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1974 MGB GT - The Mustard (Mit) Mobility Scooter - 6yrs ownership & the end is potentially nigh!


SiC

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So. Summer is looming, time for this to be recommissioned?

I really was hoping to have moved house this month. That would have meant two things. One I needed to drive it 25 odd miles to the new house, giving it a much needed run. Two it would/could live in the garage at home, making it easier to take out and do any work needed on it.

 

I did go up and see it last Thursday. It did look very sorry for itself. Dust and dirt has blown in through the top of the garage depositing all over it. The rust spots haven't got any worse though which is good.

 

Last time I took it out, it ran like crap once warmed up and lumpy/misfiring. I was thinking about this earlier and I wonder if that's because I did the tappets up a bit close (in an effort to quieten them). So once it warmed up the gap was a bit too small.

 

It also sounds like a bag of crap. Best way to describe it, is it's like a 30 year old Briggs and Stratton that has been run low on oil and never serviced. Quite embarrassing driving it along with it making such a god awful noise. Ideally it could do with a new oil pump and main+big end bearings. Hopefully that will increase the oil pressure a bit and make sure the top end gets some oil. Last time I had the cover off, it was running pretty dry up top.

 

All which I intend to do later but give it a drive first. However the house moving falling through and put a right spanner in those plans. If the 1100 was in a working and drivable state, it would be a lot easier as I can then just use the bastard MGB and when it inevitably breaks I actually have space to fix it.

 

I'll get something sorted soon.

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They all sound like that

 

BMC weren't exactly rolling in cash at the time that was made and the machinery making it was probably more worn than your engine is now.

 

It's not gonna go bang, get it hot, set the clearances HOT and go give it a jolly good thrashing. Once you have all the sticky gunk that's built up will clear out or burn off.

 

It's never going to sounds like a sewing machine. That's why people were unsure of Datsun and their ilk when their engines were introduced. Compare an A-series at idle to a CVCC engine and you'll know what I mean.

 

There's plenty of roads around there that are spectacular flat-cap and gloves. Go look up Dunkery Beacon and go drive there on a sunny day. Take a thermos and a walking stick, park up at the top and go walk up to the top of the hill. Take in the view (all the way across the Severn to Wales), enjoy the crickets chirping in the bracken and then give the brakes a run for their money on the way back down.

 

Go have fun in it. So long as the needle doesn't read 0 it's fine! It should smell slightly of hot oil, dusty EP90, a bit of ethylene glycol burning off and vaporizing fuel, and carpet with brake fluid slightly soaked in. That's the correct MGB experience.

 

Pop crackle fnnnNNNNNRRRRRRRT BuuuUUUUEEEEEE

 

Phil

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As long as the oil pressure hovers vaguely around book figures at a warm idle (somewhere around 20psi IIRC) I'd just drive it. Given the length of time it spends sat between short trips around town at low speeds/rpms I'd not be surprised if it was sludging up the oil passages.

 

Regardless of how I set the tappets on the Dolly it rattled like a bastard, it also seemed to have very little effect on how the car ran. I imagine the tolerances are just so vague that unless they're properly closed up it'll not really matter, that's not counting the fact it had done over 130,000 miles and was running a second hand rocker assembly. As PhilA said the machinery being used to build these cars was all pretty worn out during production and it's probably the same shagged tooling that is making repo parts now!

 

There are some people that fit aftermarket oilers to the top end of Triumph OHV engines to get it more lubricated but the accepted wisdom is that you're better off saving the oil pressure you have for the bottom end as even if the top end is a bit dry it'll take ages for it to wear out and is much cheaper/easier to replace than the crank!

 

Ignition timing and carb setup had a massive effect and seemed to require frequent tinkering and mid-trip tweaks. The 1300 in particular required weeks of quarter turns of the mixture settings on the carb until I got it running how I wanted it. The 1850HL ran decently at speed but always idled like garbage, although even now after 5 years in a field it still starts first turn of the key! 

 

The Acclaim is a different beast, even now with it's crap state of tune and unknown engine service history the clearances and way the thing is built are miles from BL's home grown standards. There is a guy on the FB page who runs his EN4 engined Civic on 5w40 with no issues, I reckon if you put that in a BL product it wouldn't even stay in the thing, let alone run properly...

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I'm not sure I've ever seen or heard of a bad oil pump on one of these, and I wouldn't think about doing bearings "just because" unless I was routinely getting below ~30psi hot idle with 20W-50. IIRC, you're higher than that. Bear in mind too that short tripping and long term storage can both contribute to temporarily low oil pressure-short trips tend to cause a lot of fuel dilution of the oil, while storage can cause condensation in the oil pan. A nice long drive(30 minutes+ of spirited driving) will get the oil up warm enough to drive off a lot of these.

 

Don't expect the top end to be awash with oil-the valve train is fed via one small hole that comes up to the rearmost rocker pedestal. It has to make its way down the rocker shaft and and just kind of dribbles out on each of the rocker pedestals. Even with the cover off, I can run mine with up fast and barely get any oil splatter from it-it's not a V8 with hydraulic tappets that throws oil all over kingdom come, especially when revved.

 

Also, I wouldn't want a cold clearance much smaller than 13 thou or so, but I doubt that would cause a lumpy idle or anything of the sort. If you think the tappets are set too tight, fix it as you can burn a valve.

 

I wouldn't automatically go there, though, with rough running when hot, although it's worth checking. Assuming it checks out, double check and make sure your condenser isn't acting up or you're not having some other ignition issue. Beyond that, check the mixture when hot-if you set it "correct" when cold or less than fully warm, you can end up with a rich mixture when hot. Do the piston lift test with the engine hot and see how it responds.

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You can always have a weak lemon drink in your thermos.

I hate squash too! It's water, orange/apple juice, cider or something with alcohol mixed in. Fizzy only if got alcohol in too.

 

This is not for health reasons, just I don't like them! I probably could make myself like it, but why bother? I eat enough chocolate to have enough of a sugar rush anyway.

 

Yes I am weird.

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DAILY THE BGT - there - had to be said………..  You know it makes sense - it's the perfect time of year, before top down Porkerness demands all of your summer miles.

Definitely don't worry about rattles/noise - it's never usually to worry about until it detonates - and then it's usually only 5secs later!

 

Get her out n about dude - it's necessary

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I hope not, it's got a full tank of expensive Shell V-Power! Just reading that Esso doesn't put any Ethanol in their Super Unleaded. Unless you get it from Devon or Cornwall. They're special* places and seem to get it still.

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The gas is PROBABLY fine, but there's a reason why I put a dose of Sta-Bil in my car any time I fill it up-I never know how long it will be before I get it out again, although obviously I hope not long.

 

Granted we have to go out of our way to find gas without ethanol here-even the expensive Shell V-Power I usually use(which my higher-than-stock C/R really likes) is 10% ethanol..

 

I did invest in marine grade Sta-Bil 360, which isn't that different from the standard red kind aside from the fact that it's significantly more concentrated than the auto stuff-it takes ~1 oz. per tank as opposed to 3 oz., so the fact that it's ~1.5x more expensive by volume is actually quite a bargain.

 

I should just order a kilogram of BHT and call it a day-Sta-Bil is basically a compound similar to BHT dissolved in kerosene(not sure exactly what it is-maybe I'll shoot some in the GC-MS tomorrow) and a gram of BHT dropped in the tank during a fill up would probably do as much good.

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  • 2 weeks later...

Drive it day today. So went up to the garage to either give this a run or just start it up.

 

As per a brief mention in News24, I have a longer term plan for this car. Now the weather is getting nicer (i.e. less rain), I will put the Boxster up in the garage for a month or two and have this down on the drive. This will make it a lot easier to go out in it and also force me to actually use it. BUT I promised/forced myself first that I needed to get the 1100 subframe mounts done. Otherwise I'll just get distracted/procrastinate from doing that.

 

Anyway back up to the garage. She's in a pretty sad state. The garage roof that she's in, appears to leak through the asbestos roof. Looks to be a chip out of it, so I'm guessing it's running through there.

 

So she's not only all dusty, but has water marks on the roof from water getting in. Thankfully no rust on the roof - paint is pretty good on top. I think it's not enough for it to be a big concern to run down and leak into the car.

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General rust isn't any worse. This bit came through from last year being outside over the winter. Should clean off with a bit of polish.

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Engine bay is all present and correct. It's cleaner than I remember too. Dipstick reads normal and dashpots still have oil.

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Fusebox terminals aren't the shinest. Once I get it back down, the first plan is to clean all these contacts up. It's not uncommon for these to give a bad connection and give all manor of crap running + unreliability. Easy enough job to do.

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Radiator is wet at the bottom of it. Not sure if this is from a leak or water sitting there from its previous outing. Hopefully not leaking.

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She does like to mark her territory. I think this is from the gearbox. It could do with a gearbox + overdrive oil change anyway. I have the oil sitting on the shelf ready.

Diff oil too. That looks to be dripping a bit as well. I've got a replacement gasket, so may get a garage to replace that for me. Easy job when up on a lift.

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Get in, go to take off the steering lock. Hmm, that light is awfully dim!

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Unfortunately I didn't disconnect the radio and I think it's got a power feed for all the time. Standard wiring doesn't but this could have been modified. If so, then that must have drained it.

 

No drive today then. Bugger.

 

Better get the battery out and put on charge then!

 

Remove back bench seat. Noticed the top corner screw is missing. Not sure how that happened. Must have a family of borrowers living in the car or something.

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Remove cover.

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Disconnect battery + retaining bracket and pull out.

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Battery terminal voltage was 6.9v if you were wondering. My charger refused to charge a battery this low. Actually it thought it was a 6v motorcycle battery.

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So gave it a bit of a boost with my bench supply to put a bit of energy in and bring the voltage up enough for the charger to take over.

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Not entirely confident that this battery is any good now. These lead acids really don't like to be run flat and it reduces their capacity. I'll give it a go but I fear it may not store anywhere near as much charge as it used to. This will be compounded by the fact this is a very small 12v battery.

 

Originally the car had two 6v batteries in series. You can still buy 6v batteries but they're frightfully expensive. Plus the series interconnect is just another thing to go wrong.

 

This particular 12v battery fits quite nicely in the hole. Capacity wise it's enough for a good few starting attempts when fairly fresh. However if this has lost some of its capacity from being run flat, it may not have as much umpfh. Will be ok if the engine starts every time on the first turn of the key. However I don't have much confidence in the car as it is. Let alone being stranded because the battery was damaged from my own fault.

 

I wonder if it would be rather a bit cheeky if I returned it under warranty at ECP?

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If I do press this into service again soon, it will need a few things seeing to. Firstly I need to get a proper distributor put on. Currently has a brand new £30 eBay special on it. No idea of the timings it has and probably will be all wrong. This is low priority though as the engine does run with it.

 

However as mentioned before, the engine runs crap at idle when warm and the idle doesn't sit in any one place. I've been reading up and I think these problems lie in the carb.

 

The rough running when warm I think is a quirk of these SU HIF carb. They have a Bimetallic temperature compensator that works on the needle jet. A similar idea to the wax stats on the older HS carbs, but reworked to supposed to be better (when new). Essentially when the engine/fuel warms up, the needle will move to lean out. Idea being that the fuel viscosity changing with temperature is automatically delt with.

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People have mixed reports if these are any good or not. However one key thing is that you must set the mixture when the engine is fully warmed up and have been gone on a run. When I set the mixture I might not have had done this. Possibly why it runs a bit rubbish when warm. Probably leaned out a bit too much.

 

It can also cause problems if the engine bay gets particular hot after a run and you try a hot start. As the fuel as warmed up in the float bowl, it will lean out the mixture. Not everyone seems to have this problem though. Seems to be either some accelerator or a small amount of choke will get it going again if this happens. Once cool fuel comes back in through the fuel lines, it'll clear itself.

 

The second problem of the idle being all over the place I think is caused by the poppet valves on the throttle body discs. Mine definitely has them and when I serviced the carb, I didn't know too much about the problems that these can give. These are the discs in question.

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The idea behind them is on overrun they allow air to still flow into the engine. This reduces excess hydrocarbons being emitted out of the tailpipe for emissions reasons. Also they prevent popping on overrun from this too.

 

Great in theory and when new. When they age though, the springs go weak and they don't seat properly. This causes effectively an air leak on the throttle plate. Thus causing the idle to wander around, depending how well they are sealing at the time.

 

Most people seem to remove them completely. Two ways. Either solder then up or replace them with the disc from a SU HS4 carb. The replacement discs aren't that expensive (like a tenner each with gaskets included) and also have the benefit of removing an obstruction in the manifold.

 

Hopefully with those things sorted (especially the carb) it should run more sweetly and give some much needed reliability. I would absolutely love to be able to trust and use this car. Just getting back in it today reminded me of the smells it has. Smells just like a car museum and like a proper old car should.

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1. I changed out the battery in mine last week. It was 11 years old and had finally decided to not hold charge overnight. They tend to have a pretty long life in these vehicles. I threw a $50 Wal-Mart special in it, to replace the 11 year old Wal-Mart special.

 

2. Don't try to solder the poppet valves. At best, you end up with an obstruction in the manifold, and at worst a warped disk. Just replace them-it's not a big deal. Be sure you replace the screws that go through the shaft also-they're normally included.

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1. I changed out the battery in mine last week. It was 11 years old and had finally decided to not hold charge overnight. They tend to have a pretty long life in these vehicles. I threw a $50 Wal-Mart special in it, to replace the 11 year old Wal-Mart special.

 

This battery would still have had plenty of charge and life in it if there wasn't a parasitic drain left on it. I didn't know the radio consumed power when the ignition was off and I would have disconnected the terminals if I knew. Also didn't really intend to not drive it for this long a period either.
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Get it running, drive it down here and leave it with me to exercise on a regular basis. I'll even valet it for ya.

 

This, but take it up to me. I'm thoroughly bored with not having an old car to tinker with... I probably won't wash it but I will provide video evidence of it doing 100mph.

 

The battery on the Acclaim was being flattened by a drain from the clock of all things, I thought the battery was goosed as on a cold night it'd die overnight even with the clock disconnected but once the car was in daily use it seemed to heal itself.

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Just rebuilt the brake master cylinder on the roadster. Well twice, contrary to HBOL, the seals aren't all the same.

 

Asbestos roofs seem to attract condensation on the inside, certainly mine and other mates do.

 

Charge battery (return if under warranty), Italian tune up.

 

Get it driven!

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Battery now charged. Took a good day and a half on the trickle charger to charge up. This is good as it means it should still have a fair amount of life in it and hopefully not too damaged. Can't take the electrolyte reading unfortunately as these modern batteries have the plugs sealed away. 

Also went shopping at Moss earlier today...

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A bunch of stuff including spare dizzy cap+rotor+points+condenser to keep in the car as emergency spares. Need to sort out my CSI ignition distributor so I can put something half decent in with reasonable timings. The new oil cap is to replace the old - supposed to replace them every 12000 miles as they have a filter in them that bungs up. I know you can pull them out and clean them but this was only £3.50 and I can at least still do it on the old one to reuse that next time.

Fuses are to replace all the old original and corroded ones. I was tempted to buy a new fusebox but to be honest the quality is no where near the same on them. I'll just take it off and give a good clean up with the fibreglass pencil and contact cleaner. 

Finally the main reason I went shopping was to pick up a pair of flat throttle disc kits with gaskets to replace the poppet valve ones in mine.

I was seriously considering getting new carb thermal compensators and replace them just in case. However that'd been an additional £50 or so in parts (including replacing the seals and springs) and I'm not entirely convinced they can go bad to be honest. Can bimetallic strips loose their properties? Surely not as it's only bits of dissimilar metal?!

Anyway I'm hoping this weekend I'll get a chance to fit this all and give a quick fluid change on it. Also need to phone the insurance for the Boxster and check it can be abandoned left up in the garage at the top for long periods. 

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