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MG MGB Technical - Rear drain plug on block?
| Can anyone give me an idea of how large or small of a hole I should be finding after removing the coolant drain plug at the rear of the block? My '70 MGBGT has just the plug,no tap. I removed it and it is bone dry. I have tried to push/tap a small awl thru but am not sure of what size or how hard to try to knock it thru. I can get in about 1/2" to 1" past the threads. I would expect to see some coolant coming from it even though the radiator has been removed and most of the coolant. Any help is appreciated. Mike |
| MK Mike |
| This is in the archives. It's normal not to see anything come out of that tap. |
| Stan Best |
| I finally got the right combo of words to search the archives. From what I see I don't think I would call it "normal". I guess it's common. I am not finding all the sludge and crud. It goes in a good inch or so, and it's as wide as the plug but I cn't feel any other small hole to poke thru. Don't want to do any damage so I may just have to leave it alone... but boy will it bug me. Mike |
| MK Mike |
| Mike. This hole should allow you to view the rear section of the number four cylinder and some of the area behind the cylinder. I am preparing a block for reassembly, one which had been "hot tanked" for two days, and am amazed at the amount of crud I am pulling out of that area. A small flashlight allows you to see inside. A small screwdriver, with the last 1/8th inch of the blade heated and bent at a 90 degree angle, makes a good tool for cleaning out this area. Les |
| Les Bengtson |
| Based on my experience after it's cleaned it will be clogged again in a few months. Clifton |
| Clifton Gordon |
| Clifton, May be your experience is not the best one. Use a modern and efficient permanent coolant and you will no longer get back any deposit around the 4th cylinder bottom. Regards. R.G |
| Renou |
| MK Mike- The drain tap (Original Equipment Part # 3H 576)was a common feature of the earlier B Series engines that was continued into the production of the 18G and 18GA engines destined for use in the MGB. Its purpose was to allow coolant to be drained from the cylinder head and the upper sections of the block without going to the trouble of draining the cooling system from beneath the car, thus permitting the easy removal of the cylinder head without having coolant run down the sides of the block. Unfortunately, the coolants of that era did a rather poor job of protecting the coolant passages inside the cast iron block from corrosion. As the engine expanded and contracted during heating and cooling, small particles of rust would flake off from the walls of the coolant passages and settle into the area around the base of the #4 cylinder and the adjacent drain tap, clogging it. Ultimately, its installation on the B Series engine was discontinued after the end of the production of the three-main-bearing 18GA engine. However, modern formula coolants have largely eliminated this silting problem, making the drain tap a viable option. Just be sure to get all of the rust out of the inside of the engine and you should be fine from there on. |
| Steve S. |
| R.G. Thanks for your comment. I started with a clean engine 5 years ago. I used distilled water and a 30%-40% anti-freeze mix and change it yearly, but it was plugged again in less than a year. The same formula and two year drain interval works well on my other cars without clogging the drain. When I drain my coolant it looks new and I never have to add coolant between changes. If you take a close look at the block the drain plug is below the oil gallery and is not part of the water jacket, it's below the water jacket with one opening to the drain cavity. There is no outlet other than the drain plug, consequently there is not likely to be any circulation. I would think the coolant in drain cavity contributes nothing to cooling efficiency. BTW, Not to argue, but you suggested that if I used a permanent modern coolant I wouldn't have that problem. Permanent, to me means it never gets changed, so how would one know if the drain is clear if it's permanent? Regards, Clifton |
| Clifton Gordon |
| Clifton Good points. It is a bit clearer now I know it's not thru to the water jacket. It must be a pretty small opening that I thinks goes towards the rear of the engine. I can get in about 3" now but no sign of coolant. I'm a little more at ease as it seems getting a drain/flow thru this plug really does nothing in terms of cooling. Maybe they should have just left it closed off? Thanks Mike |
| MK Mike |
| Mike, That is exactly what the plug does! Using antifreeze means there is no need to completely drain the block and there is no "need" to clear out the passage. |
| Chris at Octarine Services |
| Steve S., "Ultimately, its installation on the B Series engine was discontinued after the end of the production of the three-main-bearing 18GA engine." Perhaps trivial, but - the original 5-main, 18GB engine (#32250) in my first 'B (1966, bought new) and a documented original engine (#27237) to another '66B bought for restoration both came with brass drain taps positioned just behind the distributor. Additionally, two other GB engines (#5288 & #57558) in my inventory have this brass drain tap, as well. So, it appears the accessory engine drain tap was continued into 1966, at least. |
| Steve Buchina |
| I note that the block in my 18GG engine (Oct '68 casting date and these were assembled in England) also had the brass drain tap. The car is a 69 roadster - built here around June/July '69. The radiator also had the same drain tap. Regards Roger |
| Roger T |
| Take a stiff piece of wire, about 1/8", and hammer it up & back. If you don't hit water, there may be a very large amount of garbage in the water jacket. It goes right into the space behind #4. I have found engines that still had the casting cores around the back of #4, so that there was NO water circulation there. One was on a rebuild after the block came back from the machine shop & hot tank; it took two days of hammering shaped rods in from all angles to get it out. Oddly, the car had a history of running hot! FRM |
| FR Millmore |
| Gentlemen- Thanks for the information. Upon further investigation, I've discovered that the drain tap was discontinued as a standard fitting at the end of the GA Series. However, it continued to be fitted to the 5-main-bearing engines "as required". Just how the factory determined when it was required is as yet obscure. Clifton- The purpose of the block drain tap wasn't for changing the antifreeze, it was for partially draining the block so that a new head gasket could be installed alongside the road without losing too much coolant. It's a quaint holdover from a bygone age of motoring, much like the micro-adjuster on the Lucas 24D distributor. It was intended to be used to conveniently fine-tune the amount of ignition advance while traveling when using a different from standard fuel. Better quality fuels with more consistent octane ratings lead Lucas to drop this feature on their later model distributors. |
| Steve S. |
| Fletcher. Good to see you back here. My experience is very limited. I have only had a single engine which I had to tear down after a rebuild. My daughter's engine had about 2K miles on it when the three year old line to the oil cooler split while she was driving at highway speed. Full rebuild which required turning the main bearing journals and the rod bearing journals. Piston rings were not fully seated yet and were reused. Engine running very fine now, some four years after the incident. No "crud" noted in the rear area of the cylinders visible thorough the plug for the previous drain tap. I had used a good quality anti-freeze and distilled water for the cooling system. My other rebuilds, using a good quality anti-freeze and distilled water, do not demonstrate any form of "over heating" in their daily use. This is in line with the experiences of friends who are professional mechanics and far more experienced than I. Clean out the block as best you can, taking time to ensure that you remove all of the debris that you can get out. Run the new engine in with distilled water/25% anti-freeze. Retorque the head gasket after initial run in, at 250 miles, at 500 miles, then at 1,000 miles. At the 1K mile point, drain the coolant and flush the cooling system to remove anything which was not removed in the rebuild process. Refill the cooling system as necessary. My thoughts on this are available at my website, www.cusompistols.com/ in the MG section. Les |
| Les Bengtson |
| Dear Steve. Glad you are back. Have missed your insight. It was, however, the Lucas 25D4 distributor. "Got You". Hope all is going well for you. Les |
| Les Bengtson |
| I don't know where Steve S got his info, but Clausager notes that the drain tap was discontinued from the 18GD engines in Nov 67 - all GB engines had a tap. |
| Chris at Octarine Services |
| Clifton, Permanent is a way to tell you never need to replace it during winter/summer seasons, nothing else. On modern cars we used so said "permanent coolant" and in reference to user's guide, you have to swap them regularly: these products efficiency decreases on time. And refering to MG factory manual, flushing helps maintening the block in proper condition. Hope that help! R.G |
| Renou |
| Les- Opps! A typographical omission! Thanks, I've got it corrected. Chris- Roger's 18GG engine with its October 1968 casting date obviously post-dates Clausager's November 1967 discontinuation date, so Clausager may be only partly right. It all depends on what he meant by the word "discontinued". Perhaps the factory discontinued the drain tap as an all-markets standard fitment, but it continued to be fitted as needed only for certain markets. I do know that I've never seen an 18V engine with a drain tap as an original item. This bit of MG trivia could bear some further research. Anybody out there ever see a factory drain tap on an 18GH, 18GJ, or 18GK engine? |
| Steve S. |
| Even if there are 18GG or later engines around with drain taps fitted, they are probably fitted by previous owners. Clausager states that from the introduction of the Mark II models (Nov 67) the block drain tap was replaced by a simple plug. |
| Chris at Octarine Services |
| Chris- I think that it would be a rare owner who would go to the trouble of installing such a quaint item as a drain tap. I admit that I did, but that's just my sense of perfection coming through. Clausager has been known to be inaccurate, though less often than most. In this case I think that the information he has supplied is vague. One is left to wonder how and why the production planners at the factory would justify the expense and trouble of the machinework to install a plug (drilling, surfacing, tapping) if they had no intention of continuing to install a drain tap for certain markets. After all, why bother? A solid metal casting is cheaper than a machined one, right? It won't require assembly on the production line and it won't leak, either. |
| Steve S. |
| "I think that it would be a rare owner who would go to the trouble of installing such a quaint item as a drain tap" I agree, but it surprises me the number of people who recommend retro-fitting them to radiators. Someone else cast the blocks, not BL, and if companies I have dealt with are anything to go by it costs as much to delete something as add it. Far easier and cheaper to leave the block as is, but fit a cheap plug instead of a tap. |
| Paul Hunt 2 |
| Paul- It would be cheaper if the threads were cast in, but machinework on a casting costs extra. Having a drain tap on the radiator is a much cleaner and more convenient way of draining the coolant than removing the hose to the coolant pump. Incidentally, the B Series blocks were originally cast by the old Nuffield foundry at Cowley, displaying the now-cryptic acronym of MOWOG in raised letters. MOWOG stood for MOrris, WOlseley, and MG, the original car companies that comprised the Nuffield Group, which originally owned the foundry. Later, due to growing production demands, this output was supplemented by the Austin foundry at Longbridge, the casting molds still being solely produced by the Cowley facility with the traditional MOWOG acronym proudly included. In the early 1970’s Qualcast took over the work, but, as before, the casting molds were still produced at the Cowley facility, complete with the traditional MOWOG name. |
| Steve S. |
| My car with 18GB engine built in Dec 66 had the drain tap fitted. I removed it a few years ago and put the blanking bolt on, one less thing to go wrong. |
| Stan Best |
| Steve, the taps screwed into the block - the threads being cut to allow this. Paul is suggesting the cheapest solution to closing this casting hole was to fit a threaded plug in lieu of the tap. Chris, I am confident that the tap in the block on my car was original. The car had only two POs, friends from law school I discovered, and both still living here in Canberra at the time I bought. The original owner sold the car to his mate in late 1971. I have a file of papers on the car going back to 1969 -more detailed from 1971 (remember, these blokes are solicitors, very detailed file - service records, registration receipts, insurance contracts, notes on phone conversations obtaining prices on spares etc). The only evident changes to this car at the time I bought it six years ago were a replacement alternator (a 1971 stamped Lucus), wiper blade arms, steering wheel and gear knob (both Fathers Day presents) and a replacement carpet set. The car still has the original spare tyre, an Olympic GT radial, with 4mm of tread remaining and the tell-tale rubber moulding 'fingers?' still largely intact. I will endeavour to contact the chap I purchased her from to confirm my view but would be very surprised if either had retro-fitted the tap - they were not 'hands-on' owners, everything appears to have been done through service providers. Of course we have to remember that there were only 9,900 odd of these cars sold here from 1962 to the end of local kit production late 1972. MG/BMC/Leyland sold a range of other Morris/Austin/Leyland cars here at the same time. There may well have been an Australian market preference for retaining the taps over the replacement plugs for local reasons. However, I don't believe any of the above would support a view that Clausager had got this point 'wrong'. His primary source of data was factory records. It would be quite plausable that a factory decision (hence a record existing) could be made to discontinue the tap in lieu of a plug - for home market and US export, for example, whilst continuing it for, say, kit production cars being sent to Australia. At the time the number of units involved in the exception would have been so insignificant as to not justify recording. Regards Roger |
| Roger T |
| Hi Guys For what it's worth I have an 18V engine with a brass plug where the drain tap was fitted to earlier engines, Peter M |
| Peter M (member) |
| Roger- Now that I think about it, it could well be that the coring for the block casting incorporated an extension for forming a passageway into the block for the drain tap in order to save on production costs. It would be cheaper to drill out the walls of a hole than to drill a passage into a solid casting. If this was the case with the coring, drilling and tapping would be necessary in order to install a plug. If the coring design went unchanged, that would explain the presence of the plug after the drain tap was dropped from standard, mass-produced engines. In fact, it would be a necessity if the coring design was left as original. So, why wasn't the coring design simplified in order to save on the production costs of drilling and tapping? Because they wanted to retain the option of installing a drain tap for certain markets. Makes sense to me. |
| Steve S. |
| "So, why wasn't the coring design simplified in order to save on the production costs of drilling and tapping?" Probably cheaper to drill (and wasn't a hole cast like all the others?) and tap ones-self, rather than pay the casting manufacturer to change the design. Like I say, it can cost as much to take something out as add something. The Parts Catalogue shows a tap for all 3-bearing engines and a plug for all five-bearing, no variations. My V8 has a plug on the right-hand bank and a tap on the left! Both need to be opened/removed to lower the level of coolant in the block, after draining the radiator, below the tops of the bores. |
| Paul Hunt 2 |
| Guys That does seem to make sense, There has to be a reason the plug is there... I just wish I could get the coolant to drain out of it. Would like to get the old remaining stuff out especially now I can see it with the head removed. I have hit a wall. I can get a short sharp awl in there but have stopped trying to hammer it in because of the fear of breaking something. Mike |
| MK Mike |
| On A-series engines, it helps to put a twist drill in there and turn it by hand to pull the debris out. |
| Dave O'Neill 2 |
| The plug is there because it is necessary to have a place to drain the cooling system - this is the low point of the water jacket, by design. There are a number of reasons to do this. It was formerly common practice to use water only and drain it in winter, even overnight. That's why a tap was provided originally, and that's why many postwar British cars had plates: "It is impossible to drain heater system, Bluecol antifreeze must be used under freezing conditions". (plates no doubt provided free by Bluecol!) "Permanent", ie glycol, antifreeze was a WWII development, and even into the late 1950s alcohol was used, but it evaporated around 175F, so many people just did not use it. (that's also why there are such as 160F thermostats). Many people did not believe in the new-fangled "permanent" antifreeze; as now, everybody "knew" the truth and were incapable of learning anything. It is also good engineering practice to provide drains for any liquids in any machine, notwithstanding the current cheapskate BS re "lifetime" fills of various things - when the stuff is all gone, used up, or wore out, that's the lifetime of your machine! One reason for the provision of drains is that liquid containing systems can be designed, by accident or otherwise, such that circulating crap will accumulate in certain "dead" areas of flow. This gives both a lurking trouble point and an opportunity to catch garbage so it can be removed. Note it also gives you a tell-tale of impending disaster, ie metal flakes or pieces of water pump impellers. This drain is such a catch-point. If the system is opened here periodically, sediment will be removed and the circulation can be maintained; if it is not attended to, then the crap builds up until there is no circulation, and you begin to get local or general overheat problems. Get this through your collective heads - IF the drain clogs because of sedimentation, then you have solid proof that it NEEDS to be there and it NEEDS to be attended to more frequently! Further, if the crap isn't caught there, it circulates until it blocks the main & heater rads. The only problem with the tap was that once the hole clogged, you had to remove the tap anyway, and the plug is much easier to remove. Also, the cost of the tap was around 20x or greater over the plug. Mike- You are not going to break anything, unless you use a large hammer - like over two lbs, with a violent disposition. Since you have the head off, get in there from every angle and break all that crap out. You will soon learn the difference between beating on garbage and beating on iron. It is not uncommon to find, on careful observation, that there are metal "fins" from casting that are obstructing flow in various places - attempts to break these off will show you how hard it is to break anything! Reread my post above - you will find that there is probably a LOT of crap around the back of #4 cylinder, and it has to come out. The engine I mentioned still had the casting core largely intact there. I used a bunch of oddly bent 3/16 & 1/4" rods with blunt chisel ends to attack the water jacket insides from all available holes, with the core plugs out. While that was the worst engine I've had, lesser amounts are common, like a pound or two of sediment. Had a TD with about 5 lbs in there; that one was up over the core plugs, which caused anaerobic corrosion of the plugs. FRM |
| FR Millmore |
| Having worked on a number of B series engines over the years, I have to concur with Fletcher 100 percent. Since the head is off the block it will allow you to take a 2 prong approach - from above and from the side. I've used a loooong screwdriver to dig down from the top and a small bladed screwdriver to attack from the side. I suppose that a dullish 1/8" drill bit will work nicely to clean out the passage from the side. I wouldn't want to ruin one of my good bits on the junk you'll pull out of there. The passage will lead on an angle toward the back of the block. Keep at it. It's very satisfying once you break through! Tom |
| Tom Sotomayor |
| <<It is also good engineering practice to provide drains for any liquids in any machine>> The last of the 1500 midgets had NO drain plug in the rear axle. Sealed for life? How long was that? |
| Dave O'Neill 2 |
| The life of the parts is c 7 minutes more than that of the lubricant. Good engineering practice has succumbed to short term accounting practice, abetted by lousy maintenance practice. As long as it usually lasts past the warranty period... Seem to be a lot of gearboxes of various sorts that have no drains these days. "Sealed for life" wheel bearings, where you get to throw the whole hub/spindle assembly away when it packs up; I've recently talked to a number of people with small Ford trucks suffering from this at as low as 20,000 miles on new parts - cost anywhere from $150 to $1000 to fix, depending on where they were when it died. That's with no collateral damage - simple front bearing/hub assembly replacement. Upshot - take care of your old tech car - you can replace the whole thing for less than "normal" maintenance on new ones! FRM |
| FR Millmore |
| The cost of maintenance depends on who is doing it... I don't know the current main dealer rates (I have a company car) but they must be up at £75 per hour. So the cost of parts may be small in comparison with the cost of labour; replacement of whole systems is quick and easy, but strip down of components and re-assembly can take a long time. So it is clearly about throughput - although the total labour income at the end of the week is the same, the more parts they have fitted in the time (particularly if they are more expensive parts) the higher the turnover. Of course, if you are doing it yourself then the balance of cost is different! The engineering of modern cars is unquestionable. Okay, engineers have better materials to work with (developed of course be engineers) and electronics (ditto), but cars are way better than they ever were. Accountants may have an input, but modern cars go, stop and handle better than ever before. And they're safer and more reliable. And on the whole they're cheaper too (relative to average salaries anyway, and particularly if you take into account the specifications nowadays). They sometimes break down, but on the other hand a fairly high-tech yet modestly priced car like a Mondeo might make 100,000 miles without a hitch. It's only the good engineering practice of current owners/enthusiasts that make our MGs reliable etc. Modern stuff might not have all the 'character' of older cars, but most people don't buy cars for their character. And if they do, they'd probably buy an Alfa, or a Citreon, or a TVR, or a Ferrari - all of which are most definitely not sold on the basis of their reliability! Neil |
| Neil22 |
| Fletcher,Tom To know me you would know I have nto been sleeping well nights thinking about having to leave that drain plug clogged. So after you lastest posts I had new hope and got to it again. SUCCESS Funny I was expecting some trash to come out of the drain plug hole but with all the digging I did there I removed less than a level teaspoon full of grit! Went in from the top with a screwdriver and felt a slight "give" when tapping it down. So just kept at it for a few more tries, tapping , turning the handle back and forth and wow a good gush of coolant came out the hole. I think I got lucky and if I had not removed the head I don't think I could have done it , at least not so easy. I got a bunch of records/receipts with the car and it seems it was well maintained. Had 2 PO's who took the car to a shop for everything. Lucky I do have a new question about the deck of this block I will start a new thread since this one is getting long. Thanks to everyone for their imput. New thread will be Water passage on block. Mike |
| MK Mike |
| FR- And a special word of "Thanks" to you for your information. I had completely forgotton about drain taps being located in "dead" areas of flow. Industrial engines have had them since the earliest days of liquid-cooling. My only question is (and I'm not being facetious): since they're located in "dead" areas of flow, the sediments fall to the floor of the coolant jacket, so how can simply draining the jacket remove them? They need to be lifted off of the jacket floor somehow, right? The only way that I can think of to acheive this is to remove the coolant pump and spray a strong jet of water into the engine while the drain is open? Am I missing something here? |
| Steve S. |
| Steve, I suspect that draining the system twice a year to swap thermostats (one for summer, one for winter) was enough to keep this area from clogging. Draining can generate a fair bit of flow / velocity. I don't think you'd have to flush it as you suggested. We'll see on mine in the next few weeks. I've been swapping out 'stats twice a year now, but have always drained from the radiator tap. I'll make a point of pulling the drain plug this time to see if it's silted up in the intervening 17K miles since the engine got rebuilt. Tom |
| Tom Sotomayor |
| Mike- Great! Be sure to probe around all available holes to the bottom of the water jackets, but especially around the rear cylinder, since that's where it's usually worst. Steve - The drain is located in a sort of pocket, where stuff settles. If that pocket is kept clean, the circulating crud will keep settling there, and can be gotten out by draining off a bit of coolant frequently. Once the pocket fills, stuff then settles in other low velocity areas and can be very hard to get out. That's what cooling system flushing chemicals are supposed to do, sometimes it works, sometimes it doesn't. I probe around in there to what ever extent is possible; always wished they'd made the geometry a little friendlier. Tom - Changing tstats is old hat, and a waste of time; engines like to run at consistent temperatures, and there is no advantage to running them lower in summer - it's another of those hangovers from ye olde daze. Dirty cooling systems are a result of what water is used, what corrosion inhibitors are used, and various operating conditions. Under all good conditions, the systems will stay clean. It is pretty common for even hot tanked engines to still have deposits in situ; careful examination before building is important. Another tricky point is that of poorly grounded engines; I don't know the exact details of the complex interrelationships, but certainly electrolytic corrosion from bed grounds has been reported as a cause of radiator failure, to the point that replacement rad warranties are void if there is more than the slightest potential from ground to coolant. One report: "From David Read, South Oz BTW, on a ground related note ... I recently replaced an aluminium cored radiator with plastic tanks in my daughter's car. The installation instructions with the new OEM rad. were very specific. Connect a digital voltmeter between battery ground point and the coolant. If the meter reads in excess of 50mV, go look for the poor ground and fix it otherwise there was no warranty!" FRM |
| FR Millmore |
| "so how can simply draining the jacket remove them?" It's a good question, and the answer is that they don't in either block or radiator. If you look at the hydraulics of a dammed river valley that floods to form a lake, you will find it rapidly fills with sediment reducing the volume of water held. The only place where that doesn't happen is at the outlets, i.e. for hydro-electric turbines, and that is because they are open more or less constantly and the flow keeps them clear. When flushing heater, block and radiator after many years use you will have to reverse and forward flush many times before the water runs clear, and that will only remove sediment from the areas that the water is passing over, not 'dead' areas. |
| Paul Hunt 2 |
| Fletcher, Changing T-stats is 'old hat' but I found running a 190* stat in the summer a bit warm. Sitting in rush hour traffic with a hotter engine is not all that pleasant in the cabin. Running a warmer stat in the winter is a benefit though when the temps drop below zero F. Engines like to run at constant temperatures - so do I! ;o) Tom |
| Tom Sotomayor |
| FPM,Steve, Tom Once open I shot a a high water hose pressure down all the water jacket openings and especially the back one and got full bore water out the drain hole, so feel it's pretty clean. I wonder if this would be a good place to reverse flush during routine coolant change. after you drain the system front and rear? I think I figured out my other question by looking at the deck of another block I have. The spark plug side of the deck,inbetween cyls 2 and 3 just in front of that middle head stud, that hole has a plug, actually that side has 3 in the middle of the deck. The face of the cylinder head has a large hole at that point where it mates with the deck. I thought for awhile it may have been corroded but my other block is the same, guess it should be that way? Mike |
| MK Mike |
| Neil22 Just because it is new doesn't mean it is reliable. Talking to an old college roommate this weekend. He has an older Miata and his neighbor recently bought a new Corvette. While the Corvette actually gets better highway mpg than the Miata it has been MUCH less reliable. FWIW Larry 72 BGT daily driver |
| Larry Hallanger |
| Nothing to do with age, one is Japanese and the other American ... But my old Celica was more trouble than either of my MGBs, for oil leaks, MOT failures, parts failures and sheer bloody difficulty in working on. |
| Paul Hunt 2 |
| Larry, You can call me plain Neil! FRM was implying that the engineering standards have declined. They have not. Modern technology requires closer tolerances, better finishes, more accurate assembly, etc. Older designs need to be adjustable to take up tolerances, parts needed to be easy to change because they were less reliable. Although there will always be an exception to every rule, I would argue that most new European cars are way better than old cars were when they were new (if you see what I mean). Neil |
| Neil22 |
| Neil. I agree with you in some measure. CNC production has allowed parts to be made to very close tolerances on a consistent basis. The CNC-ed parts are also produced far more quickly than parts made on manual machines. It takes 16 minutes to produce a brass garden hose nozzle on a manual machine operated by a trained machinist. On a CNC machine, it takes 29 seconds. The machines making the parts for the machines are some of the best they have ever been and the possibility of rapidly turning out high quality parts is significantly higher than in the past. So, the question is, why are modern cars not even better than they currently are? My wife's Mini Cooper, purchased new in 2003, has not proven to be any more reliable than the service records of my 1979 MGB indicate it was when the same age. In fact, the Mini has had to have both the front and rear brake systems replaced (which the B did not require at similar mileage) and both of the cooling fans replaced (B had to have one of the twin fans replaced at same mileage). The Modern car does not demonstrate any real advantage over the older car in terms of service life of the parts expected to wear in service. Ease of maintenance is also something worth considering. To replace the cooling fans on my MGB, I have to remove the radiator, remove the fan guard, remove the fan motors, install the new fan motors using a .025" shim between the motor body and the inside of the mounting bracket (just because we can make better parts to closer tolerances does not mean we will--fan motor bodies are .025" undersized), reinstall the radiator, reconnect the radiator and refill the cooling system. Takes a little over an hour to do. Just went through this with the Mini as both of the cooling fans had gone bad and it is out of warranty. Work done by professional mechanics. Everything required to be done on the B, was also required on the Mini. But, the Mini required the additional step of removing the front end before the radiator could be removed. Takes about four hours work, instead of 1-1.5 hours. I can see where Fletcher is coming from as I see it myself in my own work. There is a potential today to produce parts of much higher quality and significantly longer working life. There is a potential to design systems for ease of maintenance, reducing the costs of such maintenance to the owner/operator. But, what we find is that, quite often, the more complex new systems are assembled in a non-mechanic friendly manner using parts which are of inferior materials (regardless of how well machined they are) and the net result is to make the older cars more attractive because the owner can work on them easily. Interesting commentary on the post-modern technical society. Especially to a Sociologist. Les |
| Les Bengtson |
This thread was discussed between 30/09/2007 and 17/10/2007
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