This is the ongoing story of our MGB, following on from the restoration, and contains potted history of its mechanical maladies.
A number of local shakedown runs suggest that most things are working well, other than developing an occasional chronic misfire under acceleration when hot. Diagnosis is difficult, as the problem refuses to show itself on the driveway, with all sorts of theories being suggested and disproved. Finally, with time getting short, a wholesale replacement of ignition components – coil, leads, points and condenser – appears to do the job. The leads are a very nice set of Magnacore copper leads – none of this modern carbon based stuff to break up.
One other point was that the seal of the fuel filler cap had died. We found this out by seeing a pool of petrol on the floor after we had parked on a hill with what had been a fairly full tank!
Off to Le Mans and Magny-Cours via way of La Rochelle. On the way down, I notice the horn isn’t working and on entering a town to find lunch it looks like the fan isn’t playing either. Inspection shows the fuses are ok and we are getting volts, so the mystery deepens. Using some spare wire gets things going and it transpires that the contacts on the fusebox were, for some reason, not wanting to conduct much power. Cleaning them up with screwdriver blade and carefully tightening the spade connectors seems to do the trick, so we can settle down to a relaxed lunch.
Later in the trip our dreaded misfire returns, albeit in slightly different form. It will now miss during normal cruising, giving us and the car a good shake as it does so, but will then suddenly start working properly again. We make a couple of inspection stops, but with nothing visible and no more information to go on, we press on and hope for the best. To add to our woes, a short rainstorm shows we have leaks at the bottom and top of the windscreen.
It’s not looking good. Our misfire is now accompanied by load bangs as unburnt fuel meets a hot exhaust and we are notably down on power. On the final leg of the journey home we have a noisy and erratic full throttle maximum speed of initially 60mph on the flat. Hills are becoming a challenge and as we finally arrive home it needs a push to get us up the driveway.
More playing around is not solving the problem, but it’s becoming more than frustrating. Finally, inspiration strikes. I remember noticing at one of our unscheduled inspection stops in France the coil had felt hot. I wasn’t really sure how hot these things should run, but I would surely have noticed something that hot on other cars I’d worked on. Measuring the resistance of the low tension side of the coil showed 1.7Ohms, well below the 3.0 Ohm specification, but also higher than a ballasted coil should be. Checking the old coil showed this to be about the same.
Now suspecting this to be the root cause, I went armed with a multi-meter to Midland Sportscar and Classics, where they were good enough to let me check the resistance of a new coil in the shop. Sure enough, the DLB101 was below specification again at 1.9 Ohms, but the more expensive DLB105 sports coil clocked in at spot on 3 Ohms. It therefore seems as though there is a whole batch of incorrectly produced coils out there waiting to cause trouble.
On fitting the sports coil the engine fired up cleanly and now runs without backfire or hesitation – only 6 months frustration to find that one!!
During a garage clear up I find a couple of gaskets for the rear axle / hubs and realise I hadn’t fitted them. Obviously can’t be too much of a problem, but may as well get things set up properly. When doing the left side, I end up with some excess oil from the differentiation spilling out of the end which ends up on the brake drum and shoes. Hopefully though I’ve cleaned it all off.
Also decide to do the annual service although given the limited mileage I decide that in reality that comes down to a check over and an oil and filter change.
MoT time, although suitably delayed to find a day when I was home, Rick at the garage had time, and the weather was half decent – particularly bearing in mind we still have those leaks found last year. After a few months rest the battery has about had it but just manages to fire up the engine. That battery has done five or six years, so a replacement would be justified. I’ll probably get one at a show in springtime.
The MoT itself is a pass, although the left kingpin needs packing with grease to take some of the play out and there is are a couple of advisories on suspected leaks from the rear left shock and around the hub. The latter is most likely down to last month’s spillage, and on taking the drum off later at home it’s apparent that I hadn’t cleaned things up as well as I hoped. After cleaning everything up again, I go around all the dampers and top them up with jack oil as I hadn’t done this during the original rebuild. Getting the oil into the rear dampers is fiddly and needs a thin tube attached to a small plastic funnel, but we get there.
The clutch is making something of a squeal, which may be down to dryness having been rested for a while. I try to spray a little WD40 on to the legs of the release bearing by removing the clutch fork boot, but I don’t think it’s really been a success. Notice though that there seem to be some oily deposits and inspection of the gearbox oil level shows that has dropped below max so we may have a failing seal. Filling up the gearbox is another tube and funnel exercise, followed by another fight to persuade the rubber plug to go back in its hole.
Getting enthusiastic about the coming year, I see a pair of reconditions carburettors on ebay and decide to buy. I’ve never been 100% happy with the current ones and I know they leak air around the throttle spindles, so it will be interesting to see what difference the new ones will make. However, when they arrive the difference is that, other than being very nice and shiny, they don’t have ports for the crankcase breather pipes. To overcome this, I fit a neat breather filter on top of the metal breather pipe at the front of the engine.
Balancing and tuning the carbs is fairly easy, probably as a result of no longer having the air leaks, and we have a very good low speed idle for the first time in living memory.
It’s the 80th anniversary run down to Windsor Great Park. We have a good run along the A4 to meet up with Newbury MGOC at Chieveley Services and get our route instructions etc. On restarting though, there is a horrible metallic grating noise from the clutch, when the pedal is depressed. It doesn’t seem to affect progress, but each gearchange is a moment of trepidation until the coffee kicks in and I figure out that the release bearing must have collapsed leaving us with metal on metal contact. Not good long term, but should be ok for now – I hope!!
We have a good day out, meet up with some friends south of Bracknell and get back in one piece – this car does seem to have the habit of surviving!
Time is running out before this year’s Le Mans and I need to get the clutch done. As this is an engine out ( or at least half out ) job, it needs a good day with two of us and I fear that I’m not going to have the time. Hence a call to Rick at the local garage who is able to do the job and tells me afterwards there was no sign of the carbon release bearing, it must have completely broken up. He also said the bearing mounting was very stiff on the clutch fork, which may have been the problem so he’s released and greased it up.
Afterwards, the clutch is great but it seems like he may have accidentally done something with the ignition or carburettors as the idle rpm is initially high and then gradually falls away. A quick run into town also shows that the fan has packed up working, so that also needs looking at prior to Le Mans. Checks show that the temperature operated switch has died, so I decide to replace it with a nicer set up involving an electrical sensor in a housing which is effectively cut into the middle of the top hose and therefore doesn’t have the copper wire poking out the end of the hose like the current set up, which always looks like a leak waiting to happen.
A timing check shows we are still at 12 degrees BTDC, so that’s all ok, but it looks like the carbs may be out of balance as a result of hastily increasing the idle speed to overcome the drag of the failed release bearing. Unbolting the linkages, rebalancing and then resetting the linkage clearance makes it all look better and the idle is certainly happy, but we will have to see what happens on a run.
We’ve also noted that the handbrake needs to be pulled up a long way to be effective and there’s no adjustment left on the cable. The brakes themselves are nearly at the point where I could turn in the adjusters by a notch, but not quite as there is still a bit of drag and I don’t want to cook them. Hence it looks like the cable may have stretched, or it could even be the wrong one as the records show I didn’t buy a new one.
It turns out that the new one is pretty much the same length as the old one, which must therefore have come with the axle and body shell. However, the old cable was quite sluggish to slide through the outer cover, so it still makes sense to fit the new one, which then does seem to adjust up a bit better. I do wonder though if I may have got the actuating arms on the shoes the wrong way round - I read that they are handed – as it still seems to need more adjustment than you might expect for a new part.
Off to Le Mans, and all is running well other than an early morning shower. I had slipped a bit of silicon sealant under the windscreen rubbers, in particular where they go over the joins to the wings, which has stemmed a couple of the leaks but we still have some water coming in around the corner of the screen and at the top where the retaining strip on the hood is just about shot. To add to the excitement, the wiper switch doesn’t want to allow us the fast speed and so there’s some trepidation over how long that will last. We survive, however, and once in France the hood comes down and we enjoy an apparently faultless drive down.
Once arrived, and with beers in hand, we check on levels. Fuel consumption has been a remarkable 35 mpg for a mostly 80 mph cruise, but the coolant level has dropped significantly and needs a pint or so to fill back up. A trip to St Saturnin is fun as always, in particular being ushered into the main display area whilst much smarter euro-boxes are pushed into the public parking area, much to the irritation of their owners.
We have major rain on the way home through France, but no problems other than a steady drip of warm rain from the hood seal. Once back in the UK, the hood is down again and we make good progress until a couple of miles short of Chieveley services, at which point all power is suddenly lost and we coast to a halt. There is no interest from the starter, so I check under the bonnet and see what looks like a fair amount of coolant around the left side of the engine, which may be allowing the spark to track away from the distributor. Drying everything out allows the engine to start, but there is no power and after a couple of hundred yards we stop again and phone the man.
Sometime later we are recovered to the services, at which point we can verify we have spark but no fuel and there is a small puddle forming under the fuel pump and no tell tale clicks. Sharp taps with a hammer get some response, but it soon stops again so we are doomed to a ride home in the tow truck.
Our driveway is far too narrow and steep to be able to get either the tow truck in there or push the car up. However, we get lucky as a few more taps on the fuel pump gets enough life to fill the float chambers and get the engine running enough to make it into the garage before all is lost once again. So the final tally of the journey looks like fuel pump, coolant leak and rain leak – but still doing 35mpg so not bad overall??
Replacement electronic style fuel pump arrived and is duly fitted – bit of a fiddle underneath the car but no major drama. Check the timing after my fiddling about, which will also determine if I’ve messed the gap up. However, it’s still about 12 degrees BTDC which is where I wanted it, so all ok and it fires up straight away and runs cleanly.
There is evidence of escaping coolant underneath the heater valve and plug number 3. Hopefully this means our leak is just the gasket, but could it also be a head gasket problem as there does seem to be a small but steady amount of steam coming out of the oil filler cap. Not sure if this is just normal condensation or not, but I the plan is to start with the heater valve gasket and work from there!
To great relief, the new heater valve gasket fixes the coolant leak, so all is well. I also buy and fit a new piece of retaining channel for the front hood seal. The approved method is to remove the whole assembly so that the remnants of drilled out rivets can be removed from main hood structure, but with time short I figure that any rattling of surplus metal is likely to be lost in the overall cacophony of MG motoring so we will take the risk. Fixing the channel in place is simple enough, though I must buy a rivet gun with a thinner head for future jobs and inserting the rubber strip is easiest done by using screwdrivers to push it into place from the slide rather than trying to push it along the channel, even with the aid of lubricant.
We are enrolled in the MSA Classic, starting out from the Army Flying Museum in the Whallops, which we passed only a couple of weeks earlier on a trial run to check the fix to our coolant leak. In preparation for the run, the by now almost pure water in the cooling system is mixed with new antifreeze, by the simple expedient of removing the bottom hose to drain the hold and then pouring in the new. In addition, it seems like the rear nearside brake will take a notch of tightening and improve the feel of the brakes.
On arrival, however, the smell of burning brakes suggests otherwise and so urgent action is required prior to the start of the event. A handily placed RAC man offers me use of his soap and water; I don’t know what they use, but it definitely works well and my oily hands are quickly clean and soft. The work has, however, eaten the time available for breakfast so we grab a coffee and prepare to leave.
The route takes us on familiar roads up to Williams F1 in Grove, where we stop for a look around and another snack and coffee. Then on a less well known route to Prescott, where we are allow a run up the narrow, twisting road up the hill. The hairpin corners needed a fair amount of lock to get around, but at speed the most difficult challenge was turning into the sun and immediately losing sight of the lines of the road ahead.
Our third stop was at the Gaydon Motor Heritage Museum, which is predominantly contains cars from the ex-BL / BMC marques, including some very interesting prototypes. MG representation is limited, and there is even less Jaguar, and even the restaurant is down to a few sad looking sandwiches and you get the feeling that the demise of BL still hangs over the place.
Finally to Silverstone, where we are awarded medals for arriving (around 100 of the 800 odd starters didn’t!) and allowed out for a couple of laps on track. We have a lap each, and are able to stay with more exotic machinery through the corners but are shown-up as underpowered down the straights. Great fun though and definitely recommended.
The following weekend, we turn go to the Shalbourne Classic Car show. I had expected this to be a small event, but over 250 cars have turned out with everything from a vintage LaFrance to moderns such as DB7s and our own XKR also allowed in to play. A great way of spending time on a sunny Sunday, but one word of warning – leaving the event involves a track not suited to low-slung cars, and we had something of a Top Gear moment trying to get the XKR out without grounding out the front spoiler! MG was fine though – clearly the right choice!!
Starting to think of winter now, and what jobs will need doing. I’ve tightened the overdrive switch, which came loose during the MSA run, and also got a new wiper switch ready for fitting. The old fuel pump has been taken apart though I can’t see anything visibly wrong, so we’ll need some volts and water to try running it to see what the problem was. In addition, there will be a regular service and the battery is now 7 or 8 years old and must surely be on its last legs. We have tickets to Top Gear at the NEC in November, which also give us entry to the MPH show and Classic Car show, so that will be the time to look for parts.
After a long and cold winter it’s time to get ready for spring. I’ve tried a couple of times to charge the battery and start up, but although the engine turns over I don’t get much more than a cough and the battery quickly loses power. I obtain a new Bosch Silver battery for under £50 through the web, and fit this along with new plugs. It takes a few attempts, but the engine then splutters for a few seconds before roaring cleanly into life. I leave it a fast tickover to warm through, whilst conducting a pre-MoT check on lights etc. No problems there, so I then change the oil and filter, clean and re-oil the K&N air filters and take a look at the nearside rear brakes. There are some traces of oil and slight ridge on the drum and shoes, so something to keep an eye on. It also feels like we can take another notch on the brake adjuster, but bearing in mind the experience on the MSA run I’ll do a short test drive and check for excessive heat before I’m totally happy with it.
On the way back from taking the car on a long round trip to work, around 190 miles, the temperature gauge rises and although I slow down to reduce the heat output of the engine it continues to head for the end stop. It’s only a couple of downhill miles to the nearest garage where an inspection shows a lack of water. Once home, closer review shows a trail of water from the head gasket from between pots 2 and 3 – a common problem according to one or two websites, but the main problem here is that it’s only a couple of weeks until Le Mans.
The head gasket replacement is a reasonably quick job, although it would have been quicker if I’d remember to put the pushrods in place before dropping the head onto the studs, and it would have been easier on my back as well. To try to combat a repeat failure, I add a smear of blue haematite around the offending area, hoping that the overheating hasn’t caused any lasting damage. I also temporarily refill just with water, as there’s no anti-freeze to hand and in any case it would be a waste if we can’t get a good seal.
After a short trial run, it’s time for Le Mans Classics, and we set off with everything firmly crossed. All is well, however, and the car performs brilliantly until we leave the motorway a couple of miles from our destination, whereupon the overdrive refuses to kick in. I wonder if it is simply low gearbox oil pressure given the high ambient temperature and heat soak from a long, fast run. Tests the following morning indicate this isn’t the case, and investigation shows a lack of volts which is traced back to a failed switch. This is temporarily swapped with the reversing light switch and normal service is resumed.
Although the temperature gauge shows no ill effects, inspection of radiator levels on arrival home shows we have again lost coolant – hmm!
Later, after a shortish run close to home there seems to be a lot of steam coming from the engine breather, which doesn’t seem to bode well.
Various local runs haven’t seen any further drop in coolant levels, although other commitments have stopped us using the car for longer events. A sudden onset of cold weather and frosts reminds me I still have just water in the radiator so I take advantage of a period of jet lag following a business trip to the US to drain a couple of pints from the bottom hose and top up with some orange anti-freeze which I had in stock. I suspect the car won’t be going out again for a while, so it’s time to make a list of things to do over the winter:
Touch up some paintwork
Replace the failed overdrive switch, which is now in fact a failed reversing light switch
Fix the heater valve / Bowden cable / heater control which is slipping rather then changing the heat setting
Check rear nearside brake for oil
Investigate why handbrake is weak, even when fully adjusted up
Consider moving the engine breather, which is leaving a film of oil on the otherwise shiny carburettors
Think about a reconditioned rear differential to solve the clunk on setting off
Think about a new camshaft to get proper lift on pot number three again – but then the engine is generally quite old, and there’s still the worrisome head gasket, so should I bite the bullet and do a proper rebuild??
Recondition or replace sticking vacuum gauge
Routine service
Ok, so it's the end of winter and time to get ready for summer usage. The car has been started a couple of times to keep the battery charged but otherwise no activity for 6 months or so and, in particular, no action on the list of jobs above.
However, service parts have been bought at the February parts event in Stoneleigh, along with a new switch which is quickly fitted. By putting together parts from a couple of stalls I also end up with a 'mushroom' style engine breather, complete except for the plunger. Installation is easy, but running without this creates far too much vacuum and is pulling engine oil through the valve and into the engine. A temporary fix is to use a suitably sized bolt but it's less than ideal and a proper part is ordered and installed.
This still leaves the engine running very lean, with a significant volume of air being pulled in through the breather. Assuming that is normal, we obviously need to retune and balance the carbs.
Most of the routine service passes without incident. We've lost a bit of gearbox oil and there's still a bit of gunge getting into the rear brakes but nothing of concern. The points gap has widened and, after resetting to about 15 thousandths of an inch, a static timing check shows about 6 degrees BTDC. Whilst less than I'd be running before, this is close to the official specification of 7 degrees and arguably on the right side given use of standard unleaded petrol.
This makes cold starting easier and has certainly cured the mild pinking under load in hot conditions, but the engine feels subjectively less willing at high rpm. I may play with that later in the summer, but given that the distributor doesn't want to turn even with the clamp bolt loosened then it can wait for now!
Whilst cleaning the brakes I also wanted to look into the issue with the weak handbrake. I had read somewhere that the actuating levers were handed and it was possible to install them the wrong way around, resulting in this problem. By swapping them over from side to side I've verified this is the case, but also that my original install was correct. Maybe I'm expecting too much of the mechanism, and it does pass the MoT, but not being able to reliably hold the car on a slope can cause inconvenience from time to time so a fix is needed. As shorter cables are available and I'm out of adjustment then we may need to get creative!
The heater valve problem is similarly reluctant, although improvement is made by clamping the sleeve of the bowden cable such that the outer is as close as possible to the operating lever when fully on, thus shortening the amount of exposed inner cable. However, it still sticks when going to/from full cold and its clear that it's caused by the profile of the slot in the valve itself. I will look out for a new valve of better quality manufacture and put in stock for when the cooling system next needs to be drained.
Our first major run out is the MGB Register Spring event, starting near Abingdon and ending up on the front lawn at Dhyram House near Bath. The sun is out and it's a fantastic day, made even better by the fact that we aren't losing any coolant or oil and the mechanical maladies are limited to a tweak on the carburettors, looking to get the tune just right after the installation of the breather system.
A visit to ebay results in a replacement vacuum gauge arriving in the post, but on connection it shows little sign of life. However, disconnection of the old one has allowed significant amounts of oily fluid to drain out and, with a spare available, I'm brave enough to dismantle the unit to see what might be happening. It turns out these are incredibly simple units, with a small piston driven by engine vacuum moving the pointer against spring pressure. The sticking needle is caused by wear and/or obstruction in movement of the piston but after a few end to end movements it seem better and, on reassembly, the gauge seems to work a little better – time will tell!
Next up is the Regency Run to Brighton. It looks like being a chilly and possibly damp morning, so we put the hood up the night before. It's a bit of a struggle, demonstrating that we are out of practice and also that the frame has got slightly bent during it's months in the down position. Having identified the problem it's easy to overcome but we'll have to keep a watch on future developments.
We meet everyone else at Epsom race course, drop the hood and have a pleasant run down to Brighton. A following car reports that our brakelights have failed, and inspection shows that the Lucar connector has parted company with the pressure switch, so there's not much to be done about that on the day! The run back is most enjoyable along the surprisingly unbusy A283 and A272 towards Winchester and finally home via Stockbridge. Other than a slight tendency to lose revs when idling for long periods ( still a tad rich? ) everything runs well.
Once home, a check on the plugs shows a healthy colour, though perhaps a tad on the brown side and certainly not lean so a quick tweak up on the SUs and we'll see what happens next time. A new pressure switch from the MGOC restores the brake lights and is an easy replacement, although you need to put a rag underneath to catch the trickle of brake fluid and be quick to not allow too much to get out. In theory, fluid being expelled means it shouldn't be necessary to bleed the system but we'll test that theory on a quick test run.
One other job is to – finally – fit proper fuel overflow pipes to the float chambers. A spare p-clip is attached to the engine mount to locate the pipes, which are then bent to suit. After bending the short length of rubber coupling pipe through ninety degrees, the front pipe can go more or less straight down with just a gentle initial bend and a further bend beneath the p-clip to follow the curve of the bodywork. The rear pipe is slightly more elaborate, needing a couple of ninety degree bends to follow the line of the manifold heatshield from front to rear.