Is Your Engine Tired?
I talk to a lot of MG owners about the condition of their engines. Over and over, I hear the phrase, “My engine is tired.” I tell them there is no such thing as a tired engine. The real question is: does your engine have what it needs to run well? Think of your own body – if you were thirsty, hungry, overheated, and constipated, would you feel great? Of course not!
To give your engine more pep, consider these five factors that determine its health:
1. Water leaks. Do the freeze plugs leak? Is there a crack in the head or the block? Is there a leak at the water pump, thermostat housing, heater control valve? Many of these leaks are easily repaired, but not the cracked head or block.
2. Oil consumption. Does the engine use too much oil? What is too much? Personally, anything more than about one quart per thousand miles is too much for me – but oil is much less expensive than engine work. The engine consumes oil because it leaks it or burns it.
The engine might leak because the PCV system is plugged and the engine is pressurizing. It might leak because seals, gaskets, or fittings are faulty or loose.
The engine might burn oil because the PCV system is plugged. It might burn oil because the valve guides are worn. Oil burning is almost always because the rings are faulty.
3. Compression. The compression should be consistent within 10%. Faulty compression is usually caused by a burnt exhaust valve, but both the intake valves and compression rings can and do burn.
4. Oil Pressure. The oil pressure on all our engines, TC through 1980 MGB should be about 75 psi running down the road (MGCs about 35). Low oil pressure is an indicator of wrong or diluted oil, a faulty oil pump, or worn bearings.
5. Camshaft Condition. The lift at each lobe on the cam should be the same within 0.010”.
That’s it! No where in these factors can you find or use the word “tired.”
Replacing the water pump is less expensive than rebuilding the engine. Fitting new oil rings is less expensive, too. So it goes for a valve grind or new bearings or a new cam. On the other hand, if three or four of these factors are faulty, one can make the case for an engine rebuild.
Always approach each problem with the simplest, least expensive option first!