Join Date: Jun 2009
Location: Almost Heaven West Virginia
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Re: Volvo Penta MD7A Where are Timing Marks? Which is #2 Cyl?
To find or make your own timing marks.
First put the piston up.(either one) Then put a cellophane drinking straw through the (removed) injector hole. Back the crankshaft pulley until the straw goes down a bit. Mark the straw and the crankshaft pulley. Turn turn crankshaft pulley forward. Straw will go up. Keep turning till the mark on the straw is back down to the mark. Mark the pulley again. Top dead center will be 1/2 way between between the marks you made on the crankshaft pulley. Mark it.
Pump timing. Some pumps have an inspection cover. Usually held by 2 screws with marks underneath. If so there will be marks under it. If not turn crankshaft one complete turn and look for marks.
If no inspection cover then look for a bolt near the drive end that is doing nothing. Pull the bolt and look for a dimple in the shaft that the bolt will enter. If so turn the motor until the bolt enters the dimple and locks the shaft. If so this will give you factory injection pump timing.
If neither method works then you must set up a system that allows fuel to flow through the pump. Use an electric pump or a gravity set up. Through most of the cycle fuel will flow through the pump and out the return valve and hose. Back motor up a little, let fuel run through the return line and turn motor till fuel stops running. That is the moment of injection. It should be near the mark you made at TDC. This will vary from one to about 8 degrees depending on engine type. All diesels will run safely at zero. Most are set to start at that but not all by any means.
To look for marks. Crankshaft pulley ; Flywheel, either under starter or inspection cover or a slot in flywheel that lines up with a pointer. A dot on the flywheel that lines up with a hole usually near the starter. An inspection cover atop the flywheel housing with marks on flywheel.
Again some Volvos do not have marks period. Then you must do it the hard way.
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