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Discussion Starter · #1 ·
I'm in the middle of changing the cam belts on my '99 Esprit and ran into what could be a major problem. I installed both new Gates blue belts and was starting to rotate the crank twice to verify the tolerence pins would still go in. The right side belt jumped a tooth (or two, no way to tell) after it was less than 1/4th of the way through the first revolution. I guess I didn't tighten the tensioner pulley enough on that bank. Anyway, I'm unsure how to continue. Do I need to follow the service notes and reindex the cams (they don't give any indication on how to get the engine into the "safe" position when it's out of sync. If I continue to rotate the crank it hits a valve) or can I rotate the crank counter-clockwise until I can put the tolerence pins back in, remove the belt on that side, and continue to rotate the crank until I can get the crank locking tool in place. I assume rotating the crank counter-clockwise is a no-no, but I'm not sure why other than the risk of loosening the crank bolt. The left bank is fine.
Any ideas would be appreciated!
 

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I can’t speak from experience to the ‘do/do not’ reasons for rotating the crankshaft counterclockwise ~1/4 turn to reset the camshaft tolerance pins, but I would say that the torque applied counterclockwise to the crank bolt would be negated (ultimately) by the number of clockwise revolutions needed to set the cambelt tension later.

The service manual does say “The engine should be turned only in the normal direction of rotation; i.e. clockwise as viewed from the front. Turning the engine backwards causes cam drive loading to be applied to the belt tensioners, and may result in loss of valve timing due to a cam belt jumping teeth.”

If you decide to rotate the crankshaft counterclockwise ~1/4 revolution to begin the reset process, when the notch/vane on the crankshaft pulley is aligned to the crank position sensor hole, install the crankshaft locking pin and camshaft tolerance pins in the ‘good’ left bank. Then, you could use a relatively inexpensive ($15~$20) USB endoscope/borescope to help see where the alignment hole(s) in the wayward right bank camshaft(s) is/are positioned relative to the access/alignment holes on the cam cover/bearing cap. Finding out which direction to slowly rotate the camshaft (once the cambelt is removed) will allow you then to use one hand to rotate the camshaft (using a 18mm box wrench) and the other hand to install the camshaft tolerance pin when aligned. Much better than having to guess which direction to rotate the camshaft, and it should (hopefully) only be a few degrees of rotation to achieve hole alignment.

The other option is to do as you stated (reset the cams), which involves removing the intake plenum to gain access to the cam cover.

Good luck! Just take it slow and be methodical. It’s supposed to be a hobby, right? 😊
 

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1974 Europa TC, 1990 Esprit SE, 2003 Esprit V8, 2005 Elise
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If the engine is in the car then I would remove the spark plugs and very gently and slowly back it up to the original "Safe" position. With the plugs out the engine should move very freely and with enough caution you should be able to feel any obstructions pretty early. Slow and with great caution. If anything gets bent the engine is coming out. There are probably others who would recommend otherwise but this is probably what I would try first.
 

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Also, I would recommend changing out the original tensioner bolts for the replacements from ARP... available not directly from ARP but from JAE.
 

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I've had this happen before also, and I've always been able to correct it without much work. I'd do exactly as DailyDriver suggests and get the spark plugs out so you aren't confused by compression. If you are only 1 tooth off, you won't have a collision because the valves will be late to open and close. If it was my car, and I was only 1/4 through the first turn, I wouldn't hesitate go backwards after getting more tension on the problematic belt. The further you go forward, the more chance you have at getting "lost". Two teeth off starts to get risky, though you do get a little "give" in the hydraulic tappets to warn you ahead of any damage if you go very slowly.

But this is not something you want to risk, so you have to stop and re-think if you feel any binding. You don't want to put a big ass breaker bar on the crank and use any muscle, or you are going to have to tear down the whole engine to fix it. If you can rotate it around the two revolutions without a collision, you will be able to loosen the belt tension and use a wrench to gently rotate the cams until you get full engagement of the set or tolerance pins. Then start over again and make sure your belt tension is high enough. They should feel taught on all of the runs before you start rotating the engine. --This is also maddening on the Esprit because it is possible to have way too much tension on one portion of the belt run, and almost nothing on the opposite side because the act of moving the tensioner really only tensions 1 area until you rotate the engine a couple of times afterward. The belt can also ride high on the gear teeth, not be straight on the cams, or any number of other things to drive you to the edge of reason.

If the worst should happen, and you lose track of the position of everything, you are better off to just remove the cams entirely. Then you can get the pulleys off out of the car, replace the lip seals, and start the procedure in the book to reindex. You can't easily get the pulleys off with the cams in the car anyway since you have to get a wrench on the cams to get enough torque on the pulley bolts to safely remove them.

I think you will not have to worry about any of this. In 1/4 turn, I highly doubt you jumped more than 1 tooth. I would go put more tension on that belt, turn the engine slightly backwards to set position, ask the Lotus engineers for forgiveness for doing that, then turn the cams forward gently with a wrench until your pins will fully seat. Then sigh, relax, and start all over again.

One other thing to add to this long post: ALWAYS rotate the engine by hand afterward, several times, to be sure of your belt tension and cam timing. On a typical belt change, I probably rotate the engine 15-20 times by hand before I'm satisfied with consistent tensioner readings. If you've done this, you can be confident when you start the car, and you'll know not to panic when the engine clatters for 20 minutes while the tappets pump up.
 

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Discussion Starter · #6 ·
@04ESPRIT - I happen to have a borescope, so using it to make sure the cams are close to the locking position is a done deal. I've already used it to look down the sparkplug holes to check out the tops of the pistons. It's a very cool piece of equipment! The only way I can think to reset the cam timing without rotating the crank counter clockwise is to remove them. Otherwise I can't move the crank without valve/piston contact. I didn't see anything in the service guide about how to do this, but I haven't spent a lot of time looking yet.

@DailyDriver - I have removed the sparkpulugs, so turning the crank is fairly easy. I am using the ARP bolts that came with the kit I got from JAE, they’re much better than the factory bolts! I had spent a lot of time getting to this point and like a friggin idiot didn’t fully tighten the tensioner pulley before I moved the crank. This is what happens when you step away from a project mid-way through and come back to it weeks later… live and learn!
 

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We've all been there. Most of us admit it. I think your plan will work. If you only slipped a tooth or two and only rotated the crank about 1/4 turn I believe you should be able to see the alignment hole in the offending cam before you fully return to the Safe position. Return in small increments and you may be able to spot the hole as it appears before fully returning.
 

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Discussion Starter · #8 ·
A quick update - I was able to recover from my mistake and get all the setting pins installed and the crank locked after rotating the crank counter clockwise. I was able to set the tension (it settled at 118 Hz left, 108 Hz right) on the new blue belts (new idlers and tensioners as well) after three tries. I checked that the setting pins went in with the crank locked before moving to the two tension setting positions each time I adjusted the tensioners. The last go-round three of the pins went in with no friction, but the left intake side required me to wiggle it a bit before it was fully seated. After the serpentine belt went in I started it, and heard a loud ticking sound. I shut it off after about 10 seconds. I looked around the engine bay and couldn’t see anything, so started it up again for about 10 seconds. Still ticked… The engine hadn’t been run for a few months, not sure if this has anything to do with the noise. I can’t work on the car until Monday, but I’m planning to pull the spark plugs and use my bore scope to see if any of the valves hit the pistons. Not sure how it could happen, but I don’t know what else to do. Any thoughts on what would cause this would be appreciated!
 

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I think its most likely a lifter tick if the engine hasnt been run in a few months. How did it run in the few moments that it was running? Personally I think that if you had valve to piston contact the engine would not run good. To be on the safe side you can check the piston tops for contact but i doubt you will see the valves good enough to determine if they were damaged. You would have to check the top of the piston for any marks.
 

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It seems like it would require a fair amount of force in turning the crank and/or cam by hand to bend a valve via piston contact, so if you'd done it during the cam belt change you'd probably know it.

And if the cam timing was correct before engine start it's not likely there was contact at that point.

Borescope might reveal something but probably better to also run a compression check and leakdown test on each cylinder. That should reveal if there are any valve seating issues.

EDIT: Best to start with the leakdown test since that can be done without cranking the engine on the starter, just in case. If there is excessive leak down in a cylinder try squirting engine oil into it and run the test again, this will help isolate to a valve or piston ring issue.
 
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@Patmandu
I've experienced the loud ticking sound after more than a month or so of not having run the engine. It's incredibly nerve-wracking, and I'd imagine even more so after a belt change! It finally went away after about 30~60 seconds. The longest minute ever...
However, if the engine otherwise sounded strong (good idle, not lumpy), I think it's probably the lifter(s) as others have described.
 

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My '99 had a bad lifter tick when I first got it. It comes back from time-to-time especially if the car hasn't been run in a while. When I change the oil I use engine flush before the change and it has reduced the tick significantly. It can take quite a while for the tick to go away, basically the engine has to warm up. The ultimate fix would be to either replace the lifters or clean them. The tick doesn't seem to be doing any harm.
David Teitelbaum
 

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Discussion Starter · #15 ·
When I started it up it ran fine, smooth idle and no unusual exhaust note. I think I’m going start it up again tomorrow and let it run for a minute or two after I check all the bolts on the pulleys and bearings. I hope it’s just lifter tick!
 

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Discussion Starter · #17 ·
I just ran a compression test on each cylinder and it doesn’t look too bad. On the drivers side, front to back I got 160, 150, 175, and 175. The passenger side is a bit lower at 155, 150, 160, and 150. Do these numbers seem reasonable? I started it up again and let it run for about a minute, the tick is still there. It idles fine but stumbled a bit when I gave it gas. I looked in each cylinder with a bore scope and didn’t fine evidence of valve to piston contact. The cylinders still have a nice cross hatch on them. I just got a leakdown tester, I think that will be my next test unless someone has a better idea!
 

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The numbers you got for a cold test would seem to point that the valves are okay. Perhaps checking if you can narrow where the ticking is coming from a bit more precisely, like with a stethoscope or something, it could help narrow the problem down to a specific cylinder. In fact, I don't recall seeing a description of exactly where the ticking is coming from.

I have had a valve spring fail. I don't recall any ticking from it but don't know if it broke while driving or at idle. It did bend just one valve. Perhaps you have a failed spring? Just a shot.

Have you let it idle until it warms up yet? Perhaps record the sound and post an audio clip. Sometimes the sounds can best be identified when heard and recognized.
 

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Discussion Starter · #19 ·
@DailyDriver - I haven’t run it for more than 90 seconds so far. I’ll put the plugs back in and let it warm up for a few minutes. I can’t pinpoint where the noise is coming from, but I have a stethoscope on order that should help. I noticed something odd though. The new serpentine belt has shallow groves in it. Nothing is rubbing on it and the tensioner is clean. Very odd as I confirmed it’s routed correctly.
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