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The "Dollar Bill" Test

Contributed By: Bill "Willy" Trautman

I don't know what you would like to call this but its in reference to "rough"checking to see if you need to have a valve job or a new timing chain installed;

If your FSJ or any vehicle for that matter, runs poorly and possibly backfires through the exhaust or carburetor you may want to check to see if its in need of a timing chain or valve job. listed below is some very simple test`s that you can perform that dont cost any money.

  1. Put a dollar bill up to the tailpipe and if it sucks it up intermittently you may need a timing chain or a valve job or both.
  2. You then go to the front of the motor and pull the distributor cap off and put it out of the way so you can watch the rotor move for the following steps.
  3. Use a breaker bar or a ratchet with a socket on it that fits the balancer bolt and turn it until the rotor turns and stop.
  4. You dont have to mark the balancer if you can keep an eye on it and watch the rotor at the same time but you may want to. You make a mark on the balancer at the timing marks on the front of the timing cover for a reference.
  5. Turn the balancer again in the opposite direction until the rotor JUST starts to turn and then STOP!
  6. If the distance is more than approx. 1/4" you need to replace the timing chain.
  7. If after you replace the timing chain the tailpipe still sucks up a dollar bill the next thing is to check the valves.
  8. There are several ways that you can check this:
    1. a cylinder leak down test that you use an air compressor to do it.
    2. A pressure test where you use a cylinder pressure gauge.

The easiest way is to do a pressure test ( for the most of us that is)

You will need a manual to know just what pressures that your engine should be at so I wont go into anything on this because it will tell you in the manual how to do it.

I learned these simple test`s a long time ago and they sure come in handy when your trying to buy a used vehicle. Its not to hard to pull out a dollar bill and put it up to the exhaust with the owner of the vehicle standing there.:)

I had done this test with the Jeep that we currently own now just before we bought it and it sucked up the dollar and after checking the timing chain, I discovered that it was bad..... the balancer moved about 1 1/2 in!!! Its a wonder that it even ran.( which,by the way, it barely did.)

After I replaced the timing chain it didn't suck up the dollar bill anymore but it still didn't run right so I did a pressure check and discovered that the pressure was below normal in two of the cylinders and I had a blown head gasket!! Well, now the engine is out and I am planning on getting a short block in the first part of March. Our Jeep had 177,775 miles on the speedometer so a rebuild was due. :(

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