# 3.3L V6 VG33 distributor not turning



## garyS-NJ (Nov 17, 2014)

am I in the right place? I know there is a better site for this Xterra post but this is close to my club frontier home.. that said, my buddy has a 2003 xterra 3.3L V6 VG33 supercharged and at 180K miles, the truck just shut down on the highway.

he pulled the distributor cap and sees the rotor isn't turning as he cranks the engine over. I found a repairpal problem report about rusting distributor shafts and he had a distributor drive go bad about 100k mikes,... So I'm thinking same thing. can anyone help/advise on easy way to see if the tining belt is still in tact (I'm just helping over the phone from a distance) or if the belt has anything to do with the distributor turning...


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## rogoman (Dec 16, 2004)

The distributor is driven off the left side camshaft so it's most likely that the timing belt is broken. To verify this, remove the left hand valve cover; when the engine is cranked over, the cam should also be turning.


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## smj999smj (Jan 1, 2006)

The problem with removing the left side valve cover is that the intake plenum is over it. It would be a whole lot easier to pull the distributor out and check the distributor shaft. If the distributor is ok, then likley the timing belt has broken. The next big question would be if any valves got damaged if the belt did break?


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## MikeS-NJ (Jan 16, 2015)

*How do i diagnose the valve damage?*



smj999smj said:


> The problem with removing the left side valve cover is that the intake plenum is over it. It would be a whole lot easier to pull the distributor out and check the distributor shaft. If the distributor is ok, then likley the timing belt has broken. The next big question would be if any valves got damaged if the belt did break?


Is there a foolproof way to determine if the valves got damaged w/o disassembling the engine?

Thanks,
Mike


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## smj999smj (Jan 1, 2006)

My recommendation is to not get ahead of the problem. Whether the valves are damaged can be tested via a compression test or better, a cylinder leakdown test, neither of which requires disassembly other than spark plug removal. However, in order to do those tests, the engine cams and crank must be in time, so there's no sense in doing those tests in this situation. 
It's not hard to remove the distributor to check it. I believe the hold down bolt is 12MM. Remove the cap and use a Sharpie, wax pencil or paint to mark the location of the rotor. There will be a shadow left from the hold down bolt washer when it is removed that will help reset it to the correct time. Unplug the distributor harness connector. As you pull the distributor up, the rotor will turn; make a second mark at the location where it stops turning. Inspect your distributor. To install, line up the adjustment slight to the location of the bolt hole and line the rotor up to the second mark you made. Install the distributor straight down and as the shaft gear engages the camshaft, the rotor will start to turn. Insert the distributor all the way down and the rotor should be lined up with the first mark you made. Install the hold down bolt and use the shadow left by the bolt washer to help line up the distributor base and tighten the bolt. 
If the distributor is okay, then it is likely that the timing belt has broke. VG engines are funny in that they are interference engines (except those used in the Quest) but don't always bend valves when the belt breaks. The teeth of the belt usually strip at the crank sprocket when they go. What you would need to do is take apart the front of the engine and confirm the belt is broken. If it is, install a new timing belt (putting the crank and cam sprockets in time with the marks on the belt), the guide plate and crank pulley need to be installed (I'll usually install the lower timing cover as well) and then one can attempt to start the engine. If it fires up and runs well, then the engine can be shut off and one can resume reassembling the front of the engine. If there are one or more bent valves, then the engine will either not start or start and run poorly, misfiring on the cylinder(s) with the bent valves. If that occurs, it no longer makes sense to reassemble the engine because either the heads will need to be sent out for a valve job or the engine replaced with used or new, depending on what makes the most sense.


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## MikeS-NJ (Jan 16, 2015)

smj999smj said:


> My recommendation is to not get ahead of the problem. Whether the valves are damaged can be tested via a compression test or better, a cylinder leakdown test, neither of which requires disassembly other than spark plug removal. However, in order to do those tests, the engine cams and crank must be in time, so there's no sense in doing those tests in this situation.
> It's not hard to remove the distributor to check it. I believe the hold down bolt is 12MM. Remove the cap and use a Sharpie, wax pencil or paint to mark the location of the rotor. There will be a shadow left from the hold down bolt washer when it is removed that will help reset it to the correct time. Unplug the distributor harness connector. As you pull the distributor up, the rotor will turn; make a second mark at the location where it stops turning. Inspect your distributor. To install, line up the adjustment slight to the location of the bolt hole and line the rotor up to the second mark you made. Install the distributor straight down and as the shaft gear engages the camshaft, the rotor will start to turn. Insert the distributor all the way down and the rotor should be lined up with the first mark you made. Install the hold down bolt and use the shadow left by the bolt washer to help line up the distributor base and tighten the bolt.
> If the distributor is okay, then it is likely that the timing belt has broke. VG engines are funny in that they are interference engines (except those used in the Quest) but don't always bend valves when the belt breaks. The teeth of the belt usually strip at the crank sprocket when they go. What you would need to do is take apart the front of the engine and confirm the belt is broken. If it is, install a new timing belt (putting the crank and cam sprockets in time with the marks on the belt), the guide plate and crank pulley need to be installed (I'll usually install the lower timing cover as well) and then one can attempt to start the engine. If it fires up and runs well, then the engine can be shut off and one can resume reassembling the front of the engine. If there are one or more bent valves, then the engine will either not start or start and run poorly, misfiring on the cylinder(s) with the bent valves. If that occurs, it no longer makes sense to reassemble the engine because either the heads will need to be sent out for a valve job or the engine replaced with used or new, depending on what makes the most sense.


Thanks for the info! I'll do what you suggest and let you know how it works out.

Mike


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## mtippins123 (May 25, 2011)

Gee...hate to put my 2cents in lol,....the distributer gear could have come loose or worn down. That happened to me once with another non nissan vehicle. The gear had a small screw in it aand it came looseand the gear slide up the shaft and stopped spinning.
a buddy changed some timming parts and didnt match his timeing gear (which wss aluminum and he need a brass one) and its basically shredded the gears. It lasted about 5 miles tho


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## Ed Mc (Aug 31, 2006)

Seems to me that a smart twist of the rotor in the CCW (or CW, for that matter) direction would tell you pretty quickly if something is broken on the dist. drive. 

If it won't turn more than just a wee bit either way, I wouldn't think it very likely to be stripped/broke.

Try that and see what happens, it couldn't hurt.........ed


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## smj999smj (Jan 1, 2006)

I agree for the most part and it's more likely that the belt broke and not the distributor. The gear is held on to the shaft with a roll pin, so if the shaft seized in the bushing of the distributor and the sudden seizing of the shaft caused the roll pin to break as the gear on the camshaft continued to drive it, the gear would spin freely on the end of the shaft but one wouldn't be able to turn the rotor freely by hand, so that would be one good reason to pull the distributor for inspection. As I said, it's not likely, but nothing suprises me anymore when it comes to cars!


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