Engine Tuning/Set-up Tour

This “tour” outlines the steps to systematically work through all the adjustments on a W113 to get it running properly. It is probably most applicable on a car where you have no history (a new purchase, for example) and just need to start at the beginning and work through everything. If nothing else, going through everything serves to create a valuable, baseline knowledge of your car, and confirmed what's working properly, and what's not. On cars where you already have history or some baseline knowledge of what works correctly, then many of these steps can be bypassed.

The order of the steps is important, as many adjustments are dependent on and changed by adjustments made in previous steps. Since in many cases changing one thing also changes another, if you go about them in the wrong order you can waste a lot of time chasing in circles.

Embarking on these adjustments requires that the car at least starts and runs. If it doesn’t, you will have to figure that out first. These steps may provide clues, but are not intended as a step-by-step “how to get my car running” guide.

Tuning/Setup Procedures

Some of the procedures need to be carried out on a cold engines, and others on a hot engine. This sequence attempts to group activities together to minimize the number of times that you need to let your engine cool back down (the part that takes the longest). Regardless, you will probably find yourself having to spread this out across a couple of days to allow ample cooling time between steps.

  • Check and adjust throttle linkages
    • Don’t assume they are correct – assume they are incorrect. Over the 40 years your car has been around, chances are someone incorrectly made adjustments that you now need to correct. (Link to Linkage Tour).
    • See Engine Linkage Tour
  • Check cold start devices
  • Check Fuel system (links to other articles)
    • Check fuel pressure. Easier said than done unless you have the gauge and fittings.
    • Check fuel flow rate. See Fuel flow measurement
  • Replace fuel filter
  • Replace air filter
  • Ignition
    • See Ignition system
    • Replace points, condenser, cap, rotor, and plugs. They are cheap and will eliminate a lot of possible problems.
    • Check the points’ gap and dwell. Changes to dwell will subsequently change timing, so this needs to be done before setting timing.
    • Check resistance of coil and resistor to be sure they are correct
    • Check resistance of plug wires to be sure they are correct
  • Setup to monitor and check warm up process.
    • Remove FIP Warm Running Device (WRD) air filter. Find something to reach down and cover intake hole. A metal ruler or paint scraper will work. You will need to cover the intake at various times while the engine is warming up.
    • Rig a test lamp or volt meter to check operation of time/temp switches. (Author's note: I think this is already covered earlier under starting aids?)
    • Connect a vacuum gauge.
  • Start engine and monitor warm-up process.
    • Check immediately after starting
      • Check for suction at WRD intake. There should be strong vacuum at the port.
      • Check for proper vacuum on gauge (what should it look like during warm up?)
      • Engine RPM should be 1100? Note RPM if different.
    • As engine warms up
      • Temp/time switch should change state at what temp and what time? (author's note: I think is already covered too)
      • RPM should slowly come down, and reach 700-800 by around 150-160 F. At that point, there should be little to no vacuum at WRD intake port.
    • Misc checks
      • Confirm stable, correct vacuum (value?)
      • Carefully check for vacuum leaks. Check the brake booster line, line to automatic transmission, and line to distributor. Spray WD-40 around manifold/head joints and other fittings to check for leaks.
  • Ignition
    • Confirm dwell reading
    • Confirm timing. Check at Idle, 1500, 2000, 3000 RPM. Timing should be stable, not wondering around. If not, you might have a worn distributor.
    • Confirm vacuum advance/retard is working correctly.
  • Re-torque head bolts
  • Allow engine to cool, then adjust valves
    • Be prepare to replace the valve cover gasket if it has become brittle and hard. If breaks or cracks after bending it sharply, it should be replaced.
  • Check compression (after reinstalling the valve cover to avoid an oil shower)
  • Idle mixture adjustment (only after engine is fully warmed up)
  • Full range mixture check/adjust (this is more complicated)
  • Confirm operation of dash pots (which ones, and where are they?)
  • Confirm operation of Constant Speed Solenoid (automatics and/or AC equipped cars)
  • Automatics


For regular maintenance procedures, see Maintenance