virden Posted September 29, 2011 Share Posted September 29, 2011 I fluffed a gear change and buzzed my std 1700X to an indicated 7500 yesterday. (Caterham rev counter probably over reading?) Every thing seems alright and still working as it was. Are there any visual checks I should make- for broken valve springs etc? Or just light another candle in thanks to St Makepiece, the patron saint of bodgers? Link to comment Share on other sites More sharing options...
6speedmanual Posted September 29, 2011 Share Posted September 29, 2011 If it all sounds ok, keep driving! Peter Link to comment Share on other sites More sharing options...
andy couchman Posted September 29, 2011 Share Posted September 29, 2011 7,500 should be OK - but maybe don't do it too often. I used to have my car set at 7,500 but have now cut that to 7,000. You just never know whether you will always be able to get away with it or whether the engine will say 'no' at some point. Meantime, if its sounds OK (i.e. rattly, noisy) and is belching smoke and leaking oil as usual then it probably enjoyed it! Andy Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted September 29, 2011 Area Representative Share Posted September 29, 2011 Meantime, if its sounds OK (i.e. rattly, noisy) and is belching smoke and leaking oil as usual then it probably enjoyed it! 😬 GJT (Crossflow AX owner) Link to comment Share on other sites More sharing options...
Graham Sewell Posted September 29, 2011 Share Posted September 29, 2011 Did this once myself. Motorway slip road, 3rd gear at 6000rpm, hit 2nd instead of 4th. Massive scream from car, same from me! Watched revs drop away from what I can only guess was 9000rpm. Paranoia mode on, thought that the engine sounded a little odd, but settled in a few hundred yards. Been fine for the last 8 years! Link to comment Share on other sites More sharing options...
virden Posted September 29, 2011 Author Share Posted September 29, 2011 Thanks guys, my wallet is feeling much less doom ladened.... think I shall go out for blat to perfect that gear change...ooops! Link to comment Share on other sites More sharing options...
Eugene Posted September 29, 2011 Share Posted September 29, 2011 I have my old X-Flow rev-limited at 7200... Was fine, until the crank blew apart on the M25. But I had done some 80K miles by th4en 😬 😬 😬 Link to comment Share on other sites More sharing options...
Sheds Moderator Posted September 29, 2011 Share Posted September 29, 2011 If it's still running sweetly, don't worry. You may have taken a few thousand miles off the life of the thing, or not. Either way if there's no damage now then just enjoy it. After all, you can't go back. Link to comment Share on other sites More sharing options...
Sheds Moderator Posted September 29, 2011 Share Posted September 29, 2011 I used to know a FF1600 racer, he had broken many XFs. His favourite was snapping the crank between 3 and 4 through overrevving, you haven't so think yourself lucky. Link to comment Share on other sites More sharing options...
dalongbloke Posted September 29, 2011 Share Posted September 29, 2011 Glad there was no damage. Why don't you fit a rev limiter for around 100 pounds. Dead easy to fit as well... 2 bolts and 2 connections. Saved my Bacon a couple of times.... Andy Link to comment Share on other sites More sharing options...
Sheds Moderator Posted September 29, 2011 Share Posted September 29, 2011 Good idea, all 7s should have one. It won't stop you buzzing an engine by fluffing a gear change though, as has happened here. Link to comment Share on other sites More sharing options...
Graham Sewell Posted September 30, 2011 Share Posted September 30, 2011 I had a rev limited (Omex) on my Seven until it decided to die one day during an overtake and left me without any engine at all. That was scary.... Link to comment Share on other sites More sharing options...
dalongbloke Posted September 30, 2011 Share Posted September 30, 2011 Hi Batterred.... I don't understand. Won't the limiter just stop the engine from over revving? Link to comment Share on other sites More sharing options...
Graham Sewell Posted September 30, 2011 Share Posted September 30, 2011 A rev limiter will stop an engine accelerating past a limit by cutting off the sparks. However, if the car is doing 80mph (6000rpm in 3rd) and you grab 2nd instead of 4th, the engine will be accelerated by the momentum of the car and no removal of sparks can prevent it. Hence the engine gets buzzed to 9000rpm. By contrast, I find without a limiter I am more cautious on the throttle and drive a little slower even though I know that the red line can be abused. I used to love timing a gear change so that I just hit the limited going under a bridge so that the misfire could echo around. Edited by - Graham Sewell on 30 Sep 2011 14:08:02 Link to comment Share on other sites More sharing options...
6speedmanual Posted September 30, 2011 Share Posted September 30, 2011 I take it from the above postings that crank breakage is one possible failure mode on an over-revved cross-flow.... One great thing about a cast iron crank is it is either broken or it's not! CI does not bend much before it pings. Is you engine still running? Crank is most likely ok. Is it running without misfires or unevenness? Valve gear is most likely ok. Oily rag diagnosis rules! The sun is shining - Go Blat! 😬 Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted September 30, 2011 Area Representative Share Posted September 30, 2011 I have a limiter on my rebuild and wonderful Crossflow. Great for your peace of mind. Link to comment Share on other sites More sharing options...
Barry Posted September 30, 2011 Share Posted September 30, 2011 Thought I had a limiter on my 1700 Supersprint xflow, I was later told that I hadn't and what I had been experiencing was likely to have been valve-float. So unless you've changed valve springs you probably have the same limiter as I did. Link to comment Share on other sites More sharing options...
dalongbloke Posted October 1, 2011 Share Posted October 1, 2011 Thanks graham, that makes sense. My worry has always been not slotting into a gear and putting my foot flat to the floor. A box full of neutrals is the term I like! Andy Link to comment Share on other sites More sharing options...
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