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Discussion Starter · #1 ·
Hello! I love this forum, and the redesign is great!

Thanks to y'all, I got great guidance on replacing my beloved 2000 X VG33E timing belt a few years back. Being an organized guy, I assembled instructions from all over my Haynes manual into a spreadsheet and executed it step by step. Also replaced the valve cover gaskets at the time, wow was that a (pain) adventure!

Now 80k miles later, figuring another change out was on the horizon, the belt broke while I was driving at highway speed while towing a light trailer. Yes the prognosis doesn't seem good regarding the valves, but I haven't gotten that far just yet.

Tore the front end down and when I got the timing covers off, I found a very gunked up mess underneath with about half the teeth sheared off the belt. Lots of belt particles on the timing covers! When I did the job before, I didn't get the water pump seal right, because ever since then, there was a slow antifreeze leak from the weep hole underneath the crankshaft timing gear. Maybe that leak aged the belt? My love of towing things probably didn't help much.

I am 95% sure I got the crankshaft to TDC by checking for the compression cycle on piston 1. But now that everything's off, both camshaft gears point to the 9 o'clock position. I am pretty sure they should be closer to the 12 o'clock position, but before I screw something up, I wanted to see if someone's done this and how to best proceed. I know the cams can be turned using a wrench on the bolt, it's just a question of whether I should do that to align for the new belt. The Haynes only tells how to replace a good belt, and isn't very clear about what to do in the case of belt failure.

Second question: I used a spray bottle of water to wash out the timing area; it was very effective! (It also confirms the mess was water/antifreeze but not engine oil.) But I should probably lube it all up so it won't rust. what should I use? (WD-40 is a penetrating oil which displaces lubricant, so I already know that's not the answer.)

Have a great day! Can provide pictures & more if desired.
 

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Yes antifreeze is bad news for timing belt , i would not worry about rust the engine is all alum. Just make sure its clean and antifreeze free.
If you are sure the crank is on TDC ,turn pass side cam so dist rotor is pointing to #1 spark plug wire ,and drivers cam to correct mark with belt.
 

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Discussion Starter · #3 ·
thanks dennis
used a long screwdriver in the #1 plug hole and when it got near the top on the compression stroke (air rushing out around the screwdriver), I lined it up to the farthest left mark on the crank pulley.

distributor pointing to #1 wire - neat trick!

It won't cause any problems or interference damage to turn the cams?
 

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Discussion Starter · #5 ·
Dennis,
Adjusting the passenger side cam does not affect the distributor, it's the right/drivers' side cam that turns the distributor.

The cams 'click' about 120 degrees, so it is difficult to turn them to a point between the 'clicks'. Because of this, turning the drivers' cam to point the distributor to the #1 plug wire seems nearly impossible.

Bottom line: should I turn both cams from their 9 o'clock positions to the ~1 o'clock position and try to finely line them up to the marks on the new belt?
 

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Discussion Starter · #7 · (Edited)
No prob Dennis! Thanks for the help.

Doh! Didn't read that I could try-start the engine earlier than this, but I reinstalled the timing belt, tensioner, plugs and wires, as well as the water pump, thermostat and all the front pulleys and belts. Everything new except the pulleys, though I did replace one of them due lots of whistling lately.

Before I reassembled past the timing belt, I stuck a compression gauge in the empty plug holes and proved that at least 5/6 of them had some compression. (I did not take the time to get lbs, and as for plug 5 , I figured if the valves were bad, more cylinders would be bad.) Had to make the most of a limited-time saturday afternoon!

Connected the battery negative and when I turn the key the fuel pump makes its charge-up noise and it cranks, 'r - r - r - r' then makes a weird noise and stops. Like r - r - r - r- rwowr. On the 'rwowr' the lights and stuff drop as though there's a power drain at that moment. It's a new battery, and the connection is tight at both terminals. Fuel filter was just replaced before I realized the timing belt was the issue. Also the alternator's only a few months old.

Here's a link to a video https://youtu.be/8HJsHoHUhcM - searching the web and youtube haven't shown anything like this. Maybe I should check the distributor? I figure that adjusting the distributor isn't the culprit, since it should at least start.

Before I waste a bunch of time going in the wrong direction, what do you think is going on?
 

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Discussion Starter · #10 ·
Thanks for the input!
Tore it all down to the upper timing cover off, and yes, the cams appeared to be off; with the left on mark, the right appeared to be advanced 1/2 tooth.
So I took off the pulley and the belt and reinstalled the belt. Counted the teeth this time and everything. Put tension back on the belt and tried starting it. First go round it had a hard time (probably from built up pressure from crank turning with plugs in.) Then I tried again, and the same exact result r-r-r-rowr.

I will try the distributor adjustment next...
 

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Just to be clear...you made sure you were in TDC when on #1 when you performed the initial install right? Just making sure...not second guessing ya or anything, I've done it myself and cost myself a nice pretty penny on a new head.

Darin
01 Xterra SE 4x4
PML, EFan, stock intake mod, shocks, a bunch of maintenance, and a tune up coming soon
 

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Discussion Starter · #12 ·
What do you mean by a new head? No worries, I'm really scratching my head on this one.

I am reasonably certain it was TDC; had all the plugs and wires out and turned the crank with the wrench until air was rushing out of plug #1 , then stopped turning when the far left mark lined up to the timing cover arrow.

I ask because I may need 'a new head' anyway, I'm wondering what the symptoms are.

I messed with the distributor; unless it's bad on the inside, that's not the problem. Tempted to do a return-exchange on it to make sure.Also ruled out PCV.

Interestingly, the newly installed spark plug I pulled today had charred black on it.
 

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First I want you to do one thing. Get it to TDC again and check to make sure your distributor is aimed at #1 , if so, I would do a compression check, if you have a compression gauge, if not Auto parts stores rent them, and just check every cylinder for the variation. Usually when a head is cracked, bent valve, or the gasket is blown, compression can fail on one or more cylinders leading to missed combustion. I am sure TJTJ could chime in with his infinite knowledge(not a dig, I am seriously impressed), but so far that is my guess without knowing every detail about your engine condition, etc...

Darin
01 Xterra SE 4x4
PML, EFan, stock intake mod, shocks, a bunch of maintenance, and a tune up coming soon
 

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Also, did you say your timing belt has broken, while it was running? I just noticed that, IDK how I missed that, but if so man, you might need two heads...our engines are interference engines, and if the belt goes, the head goes probably 90%+ of the time.

Darin
01 Xterra SE 4x4
PML, EFan, stock intake mod, shocks, a bunch of maintenance, and a tune up coming soon
 

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Discussion Starter · #15 ·
Yeah, the conditions of the failure make me think bent valves+ might be the real problem. (Sorry, I don't know how the "head" relates to that.)

Sure I can check the distributor pointing to #1 at TDC...but what does it mean if it doesn't? Early in the repair I tried that and it pointed to the next one (6?) but I don't remember what stage I was in.

Yesterday when I had plug #1 out and checked compression on it, I was turning the crank by wrench and it maxed out at 30 pounds. I didn't look very closely at the method for checking compression, because I was only trying to find TDC. So if that was the correct compression gauging method, I know that's nowhere close to the ideal pressure. I assumed that hand cranking would only generate so much pressure. It did hold the 30lbs until I hit the release valve on the gauge.

So if compression is an issue, what do I need to go after? The real challenge here is the uncertainty of what's actually broken, you know?
 

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If the timing belt broke at high speed, your pistons will have hit the valves and caused serious engine damage, it must have sounded awful when it happened and I'm not sure why you'd have bothered replacing the belt without pulling the heads? chances are you need new pistons as well as new heads..
 

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Discussion Starter · #17 ·
I hear ya, grease monkey, but it didn't make any unusual noise. I had issues in the past with the distributor rotor coming loose; the engine would die at highway speed; that's what I thought happened at first, because that's all it did, really.

I have approached this from a 'eliminate the obvious and easy first' perspective, especially because so many had no damage with a TB failure.
 

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The valves are located inside the head...that is where one half of the combustion chamber is(the other is the piston and cylinder wall), and the valves come down/open up to let fuel/air in or out, and with an interference engine, the pistons can come in contact with the valves if they don't open and close in synchronization with the pistons...sorry I didn't completely comprehend the title, but the first thing you need to do is check compression on every cylinder, I was having you check the distributor, because at TDC it should point to number 1, because that is the ignition point of that cylinder...so if it pointed at the wrong cylinder it won't start...but first check your compression on EVERY cylinder...just to be safe, but I am guessing you have internal damage, unless your distributor is just off

Darin
01 Xterra SE 4x4
PML, EFan, stock intake mod, shocks, a bunch of maintenance, and a tune up coming soon
 

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Discussion Starter · #19 ·
Darin, you were correct!

When I read your post, I was about to comment that I'd already ruled out the distributor unless it had catastrophic internal failure. So I yanked it out to go exchange for a new one to be sure.

AZ had to order a replacement, so I went to get some coffee and read. I was thinking about how a distributor could be "off". I vaguely remembered having to pay attention to the rotor direction when replacing it a few years ago. It couldn't be that simple, could it?

When the truck first broke, I suspected the distributor. The rotor was fine, but when I got it home, I swapped out an old one I had that worked (roughly.) After that I video recorded the dizzy rotor not turning and diagnosed the timing belt. But when I swapped the dizzy back, I completely ignored rotor direction.

Got home from the coffee shop, aligned the engine to TDC and installed the distributor so the rotor pointed to #1 . Connected the battery, and...


Immediate startup!

Sounds a little rough, but a tap on the gas returned a very exciting vroom. There's nothing like the feeling of fixing what's broken!

I'm going to chalk this one up to "I have a 1 year old" and thank God I didn't have bigger issues!!

Thanks for your help!
 
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