Been tinkering on the depot hack since i brought it home. Put it in its first show yesterday. Last week i took in the play on the rod bearings as i had a faint rod noise. I also made sure the mag oil line was flowing oil. Now i have a new noise. It only does it when its warm from driving, at a high idle driving or sitting still with the advance lever all the way down it consistently "hammers". I can feel it thru the floorboard. If i move the timing lever up to about 1/3 from fully retarded, it goes away completely. Any suggestions what to check?
My suggestion is if it hurts (or makes noise) don't do it. The timing should not be fully advanced unless running at full speed.
This may give some guidelines on timing:
The owners manual does say that an overly advanced spark will cause a dull knock - read below:
How are Spark and Throttle Levers used? Answer No. 4
Under the steering wheel are two small levers. The right-hand (throttle) lever controls the amount of mixture (gasoline and air) which goes into the engine. When the engine is in operation, the farther this lever is moved downward toward the driver (referred to as "opening the throttle") the faster the engine runs and the greater the power furnished. The left-hand lever controls the spark, which explodes the gas in the cylinders of the engine. The advancing of this lever "advances the spark," and it should be moved down notch by notch until the motor seems to reach its maximum speed. If the lever is advanced beyond this point a dull knock will be noticed in the engine. (See chapter on Ignition.)
How is the Spark controlled? Answer No. 14
By the left-hand lever under the steering wheel. Good operators drive with the spark lever advanced just as far as the engine will permit. However, advancing the spark too far will cause a dull knock in the motor, due to the fact that the explosion occurs too early. The spark should only be retarded when the engine slows down on a heavy road or steep grade, but care should be exercised not to retard the spark too far as this will result in late ignition, which causes loss of power and overheating of the motor and may also result in warped, burned or cracked valves. Learn to operate the spark as the occasion demands. The greatest economy in gasoline consumption is obtained by driving with the spark advanced sufficiently to obtain the maximum speed.
Thanks for the info guys, and i have heard the dull knock you speak of, but this noise is a metallic hammering sound. I understand that the car shouldnt be operated as such normally, but i discovered the sound by accident and that is the only way to repeat the sound.
What you are describing is almost identical to the sound I was hearing in my engine. Here is what the Dyke's manual has to say about the knocks.
If I went to full retarded position it stopped, and as soon as I gave a little bit of advance it started again.
My cam to crank gear slop was visually plenty, and that can make the sound too.
As Frank says...
You've taken up the rod bearings, why not check the mains...
Mine were hammered to pieces
Not to question your mechanical abilities but, could you have done something wrong in adjusting your rods? Maybe it's worth a look to see if everything is as you wanted it to be. What did you set your rod clearances at?
Jerry- i like to think im pretty handy at mechanicing on anything from the lawnmower to my harley to my unstyled deere and steel wheeled case, but i am fairly new to the model t, and very far from claiming im any kind of expert. I used the newspaper method, and i did take pictures of the rods and caps as i went along. In one of the pictures i now notice it looks as if the babbitt is only wearing on about 50% of the surface. It looks like the pan cover will be coming off again. This time ill plasti-gage the mains while im in there re checking rods again. Thanks for the info.