Timing Belt Problems

[term117]

When I was putting everything back together I realized that the Idle Pulley bearing is totally shot, and the Serp Belt Tensioner bearing is not so hot either. Im looking up replacement bearings for both.

Jennie im available for hire lol or if you ever need help let me know.

I went to USF for a while but I decided to finish my degree at St. Petersburg College(graduating in fall!).

[term117]

Good Lord, got it back together and it ran terrible for about 2 seconds and stalled. Started again and car shook for a second and stalled. Maybe the TSB is wrong and your guide is correct. This is so frustrating.

[nfpgasmask]

Good Lord, got it back together and it ran terrible for about 2 seconds and stalled. Started again and car shook for a second and stalled. Maybe the TSB is wrong and your guide is correct. This is so frustrating.

Well, in my own defense, I had ZERO problems with my method, and she fired up right away when I was done.

From your above description, it does sound like your timing could be 180° off now. So, at this point you need to watch the video that shows how to get your timing back if timing is lost.

Good luck,

Bart

[nfpgasmask]

There you go. Thanks for posting those vids, Mark. They are helpful indeed.

Bart

[term117]

I knew that I lost my timing so I followed the TSB. This summarizes it - Rotate the Passenger Camshaft pulley until it springs to 12 o'clock pointing directly at the timing line. Rotate the driver side camshaft until it points 90 degrees to the left of the alignment mark. Rotate the drive camshaft 90 degrees to the right so it matches the alignment mark.

Rotate the crankshaft until it aligns with the mark on the oil pump. I did all this already and it did not work. What I did not do is anything before step 21 in the tsb(opening the engine and such). Also I may have not made sure the crankshaft was on the compression stroke(This has to be the problem I think?).

Do I have to take my engine apart to fix the timing. I don't exactly understand how it works so im sure that making it more complicated. I did what I stated above to correct the timing and that does not work. So im thinking I might have it towed somewhere.

I watched all the videos and read everything I could find.

[SlowPro48]

Dude, you're not making it complicated - it IS complicated. It's a DOHC even-fire V6 - crank throws are 120 degrees apart - but the vee angle is 75 degrees so there's some trickery with cam timing. It will give you a headache if you think about it too much.

Two things you DON'T need to worry about: First of all, don't worry about whether #2 was on compression stroke or exhaust. All you have to do is make sure #2 is at TDC then by making sure the cams are lined up properly YOU determine that #2 is on the compression stroke and its partner #5 is at TDC on exhaust stroke. Second don't worry about whether you did it Bart's way or the Isuzu way. The Isuzu way most definitely works. (They designed the thing so it oughta!) Bart's way works too. Plenty of people have proven that. I have no idea HOW since he has the cams lined up as if #2 were at TDC but his crank is actually turned so it's half way between #3 and #4's TDC. I guess an engineer could explain it based on number of teeth on the cam gears, number of belt teeth between pulleys, etc - or maybe it's just a combination of luck and a wasted spark ignition - but either way - by logic or by luck - it works.

Two things you DO need to worry about: First, after you installed the belt, did you do like the manual says and turn the engine by hand through at least two complete crank revolutions, making sure there was no resistance? If you did, then you probably won't have to replace any valves. If you didn't then ahhhh... you may have just settled the debate about whether the 6VE1 is an interference engine or not. Second, in your TSB summary you said rotate the driver side pulley "until it points 90 degrees to the left of the alignment mark" but when you did this, did it spring into place (like the passenger side did) before you turned it 90 degrees CW? If not, then there's your problem! You have to rotate BOTH of them enough turns that they spring into place, then you turn the even bank cam pulley (drivers side) 90 degrees more before you put the clamp on.

[nfpgasmask]

So let me get this straight, in my pictures below, is this the part that you all are saying I did backwards?





I've never quite understood what everyone is saying is wrong with my timing belt instructions. I suppose it should be gotten to the bottom of here and now. I am not trying to create an arguement or debate, I just want to understand what is wrong with my instructions, and also how my instructions worked fine despite there being something wrong.

Here are the things I can verify 100%:

1) When I was done with my timing belt install, everything worked fine. Not one single problem. VX fired right up.

2) When I removed my old belt, the LH and RH camshaft pulleys springed to the 12 o'clock position.

3) I never moved my crank once the old belt was off.

4) I followed this diagram EXACTLY when I lined up the new belt:


So where is the backwards part of my install?

Please help me understand so I can annotate my document.

Thanks - Bart

[SlowPro48]

Yes, that's it! The crank sprocket - it's #1 on the diagram you posted. #7 on the diagram points to the TDC notch in crank sprocket lined up with the TDC mark cast in the oil pump housing. #8 shows the dotted lines on the belt lining up with the mark punched in the rim of the sprocket.

If you check the Service Bulletin that Mark posted, you'll see a good picture at Step 26, which says, "Align the dotted-white line of the timing belt with the white timing mark of the crank sprocket (180 degrees from TDC timing notch)".

You did the opposite, however. You lined the dotted-white line up with the timing notch, not the white mark - so your cams were positioned like they were supposed to be, but #2 cylinder was at Bottom Dead Center instead of TDC i.e., 180 degrees off.

As far as why it still works.... I'm not smart enough to know the details of why it works but the bottom line answer is that if you install the belt according to Isuzu's instructions, and then you rotate the engine a bunch of times, all of the pulleys and marks eventually line up as pictured in your how-to. Everybody knows this because your VX runs. My right bicep knows it because curiosity got the best of me. I installed the belt according to Isuzu's instructions but when it came time to spin the engine by hand to make sure there were no crunchy noises I went well beyond the two turns of the full Otto cycle in order to see how many turns it took before everything would line up the way you did it. The answer is LOTS. I can't remember exactly - wish I'd written it down - but I do remember my arm felt like it was about to fall off - and I was using a 2 foot long ratchet and all of the spark plugs were out...

The relationship between cams and crank and a particular spot on the belt is set by the gear and pulley ratios and the number of teeth between the pulleys. It's nothing but math. There's a definite number of crank turns before a particular combination of marks comes around again. A high school kid with a B average in algebra could probably come up with a formula to calculate that interval - but I cant! Hey maybe one of our non-U.S. members can figure it out for us since the rest of the world kicks our azz when it comes to math skills.

Even if we knew how it happens that you can start out with #2 at BDC instead of with the piston at TDC where you would normally expect to see it when the cams are lined up for compression stroke, I'm not sure it would tell us whether it works this way by design or not. Wouldn't it be nice if we could lure an Isuzu engineer in here?!

[nfpgasmask]

OK, I see what you are saying, but this is why it is still very confusing to me.

Before I removed my old timing belt, I rotated the crankshaft pulley a few times, just so I could see everything line up and get a firm understanding of that.

Then I turned the crankshaft pulley and lined up both camshaft pulleys like so:



Once both camshaft pulleys lined up, the crankshaft pulley lined up like so:


At that point, I removed the old timing belt. With the old timing belt off, the half-circle notch on the BACK of the crankshaft sprocket is on the OPPOSITE side of the green painted tick mark on the FRONT of the crankshaft sprocket. The half-circle notch lined up with the white paint mark on the housing like so (note this pick shows the new belt installed):


I then installed my new timing belt from there to line up with all the marks, and it worked perfectly. So I still do not see how my instructions are off from the Isuzu instructions.

IMO, there is one or more of the following scenarios happening:

1) People, myself included, could be reading and interpreting the various instructions out there in different ways and thus, confusion is created.

2) The Isuzu instructions, videos and diagrams are explaining this is a way that confuses some folks.

3) My instructions are explaining this in a way that confuses some folks despite my absolute best effort to spell this out as simply as possible.

4) Some people who HAVE NOT ever done this maintenance are chiming in with opinions and information without actual experience to back their claims up.

5) People are not understanding where the marks are and where they should be lining up, or they are looking at my photos or the diagrams wrong.

6) People are not reading carefully enough and paying attention to the different things happening, ie, camshaft vs crankshaft, notch on back vs notch on front, dotted line on old belt vs dotted line on new belt, etc.

7) And lastly, the Isuzu instructions could be either wrong, or perhaps there is some variance between our VX's and the Trooper's 3.5. Meaning, maybe there are some slight differences between years or models that could be causing us to pull our hair out. Despite the fact that many of us on here could be considered VehiCROSS gurus, we don't know everything about what happened during the manufacturing process, video creation, and eveything else that happened while these vehicles were being manufactured. Errors are made, even by the big companies.

The only way that I could have done this the "right" way, would have been to remove my old belt, and then turn the crankshaft pulley 180 degrees to get the half-circle notch to line up at the opposite side, which imo, would have screwed up my timing and would have been completely wrong. The white dot and the half-circle notch line up. The green painted tick mark and the line mark on the housing line up. Both of those align opposite eachother.

I hope this makes sense, and again, I believe my instructions are right, and there is just some confusion in the interpretation.

Bart

Edit PS: Slowpro, I just reread what you wrote above.

If you check the Service Bulletin that Mark posted, you'll see a good picture at Step 26, which says, "Align the dotted-white line of the timing belt with the white timing mark of the crank sprocket (180 degrees from TDC timing notch)".

I absolutely DID NOT do the opposite of what you are saying, clearly presented in my photos above, so which one of my pictures is confusing people? Or am I still confused? The "white timing mark" the Bulletin is referring to, MUST be the white dot at 180 degrees from the TDC notch, correct????

[nfpgasmask]

OK, I just looked at the Service Bulletin again.

Step 26. This photo illustrates EXACTLY the same thing as my photos. Please compare them.







So again, not trying to argue, but I think my instructions are 100% correct, and followed the Isuzu instructions to the letter.

My goal was to provide timing belt instructions in a more clear way that Isuzu presented them, and if there is a mistake or even a tiny bit of confusion that I caused, I apologize. I just want to clear this up so no one has trouble in the future.

Bart

[nfpgasmask]

OK, had some more time here at work and so I downloaded the video and watched it again.

I think I see where the confusion is, and where my instructions could be considered backwards.

There are two marks on the crankshaft, one is the green "reference mark" on the outside of the crankshaft pulley, and the other is the half-circle notch referred to as the "timing mark" in the video. Its actually really hard to tell in the video because it is compressed and very hard to make out those fine details.

Anyway, I guess in my instructions the reference mark and the timing mark are backwards. I suppose this would not be the case had I turned the crankshaft one more full revolution.

Now, the reason why this worked obviously, is because both of those marks are just reference marks for the timing and the new belt installation. Apparently, so long as the camshaft marks are lined up, changing the belt whether at TDC or 180 degrees from TDC doesn't matter, so long as you install the new belt properly and you don't turn the crankshaft.

So, I can now say that I understand the discrepency, and I can update my instructions accordingly.

Now, to the OP, I hope that you did NOT turn your crankshaft pulley once you had the old belt off. If you did that, then you are 180 degrees off most likely. The other problem could be you are just a tooth off.

Anyway, I think my doing it backwards was simply a result of the video and diagram not clarifying between the two different marks well enough.

Bart

[PK]

Bart, I followed your instructions to the letter when doing my 3.2L JDM motor, and it fired straight up without any problems.
I don't think Isuzu made any changes to the motors in this area, provided we are all talking about the twin cam motor. (3.2L motor was also made in single cam version with about 175 HP.)

Your instructions are very clear and helpful, and I really would not change them.

PK

[nfpgasmask]

Thanks, PK. I am not planning on changing my instructions, however, I did make an annotation to them that explains the descrepency. The last thing I want to do is confuse people!

Bart

[term117]

I don't think there's anything wrong with your guide, I just didn't understand what I was doing at the time. If you just say this part is easy line up notches, remove old belt and place new belt on in the same spot. Might make it seem less complicated.

On to my problem
I did everything in this video to a T and tried to start the car without putting it back together. I didnt turn over at all. I assume it would still start.

http://www.vehicross.info/misc/timing_belt/timing.wmv
The cams spring into place every time and I am not losing a tooth. Perhaps my Cam gear retaining pin is sheared as it mentions in the video. Im guessing I don't need to take the heads off if the cams are springing to the correct positions every 9 rotations?

[SlowPro48]

Anyway, I guess in my instructions the reference mark and the timing mark are backwards. I suppose this would not be the case had I turned the crankshaft one more full revolution.

Wha? If you had turned the crank one more revolution you'd be right back where you started - i.e., still 180 degrees off. Turning the crank is not the problem. If you want to avoid confusion, the problem is telling people to align the dotted line on the belt WITH the TDC notch - when instructions from Isuzu say align the dotted line on the belt "180 DEGREES FROM TDC timing notch".

Note it's only a problem if you want to avoid confusion - it's not a problem from a practical/operational standpoint. As you well know, the VX runs just fine with the crank aligned 180 degrees off. All you're doing is making it fire the #5 cylinder when it thinks it's firing #2. Like I said in a previous post - just one of the advantages of a wasted spark ignition!

If you leave the instructions and pics as-is then, like the OP, people are going to continue to be confused during timing belt installs. And if they end up ignoring Isuzu's instructions and doing it as depicted in your how-to, it might even cause confusion well after the install. I can imagine the frustration of a future owner or his/her unfortunate mechanic when he discovers the high misfire count DTC he's been chasing on #4 is actually due to a bad plug wire on #1 and a confused PCM that thinks #1 is #4, #2 is #5, #3 is #6, etc!

Bart, I really appreciate the time and effort you put into your timing belt how-to. It helps all of us a great deal to have picture-rich start to finish instructions all in one place. If you truly want to eliminate future confusion though, modifying the instructions for that one step (installation of the belt on the crank pulley) to reflect what's in the manual and the TSB would take care of it - no further explainations/annotations/discussion needed ever again.