revilla Posted May 19, 2019 Share Posted May 19, 2019 SV K Series VVC 160 (170bhp, 142 ft.lb.) - 5 Speed Type 9 Gearbox - AP Racing Clutch (42,000 Road Miles) - Wet Sump / Ford Clutch ForkWent on the Fish & Chip run yesterday, 140 mile drive from home to the start, reversing into the parking space at the Piercefield there was juddering and rattling. Didn't think much of it, but it deteriorated around the run and the way home in the evening it was getting pretty bad.Symptoms are:With very light clutch engagement at around idle RPM (such as when holding on the clutch briefly at a junction, or parking), car judders and shakes like an out-of-balance washing machine.As you let the clutch up further it disappears.At higher RPMs with a bit of throttle, it disappears.Once on the move everything feels fairly normal.I have noticed since getting the car out after the winter that around 4500rpm there's a buzzing vibration through the clutch pedal. It wasn't there before. Only there if you rest your foot lightly on the pedal, disappears if you ease the pressure or press a little bit harder.I took the following video by placing my mobile phone on the garage floor under the rear of the car. In the video I'm just raising the clutch to the biting point in gear with the handbrake on. The propshaft can be seen juddering badly, giving the diff a good rattling and making the noises I was hearing. In fact it shakes the whole transmission hard enough to shake the trigger in the gearbox speed sensor to the point where the speedometer starts to register when stationary. (In the video it looks like there is play in the universal joint but it's just an illusion created by the limitations of the mobile phone camera).It looks like the clutch starts to bite unevenly at some points around the rotation before others; you only get the rattle when very lightly engaged where it is sort of snagging or catching each time the engine rotates. And at around idle speed it just hits the resonant frequency of the transmission and you get a big oscillation building up.I've given the engine a good tug in all directions, doesn't look to be anything wrong with the engine mounts. I've also done the same test inducing the rattle with the bonnet off and watching the engine, it's not really moving much. There's not a lot of it coming through the gearlever either so I've no reason to suspect the gearbox mount. Diff isn't moving in that video.No other funny noises, nothing to suggest release bearing failure (it's smooth and quiet with the clutch fully depressed). Nothing to suggest gearbox issues (it's absolutely fine once on the move, feels fine in all gears, an the juddering can be induced in any gear including reverse).Current plan is to whip the engine out on June 2nd and change the clutch. New clutch will be a Helix three piece full kit (friction plate, cover and release bearing) from Redline. The current clutch is AP Racing - interestingly AP's own specs for the Caterham clutch (see Specifications tab here: https://www.apracing.com/product_details/performance_upgrades/special_tuning_clutches/vehicle_applications/caterham/k_series/ford_variants.aspx) give the Torque Capacity as 136 Nm / 100 ft.lb. - many Ks will be exceeding that, my last dyno run was 142 ft.lb., my engine was already exceeding 100 ft.lb. at 1500rpm and I've had a map upgrade since then so the AP plate was a bit under-specified.Will do a bit of a post mortem once it's off. Will have a spare rear crank seal handy just in case we find any signs of it weeping oil into the clutch. If the flywheel is damaged I can rob one from a spare engine.Before I start pulling my engine out (again!) ... anything I could be missing? Anything else I should be checking first that I've missed? Link to comment Share on other sites More sharing options...
anthonym Posted May 19, 2019 Share Posted May 19, 2019 Nothing unpleasant (oil) dropped through the clutch release arm aperture any time in the past? Friction issue.No letting the clutch out when the car was moving in the opposite direction? (Dislodged spring).. Clearly the CRA itself is bullet proof. Link to comment Share on other sites More sharing options...
revilla Posted May 19, 2019 Author Share Posted May 19, 2019 Not that I know of. Boot is place and fits nicely. Boot looks clean and dry and hasn't been off in a while. Link to comment Share on other sites More sharing options...
CageyH Posted May 20, 2019 Share Posted May 20, 2019 I have seen symptoms like this due to a dodgy clutch release bearing. We thought it was the dual mass flywheel failing until we went to change the parts. So I would not rule that out yet. Nothing else on the engine side shoukd cause that issue. Unfortunately, it looks like the engine is going to have to come out, so a pressure plate failure should be easy to identify. Link to comment Share on other sites More sharing options...
rj Posted May 20, 2019 Share Posted May 20, 2019 Mine did somthing similar when the friction plate gave up. Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 20, 2019 Share Posted May 20, 2019 The original plate in mine disintegrate with 2/3rds of one side letting go. Lots of vibration and difficulty changing gear.I confirmed this by poking a metal rod into the bellhousing with gaffa tape on the end (sticky side out) and fished out a piece of friction lining. Link to comment Share on other sites More sharing options...
revilla Posted May 20, 2019 Author Share Posted May 20, 2019 Thanks all.Ian, I don't think mine has gone that far yet. Pulling away with a few more revs is fine and once on the move, gear changes are no issue at all. But I think it's a clear warning sign that it's on the way out, so engine out it is. Again. It's like doing the Hokey Cokey with my engine ... in, out, in, out, shake it all about!Got a mate coming up on 2nd June to help so will have an extra pair of eyes and hands. Onwards and upwards.Andrew Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 20, 2019 Member Share Posted May 20, 2019 Sense now checked: intact.Which is just as well for the rest of us. :-)Is John Vine's homework on CRBs relevant to your new kit?Jonathan Link to comment Share on other sites More sharing options...
revilla Posted May 20, 2019 Author Share Posted May 20, 2019 Hi Jonathan, Re: 3 - The creepy thing I was just wondering that when your message arrived! No idea, I may check with Helix. At the moment I don't have the preload springs, they are however on my short-term To Do list and I was just wondering whether the Helix CRB would need the same preload. Will let you know if and when I get a reply. Andrew Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 20, 2019 Member Share Posted May 20, 2019 First sentence of Sonnet 116, innit?:-)Jonathan Link to comment Share on other sites More sharing options...
Scotland North AR Posted May 20, 2019 Share Posted May 20, 2019 Worth checking/changing the spigot bearing at the same time. The failure of this £8.50 bit nearly stopped me getting to Spain last October! Gave the impression the clutch had gone, which it hadn't, couldn't get any gears in a petrol station car park.Premier Power changed it Saturday night Sunday morning so just made the ferry! Link to comment Share on other sites More sharing options...
thompster Posted May 20, 2019 Share Posted May 20, 2019 Don't underestimate how bad a clutch can be and still work. This half-a-clutch was working fine, other than a slight buzz through the pedal as the clutch disengaged.. Link to comment Share on other sites More sharing options...
revilla Posted May 20, 2019 Author Share Posted May 20, 2019 Wow ... I'll report back what I find! And yes I will check the spigot bearing. Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 20, 2019 Share Posted May 20, 2019 Thats how mine looked! Link to comment Share on other sites More sharing options...
Area Representative paul richards Posted May 21, 2019 Area Representative Share Posted May 21, 2019 Broken spring in my clutch gave similar symptoms. Link to comment Share on other sites More sharing options...
Nigel Riches Posted May 22, 2019 Share Posted May 22, 2019 If the car has been stored over winter there may be a bit of corrosion where the friction plate has been in contact with the cover, however this would usually disappear quickly with a bit of use, next most awful reason might be a broken spring in the cover assembly, doesn't sound like a lot of fun, especially with summer big on the horizon.Nigel. Link to comment Share on other sites More sharing options...
revilla Posted May 22, 2019 Author Share Posted May 22, 2019 Thanks. The car has done 1000 miles already since I got it out of the winter layup so I would have expected any corrosion to have polished off long ago. Yes I'm expecting (hoping) to find something obviously broken in the clutch. No worries on the approaching summer, I've got a friend coming up on 2nd June to give a hand and with two of us we should get a clutch change done in the day. Link to comment Share on other sites More sharing options...
rj Posted May 22, 2019 Share Posted May 22, 2019 In the day...How many tea and beer breaks does that include? I was hoping to replace the crankshaf seal in less than five hours. Maybe I'm naive... Link to comment Share on other sites More sharing options...
revilla Posted May 22, 2019 Author Share Posted May 22, 2019 Haha well we shall see! I've got a day to do it, if we get it done quicker all the better. Link to comment Share on other sites More sharing options...
John Vine Posted May 23, 2019 Share Posted May 23, 2019 Sorry to hear of your troubles, Andrew.To me, it doesn't seem like a disintegrating CRB, as the classic symptoms are squealing and vibration as you depress the clutch pedal. Rather, my money is on either (a) partial failure of the friction material on the driven plate (due to loss of material or oil contamination), or (b) a damaged/broken diaphragm spring.Either way, it's engine-out time, I'm afraid. If it proves to be loss of friction material, I hope your flywheel isn't scored....I was just wondering whether the Helix CRB would need the same preload.I'm not familiar with the Helix product, but given that modern CRBs are intended to run in constant contact with the diaphragm springs, I'd say that some sort of pre-load would be essential -- and probably in the range 50-120Nm. If you appreciate a horror story, this is what total driven-plate failure looks like (on my R400D).JV Link to comment Share on other sites More sharing options...
revilla Posted May 23, 2019 Author Share Posted May 23, 2019 Hi John,Thanks for the input and the pictures. To be honest I'm just looking forward to getting on with it now, I'm missing this lovely weather! I'm away this weekend so lined up for next Sunday. Nice new Helix clutch kit now in my hands. I'm not too worried about the flywheel. One advantage of not having a lightened flywheel and running the OEM on is ... they're about £25 on eBay! I've actually got two good ones on spare engines and one on the shelf, and I've ordered in some new flywheel bolts just in case, so if the flywheel is damaged it will just get changed while we're at it.Once I've got it back on the road I think I'll do your preload mod. I've got your excellent article as a PDF thanks. The release bearing looks very similar to the standard one in design so I'm sure it's designed for "constant contact" in the same way.I'll post up pictures of whatever I find!Andrew Link to comment Share on other sites More sharing options...
John Vine Posted May 24, 2019 Share Posted May 24, 2019 Looking forward to seeing the photos!Re the pre-load mod, CC told me recently that spring CQ13 is unavailable as the supplier is no longer in business. So, you'll need to find an alternative.JV Link to comment Share on other sites More sharing options...
elie boone Posted May 24, 2019 Share Posted May 24, 2019 D Faulkner spring would be my first port of call. The worst clutch i have seen ( not on a 7 ) only had the center piece left, often this sort of clutch failure is due to engine braking. Link to comment Share on other sites More sharing options...
revilla Posted June 2, 2019 Author Share Posted June 2, 2019 Clutch changed today as planned.And the fault was ...The clutch cover plate was just ripping apart! The friction plate was fine, the CRB was basically OK but the carrier was worn where it clips into the fork (presumably from the vibration of the clutch failing) but the cover plate was just a mess of cracks and fractures. I know my engine is producing a lot more torque after all the work I've done on it but I didn't expect that!Nice new Helix system fitted now, friction plate, cover and release bearing as a set and everything feel silky smooth again.Let's hope this holds up! Link to comment Share on other sites More sharing options...
rj Posted June 2, 2019 Share Posted June 2, 2019 That shouldn't happen!It's the same cover used in an R500.My own friction plate gave up after some 14k track miles which I reckon is harder work than road ditto. Link to comment Share on other sites More sharing options...
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