MiketheBike Posted September 4, 2007 Share Posted September 4, 2007 Reading this month's CMV, there is an article about "Where have all the Shermans gone". In it, there is reference to average engine mileages. Is that true....you are looking at between 1000 and 2500 miles for tank engines? At that point, do they need a total overhaul (cylinders etc), or are they totally shot? That came as a huige surprise to me. What sort of mileages do you guys get from your tracked vehicles, and are all armour similar in that the engines are stressed so hard that they do not last huge mileages? Mick Quote Link to comment Share on other sites More sharing options...
AlienFTM Posted September 4, 2007 Share Posted September 4, 2007 Reading this month's CMV, there is an article about "Where have all the Shermans gone". In it, there is reference to average engine mileages. Is that true....you are looking at between 1000 and 2500 miles for tank engines? At that point, do they need a total overhaul (cylinders etc), or are they totally shot? That came as a huige surprise to me. What sort of mileages do you guys get from your tracked vehicles, and are all armour similar in that the engines are stressed so hard that they do not last huge mileages? Mick D&M was never my forte (took the test, filed the licence under H and spent my career in radios) but if I am honest, a track mileage figure of 500 is coursing through my brains. That said, there are more reasons than simply extending the life of an engine in the day to day running of an A vehicle in service. I am quite certain our Scorpions' engines lasted a lot longer than 500 miles between replacement, but I wouldn't be at all surprise if the MBTF of a Chieftain engine was a lor shoreter than 500 miles. 1000 - 2500 miles sounds not unreasonable to me: if that's what the article said, I couldn't argue. I'd expect every engine to be rebuilt until it ceased to be viable, in the same way that the US have not built an Abrams in 13 years: they just keep rebuilding the old ones. This rebuilding programme had a name inthe Royal Armoured Corps: Bargepole was the rebuilding that Chieftains went through; Scorpions were returned for Scorpoling. Probably not a lot of help. Quote Link to comment Share on other sites More sharing options...
sirhc Posted September 4, 2007 Share Posted September 4, 2007 Mick, I think you can expect a CVRT engine to last for thousands of miles, providing it is well driven and well cared for. A set of track will last for 1000 or so miles, so you'd expect an engine to last through several sets of track. Most of the knackered engines I've seen have thrown rods through the block. This is due to a heavy right foot, starting in a high gear and the centrifugal clutch. Chris Quote Link to comment Share on other sites More sharing options...
REME 245 Posted September 4, 2007 Share Posted September 4, 2007 The radial engines fitted to some Shermans were designed to run for long periods at constant rpm's in aircraft. In AFV use they were used and abused in a way they were not designed for and consequently did not last long. I believe cylinder wear was a major problem in Radials? Quote Link to comment Share on other sites More sharing options...
MiketheBike Posted September 4, 2007 Author Share Posted September 4, 2007 The engine sounds like one of the major costs (money and time)....and now after seeing you guys around the arena in Beltring its not just a bit of fun, it could be very expensive! I suppose the other thing is that you won't be doing 10K miles a year in a tracked AFV so its maybe not a major issue....but is that the same issue with the B60/B80 engines...or are wheeled armour a completely different beast when it comes to engine life? Like someone said in another post about the Finnish auction...if you start worrying about the cost, don't do it! Quote Link to comment Share on other sites More sharing options...
John Pearson Posted September 4, 2007 Share Posted September 4, 2007 Brooklands Books published a number of wartime reprinted articles from the Autocar magazine and in one there is some sort of answer to your question. The formula used is that full revs plus full throttle equals 100% so half throttle on half revs equals half times a half or a quarter power useage for example. Due to the power to weight ratio of a 1940's car, it needed only low throttle openings to maintain speed and low revs (unless hillclimbing) so that they reckoned that a car engine averaged about 10% average power output. The tank engine by comparison was over 70% which would mean say 85% throttle on 85% revs, ON AVERAGE. To average that, it means full throttle, full revs whenever possible. The extra wear on the engine is only to be expected. Engine wear however is hardly a problem. After all, they can always be re bored, re sleeved, re-bearinged etc so the only problem is money. The wear on the clutch, gearbox and transmission is more of a problem however as they are probably financially irreplaceable except for the bearings although I suppose you could have new cogs machined. The same Autocar magazine article found an average of 80 or 90 gearchanges per 10 miles for a tank. By far the major problem with tank driving is track life. There were some exceptional examples: 40 RTR Valentines did 3000+ miles across the North African desert on one set of tracks each but the norm is perhaps 1000. Now where the hell are you going to get replacements for tracks, if they are not available surplus (EG 432, scorpion, cent, chieftain etc). If you are thinking of armour and are worried about the expense then just get it anyway and drive it only when some friends come round for a gerry can party! You get one hell of a lot of fun for a twenty pound note you know! Quote Link to comment Share on other sites More sharing options...
keviwal Posted September 9, 2007 Share Posted September 9, 2007 hi all, I can only really comment on chieftain engines( maybe of some use or not) When the chieftains came into service there biggest letdown was the engine the leyland l60 . it wouldnt be unusual to have 2-3 packs while out on a scheme. over the years the engines were much improved up to the last mod making it a 13 alpha pack. Easily identified by a red rocker cover!! Even these engines are expected only to do 300 hours before the con rod usually ejects itself through the block! The most common problem with l60 ( and i have seen this happen, very scary!!) is the governor for the engine seems to go belly up and yup it runs wild, not for very long i hasten to add !! I will dig some info out if you are interested Kind regards, Kev Walker Quote Link to comment Share on other sites More sharing options...
abn deuce Posted September 9, 2007 Share Posted September 9, 2007 wow that makes for a very delicate engine ! I m sure in that case one must keep an eye on the tachometer at all times if one wanted to avoid engine failure :dunno: Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted September 9, 2007 Share Posted September 9, 2007 wow that makes for a very delicate engine ! I m sure in that case one must keep an eye on the tachometer at all times if one wanted to avoid engine failure :dunno: The Jaguar J60 was not much better, I would like a fiver for every one with a rod through the side, which I have changed. Remember fitting a recon J60 in a Fox once, did the normal inspection test of about 25 miles or so, unit came to collect it, about 4 miles up the road, the engine gave way. I pulled it down for a technical investigation and found one camshaft broken in 4 places! Quote Link to comment Share on other sites More sharing options...
abn deuce Posted September 9, 2007 Share Posted September 9, 2007 Kind of frightening , having an engine fail that easily and thats in very light use , Who would want to have been assigned to vehicles like those in a war time environment , where that failure could be deadly! Quote Link to comment Share on other sites More sharing options...
MiketheBike Posted September 9, 2007 Author Share Posted September 9, 2007 I guess they are not made for intergalactic mileages and are transported to the field as such. I wonder if the newer offerings are more robust? Quote Link to comment Share on other sites More sharing options...
keviwal Posted September 9, 2007 Share Posted September 9, 2007 Hi again, Yes you are very correct chally 2 uses a perkins cv12 engine pretty much an "off the shelf" unit as i am told , a pack change can be carried very quickly too please correct me if i i,m wrong Mind you the power to weight ratio is alot better ,1200 horses bring it on !! the charrv is about 750hp so power to weight is alot less hence lots of broken power packs me thinks Kind regards Kev Walker Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted September 9, 2007 Share Posted September 9, 2007 The last engine in our Spartan (4th I think...) went bang while I was driving quite gently on the road. Impressive noise and lots of smoke. Thats why the owner bought 7 spare engines (NOT due to my driving I might add). I t's difficult to tell when the engine is making a clattering noise over the noise of the tracks, especially while wearing a clansman headset. It was "the usual" CVRT rod through the side faliure. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted September 9, 2007 Share Posted September 9, 2007 It was "the usual" CVRT rod through the side faliure. Before the drive shaft between engine and clutch was modified, the CVR(T) suffered crankshaft breakages. The original shaft had two Hardy Spicer u/j's and the modification was to change to a shaft with Layrub couplings, along with engine mounting changes as well. With these later shafts, it is imperitive that the gearbox is aligned correctly with the engine, else the Layrub coupling will overheat and disintergrate, have seen signs of it too. Quote Link to comment Share on other sites More sharing options...
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