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Autopapyrus · GAZ Volga (GAZ-31105) 2.3 16V ZMZ-40620 (2005)
https://autopapyrus.com/guides/gaz/volga/setting-the-timing-marks-and-checking-ignition/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

GAZ Volga (GAZ-31105) 2.3 16V ZMZ-40620 (2005): Setting the Timing Marks and Checking Ignition

The ZMZ-40620 has no distributor and no manual ignition timing adjustment. The spark timing is set by the engine control unit based on signals from the crankshaft position sensor and the camshaft position sensor. Here, "ignition marks" means the timing drive marks. They are used to verify that the valve timing and the crankshaft position are in sync. I could not find the exact positions of the marks on the camshaft sprockets for this version in publicly available sources, so a general procedure is given below.

Difficulty: Medium Time: 1-2 hours Steps: 8 Tools: Socket set and ratchet, wrench to turn the crankshaft by the pulley bolt, flashlight, chalk or marker, scan tool or tester for checking the crankshaft sensor, spark plug socket

Part

  • 🔩 No consumables are needed if you are only setting the marks. If you disassembled the timing drive, you will need a timing chain kit with tensioner and guides, seals, and a timing cover gasket

Step by step

8 steps
  1. Shut off the engine, let it cool down, and disconnect the negative battery terminal. Remove the engine undercover, the decorative cover, and the air intake duct if they get in the way of access to the crankshaft pulley and the valve cover.
  2. Remove the spark plugs so the crankshaft turns easily. Turn it only in the normal direction of engine rotation, using the pulley bolt. Do not turn it backward: the chain may jump on the tensioner.
  3. Find the TDC mark on the crankshaft pulley and the fixed pointer on the timing cover. Shine a flashlight on them and mark them with chalk. Align the pulley mark with the pointer.
  4. Remove the valve cover. The marks on the camshaft sprockets (intake and exhaust) should line up with the marks or lines on the bearing housing or on the cylinder head. Check their position only with the crankshaft mark aligned. If the camshaft marks turn out to be at the other phase, 360° of crankshaft rotation away, make one more full turn and check again.
  5. If all the marks line up, the timing drive is set correctly. The ignition marks and the valve timing are fine, and there is nothing to adjust.
  6. If the chain has jumped or the marks do not line up, do not start the engine. This is a 16-valve engine, and with incorrect valve timing the valves can hit the pistons. Release the tensioner, move the chain by the required number of links, and align the marks. Then return the tensioner to its working position and turn the crankshaft two full revolutions by hand. After that, check all the marks again.
  7. If the marks are correct but the engine runs roughly, the cause is usually not the marks. Check the toothed (reluctor) wheel on the pulley, the gap and connector of the crankshaft sensor, the camshaft sensor, the ignition coils and spark plugs, and read the fault codes through the diagnostic connector.
  8. Reassemble in reverse order. Use the manufacturer's specifications for the tightening torques of the crankshaft pulley bolt, valve cover, and spark plugs: it is better not to rely on ranges "by feel". Reconnect the battery and make sure there are no crankshaft or camshaft sensor errors.

Common mistakes and warnings

  • The ignition timing on this engine cannot be set manually. Trying to "tweak" it mechanically is pointless, and an error in the valve timing risks bent valves. If you have no experience with chain-driven timing systems, leave the chain repositioning to a repair shop.