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You are here: Experts > Home/Garden > Auto Repair > MG Car Repair > 1980 MGB
Expert: Howard M. Fitzcharles III - 11/6/2009
Question
QUESTION: Hi, I have a 1980 MGB. After warming up and driving it around. The engine doesn't run smoothly.I don't drive it everyday, now that it has gotten colder (50 degrees) out. Also, between gears it lacks full power. Any suggestion what I can do to get it running smoothly?
ANSWER: Hi Debbie,
Your symptoms do not pinpoint the problem so testing is required. If you have tools and have some mechanical abilities I can walk you through the tests to find and correct the problem. The tools required are not expensive and the work testing is not difficult. If you want to try it, let me know and I will list the tools and how to run the tests.
If you prefer to take it to a shop let me know and I will give you the info to ask for and what their result parameter should be. This way you will know if they know what they are talking about. Many shops are straight but there are some that will try to take advantage of a woman because they think that most women don't know enough about cars to know if they are getting ripped off. Sometimes terminology and communication is the problem. Here is a true example of that.
I was a service manager of an MG dealership and a lady went to our parts counter and asked the parts manager for a can of compression. The parts manager gave a laugh and said "That's a good one. So what can I help you with?" The lady got mad and said "Well, give it to me in what ever it comes in if not a can!" I overheard this conversation and realized she was serious so I asked if I could help and why she thought she needed compression. She had taken her car to a mechanic close to her house and asked to have it checked as it was not running right and the mechanic said it was low on compression and it would probably cost several hundred dollars to fix. She figured that he was just going to go to the MG dealer and buy "compression" and put it in the engine. So she figured it would be much cheaper for her to go buy the "compression" and put it in herself. She didn't know the engine had to produce the "compression" and was not a commodity.
In this case the lady thought the mechanic was trying to overcharge her as he didn't explain his diagnosis. We did get the job and we explained why her engine was low on compression.
This is not a women only problem as I have had many men who did not understand how an engine operated. Having some basic knowledge of engines and cars will in many cases keep a person for getting ripped off or purchasing some part or service they don't really need.
Let me know,
Howard
---------- FOLLOW-UP ----------
QUESTION: Hi Howard,thanks for getting back with me! Yes, I would like to know how to do the test and the tools I need!7
Answer
Hi Debbie,
Other than a standard wrench set and a few screwdrivers the only thing else you will need is a timing light, compression gauge and a vacuum/fuel pressure gauge and a "T" fitting for the fuel line. (5/16") These extra tools besides a wrench set are not expensive and can even be found in Wall Mart. Nicer tools can be purchased at any auto parts store. Unless you plan to do this as a hobby more often you can buy high grade tools from one of the mechanics tool trucks that regularly stop at all repair shops. Snap-on, Matco or even Sears are good. But for a not so often repair work the Wall Mart tools will be ok.
You need to do exactly what I would do if your car came to me in a dealership with your complaint.
First remove the spark plugs and look at the inside tips. They all four should look about the same and look fairly clean with no oil or chunks of carbon on them and the center electrode (center pin) and the negative electrode (the outer bent over pin) should not be burned away much. The Porcelain around the inner center electrode should be either white or a light tan in color. Anything different then that you need to purchase new plugs before you finish the testing.
There are two kinds of compression gauges, one type screws into the spark plug hole and the other needs to be held in hard to the hole. Before you run the compression test remove the white with the black tracer wire/s off of the ignition coil. Put the gauge in #1 hole and have someone hold the throttle open and spin the starter so that the engine spins at least 4 or 5 revolutions and write down the gauge reading. Do the same test on each cylinder (be sure the throttle is held open). The readings should be at least 125 PSI or higher and each should not be a lot different from each other. If it does not pass this first test it is no use going any further as this is a test of the engine itself. If it failed this test let me know and I will give you the test to see what is wrong with the engine.
If it passed the first test you can put the plugs back in (or the new ones) and the wires back on the plugs and on the coil.
Now, loosen the clamp on the fuel hose at the carburetor and remove the fuel hose from the carb and install the "T" fitting on the hose. If a couple of short pieces of fuel hose didn't come with the "T" get at least one short piece and some clamps and connect the "T" to the carb and to the fuel gauge. (be sure to put clamps on all the hose connections.) The fuel line should now be connected to the carb and the fuel gauge with clamps on all hose ends.
You can also connect up the timing light (instruction are usually included) If not let me know.
Now start the engine and read the fuel pressure gauge. It should read from 1.5 PSI up to 3 PSI but not higher.
With the engine running at idle check the ignition timing on the front crankshaft pulley and marks on the front timing cover. It should be at 10 degrees before top dead center at 1500 RPM (fast idle) If this is not correct let me know and I will tell you how to correct it.
let me know how you do up to this point.
Howard
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