Peter Carmichael Posted May 18, 2001 Share Posted May 18, 2001 Roger King (with Dave Walker as a witness) has just discovered a big end in my k-series that has seen better times, with a very pretty heat damaged Arrow conrod looking in need of replacement. (That's lucky... I wanted one of those for my mantlepiece...) At the moment I am blaming jetlag for driving around with the oil filler off and losing more than a litre of oil onto Graham Ridgway's driveway on December 23rd last year when I had just arrived back from Australia. A circumstance immediately followed by the observed oil pressure anomaly that made me pop the engine out for a quick look see. Or it could be from when the scavenge pump belt disappeared at 9000rpm. After the rebuild it will all be better again and measures will be in place to mitigate against such disasters (like getting enough sleep!!). I will keep you posted as I find out more and at least it hasn't exploded yet. (From the first pickup, how long does it take to run a bearing??) Link to comment Share on other sites More sharing options...
murph7355 Posted May 18, 2001 Share Posted May 18, 2001 Bummer. Good luck in getting it sorted Peter and hope it didn't hurt the pocket too much. Link to comment Share on other sites More sharing options...
oilyhands Posted May 18, 2001 Share Posted May 18, 2001 Bad luck Peter, but I think you've had a narrow escape.. a thrown rod would cause mayhem amongst all that expensive metal, precious little would escape alive. Oily Link to comment Share on other sites More sharing options...
Rob Walker Posted May 18, 2001 Share Posted May 18, 2001 You have my sympathy Peter. I lost all the oil from my Esprit some years ago a stone had gone through the oil cooler on the motorway. I pulled off the road within seconds of noting the drop in oil pressure but it was too late 3 of the four big ends were run and examination of the crank revealed heat damage that was still visible after the regrind. On your rebuild I hope you are aware that upgraded Vandervell VP2 big end shells are available from Caterham. Link to comment Share on other sites More sharing options...
pfreeman Posted May 18, 2001 Share Posted May 18, 2001 Sorry to hear about your engine Peter. Excuse my ignorance, but are the "upgraded Vandervell VP2 big end shells" the same ones as they now fit into the R500 ? Also, you mentioned in a previous posting that there may be some kind of sender that can be fitted to check tension on the oil belt so as to have an early warning before you notice the oil pressure has gone and all is too late - can you elaborate ? Link to comment Share on other sites More sharing options...
DonkeyDave Posted May 18, 2001 Share Posted May 18, 2001 Yes Paul, you have these new types fitted to your R500 Link to comment Share on other sites More sharing options...
julians Posted May 18, 2001 Share Posted May 18, 2001 Peter, What were the symptoms of your problem, ie how did you know you had a problem? Julian Link to comment Share on other sites More sharing options...
Peter Carmichael Posted May 19, 2001 Author Share Posted May 19, 2001 The symptoms were pointed out by Graham Ridgway as I reversed out of a parking space putside his house - there was a huge puddle of oil. Popped the bonnet to discover the top of the conning tower was not screwed down (I had been meticulous in checking the oil level, but daft in not doing up the filler). We cleaned up that mess and topped up with a bit of oil (thank you Graham), but for some reason (jetlag having arrived from Australia 2 hours before) after about a litre had gone in I refused to accept any more of Graham's generosity. Chances are that the damage was done under power, driving to Graham's. Drove off and shortly after doesn't sound right and watching the oil pressure it flutters and disappears, with a metallic note to the fumes being vented from the catch tank. Shutdown and coast to halt. At home, crank engine to see oil pressure reestablish itself, but exercise caution by extracting engine (on Christmas day) for investigation. Don't get a chance to deliver engine to RK until a couple of weeks ago. ------- As for an early warning for the scavenge pump belt... ... my ideas are clear, but the detail is not sorted out. I want to integrate the warning with the Stack unit, but there isn't a spare channel. My plan is to wire the oil temperature sender via a switch which registers when the scavenge pump belt tensioner flicks back on its stop. The switch can take the oil temperature appropriately open or short circuit, giving a full range reading to the Stack and raising the alarm in the usual fashion. The alarm will say "OILT" so I know it is something to do with oil, but the oil pressure datalogging will be unaffected so I will be able to monitor whether there was a pressure fluctuation right up to shutdown. Oil temperature never moves that quickly, so I won't obscure any relevant oil temp information. Cunning, eh? I haven't come up with a mounting point for the switch yet, but that is all that I need to sort out. Link to comment Share on other sites More sharing options...
Rob Walker Posted May 19, 2001 Share Posted May 19, 2001 Peter I would have thought the rod will still be servicable. If you consider that on the R500 they run with interferance fit gudgeon pins as do many other high performance K`s. In fitting the gudgeon into the little end its one common method to heat the end of the rod to about 300C or when it starts to blue and then fit the pin whilst its expanded. I can see no reason why this is heating would be any different to your heat damage from the lack of lubrication. The rod will still be EN 24 and have retained its carbon content. This localised tempering may even prevent brittleness and cracking. Oh as you probably know the best method of fitting interferace fit gudgeon pins is to freeze them in liquid nitrogen and gently heat the little end with a hot air gun. Edited by - Rob walker on 19 May 2001 10:46:45 Link to comment Share on other sites More sharing options...
AMMO Posted May 19, 2001 Share Posted May 19, 2001 Peter I had a Carrillo rod which had gone blue after a big end seizure. When I checked with Jack Sparks at Carrillo in the USA he said it was OK to re-use it as long as it was still round. If not it could be re-sized and peaned. Carrillo offer this service. May mean you will have a little less compression on that cylinder as the rod will be as few thou shorter after being re-conditioned. If anything the Arrow rods are better quality than the Carrillos and should still be up to the job. Check with Arrow they might be able to fix it for less than the price of a new one. AMMO Link to comment Share on other sites More sharing options...
oilyhands Posted May 19, 2001 Share Posted May 19, 2001 Reclaiming a rod is a well used procedure, a light machining of the caps mating surfaces and a hone is usually all that is required, it wont have got hot enough to really hurt it, do check for ovality of the big-end eye and straightness of the rod. You may feel more comfortable with a new one though.. Dave Link to comment Share on other sites More sharing options...
EFA Posted May 19, 2001 Share Posted May 19, 2001 Peter, With my recent problem, Swindon were absolutely rigid on replacing a rod if it was out of round by more than 2 thou. I bought a new set from Arrow as Farndon wanted 7 weeks to make some. Arnie Arnie Webb The Fat Bloke blush.gif in a Fast Temporarily Indisposed Vauxhall wink.gif See the R500 eater here See the Le Mans Trip Website here Link to comment Share on other sites More sharing options...
Roger King Posted May 19, 2001 Share Posted May 19, 2001 Peter (and all other interested parties). There are a number of issues to be considered here with regard to the possible reuse of the damaged conrod. 1) This is an extreme engine revving to 9000rpm+. Therefore it is sensible to be cautious to a degree not needed in lesser engines. 2) Yes, it is possible to resize a rod and to straighten it. But this rod has run it's big end bearing to the extent that only the steel backing of the shell is left and even this has become almost as thin as cooking foil. This means that the rod has been hammering up and down on the crankshaft with a clearance of possibly .070" (instead of a nominal .0018"). This extreme hammering effect may well have started all sorts of nasties such as fatigue cracks hidden away in threads cut into the caps. Such nasties are not always possible to reliably detect by conventional crack testing methods. 3) The rod has got hot enough to become blue. I make no claims to be an expert metallurgist, but the normal procedure amongst experienced engine builders would be to replace it when it is destined for such an application. 4) We haven't made a detailed analysis of the rod yet; the jury is out at the moment. Edited by - roger king on 20 May 2001 23:29:40 Link to comment Share on other sites More sharing options...
AMMO Posted May 20, 2001 Share Posted May 20, 2001 Point taken Roger. My rod probably was not that bad. Maybe only 0.001" out of round when bolted up to the correct torque and checked with a bore gauge. It was from a race engine with a 9,200 rpm limit. Carrillo wanted 16 weeks to make new ones and Arrow wanted 5. We repaired it so we could get back out on the track two weeks later. After being repaired it went on to win a National championship and is now running in a road engine some five years later. So no hesitation to do it again. Obviously if it has more than light damage the situation is different. If in doubt stick it in the bin (or on the mantelpiece). AMMO Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted May 20, 2001 Share Posted May 20, 2001 Sorry to hear of this Peter. One day I really will see this 'beastie' in the flesh! My god Roger; that rod has got VERY hot!! You're right that with so much clearance it really would have been hammering away, literally! Where did all the excess shaving end up; filter? Are the rods 'selected'; ie. all four come as a batch to the same weight + or - nil (well, it would be nice, but v. similar) ? Good Luck! Link to comment Share on other sites More sharing options...
Roger King Posted May 20, 2001 Share Posted May 20, 2001 Hi Ammo, Yes, it would normally be perfectly acceptable to resize a rod that is .001" out of round. This is a small tolerance error and there will be many engines running around with something of that magnitude and not having any problems, simply because rods tend to relax in service and find their own shape! In the case of this rod, the surface that the bearing mates to is torn and damaged where the shells have been rotating and although we haven't yet checked any dimensions, I wouldn't be surprised to find an ovality of .010" +. However, sometimes these things can be surprising, so it is entirely possible that it will still be within tolerance. Chris, When this sort of thing happens, the bits will normally end up in the sump, the sump strainer, the scav pump,the oil cooler, the hoses, the dry sump tank, the pressure pump and the oil filter. All neatly sorted according to particle size! This is one reason that you should always throw an oil cooler away after a blow up - it's impossible to clean internally. Rods from reputable manufacturers will come in weight matched sets, usually to the nearest gramme or better. In the case of fully machined rods, there will normally not be a huge tolerance range in a batch. Rods designed for competition will generally be as light as possible which means that there will be no spare material available to be removed for balancing; this means that balancing is achieved by selecting rods that match each other's weight. Production rods on the other hand often have 'lumps' that can be deliberately removed in order to balance an unmatched set. Edited by - roger king on 20 May 2001 23:50:32 Link to comment Share on other sites More sharing options...
Roger King Posted May 21, 2001 Share Posted May 21, 2001 I've just noticed that I split an infinitive in my contribution of 20th May. Perhaps now would be a good time for me to boldy go and do something else for a living. Link to comment Share on other sites More sharing options...
FH Posted May 21, 2001 Share Posted May 21, 2001 Split infinitives, Roger question.gif My English mistress also told us ad nauseam that "There is no such word as 'got'!" wink.gif but I think it is now just about acceptable teeth.gif FH Link to comment Share on other sites More sharing options...
Rob Walker Posted May 21, 2001 Share Posted May 21, 2001 Roger/Peter, Has the crank survived ? Its a great pity that this has happened I for one was interested to know how your mains had lasted in view of running with grooved shells top and bottom. Obviously no sensible conclusion can be made now. Link to comment Share on other sites More sharing options...
Roger King Posted May 21, 2001 Share Posted May 21, 2001 Personally, I've got to say that I'd be more likely to take notice of my French Mistress (if only). Regarding the crankshaft. The great irony here is that the mains, which were thought to be the weakest link, are fine - goodbye. Link to comment Share on other sites More sharing options...
Mike Bees Posted May 22, 2001 Share Posted May 22, 2001 Roger wrote - "Perhaps now would be a good time for me to boldy go" - so nice to see that the follically challenged retain their sense of humour wink.gif MIke Link to comment Share on other sites More sharing options...
Roger King Posted May 22, 2001 Share Posted May 22, 2001 I would just like to take this opportunity to point out that Mike Bees is a dead man. Link to comment Share on other sites More sharing options...
Mike Bees Posted May 22, 2001 Share Posted May 22, 2001 blush.gif Link to comment Share on other sites More sharing options...
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