SeVen Link to comment Share on other sites More sharing options...
AdamQ Posted September 25, 2008 Author Share Posted September 25, 2008 Crikey - the pressure to find the cause mounts! I shall redouble my efforts. In my searches, I found this post here, which describes almost identical symptoms. Is anybody still in touch with Eddie Guest and, if so, please would they find out whether or not he ever found the cause of his problem! Adam Link to comment Share on other sites More sharing options...
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