MGB FAQ
MG Experience Library – Frequently Asked Questions Section
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Should I buy an MGB?
If you love a visceral driving experience, and are willing to do or have done the (very reasonable) maintenance needed by a 30+ year old car, then absolutely yes! Read LBC: Fact and Fiction and my little essay in Buying Your MGB for the whole story. Both can be found in the Library section of The MG Experience.
Where is the transmission dipstick & fill hole?
Cleverly hidden! It's on the transmission tunnel behind the center console (behind the speaker on early MGBs). You have to access it from inside the car. Lift up the carpeting and there will be a big rubber plug on the tunnel. Under that is the transmission dipstick. Spilling oil on your passenger side carpet while filling the transmission is a rite of MGB ownership.
Where are the jack points on the MGB?
The original jack points are the little tubes below the doors on either side of the car. However I would NOT recommend using these, or the original jack, for a couple of reasons. One is the sills are often rusted out on MGBs and they might disintegrate under the presssure. The other reason is because it's not a great design and the jack could slip out, causing the car to fall. At best you've destroyed your door skin and paint job and at worst crushed your head while you're working on it. It's happened, unfortuately.
To lift the front of the car, put a trolley jack under the front crossmember (the huge beam bolted under the engine that the suspension is attached to). For extra safety, position the "cup" on the jack at the rear edge of the crossmembers, so that as the car lifts, the edge will tend to locate itself in the gaps in the cup. Then place jack stands under the frame rails (raised box sections under the car, behind the engine, which run parallel to the transmission tunnel). If you only need to raise one wheel, its safe to jack under the lower spring pans.
To lift the rear of the car, jack up under the axle differential housing (the big bulbous part in the middle of the axle), and place stands under either end of the axle beside the leaf springs (be careful not to squish the brake lines when you lower the car onto the stands).
ALWAYS use jack stands when working under the car. DO NOT rely on a jack, or cinder blocks, or wood, or anything else you have around the yard to hold the car up.
How do I tell what year an MGB is?
The easiest way is to compare the VIN plate on the top of the dash to the numbers below (for more accurate production data, check out Production Specs in the Library). At a glance, chrome bumper B's were made from 1963-1974 and rubbernose B's were made from 1974½-1980 (for the North American market).
For information on changes throughout the MGB's long production run, please see the MGB Evolution article.
Where is the VIN?
Looking for information on the MGB VIN location and decoding?
The article has moved here to it's own page.
How can I find my car's build date and original options?
You probably want a Heritage Certificate for your car.
These can be purchased at the Heritage Motor Centre UK.
If your car has the original window glass, you may be able to estimate the build date using the Triplex Date Code.
Common terms and acronyms:
(This list is far from complete!)
- BFH
- Big Freakin' Hammer. See also, BFS and Large Rock.
- BFS
- Big Freakin' Screwdriver. See also, BFH and Duct Tape.
- BMIHT
- British Motor Industry Heritage Trust. Maintains records of all the old British marques and is involved with pressing new bodyshells for some years and models. Located in/around Stratford, England I think.
- Bondo
- What many MGBs are held together with. See also Duct Tape.
- CBB
- Chrome Bumper (pre 1974½) MGB. See also RBB.
- Blowby
- Post-combustion gunk that gets from the combustion chamber past the piston rings and into the engine oil. Usually caused by broken rings or scored cylinder walls.
- Crack of Doom
- A common stress crack that develops on the door skins just behind the vent window. The only known design flaw in the MGB.
- Death Rattle
- Common to Midgets, a "marbles in the dryer" sound on startup that indicates your main bearings are on their way out.
- Detonation
- Detonation occurs when excessive heat and pressure in the combustion chamber cause the air/fuel mixture to ignite before the spark. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel. When these multiple flames collide, they do so with explosive force that produces a sudden rise in cylinder pressure accompanied by a sharp metallic pinging or knocking noise. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading. Avoid.
- Dieseling
- When your car continues to run after you've turned the ignition off. Caused by pressure and excess heat in the cylinders igniting the air fuel mixture without spark (like a diesel engine).
- DPO
- Dreaded Previous Owner, usually used when one finds a bodge or a hack used to cover up a problem instead of purchasing the correct part to fix it. Also used in conjuction with other adjectives when Bondo is discovered.
- Duct Tape
- The Handyman's Secret Weapon. The rear tail light had been held on by duct tape for years when I bought my LBC. See also DPO.
- FAQ
- Frequently Asked Questions
- FWIW
- For What It's Worth
- HT
- High Tension, or high voltage (20-40kV) half of ignition system comprising of coil secondary winding, distributor rotor and cap, spark plug wires, and spark plugs. This can kill you if it discharges through your body. See also LT.
- IMHO/IMO
- In My (Humble) Opinion
- Knocking
- A catch-all term which could mean Detonation or Pinging
- Large Rock
- A tool commonly available at the side of the road in the middle of the night when you need to "fix" something
- LBC
- Little British Car (or Convertible). MG, Triumph, Austin-Healey, Morgan, etc
- LT
- Low Tension, or low voltage (12V) half of ignition system comprising of coil primary winding, distributor points (or equivalent), electric tachometer, and possibly ballast resistor. See also HT.
- Lucas
- The manufacturer of most of the electrical bits in British cars and motorcycles. Unfairly given a bad rap for the tendancy of cars neglected for many years to break down. See also "Have you checked the ground connection and the bullet connectors?"
- MG
- According to MG it doesn't stand for anything, but it originally meant Morris Garages
- MOT
- Ministry of Transportation - Yearly roadworthiness check all cars in the UK must go through
- MOWOG
- MOrris WOlesley mG (or Group or Garages depending who you talk to)
- NOS
- New Old Stock. It's 'old stock', but never been used. This is important for items which are no longer manufactured, or for which only poor quality reproductions are manufactured. For example, if you find a dusty 30 year old box with an unused Lucas switch in it, it's NOS.
- Octane
- The ability of gasoline (petrol) to resist detonation. Higher octane fuel burns slower than low octane fuel. Two systems mesure octane, MON and RON. Despite what some people think, there's no gain to be had by using a higher octane above whatever doesn't cause pinging in your engine.
- OEM
- Original Equipment Manufacturer. Correct parts made by the company that supplied the factory. Think of things like AP/Lockheed brake parts. Still made today to for our cars. In contrast, you have Borg & Beck clutches, which are OEM, and Quinton Hazel, which while they fit and work, are aftermarket parts.
- Overrun
- The period between taking your foot off the gas pedal and the engine RPMs dropping to idle
- Oversteer
- When the rear tires lose traction while cornering (fishtail)
- PO
- See DPO
- Pinging
- Technically, pre-ignition. Caused by hotspots igniting the air/fuel mixture before the spark, like the pointy bit in the head of early MGBs. Can be caused by too-advanced timing, low octane fuel, too high compression ratio. Less severe form of detonation. See also Knocking.
- Pinking
- Just another word for Pinging, I think its the UK version?
- Prince of Darkness
- See Lucas.
- RBB
- Rubber Bumper (post 1974½) MGB. See also CBB.
- Rostyle
- Rubery Owen mag-style wheels
- Run-on
- See dieseling
- Smiths
- Manufacturer of gauges that usually work, and sometimes show the correct value.
- SU
- Skinners Union. Carburettor manufacturer (early cars, and later cars with smart owners). Originally, carbs had leather parts, hence the connection to tanneries. MGBs have two SUs, each feeding two cylinders. May also stand for "Seldom Understood". A wise man once said "90% of carb problems are electrical". See also Weber and ZS and WAG.
- Tickover
- Idle at lowest possible RPM, about 800 rpm, although some tuning manuals call for 600 rpm (good luck!)
- Understeer
- When the front tires lose traction while cornering (and you end up going straight instead)
- Weber
- Carburettor manufacturer popular with people who have too much money in their pocket and not enough books in their library.
- WAG
- Wild Assed Guess
- YMMV
- Your Mileage May Vary
- ZS
- Zenith-Stromberg carburettor manufacturer (later cars)
Comments on "MGB FAQ"
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Comments on "MGB FAQ" –
Over many years as a tech it was my experience that dieseling (engine running after the key was turned off) could be defeated by turning down the idle speed. Whatever the internal reason for it (a subject for sometimes great debate) if the idle speed is slow enough the carbs can't work well enough for this condition to keep going.
Naturally, the idle has to be fast enough so the engine won't stall when idling. I was almost always able to set that balance to eliminate dieseling.
FYI, I worked in sports cars garages and new car dealerships for about fifteen years starting in the early 50s. I prepared many MGAs and Bs for delivery to their proud new owners.
Don
Are there parts depending on this voltage(starter,dynamo etc)or just the bulbs.
The car is pos earth (till 1967?)
Thanks.
the MGB Evolution article for more info: http://www.mgexperience.net/article/evolution.html
A member posted an undocumented location for a VIN stamp. The passenger side (this is LHD)frame rail aft of the motor mount bears a faint stamp of the car number. There is a reinforcement plate which wraps up around the chassis and bears the stamping at that location.
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