RogerB Posted September 25, 2019 Share Posted September 25, 2019 Further to the recent thread on 'K Series Let Go', which I have just read with increasing levels of anxiety, my 1.6 K series engine has developed an unusual noise from the exhaust side during the Croft Trackday. I thought I had cured this by the simple expedient of removing the heat shield which I'd wrapped round the starter motor. Flushed with success I took the car round to my pals who had also witnessed this noise at Croft. We both agreed it had gone. Sadly a couple of weeks later I started up to check her out for my last track day of the season at Knockhill to find the noise has returned. I then removed the starter motor and bump started down the drive - noise still present. I've had the cam cover off and spark plugs out - nothing untoward there.My best description is it sounds like marbles bouncing on a tin tray coming from the exhaust side of the cam box. I have just received a copy of Rover K Series, Maintenace, Repair and Modification by Iain Ayre and Rob Hawkins.However it would be good to get the opinion of our K Series experts before I go any deeper.Roger. Link to comment Share on other sites More sharing options...
Sim Posted September 25, 2019 Share Posted September 25, 2019 Exhaust manifold touching the chassis?Simon Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 Do you get this noise at idle or under load? Can you record it, maybe upload to YouTube? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 25, 2019 Member Share Posted September 25, 2019 As above, recording please.How about making or buying a stethoscope to help localise the source? And can you reduce the sound by holding eg a piece of wood against likely sources?Jonathan Link to comment Share on other sites More sharing options...
TomB Posted September 25, 2019 Share Posted September 25, 2019 A few things it could be that don't mean impending doom: water rail rattling, loose manifold, manifold touching chassis, spark plug cover, loose spark plug? Do you have hydraulic or mechanical tappets? A top tip for listening is a long, wide screw driver held with the handle in your ear and the pointy end on the engine. You'd be amazed what you can hear inside the engine, and allows problems to be quite accurately located. Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 Also, does it do it cold, hot or both?Any other running symptoms, or is it just the noise? Performance same as it always was?Just a few random stabs in the dark of things to check:Exhaust headers all secure?It's definitely not coming from the alternator?If it's a distributor type engine, everything secure around / inside the distributor? Probably unlikely but an easy check.Cam belt feels reasonably tensioned (i.e. not flapping about) and is undamaged (I've seen a belt with frayed bits hanging off the edges making an almighty rattling as the flailed about). I've also seen an engine where somebody ( ) hadn't torqued up the cam belt tensioner and that made a clanking rattle that might fit your description. Easy to take the upper front cover off for a look if there's anything obvious.If it's got vernier pulleys on the cams, are they secure? Nothing to suggest the cam pulley centre bolts are coming loose?Sometimes a stethoscope lets you pinpoint the source of a rattle more easily - I'm thinking a long screwdriver and a tin can! Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 Posts crossed - a lot of common ground! Link to comment Share on other sites More sharing options...
TomB Posted September 25, 2019 Share Posted September 25, 2019 Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 I'm just glad you made it clear that the point end doesn't go in your ear Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 25, 2019 Member Share Posted September 25, 2019 "It's coming from somewhere in the boot."Jonathan Link to comment Share on other sites More sharing options...
TomB Posted September 25, 2019 Share Posted September 25, 2019 Believe it or not, I did actually learn that tip from Johann the Ghost. Link to comment Share on other sites More sharing options...
RogerB Posted September 25, 2019 Author Share Posted September 25, 2019 Thanks for such prompt responses. Some of the suggestions I have covered. I will investigate other suggestions and see if I can upload a U tube recording. The sound occurs hot or cold however does seem to reduce when revs increased offload.I'd love a quick and easy fix that would get me to tomorrows track day at Knockhill ! Link to comment Share on other sites More sharing options...
SM25T Posted September 25, 2019 Share Posted September 25, 2019 Manifold to head nuts tight ? ... tight, not gorilla thread-stripping tight. Link to comment Share on other sites More sharing options...
RogerB Posted September 25, 2019 Author Share Posted September 25, 2019 I have now recorded and posted U tube clip however I can't seem to paste the link in here.I have titled it as 'Caterham engine unusual sound'The lower pitch and lower frequency sound is normal and clears when clutch depressed.So I have now checked:-Starter motor - Run Engine with motor off.Alternator - Run engine with drive belt slack.Exhaust manifold - For tightness, leaks, contact with chassis/Body. (I once had a metallic sound on my Griffith 500 which had a blown manifold gasket - different to this sound though)Cam belt cover off - All tight and belt in good order.Listened with long screwdriver - Can only hear the usual sound of tappets (By the way I like the photo of the Marine Engineer, especially as I'm a retired Marine Engineer, although we never wore Steaming Bonnets in my time)Spark plugs - Looked good apart from a little sootie with pale brown tips (Running a little rich I guess)Distributor - So far unable to loosen one of the distributor cap screws as the column on top of the bell housing dry sump tank restricts access with my screwdriver. Link to comment Share on other sites More sharing options...
RogerB Posted September 25, 2019 Author Share Posted September 25, 2019 Oh I also forgot to mention:Mechanical tappets.No loss of power or other abnormal running.However and this may be a red herring - During my Croft track day I tried to accelerate in 2nd out of the hair pin and the engine just temporarily died. I thought I was going to have to coast onto the grass until I restarted, checked for oil pressure and temp which where fine so continued with no re-occurrence. It was at the end of this day that we noticed the sound which can't be heard when on the road. I also drove the 250 miles home to Scotland with no other abnormalities. Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 Ooh err that doesn't sound healthy! I know that's not a great help but I'm not quite sure what to suggest. It sounds a lot harder and more mechanical than I imagined. I'd be tempted to wonder about a broken valve spring or something, but I would imagine you would notice that running. Link to comment Share on other sites More sharing options...
revilla Posted September 25, 2019 Share Posted September 25, 2019 If it has solid lifters, does it have double valve springs by any chance? If so I could possibly imagine one spring of a pair being broken and it still running reasonably well, especially at low RPM, on the other spring. Just a stab in the dark really ... hopefully somebody will have heard that before and will be along to tell us shortly, I'm as intrigued to know as you are now! Link to comment Share on other sites More sharing options...
Wrightpayne Posted September 25, 2019 Share Posted September 25, 2019 The only noise I’ve had from that vicinity is one of the primaries rattling in the collector.That sounds a hole different level of mechanical noise. Me thinks a strip down is needed.Ian Link to comment Share on other sites More sharing options...
TomB Posted September 25, 2019 Share Posted September 25, 2019 It’s very quick and easy to take the cam cover off. You could turn the the engine over my hand and see if there is anything remiss there? Link to comment Share on other sites More sharing options...
RogerB Posted September 26, 2019 Author Share Posted September 26, 2019 Ok thanks guys and that was also my line of thought. I don't suppose its possible to change a valve spring without removing the cyl head. I once recall a Cummins Service Engineer changing a valve spring on a K19 generator engine without lifting the head.It could well be double valve springs as its a high speck Steve Parker racing engine kicking out 190 BHP at 7200 RPM.. Unfortunately Steve Parker had passed away before I bought the car and I don't have any build spec for it.I will have to start reading my new K Series Engine book in ernest. Also Toms suggestion of turning over by hand with cam cover off sounds good.So that's me off to Knockhill with my pal as a passenger. The newly formed Leven Sports car Club have been running these all summer as a marketing event. Hopefully I'll get some hot laps in an Aston Martin or Zenos.. Then back to work on mine. Link to comment Share on other sites More sharing options...
RogerB Posted September 26, 2019 Author Share Posted September 26, 2019 I wonder if there is a way of identifying the spring of perhaps best to change the full set. Link to comment Share on other sites More sharing options...
revilla Posted September 26, 2019 Share Posted September 26, 2019 With the K Series the springs are underneath the lifters set deep into the head under the cams, the only way to get at them is to at least remove the cam ladder. Although there are supposedly tricks to remove valve springs with the head on the car (compressed air or rope down the plug holes) if they do work I think they would be more trouble than just taking the head off and using a regular valve spring compressor. Once you've reached that stage it will be clear what has gone and you might as well inspect everything. Link to comment Share on other sites More sharing options...
p.mole1 Posted September 26, 2019 Share Posted September 26, 2019 Hi Roger if you check the video no 2 spark plug lead cap is wobbling around have you checked the plugs carefully I have known them to break and leak. What is your oil pressure like, if its low it's possibly an indicator of bearing damage. That's not always the case my engine let go and it was showing 60 psi ! Are you using forged pistons it could be piston breaking up.That said check all the simple stuff first Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 26, 2019 Member Share Posted September 26, 2019 Have you got the URL, please, Phil?ThanksJonathan Link to comment Share on other sites More sharing options...
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