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93 Nissan Pathfinder: Timing belt replacement question(s)


MrEviLDeD
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Hey everyone,

 

Weather has finally warmed up a bit and I can get back under the hood to get more done on the waterpump/timing belt/tensioner task. I have only removed the upper cover and removed the harmonic balancer etc. Today I am going to remove the spark plugs, and do my best as getting the engine at TDC.

 

My question is this and is based on other posts I have read here on the napora forums that the timing gears move or can move once the belt is removed. As I will most likely not be able to get the entire job done today I am concerned that I will walk away from the truck only to come back the next day and the valve cams be out of whack and my being to stupid to know how to put them back...

 

Do I have that much to worry about.. Do I mark them so I know? Will they move that much? Do I just put the old belt back on with with right tooth count to keep the gears from moving when I close up for the day?

 

Please excuse all these additional nagging questions. Maybe I am over thinking things?

 

Be well everyone,

 

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Just a note. I remember sparkplugs being much easier to remove. You could really tell the difficulty of access for the previous owner (whomever changed sparkplugs) as the ones that were easy to reach were WAY over torqued and the ones that were almost impossible to access were easy as heck. :) that one right in the back by the firewall that is a pita to access.. Needs a special length extension bar... Also the gaps on the plugs were no less than 2 1/100ths of an inch wider at 0.05 - 0.055 instead of 0.31-0.35 I hope when the new plugs get put back in that she is a little snappier just by having the proper gapping.

 

More updates to come tomorrow :)

 

(still looking for some experienced feedback regarding my questions if anyone happens to have anytime)

 

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If you line the motor up to TDC before removing the belt, the cams will not jump. In other positions, they may. I still had to build a tool to reorient mine, but that was in part because I removed both sprockets to do the cam seals. I did have one of my cams jump a little when I was trying to remove a cam bolt (before I made the tool), but I just moved it back again and it didn't hurt anything. Count the teeth when you put the new belt on, move the cams a little if you need to, and you should be alright.

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Seems without the plugs there is little to no tension at all so I was clearly over-thinking. The person that did the timing belt previous didnt seem to use the lines on the belt as a guide but instead counted teeth. It might be a tooth off actually based on what I saw today. I stopped because I was unable to be certain I had the engine at tdc on cylinder 1.

 

Hopefully tomorrow will be the "winnar!"

 

=)

 

 

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Plugs in/out shouldn't matter, if the cams jump it's because of the valve springs pushing the lifters against the cam lobes. Don't worry if the paint marks aren't lined up--they don't line up each time the engine is at TDC. They'll line up when you're installing the belt but if you roll the engine over by hand with the cover off while you're setting the tension, the marks won't line up again unless you turn it backwards to where you started. This is normal. If the tooth count is correct, the engine is timed properly. Think of it like a tank track... it takes quite a few turns of the drive sprocket to pull the whole track around, and if the number of teeth on the sprocket and the track don't have a common denominator, that track might have to go around a few times before the same tooth engages the same link.

 

If it does turn out that the last guy got it a tooth off, then congrats, you've freed some hidden power! If it's the count between the crank and the driver's cam that's off, you'll need to set the ignition timing when you're done.

 

Also, don't worry if the cam sprockets don't line up perfectly with the marks on the back timing cover. Mine were a little off. Again, tooth count is your friend.

 

And if you get the cover off and it doesn't look like it's on TDC, you can thread the crank bolt back in and roll the engine over by hand until it is. This is the only thing I'd use the timing marks on the back cover for--if you get the cam sprocket dimples reasonably close to lining up with those, then you should be close enough to TDC.

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Ok, well I lined everything up best I could. I used a coathanger straight to see tdc best as possible based on your advice. It all seemed to go ok. I replaced the belt. However.. When turning the engine (not sure how many times that is) to bring it back to tdc on cylinder 1 I cannot seem to get any of the lined on the belt to line back up properly. I have turned the engine by hand quite a number of times and no matter how many I cannot seem to get those timing belt lines to line back up.. What did I do wrong?

 

I have turned and turned and turned. When I get all three markes, cam pulleys, and crank to point to their marks (crank mark isnt there it is worn off or something but was in the area it should be based on all pictures etc) there are the proper teeth between sprockets. 40 between cam spockets and 43 between LH sprocket and crank sprocket. so like I THINK its right.but without being able to physically being the lines all together again makes me wary to close everything up...

 

Any further thoughts or encouragement? Maybe I have done something wrong? Tensioner too tight maybe?

 

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Like I said on your other thread, those lines are only useful for initial setup. There are a lot of teeth on that belt. It would take an awful lot of spinning the engine over to find a point where they line up again. This is normal. Get it to TDC again (or thereabouts), count teeth between the dimples, and if the tooth count is right, then the belt's on right.

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Thank you. Don't mean to be over paranoid of neurotic.

 

I will finish the rest tomorrow.

 

As always appreciate the patience and the help.

 

Now to find my cable for my timing light :) Always something =)

Edited by MrEviLDeD
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Ok guess I did it wrong or something. Nothing is smacking or banging. I hear no knocking however when the engine starts (only running a few seconds at a time since there is no coolant) it starts.. seems to idle.. if I add any throttle to it it will make a bunch of fluttering sounds (like air isnt is being squished out, guessing valve blow through? and it will stall..

 

Please any help here would be appreciated.

 

Did I have the TDC wrong? and on the wrong stroke? Was the crank shaft slightly out of place? I am at a complete loss. Watched everything, read everything I could.. Took the advice here and well just like I expected I screwed it up somehow..

 

How do I fix it? I guess spin the crank until I get to TDC again pull the belt and try again?

 

Edited by MrEviLDeD
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Like for example when I press the gas it sounds like she is bogging out and then stalls. Did I do this on the wrong tdc like possibly the power stroke or something?

 

RAWR!

 

Edited by MrEviLDeD
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Could this maybe be something to do with the distributor? This has not been changed and the the tension on the timing belt is a bit firmer than the belt that was removed. I cannot stress enough that the teeth were counted and the marks all appears to line up as best they could be. All teeth matched between marks. So at a complete loss as to what to do next.

 

All I can think of is that I need to put the distributor back to factory setting and hope for the best.

 

Going to go back out here in a few moments and recount teeth now that the engine has been started to make sure there was no skipping of a tooth maybe.. I am getting desperate =)

Edited by MrEviLDeD
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That sucks! I'll bet it's something simple, though.

 

My first thought: is the rubber air intake going to the MAF sensor installed? Is the MAF plugged in? If the computer has no MAF signal, it should be able to run without it; if it does have signal, but the hose isn't connected, I would expect the mix to go super lean as soon as you open the throttle. Either put the pipe back on or disconnect the MAF.

 

If that's not the case, I would roll it back to somewhere around TDC, then count teeth. 40 between the cam dimples, 43 from the driver's cam dimple to the crank dimple. Count a few times. If it's off, make it right. If it's right, leave it alone and look for your issue elsewhere.

 

That brings us to your timing. Belt tension should not change your timing (unless it was super flappy loose and skipped a tooth). Because the belt is referenced to the sprockets, not the timing cover, I can't imagine how doing the belt with the engine a few degrees off TDC would change anything--if you wanted a challenge, I think you could stop the engine in any position and change the timing belt, and do just fine, provided you could hold the cam sprockets still and do the mental gymnastics to work out proper tooth count. If you had it on the wrong TDC, it would not run at all. You did suggest however that the last guy may have done it a tooth off. If the count from the crank to the driver's side cam was incorrect, the distributor would've been off (it's geared off the driver's side camshaft), and it's possible the lazy sod just adjusted the dizzy rather than opening the timing back up and fixing his mistake. If you suspect that the last belt was a tooth off, you could put the lower timing cover and the balancer back on, find your timing light, and see if the timing is anywhere near the right ballpark. Or do it old school: move the dizzy a few degrees one way and see if that helps, move it the other way if that made it worse, and see if you can find a timing where it runs right. Either way, once it's back together, warm the engine up and re-set the timing properly. (You might want to mark where the dizzy is before you start, either so you can see how much it was off by later or so you can put it back where it was if it turns out that your ignition timing is not the issue.)

 

The only other thing I can think of is that the cam sprockets are different side to side--if you removed them (to do cam seals), make sure you put the correct one on the correct side. I would be very surprised if this was the problem, but I remember being fairly paranoid that I'd get mine backwards.

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Actually, The MAF is indeed still connected and the plastic pipe connecting the intake plenum to the MAF is not installed. I install it tomorrow morning and see if that has any effect. I didn't think it would matter without it being connected and the MAF still wired in. I have counted and recounted (I decided to call it a night so I didn't head out to recount after running the engine, hit the hot tub instead =) I will do that in the morning as well.

 

As for the belt it is somewhat tighter than the other belt was. I can twist it 90% between the cam sprockets and I can twist it 90% between the drivers side cam and the crank sprocket so seemed like it was not overly tight and certainly not loose. I will check and recheck again. I was also of the same thought, it shouldn't matter where in the timing cycle the engine would be in as long as the tdc marks were all in the right place and the tooth count between them correct.it should be good to go. You would have to really turn the crank or the cam gears a lot I think to be out of time which I am fairly certain didn't happen in this case. Will check again.. I counted at least 5 times just to be sure. I will count 10 more :)

 

I did not remove the cam sprockets this time. It was sort of a hind sight and clearly I would have to remove the plenum to remove the valve covers to get at the lock slot for the cam sprockets. I figured this was big enough of a job without adding more to it and potentially having even larger issues. Not that I am or cannot do this but a professional mechanic I am not and in that I lack a lot of experience that someone else may have to pull solutions from :)

 

It was a great gift when I found this forum and the folks here. Even with FSM, Haynes and Chilton (which has been misplaced someplace) there is a lot to know and learn.

 

Want a small laugh? My next real project is to pull everything off my rotted green pathy and rebuild the engine. Shove the rebuild into the current pathy with the power parts from the green one... =) Delusions of grandeur my friend :)

 

Again thank your time and effort. I was in panic mode with no idea what to do next. Not so much any more.

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I have done it with the plugs in and plugs out, but I always turn the crank (obviously harder with the plugs in) several times to make sure nothing at least feels wrong. If you do the twist method that allen key will be just shy of 6 o'clock and tension should be spot on. I've done this 4 times over the years and that first start up is always a little stressful even though you have checked things many times. Good luck.

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Small update, WoooHOOO!

 

Slartibartfast called it right.

 

I had not disconnected the MAF sensor or put the hose between the intake and the MAF. Seems to do MUCH better now that I have put them back on. It still seems to lope a little when I hit the accelerator but I suspect that now I need to get the timing light out and see how we are doing in ignition timing as it seems a little off. There is a bit more slack in the timing belt now. Should I do the tensioner one more time before I put it all back together again? At least before I put the bottom timing belt cover and balancer back on?

 

 

Steve_RI when you say "just shy of 6 o'clock" do you mean hour hand ? Should it be somewhere between 5 and 6 o'clock?

 

I was so relieved. When I first put the hose back on the MAF I had left one of the vacuum off still and seem to rev up but as soon as I would release the gas it would rev down and simply stall out. Attached the one engine vacuum to the MAF hose and seemed to pick right up. With that said when fast revving the engine would seem to stumble about 2500 rpm. Just briefly but was still there.. I am assuming this is because I have not set the ignition timing and pulled the tps connector to reset the tps (saw this on a youtube video being done a vg33) on cold, and then again on warmed up timing checks.

 

There is clearly more revving power felt so that is a plus. =)

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:aok: Good to hear it was the simple thing!

 

Not surprising that it loosened up a little after running. If it's loosened enough that you're worried about it, check it and re-tension if needed. There's no TPS reset or relearn on the WD21, at least not that I'm aware of. Hopefully distributor adjustment is all it needs (which, again, makes sense if the last guy had it a tooth off).

 

As for removing the cam sprockets, I've heard of some engines locking their camshafts like that, but I don't think the VG30 is one of them. The service manual shows a special wrench to hold the sprocket from the outside while you remove or tighten the bolt. I made my own from some round bar, but I've also heard of people looping the old belt around like a strap wrench with vise grips as a handle. I can understand not wanting to complicate things, though. I did my intake gaskets at the same time as my timing belt and ended up with quite a pile of parts that all had to go back in the right order... I found a few wrong orders before it all went back together.

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Small update, WoooHOOO!

 

Slartibartfast called it right.

 

I had not disconnected the MAF sensor or put the hose between the intake and the MAF. Seems to do MUCH better now that I have put them back on. It still seems to lope a little when I hit the accelerator but I suspect that now I need to get the timing light out and see how we are doing in ignition timing as it seems a little off. There is a bit more slack in the timing belt now. Should I do the tensioner one more time before I put it all back together again? At least before I put the bottom timing belt cover and balancer back on?

 

 

Steve_RI when you say "just shy of 6 o'clock" do you mean hour hand ? Should it be somewhere between 5 and 6 o'clock?

 

I was so relieved. When I first put the hose back on the MAF I had left one of the vacuum off still and seem to rev up but as soon as I would release the gas it would rev down and simply stall out. Attached the one engine vacuum to the MAF hose and seemed to pick right up. With that said when fast revving the engine would seem to stumble about 2500 rpm. Just briefly but was still there.. I am assuming this is because I have not set the ignition timing and pulled the tps connector to reset the tps (saw this on a youtube video being done a vg33) on cold, and then again on warmed up timing checks.

 

There is clearly more revving power felt so that is a plus. =)

 

Yes, the hour hand, sorry.

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I redid the tension again before putting the lower cover on. when I ran the engine with the cover off the belt between the crank and the passenger side cam seems floppy so added just a little more tension.

 

With that said if it isnt one thing it is another.. Seems I have misplaced or lost the bolts (i have the nuts) for the fan/cluck/pulley.. so cannot go any further. No idea where they could have gotten two. I know they are 10mm. The FSM of course does not have any details on the fan/clutch to water pump. Completely lost.. not to mention the problem with the timing.

 

One step forward 3 steps back

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Ok, 2 steps back :) Realized that was what the 4 studs were that came with the water pump. I wasnt sure what they were for. know I know.

 

My question is how to you put them in without harming the threads? Do you simple finger tighten them into the water pump and then just tighten the nuts?

 

Sorry for the stupid questions above. Frustration took hold :)

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Ok, Noticed that there is more thread on one end than the other on these studs. Would it be safe to assume that the longer threaded area goes into the water pump? Short side is for the nuts holding the fan/clutch assembly on?

 

 

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Ok, finally got the alt/fan assemblies back in and belted. However I did the turn the distributor suggestion. so did my best to turn it a single tooth. harder than it sounds actually. When I put it back in the truck started sounded smooth.. so I set the timing to the the 4th mark 0, 5, 10 ,15 and it sounded good. Then the idle kicked down and it moved to the second mark when I turned the dizzy to bring it back up to the 15 it started to sound like something was knocking on the drivers side.. Not sure if its a ping or a knock. either way I turned everything off and came in..

 

This is starting to get me down. Seems I am going to have to take it ALL down and apart again and start all over.. :/

Edited by MrEviLDeD
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Ok. Even when I want to I can never give up :) Death will be so peaceful :) Just saying!

 

Update. Went back out and just kept turning the dizzy rotor one tooth to clockwise until I got her back on the scale. I believe this is where I had it once before but then thought I could squeeze an extra tooth to get a better adjustable range on the dizzy itself. With that said. Finally got the belts back on (all of them) The timing changed again (is this common?) So pulled the timing light back out again and set it back to 15 btdc. Sounds good so far with one exception..

 

if you wait long enough (and I do not remember hearing this before) but every so often, not on a pattern as best I can tell you can hear this. tat-tat-tat and then it goes quiet again. I stress that its not like every minute or some cycle just every now and then seemingly random you can hear this faint, tat-tat-tat.. Should I be worried? Is there something I should have a look at?

 

I may have messed up on the thermostat. Hopefully it will dry over night and I can tell for sure but the lower radiator hose pipe seemed a little wet. With that said I spilled a bit when filling the rad by accident.

 

 

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