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For what it's worth, you can turn the cam sprockets all you want, just don't lose track of how much you move them from the initial timing marks. I rotated both sprockets to tension the cam lobes against the valve springs to aid in setting the belt to correct time. (It eliminated the need for a helper or breaker bar and bungie cords to hold them from their 12 o'clock off-lobe position as per Barts write-up.) Set the belt to the correct position on both cam sprokets and then rotate the sprockets back to time, tensioning the belt in the process.
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Quote:
Originally Posted by
Scott Larson
For what it's worth, you can turn the cam sprockets all you want, just don't lose track of how much you move them from the initial timing marks. I rotated both sprockets to tension the cam lobes against the valve springs to aid in setting the belt to correct time. (It eliminated the need for a helper or breaker bar and bungie cords to hold them from their 12 o'clock off-lobe position as per Barts write-up.) Set the belt to the correct position on both cam sprokets and then rotate the sprockets back to time, tensioning the belt in the process.
If the cam is out of time it can take up to 9 full turns to put it back in time.So if you were to turn it 1 full turn the cam would be out of time.Yes you can turn it a little to line up the belt but I would not move it anymore than that unless you want to make alot more work for yourself. shawn
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Quote:
Originally Posted by
nfpgasmask
The "chocolate monkey" thing might just do that (:rotate:), so I always point people to the original how-to here:
http://www.nofuture.com/myvx/how-tos/tb/tbelt.htm
The above link is from my website, and if I make any revisions, you will see them there, but not in the PDF that Tom made of my original how-to back when I originally posted it. In fact I do think there are some minor changes on my site that ARE NOT in the PDF currently. Plus, I think my website is a better format and easier to follow. While the PDF is easier for people to find, I encourage everyone to visit the instructions on my site over the PDF.
Yerrrr Welcome!!!:)
I tried to be true to Bart's write up when I converted it to PDF (only took a little comic liberties). In retrospect, I should've added a hyperlink to his website so that any updates could be tracked. The PDF isn't supposed to do anything more than provide a copy for peeps to archive if they wish & print a throw-away copy to have in the garage whilst doing the repair.
Back on topic: Take the pix of the timing mark alignments to an authorized Isuzu repair facility (yes, those still exist) & find out if it appears out of spec to them.
IMHO, although the mark is obviously off slightly, it's not off by the amount that a 1 tooth adjustment on the belt would correct. If you adjust the belt by 1 tooth, the mark may actually be on the other side of the reference. This makes me think that it's a tensioner issue.
BTW, Chocolate Monkey:
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Quote:
Originally Posted by
tom4bren
IMHO, although the mark is obviously off slightly, it's not off by the amount that a 1 tooth adjustment on the belt would correct. If you adjust the belt by 1 tooth, the mark may actually be on the other side of the reference. This makes me think that it's a tensioner issue.
Take a close look at the pic in question...the camera isn't lined up square with the end of the cam, giving the appearance that the reference mark is slightly off.
If the camera moved left slightly, so that the cam sprocket bolt was in line with center, everything would line up just right.
http://www.supermotors.net/getfile/8...k-(driver).jpg
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When I helped Joh (VXorado) do his timing belt, his cam looked just like the picture above. We sat there and pondered whether his timing was actually off, or not, for a couple of hours. We moved the cams one tooth back and forth, but the marks never seemed to line up perfectly (they where that way with the old belt on too). In the end he left it, put it all back together, and it's been running just fine ever since.
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Quote:
Originally Posted by
nfpgasmask
SlowPro, not at all.
Well that's good. Looked like people were getting DE-fensive so I thought uh-oh I guess that means I came across as O-ffensive. I never mean to offend anybody here* but sometimes it happens without my even trying. :sigho2:
Yeah I lined everything up just like Isuzu says to do it - with #2 at TDC and both cam pulleys lined up withe their marks. Then I took the old belt off and put the new one on. I have no idea where the dots and lines were on the old belt before I took it off. I couldn't see them but to be honest I didn't look that hard because I knew they didn't matter. All these marks are just there for you to verify that you have the right number of teeth between each pulley when you put the new belt on.
I think what's confusing the situation (for me at least) is that the cams don't turn at the same speed as the cam pulley** so you can't relate crank position to cam position easily just by looking at the pulley. One thing is for certain: although Isuzu says line the cam pulleys up with #2 piston at TDC, there is also a point in the rotation sequence where the cam pulleys are on their respective marks and #2 piston is at BDC - otherwise your engine would not be running.
If you did what you suggested - took the belt off and spun the crank 180 degrees and reinstalled the belt, your engine would not run. If you did the opposite - i.e., kept the crank where it was but spun all the cams 180 degrees (the cams themselves, not the cam pulley since it's not a 1:1 ratio) I think it would run just fine because of the wasted spark ignition system. I don't know if #2 is on the compression stroke or #5 is on the compression stroke when lined up like Isuzu says but it doesn't matter because both coils are fired by the same trigger so if you took the belt off and spun the cams around so as to swap the suck squeeze bang blow cycle from one cylinder to the other, the engine wouldn't miss a lick since it would still be getting spark when it was time to bang. If you spun the crank like you suggested though it would try to blow when the valves thought it was time to suck, suck when the valves thought it was time to squeeze, and blow when the valves and thought it was time to bang. It would also squeeze when the valves thought it was time to bang of course - but they wouldn't care - they're lazy - even when your engine is running properly they think squeezing and banging are the same thing - they just lay there with their springs extended, doing nothing - letting the ignition system do all the work...
Buffy's the one who could put this discussion to rest. Not only has he got the timing belt covers off at this very moment but also the valve covers so he can actually see everthing that's going on. Come on Buffy - dish out some info here - how many teeth on the cam drive gear and how many on the cam? How many teeth on the crank pulley and how many on the cam pulley? Line that baby up like Isuzu said to do it - then crank away and see how many turns it takes to get to Bart's configuration and how many turns it takes to get back to the Isuzu configuration. I bet Bart's is exactly half way through the cycle. Oh, and BTW Buffy - eat your Wheaties first! :luck:
*except for SpudBoy of course. But he's apparently too busy enjoying his white bread and crackers in Idaho to post here anymore. If he ever shows up again though I'll do my best to offend him because he and his ilk actively try to kill my joy (and yours too if you like to take your VX off-road). Oh, wait... maybe he's decided to diversify his honky self and move to NC - I think I see him in the background in this video! http://www.youtube.com/watch?v=roFB7bGCAgc
**I'm guessing they turn at 2/3 speed since it's a 60 degree V engine but yet you turn the left (even) bank pulley 90 degrees after it "springs" to reset the cams when you've lost timing due to belt breakage, etc. But then again if you check the illustrations in the shop manual it looks more like 3/4 speed based on the sizes of the gears so who knows. Either way the cams are under driven and that make it hard to visualize what's going on.
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OK guys.... I'll put on my peepers and do some counting this evening / weekend and see what I come up with! May have to wait until the morning so I can have TWO bowls of wheaties.:winky:
Update:
The crank gear has 26 teeth on it
The cam gear has 39 teeth
the rest of the counting will have to wait.... skeeters are vicious out there tonight!
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I installed all the new parts, checked and re-checked and double checked the timing marks. Pulled the pin, crossed my fingers and fired it up...... :madb: :upsetgray Nothing changed! The knock is still there just as before. Rev the motor and it stops briefly but will go back to the tapping/knocking. Any ideas?? It really doesn't sound like the engine. Do I remove the passenger head? Does anyone have a write-up on how to check the valve lash???
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After reading the service manual, I decided to pull the plugs on at a time and see if it caused the noise to change (per the manual). It did not change the sound of the knocking at all. Now here's the interesting part, after testing I refired the engine with all plugs connected and it ran quiet for about 30 seconds before the knocking began again.
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Well, I did something......posting for clarity.
Following barts how to, i rotated the crank several times watching all the marks
on the three pullys. Looking at bart's crank picture, the "dot" on the front
of the crank pulley lined up with the mark on the oil pump, and the cam marks lined up with marks on covers. I removed the tensionor, and the cams snapped like Bart said they would, but not WHERE he said they would. So I continued and got the heads removed, only to discover that #2 cylinder is at BDC!
So I've got to go thru the lost time service bulletin to get my cams where they need to be. Barts write up is good! So much better than the manual, but I got confused with the crank markings. Since heads are off, I'm going to turn the crank to 2 TDC and hope that the notch in back of crank pulley lines up with oil housing. Another confusing issue mentioned earlier, how do I know if I'm on a compressionstroke on #2?
Can I use a socket to spin the cam pulley? Thinking that I heard that was not good
thing to do.
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Don't mean to be wiseasserish, but...
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Lol, yeah, I think I've read every post on timing on vxinfo!
I was posting mor on the confusion of which mark lines up with the oil pump.
Manual says line up the notch on back of crank pulley. Barts how to lined up the "dot" on the front of crank pulley, which is what I did. However, when I did this, #2 was at the bottom of it's stroke, not TDC. And the marks lined up on head covers.
I will have to go by library tomorrow and watch those videos.
And I would NEVER consider you a wiserasshimer!
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Quote:
Originally Posted by
IndianaVX
I will have to go by library tomorrow and watch those videos.
And I would NEVER consider you a wiserasshimer!
Thanx D-man, those vids are Isuzu training vids...hope they'll give you some ansrs...:yesgray:
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Yeah, there was some discussion some time ago about my instructions being sort of backwards. Which is very possible I guess, I just think that using my 'technique', you basically just keep everything in line and the timing stays the same. It still confuses me a little how it could work the way I did it if it is wrong.
:_huh: Bart
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Bart,
I followed your how-to to the letter and everything worked out for me too so you must have done something right. I do have to say, though, that when I lined everything up and took the timing belt off my cams snapped to 3 and 9, not noon as in your how-to. Doesn't really matter, I guess, as long as you line everything back up the way it's supposed to be.
IndianaVX, good luck with getting it all back together and running. Keep us updated.
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Yeah, I dunno, my photos are how it worked out for me exactly, as I snapped pics and took notes all the way through. Weird, maybe it just depends on what position you remove the belt.
Bart
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Hardeman
My cams did the same thing by snapping to the wrong place.
Went and watched (more like memorized) the video on lost time.
That is the technique I will be using. With everything tore off,
I can watch the pistons, and heads off, I can see the internal marks on the cams.
I feel pretty good about getting it back together!
Again Bart, I hope you don't take my comments as being critical.
Just posting, so that the next guy won't be suprized, and will know a way out.
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IndianaVX,
I have to say that the cams snapping to 3 and 9 instead of noon as in Bart's how-to it scared the poop out of me, but once you get the new belt on (and I HIGHLY recommend the Isuzu belt) all you have to do is line up all of the lines on the belt with the notches and lines on the cams and crank and all should be well. I also read through the Isuzu "How to get your timing back" and though it was a little vague it did seem to have enough information to figure it out. Luckily I didn't have to use it. Once I got the new belt back on I turned the engine by hand to make sure the everything kept lining up.
In all honesty, once everything was back together I sat in the drivers seat for a good ten minutes with my hand on the key taking deep breaths and hoping that when I finally turned the key the VX would start up. It did and I heaved a BIG sigh of relief.
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After watching ,and memorizing the video, I was amazed at how easy it is to set the time back! Didn't take 2 minutes to time both heads... (of course, I haven't started the engine yet) but having everything tore down, it was easy to see the inside marks on the cams, and actually watch the cylinders move up and down. I meant to look and see where the internal marks were at after the "wrong snap" but was over anxious and went right to work as soon as I got there tonight, BUT I can officially say this....
When the notch on crank pully lines up with mark on oil pump,
The #2 is TDC. When the dot on front of crank pully is lined up with oil pump mark, #2 is BDC, the bottom of its stroke. Just so we REALLY know now!
