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Technical Area => Upkeep and Performance Hints => Topic started by: amgba on December 16, 2007, 04:43:11 PM

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Title: Evaluating a Non-Running MG
Post by: amgba on December 16, 2007, 04:43:11 PM
by Art Isaacs

Evaluating an MG that has not been running in more than a year is  not that complicated, but depending on what you find, could get expensive to remedy. Let’s look at it from “3 sides” - the outside, the underside and the inside. We may jump around a bit, but there’s a certain madness to the method. Being this is your first MG experience, I will start with the very basics.

First get yourself some good catalogs with pictures and a manual. I find the Haynes or Bentley manuals to be adequate, but the sketches and pictures in the Moss and Victoria British catalogs are invaluable in understanding the assemblies and what and where the parts are you are looking at are for. Both these catalogs are available on-line, so if you are in a rush to get started, bring a laptop down to the garage so you can look at the screens until you get the hard copies. Make sure you cover the keyboard with plastic wrap or it will get very dirty as you scroll the pages. Printing the pages out is time consuming and expensive. The catalogs are free and you will definitely need them to order parts or identify them at swap meets.

Start with the outside as Side 1, as that is more obvious and readily seen and the most expensive to deal with. You say the car has a “great body”. That sounds like a very good start as an MGB is a unit-body type construction. It has no formal separate chassis as the even older MG’s do, so the condition of the body metal is more important for both visual and safety reasons. While everybody gets concerned with the mechanicals, they can be much less expensive to deal with than body rust on this type of car. Common areas that can be hidden are the floors (usually from sitting outside with the top down or damaged), lower front and rear fenders (which is usually indication of worse damage behind), door bottoms and door sills at both ends. The sills are fairly complex structural sheet metal assemblies and, though most all of the pieces are ready available, they are expensive and their replacement is involved and costly. Filling any rust here with bondo or other make-shift repair can mask the problem visually, but could present itself later and cause structural issues. Beware of replacement front fenders, patch panels and Bondo patching to cover the ills beneath. Look for sagging at the door tops where the body closes-up a bit at the tops of the door frames and such that it is forced against the doors. Binding doors and signs of wear on the body where the doors close mean you have reached this point. It is an indication of weakening of the car’s structure. Some sag is inevitable and a minor difference of the door gap from bottom to top may not be telling you anything significant after 27+ years, even on a sound car, but I think this should give you an idea. You should put the car up on jacks or a lift to look at the body from beneath and behind, so you will get a first look at the suspension, but I’ll go into more detail of what to look at in the next paragraph. A good measure of bodywork cost is that you take any figure you might have in mind to repair rust and triple it to get a true idea of the actual cost. Let’s assume from your post that the body is reasonably good and move on to the next “side”.

For Side 2, open the hood and take an inventory of what is there to see how complete the engine is. That a distributor, alternator, fan, coil, etc. are there is enough for now. Use the catalogs and manuals to help. Do not be surprised if the pollution control equipment has been removed. In States that do not require historical cars to pass emissions tests or do not check for these things (the inspectors usually would not know what belonged there in the first place), most of us removed the cumbersome gear, which was more often than not non-functional, and gave the engine bay clearer access and a clean outlook that makes it more easily serviceable. The stock late model B as this one should have a single carburetor (a Zenith-Stromberg 175CD side-draft) on a combined intake-exhaust manifold with a catalytic converter bolted-up beneath. This might have been changed as the Strombergs tended to be more difficult to maintain and robbed performance. Common aftermarket swaps are for a more reliable SU HIF-44 (a new bolt-on item that uses all the original manifolds) or Weber DGV down-draft (with new intake and exhaust manifold required and also eliminates the catalytic converter). Another variation is to fit a complete twin SU carburetor set-up with stock intake and exhaust manifolds from an earlier MGB (HS-4 or HIF-4). These could also have a new header set and would eliminate the catalytic converter with an exhaust system altered to something closer to the early cars. Carburetor floats and jets could have varnish in them and might need cleaning to get the car started. Some of these you might want to replace later, but I am firm believer in seeing what you have first, then make changes.

Check the usual things you would with any car, like coolant and oil, just to see the condition. Low levels or presence of water in the oil or vice versa are signs of other issues. All fluids should be changed before you try starting it, of course. Look for any coolant weeping along the head gasket. Common on these cars, it indicates the gasket will need to be changed. Once satisfied you have a fairly complete engine, you can start getting your hands dirty. Pull the spark plugs and spray Liquid Wrench or WD40 in each cylinder. Let that sit for a while and then squirt some motor oil in and let that sit a bit. Try to hand turn the engine over. If it moves freely, make plans to change fluids and do a minor tune-up (plugs, cap, rotor, points – if equipped – fuel filter) and move on to the suspension and brakes. If not, put in more Liquid Wrench and oil and hope it frees-up while you move on to the suspension and brakes.

In between oil treatments, you can try to determine exactly what you have. MGB’s are very interchangeable between years and, over the years, carbs, distributors and internal parts get swapped, modified, altered and changed between models and years. Whole drivelines can be swapped and they will look and work fine, but, just as an example, the distributor cap and rotor from a later B will not fit an early car’s distributor. Since the Lucas electronic ignition was so bad, many opted for the earlier points distributors and then went further to equip them with aftermarket electronic conversions. Our the almost 20 years I’ve owned my B, it has had (3) Lucas distributors – a 25D from an early Sprite (which it came with), a 45D from a 74 and, finally, a proper, rebuilt year-correct 25D, which is now equipped with a Pertronix electronic conversion. Internal parts get worse as over-bored cylinders and ground crank journals to deal with normal wear are not documented and do not become apparent until you open the engine. You can worry about that later, as hopefully, you will not have to rebuild the entire engine. Just remember to identify what you have before ordering anything.  The rear suspension is fairly simple and straight forward. The axle itself is a tube type, very robust and seldom a major problem. It has drum brakes at each end. Check for axle end seal leakage at the brakes (when you pull the drums and check the brakes themselves). There is also a typical “clunk” in driving that comes from wear and usually indicates the fiber spacer bushings in the differential have worn and cracked and dropped out of place. The gear lash becomes such that when you drop off or press the accelerator, the slack takes-up and the gears click. It sounds ominous, but is reasonably easy to address later and not critical at this point. Many I know have been driving with this clunk for years and not taking care of it. The axle rides on semi-elliptical leaf springs on bushings with a bolt through a channel in the body at front and shackles at rear of the springs. From the lower spring plate, there is an arm to the lever shocks mounted above. There are also 2 rebound straps that limit the axle travel. They tend to fray and crack, so usually need replacement. More import with them is their attachment points to the axle, which if rusted or broken will require welding to repair and also might be indicative of some rough handling of the car.

The front suspension has some hidden items that can be costly to deal with, but not deal-breakers. Expect the stock rubber bushings on the inner end of the lower suspension arms to be shot. They are not very resistant to oil and are soft, so wear and deteriorate quickly. They are also cheap and relatively easy to replace. If someone put urethane bushings or the V8 type in, you may be ahead of the game. As an aside, I found the urethane bushings (complete front and rear kit) to work and last very well, as well as improve the ride and handling. The kingpin assembly really holds the secrets. If worn, you either need buy a rebuilt assembly or find a machine shop and/or special tools to re-bush and line-bore the spindles. There are many bushings, seals and other components that will need to be evaluated, but for now just see that they are there. The upper control arm is a lever-shock, just like on old American cars. It bolts to the top of the cross member and has cast upper control arms. Check for cracks and oil leakage. These shocks, both front and rear, can be rebuilt or replaced outright, as new is now available. There are other options, but get familiar with the car and see what the budget will need to be before considering what to do with this.  The lower control arm is an assembly of 2 channel arms, front and back, running from the inside bushings at the crossmember, where there is a tube welded on for the bushings, to the pivot at the bottom of the king pin assembly, where a hole is drilled to allow a bolt through. There is a spring pan held to the arms with 4 bolts (2 each side) to the lower arms. The king pin has about 3 grease fittings and the lowest one lubricates the through bolt and allows it to turn with the arms. Should this bolt freeze to the bushing, it does not turn and causes wear the arm (the bolt hole becomes oblong) and bolt itself (the arm cuts into the bolt), which cannot be seen unless the castellated nut and washer behind is removed. In the least, this causes alignment problems. In the extreme, it can break the arm or bolt and drop the lower suspension from the king pin and cause the wheel to move out sideways. If you do not check this in buying the car, make sure you look for it in your restoration efforts.

Front brakes are solid disc-type with 2 piston calipers. Check for signs of fluid leakage or uneven wear on the discs that might indicate a frozen piston in the caliper. As long as they are complete, you can address their true condition later.

The exhaust system and hangers are obvious to see. Not that expensive or difficult to replace, but it is good if they are there, complete and functional to start.

The internals of the transmission, overdrive (if equipped) and clutch will have to remain a bit of a mystery. You can check for leakage on the exterior, but there are no inspection covers to remove to easily check the clutch or gear conditions. Also, oil leakage at the clutch end may well be the engine main seal. Since the trans uses motor oil (not a hypoid oil), it is hard to tell the difference from outside. Check the function of the hydraulic clutch master and slave cylinders and that they or the flexible line to the slave cylinder are not leaking.

Side 3 is the inside. Often overlooked by MG enthusiasts as seeing cars as always requiring upholstery and carpet, this is becoming more expensive every year.  Needless to say, if the seats in this car are in good or at least usable condition for a time, it is a big savings. Carpet is not that bad to buy and install and is usually very worn or dirty. Instruments, switches, console, radio and the dash panel itself can be very costly, but are available. Most can be found in good condition at swap meets. Wiring and switches – checking operation can wait, but see that they are all there. The stock fuse panel placement is usually under the hood at the rear of the left side of the engine bay, as you face it from the front. The fuse box is subject to the connections loosening and corroding, so in the least expect to have to clean it up thoroughly. It is available new and aftermarket items that are better are available. The battery is under the floor of the shelf behind the passenger’s seat. It is probably dead and ruined, so expect to replace it. Lucas electricals are a problem in themselves, so the better the condition of the wiring and components, the better your chances are things will work and not need too much attention.
Title: Re: Evaluating a Non-Running MG
Post by: blackRose18 on May 22, 2009, 01:07:07 AM
 I think  they may jump around a bit, but there’s a certain madness to the method.It is an indication of weakening of the car’s structure.

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