Valve timing belt skipped a tooth (or two)
Nov 7, 2005, 12:31 PM
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Valve timing belt skipped a tooth (or two)
I believe it happened when I was pressurizing cylinder #1 in preparation for valve springs/retainers installation. When the air compressor was at about 20 psi, I gave the crank pulley a slight nudge with the breaker bar and the crank moved about 1/8th a turn counterclockwise before I was able to completely stop it. I moved the crank back to TDC and gave it a little nudge again because it was slightly off and it turned 1/8th counterclockwise for the second time (when the crank moves, IT WILL MOVE... HARD AND FAST). Finally, back to TCD and everything was perfect from there.
I go on with changing all the valve springs and retainers (Revolver valve springs and retainers... Thanks Zeus!) with my wife sitting on the garage floor and holding the breaker bar. Next were the HKS 272/272 cams which went on nicely. The final components were the cam gears, but there was a problem. One cam gear can go on easily while the other can't. I placed a gear on the intake cam but didn't have enough slack to get the exhaust cam on. The timing belt tensioner tool had 4 complete turns on it already and I gave it another 4 turns (not all at once of course) to total 8. There still wasn't enough slack to get the gear on. This was when I realized that the belt might have skipped a tooth (or more).
Now I need to retime everything correctly. I looked at the service manual and found the process on 11A-57 to 11A-59 but had some questions. Can someone confirm that these are the correct steps in retiming the valve timing belt please?
1) Remove timing belt upper cover (already done)
2) Remove water pump pulley
3) Revove idler pulley
4) Remove auto-tensioner
5) Remove the crank pulley (4 bolts holding it)
6) Remove timing belt lower cover
7) Remove downpipe (so the Phillips screwdriver can go in the cylinder block plug later)
8) Align timing marks on crank sprocket and oil pump sprocket (will I be able to clearly see the mark on the crank sproket?)
9) Remove cylinder block plug above the starter (will fluid come out when I do this?)
10) Insert Phillips screwdriver into the hole and make sure it goes in at least 2" then leave screwdriver there
11) From here, I won't follow the rest of the instructions because I'm not actually removing and replacing the belt. I only need to readjust it so that the exhaust cam gear can go back on the cam, so I'll test the fittment after moving the belt one tooth counterclockwise.
12) Once I think everything is timed correctly, I take the screwdriver out and put the plug back on, place the crank pulley back on, slowly back off the timing belt tensioner tool, then rotate the crank a few times and see if all the marks line up (marks on crank pulley and valve cover).
Do the above steps seem correct? Do I really have to remove the front axle crossmember bar, the engine roll stopper, and centermember as the instructions say on 11A-50? The instructions states these to be pre-removal operations but don't say why they need to be done.
I've never had a car with a timing belt (only timing chain that never needed replacement) so any help would be greatly appreciated. Thanks in advance.
I go on with changing all the valve springs and retainers (Revolver valve springs and retainers... Thanks Zeus!) with my wife sitting on the garage floor and holding the breaker bar. Next were the HKS 272/272 cams which went on nicely. The final components were the cam gears, but there was a problem. One cam gear can go on easily while the other can't. I placed a gear on the intake cam but didn't have enough slack to get the exhaust cam on. The timing belt tensioner tool had 4 complete turns on it already and I gave it another 4 turns (not all at once of course) to total 8. There still wasn't enough slack to get the gear on. This was when I realized that the belt might have skipped a tooth (or more).
Now I need to retime everything correctly. I looked at the service manual and found the process on 11A-57 to 11A-59 but had some questions. Can someone confirm that these are the correct steps in retiming the valve timing belt please?
1) Remove timing belt upper cover (already done)
2) Remove water pump pulley
3) Revove idler pulley
4) Remove auto-tensioner
5) Remove the crank pulley (4 bolts holding it)
6) Remove timing belt lower cover
7) Remove downpipe (so the Phillips screwdriver can go in the cylinder block plug later)
8) Align timing marks on crank sprocket and oil pump sprocket (will I be able to clearly see the mark on the crank sproket?)
9) Remove cylinder block plug above the starter (will fluid come out when I do this?)
10) Insert Phillips screwdriver into the hole and make sure it goes in at least 2" then leave screwdriver there
11) From here, I won't follow the rest of the instructions because I'm not actually removing and replacing the belt. I only need to readjust it so that the exhaust cam gear can go back on the cam, so I'll test the fittment after moving the belt one tooth counterclockwise.
12) Once I think everything is timed correctly, I take the screwdriver out and put the plug back on, place the crank pulley back on, slowly back off the timing belt tensioner tool, then rotate the crank a few times and see if all the marks line up (marks on crank pulley and valve cover).
Do the above steps seem correct? Do I really have to remove the front axle crossmember bar, the engine roll stopper, and centermember as the instructions say on 11A-50? The instructions states these to be pre-removal operations but don't say why they need to be done.
I've never had a car with a timing belt (only timing chain that never needed replacement) so any help would be greatly appreciated. Thanks in advance.
Nov 7, 2005, 12:48 PM
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You should have to take the roll stop (motor mount off as along as you are just retiing the motor. They only recomend that when you are RR the timing belt because you can not get it off and on with the mount installed.
Also for future reference when you use a air to hold the springs up you should always use a TDC tool to lock the motor from turning over.
Also for future reference when you use a air to hold the springs up you should always use a TDC tool to lock the motor from turning over.
Nov 7, 2005, 12:55 PM
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Originally Posted by MM Racing
You should have to take the roll stop (motor mount off as along as you are just retiing the motor. They only recomend that when you are RR the timing belt because you can not get it off and on with the mount installed.
Also for future reference when you use a air to hold the springs up you should always use a TDC tool to lock the motor from turning over.
Also for future reference when you use a air to hold the springs up you should always use a TDC tool to lock the motor from turning over.
I didn't have a TDC locking too but I will remember your advice the next time I change out the valve springs and retainers. Thank you.
Nov 7, 2005, 01:48 PM
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Issues that I have questions on:
a) Can someone confirm that these are the correct steps in retiming the valve timing belt please?
b) #8 will I be able to clearly see the mark on the crank sproket?
c) #9 will fluid come out when I do this?
d) Do I really have to remove the front axle crossmember bar and centermember as the instructions say on 11A-50? I really don't see the need to.
Thank you.
a) Can someone confirm that these are the correct steps in retiming the valve timing belt please?
b) #8 will I be able to clearly see the mark on the crank sproket?
c) #9 will fluid come out when I do this?
d) Do I really have to remove the front axle crossmember bar and centermember as the instructions say on 11A-50? I really don't see the need to.
Thank you.
Nov 7, 2005, 02:03 PM
#5
Newbie
Re-Timing Cams
A much easier solution you can use in emergency is as follows:
Set the crank to Top Dead Centre, check the location of the timing marks on the cam gears relative to the marks on the cam cover. Turn the engine over and at the same time insert a small strip of thin aluminium between the cam wheel you want to adjust and the timing belt. Once the strip is between ther wheel and the belt you can turn the cam gear with a spanner on the end of the cam without moving the belt until you get the correct setting. Then turn the engine backwards to remove the strip and re-check your settings. Use a very thin strip not to damage the cam belt - the slack is created by pressure on the tensioner which will soon pull the belt tight again.
Also remember when checking cam settings always to turn the engine in the normal direction of rotation - clockwise, otherwise the tensioner will throw your settings out.
Note that high lift cams require adjustable cam wheels for best results and you need to set the cam with a dial gauge to the recommended setting. If you are styill using standard wheels with a high lift cam, advance the inlet cam gear 1 or 2 teeth but leave the exhaust setting standard.
Set the crank to Top Dead Centre, check the location of the timing marks on the cam gears relative to the marks on the cam cover. Turn the engine over and at the same time insert a small strip of thin aluminium between the cam wheel you want to adjust and the timing belt. Once the strip is between ther wheel and the belt you can turn the cam gear with a spanner on the end of the cam without moving the belt until you get the correct setting. Then turn the engine backwards to remove the strip and re-check your settings. Use a very thin strip not to damage the cam belt - the slack is created by pressure on the tensioner which will soon pull the belt tight again.
Also remember when checking cam settings always to turn the engine in the normal direction of rotation - clockwise, otherwise the tensioner will throw your settings out.
Note that high lift cams require adjustable cam wheels for best results and you need to set the cam with a dial gauge to the recommended setting. If you are styill using standard wheels with a high lift cam, advance the inlet cam gear 1 or 2 teeth but leave the exhaust setting standard.
Nov 7, 2005, 02:36 PM
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Originally Posted by Rallyman
A much easier solution you can use in emergency is as follows:
Set the crank to Top Dead Centre, check the location of the timing marks on the cam gears relative to the marks on the cam cover. Turn the engine over and at the same time insert a small strip of thin aluminium between the cam wheel you want to adjust and the timing belt. Once the strip is between ther wheel and the belt you can turn the cam gear with a spanner on the end of the cam without moving the belt until you get the correct setting. Then turn the engine backwards to remove the strip and re-check your settings. Use a very thin strip not to damage the cam belt - the slack is created by pressure on the tensioner which will soon pull the belt tight again.
Also remember when checking cam settings always to turn the engine in the normal direction of rotation - clockwise, otherwise the tensioner will throw your settings out.
Note that high lift cams require adjustable cam wheels for best results and you need to set the cam with a dial gauge to the recommended setting. If you are styill using standard wheels with a high lift cam, advance the inlet cam gear 1 or 2 teeth but leave the exhaust setting standard.
Set the crank to Top Dead Centre, check the location of the timing marks on the cam gears relative to the marks on the cam cover. Turn the engine over and at the same time insert a small strip of thin aluminium between the cam wheel you want to adjust and the timing belt. Once the strip is between ther wheel and the belt you can turn the cam gear with a spanner on the end of the cam without moving the belt until you get the correct setting. Then turn the engine backwards to remove the strip and re-check your settings. Use a very thin strip not to damage the cam belt - the slack is created by pressure on the tensioner which will soon pull the belt tight again.
Also remember when checking cam settings always to turn the engine in the normal direction of rotation - clockwise, otherwise the tensioner will throw your settings out.
Note that high lift cams require adjustable cam wheels for best results and you need to set the cam with a dial gauge to the recommended setting. If you are styill using standard wheels with a high lift cam, advance the inlet cam gear 1 or 2 teeth but leave the exhaust setting standard.
The issue I have is that I can't get enough slack on the timing belt to get the cam gear (Fidanza cam gear) on the exhaust cam. Your way will work as long as the belt at the bottom near the crank didn't jump a tooth. I believe that's where it happened when the crank moved on me so there's more slack on the tensioner pulley side (closer to the cabin) compared to the idler pulley side (close to the front of the car). I need to confirm that the markings on the crank sprocket and oil sprocket are timed correctly before I use your way of adjusting the belt up top.
I've set the adjustable cam gears at 0/0 until I know everything is timed correctly.
Nov 7, 2005, 11:25 PM
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Now I believe I have another issue. How many complete turns would one need to rotate the tensioner tool in order for the tensioner arm to compress the auto tensioner body rod so the holes line up? I've rotated the tensioner tool about 17.5 times (70 quarter turns) but the arm never compresses the rod. See firgure 6 on this page for picture:
http://www.vfaq.com/mods/timingbelt-1G.html
Even at 17.5 turns, I'm not getting enough slack for the cam gears to go back on. It's possible to get one gear on but not both. There is no slack between the crank sprocket and the oil pump sprocket so I don't think it's loosening the tension at all. Is there something I missed?
http://www.vfaq.com/mods/timingbelt-1G.html
Even at 17.5 turns, I'm not getting enough slack for the cam gears to go back on. It's possible to get one gear on but not both. There is no slack between the crank sprocket and the oil pump sprocket so I don't think it's loosening the tension at all. Is there something I missed?
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Nov 8, 2005, 04:32 AM
#8
Newbie
Compressing Tensioner
The tensioner is not compressed by rotating it. You have to remove it, put it in a large vice and press back the rod until you can insert a nail or similar through the hole in the body and in to the rod. After you have installed the belt pull out the nail. Take care not to bend the rod when you are compressing it by making sure you push it squarely - its quite hard but a vice can do it.
Nov 8, 2005, 05:04 AM
#10
Newbie
Wrong tensioner ?
No, I don't think so, with a new belt you must remove the tensioner completely and compress it in a vice before the belt will fit over the cam wheels. You cannot do this on the car. The main problem is making sure the balance shaft wheel is correctly aligned with the crank, once this is done my trick with a strip of aluminium can be used to get the cam gears set up correctly too if they are off a few teeth.
Of course the correct way to align the cams is with a dial gauge, but you need to get the base setting correct and use adjustable cam gears to do the job properly.
Of course the correct way to align the cams is with a dial gauge, but you need to get the base setting correct and use adjustable cam gears to do the job properly.
Nov 8, 2005, 05:58 AM
#13
Newbie
Balance belt does not have to be removed to change the cam belt, it fits behind it.
If you remove the balance belt the engine may have a slight vibration because the balance shaft will not rotate but you will hardly notice it. However you'll get better acceleration because the rotating mass will be reduced and it also avoids the possibility of the balance belt breaking and causing problems with the cam belt - I recommend you remove it.
If you remove the balance belt the engine may have a slight vibration because the balance shaft will not rotate but you will hardly notice it. However you'll get better acceleration because the rotating mass will be reduced and it also avoids the possibility of the balance belt breaking and causing problems with the cam belt - I recommend you remove it.
Nov 8, 2005, 06:03 AM
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He is trying to retime the thing with it on the motor still, not putting on a new belt. And for that case you do not need to pull off the tensioner to compress it. You can use the tool.
Nov 8, 2005, 09:28 AM
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The service manual says I can compress the tensioner adjuster (also called the auto tension in figure 6-8 on this page http://www.vfaq.com/mods/timingbelt-2G.html) by screwing in the tensioner adjusting tool (MD998738) even if it's on the car. No where does it say in the service manual to "Loosen the tensioner pulley center bolt (Figure 7)" as stated in step 10. I think here lies my problem.
I'll try step 10 before actually screwing the adjusting tool so far down. I was so tempted to just unbolt the tensioner yesterday and just compress it off the car but decided not to without asking you guys.
Yes, the balance shaft wheel (sprocket) is correctly aligned with the mark on the engine. However, the oil sprocket is not aligned with its mark. I'll haven't done step 24 yet but I will once I know I can get the belt over all the gears/sprockets.
Thanks for your help, Rallyman and MM Racing. I had no issues installing everything (valve springs, retainers, head studs, cams) until the easiest part (cam gears)... how ironic. lol
I'll try step 10 before actually screwing the adjusting tool so far down. I was so tempted to just unbolt the tensioner yesterday and just compress it off the car but decided not to without asking you guys.
Yes, the balance shaft wheel (sprocket) is correctly aligned with the mark on the engine. However, the oil sprocket is not aligned with its mark. I'll haven't done step 24 yet but I will once I know I can get the belt over all the gears/sprockets.
Thanks for your help, Rallyman and MM Racing. I had no issues installing everything (valve springs, retainers, head studs, cams) until the easiest part (cam gears)... how ironic. lol
