Leadership Team SLR No.77 Posted May 24, 2011 Leadership Team Share Posted May 24, 2011 Still doing the engine rebuild and I'm storing a few bits under the car ......... accidentally I kick something so kneel down so sort it and catch the FIA key switch ........... which is balanced on the chassis rail because the scuttle's not fitted ........... which then unknown to me shorts to the chassis without the usually spectacular array of sparks ....... Next I know (still kneeling down with head under car) is my son walking in with TomB telling me the car is on fire Oh yes I thnk, pull the other one No really it's on fire .......... the clutch cable is alight where it connects to the clutch arm 😳 😳 😳 ..... blow out the flames and it's burnt through leaving a half inch gap Bl%%dy H£ll 😳 So what to check? I've reset the Optimate conditioner and it appears okay. ECU not connected due to +ve feed being disconnected (I'm renewing the connection). Ignition key not in, but cut-out key was. Alternator? Immobilser? Stu. Link to comment Share on other sites More sharing options...
Domus Posted May 24, 2011 Share Posted May 24, 2011 I know you were looking for a heater but...................... I hope all is well Link to comment Share on other sites More sharing options...
oilyhands Posted May 25, 2011 Share Posted May 25, 2011 I have your engine bits back from the balancers drift> Hope the damage isnt too bad.. Oily Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 25, 2011 Author Leadership Team Share Posted May 25, 2011 Thanks Dave, and I thought a thread drift was a type of stud extractor I can only assume that having put the full current from the battery through the chassis, the clutch cable became the "fuse" in the circuit! It's actually quite interesting to see a cable of that thickness glow, catch fire and then there's a gap where there was originally steel cable I'd love to know the rating of the "fuse" I just blew! If the bits aren't in the way I'll leave them for now otherwise I'll collect them when passing. The rest of the "other" engine can wait till later in the year! Stu. Link to comment Share on other sites More sharing options...
metal mickey Posted May 25, 2011 Share Posted May 25, 2011 Don't understand your post - was the battery connected or not? If not how did a short circuit happen? Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 25, 2011 Author Leadership Team Share Posted May 25, 2011 The battery was connected and the battery master switch key was switched to "on", no ignition on though. Without the scuttle fitted, the battery master switch was resting on the chassis top rail, on it's plastic body. I knock it and the live terminals made contact with one of the captive bolts in the top rail that would normally secure the scuttle, hence the short circuit. I really ought to make up a small bracket to hold the battery master switch when the scuttle is removed! Stu. Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted May 25, 2011 Area Representative Share Posted May 25, 2011 I really ought to make up a small bracket to hold the battery master switch when the scuttle is removed! Or simply disconnect the battery!!! Stu I've learnt over many years to disconnect the battery before starting most jobs. It's easy on the 7 - you don't have to re-set radios, clocks etc. Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted May 25, 2011 Share Posted May 25, 2011 I think if you're mucking about with wiring flapping about, disconnecting the battery should be the first thing you do. I disconnect it every time I do anything anyway, just in case 😶🌫️ Hope it's just the clutch cable that's burned, at least it's not an expensive mistake Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 25, 2011 Author Leadership Team Share Posted May 25, 2011 I'm passed that stage Paul - the battery had been removed completely for months but now it's back in place because I'm setting up the ECU, testing all the wiring that's been renewed etc. It's all safe excepting the battery master switch which unfortunately is unsupported without the scuttle! A suitable temporary bracket would be a little like a cam-locking tool .... you don't "need" one but your asking for trouble without it! Stu. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 25, 2011 Author Leadership Team Share Posted May 25, 2011 John see above Link to comment Share on other sites More sharing options...
Drumster Posted May 25, 2011 Share Posted May 25, 2011 The only time I take the scuttle off is to do something electrical behind the dash, which ultimately means I need electrickery. However, I tend to disconnect the battery first, take the scuttle off and then wrap the BMS in rollbar padding before connecting the battery again. Still have burn marks on the sideskin where it folds over under the scuttle, been there, done that, but with less dramatic results. Phew! Stu, I like your idea of making a bracket to 're-mount' the BMS though Link to comment Share on other sites More sharing options...
Johnty Lyons Posted May 25, 2011 Share Posted May 25, 2011 Mr Foreshaw SIR what you need to do and still need to do is disconnect the + main battery cable and place between it and the battery a small piece of cable with an inline fuse That allows you to do ALL the testing you want in complete safety Consider yourself reprimanded and go stand in corner 😬 😬 😬 Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 25, 2011 Author Leadership Team Share Posted May 25, 2011 {stood in corner hanging head in shame mode on} Sounds like a good idea And not just for my car! Any thoughts on a suitable fuse holder and rating (or trip switch?) because it'll need to be enough to allow for everything that comes from the battery. I guess there's something designed for motorsport purpose made for the job? Stu. {stood in corner hanging head in shame mode off} Link to comment Share on other sites More sharing options...
TomB Posted May 25, 2011 Share Posted May 25, 2011 You need to disconnect the battery. Link to comment Share on other sites More sharing options...
naddy Posted May 25, 2011 Share Posted May 25, 2011 I am amazed that nobody has suggested disconnecting the battery Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 25, 2011 Author Leadership Team Share Posted May 25, 2011 You guys need to get to Vision Express ....... it's impossible to test electrical circuits without the battery connected Maybe that's the problem your having with your car Tom? Stu. Edited by - sforshaw on 25 May 2011 16:45:48 Link to comment Share on other sites More sharing options...
Johnty Lyons Posted May 25, 2011 Share Posted May 25, 2011 I suggest one of the wired fuse holders on this pagehere If you mail me your addresss I'll post you one from work tomorrow we've dozens of the blighters. Link to comment Share on other sites More sharing options...
tbird Posted May 25, 2011 Share Posted May 25, 2011 What about one of these, would allow you to quickly route through fuse when working on electrics then quickly revert to high current when needed, can be easily removed when not working on car Discarnect I know it gets 2 crappy reviews but the one I have permanently fitted to Audi went on without problems and works fine to isolate battery, I use without fuse to stop battery draining when on Holiday Tim Edited by - tbird on 26 May 2011 00:09:17 Link to comment Share on other sites More sharing options...
Tom White Posted May 26, 2011 Share Posted May 26, 2011 A bit strange this one, where is the main battery - line connected? On mine it goes directly to the engine block with a second small connection to the ECU. Normally a second large ground cable is connected to the chassis from the engine block. This being the case current will want to flow down the path of least resistance which is normally the chassis, touching the main +12V to anywhere were there is good connection will tend to spark as contact is made. In your case it appears to have avoided shorting to the chassis, but found a path to the bell housing via the clutch cable. It would have probably found ground where the clutch lever arm contacts the bell housing the highest resistance being probably the thinnest point on the clutch cable. There is probably good contact between the cable itself and its outer carrier so it would have been a good conductor. It could be that the engine block to chassis connection is not good. All the above assumes that your isolation switch only isolates the + side. As the cable burnt and separated, there is a good chance that there is no secondary damage (no other path found as the cable resistance went up). All very strange Good luck Tom Link to comment Share on other sites More sharing options...
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