Help is needed in Savannah, GA for some knowledgeable Model-T person to check an engine knock. An accurate assessment needs to be made to determine if the noise is actually a bearing knock, piston slap, cam bearing looseness, or just a lesser noise somewhere. Car owner wants to insure his car will be in good running condition for an upcoming tour. Your response will be answered by a PM with the contact information details. Thanks in advance.
Engine knocks in general are not a good thing. Obviously a rod or main bearing is worse than some of the other causes of noise -- but still not a good thing.
I would suggest your friend contact the South Carolina Model T Ford Club. Their web site is located at: http://www.scmodeltford.org/ and in the lower right hand corner is a "contact" button. They usually answer within a day or so if they are not out on tour etc.
Our president Susan Harrington lives in Ridgeland SC about 32 miles north of Savannah, GA. There is a good chance that she may know someone who could check out the engine and is closer to you.
I'm about 2 hours & 15 min away. I'm sure we can have someone listen to the engine. But there are some preliminary things the owner can do to help the process out a lot. First by sharing what he knows about the history of the car -- for example:
Was it recently purchased or owned by the current owner for the past 20 years?
Has it been running fine for the past 5 years but ran low on oil and is now knocking etc.? Or was there some other change between it didn't knock and it now knocks (for example a new hearing aid for some of us).
Has the oil been changed recently and were there any babbit pieces in the oil?
Have they checked to see if someone installed a screen under the transmission cover and if so is there any evidence of metal collecting there?
Have they dropped the engine inspection plate and tested for looseness of the rods. (If it is a three dip inspection pan -- I know of one engine that threw the #4 rod, and when it was rebuilt -- they didn't put the cotter pins (or lock washers or lock nuts) on the #4 rod the second time either.
When were the bearing clearances last checked and about how many miles were put on the car since then?
http://remanufactured.com/Engine_Diagnosis_101.htm has some comments on engine noise. While talking about the more modern engines – it still has some good points. Shorting out the spark plug should help you identify if the noise is related to that piston (i.e. the rod, piston slap, wrist pin etc.).
From the 1921 Ford Owner’s Manual at: http://www.mtfca.com/books/21manual.htm on the last page it has some common (but not all) causes of knocking sounds.
1. Carbon deposit on piston heads.
2. Loose connecting rod bearing.
3. Loose crank shaft bearing.
4. Spark advanced too far.
5. Engine overheated.
It has been a while but somewhere I’ve read and have a list of engine knock causes and how to help determine what is causing them.
Also be sure to let them know what type of schedule your friend is looking at – i.e. to make a tour next weekend or in May? And how long of a trip – 50 miles or a couple of hundred miles? And what speeds – 30-35 or wide open? And is the engine stock or modified?
Remember if they stop when the bearing first makes noise they often will not have harmed the crankshaft etc. But the longer they keep driving the more likely other parts will be damaged.
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By cheap automotive stethoscope. Isolate sound while running. Check for loose/sloppy fan belt pulley on crank.