QuestionQUESTION: I have a 1974 MG midget that smokes a puff when i start or when i start off from a light. I replaced the head gasket last summer and saw that the 2 brass core plugs were recessed. What else could be the cause and what is the best course to diagnoss and correct the problem.
ryan
ANSWER: Hi Ryan,
I am guessing you mean it smokes from the tail pipe?
The color of the smoke tells what it is. A pale blue smoke is oil, white smoke is coolant and black smoke is excess fuel. So what do you have? Tell me what you have and I will try to tell you how to diagnose the problem.
Howard
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QUESTION: The smoke is blue.
ANSWER: Blue smoke when accelerating is a sign of a ring problem. However, other causes need to be eliminated first. An inoperative crankcase vent system can cause oil burning or an over full oil level can also.
Oil burning on start up is also an indication of either excessive valve stem to guide clearance and / or the "O" rings that were suppose to be installed on the valve stems were left off.
The normal test for a ring problem is a "Dry & Wet" compression test. There should not be more than 10 to 15
difference between the two tests. If you are not familiar with the test procedure let me know and I will out line it for you.
Howard
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QUESTION: Please give me the procedure for the dry & wet test. And I know i possibly created a major blunder when I had pepboys do my last oil change (it was already cold and had no heat in th garage and I was lazy) could they have put to much oil in and caused this? The dip stick is reading half way with no great change.
AnswerRyan, you are not making yourself clear. You said "The dip stick is reading half way with no great change"
Half way WHAT? half way up the stick? or half way to the Full mark? and with no great change? change form what?
The dry test is to just do a compression test, throttle open and at least 4 or 5 revolutions of the crank on each cylinder test. You should see at least from 135 to 180 PSI on each cylinder with little difference between each cylinder.
The wet test is to put about 4 or 5 squirts of engine oil in a plug hole and run another compression test. This reading will be higher than the first dry test but it should not be more than 10 to 15 higher.
A higher reading is an indication of a ring problem.
Another method to test is the use of a "Leak down test" which requires leak down test equipment. Available from most tool trucks.
Howard
