Both shims on the idler were in place and appropriately positioned.





However... When I was looking at the idler assembly after I took those pictures, I was looking at the pulley alignment and it looked odd.




Now, about the above picture. The outer edges of the two pulleys will not be aligned. The construction is different. The tensioner pulley has a much wider outer lip. However, this got me to looking at things closer. I would assume the idler pulley was symmetric. I flipped it back and forth probably half a dozen times, trying to convince myself whether it was or not. I got out a stiffer straight edge and started looking at things more. There is about 1.5mm mis-alignment between the tensioner pulley and the idler pulley. Note that, as shown above, that is with one shim on the outside, one on the inside.

Now, if I double stack them and put them both on the inside, things line up perfectly. They don't show up on any parts diagram, or pictures of replacement idler pulleys. All the pictures I have, of the idler assembly, from taking things apart, still have the dust cover on the front of the idler pulley.

Somebody want to give me a hint?

I'm also assuming that alignment between the tensioner and idler will line up with the crank. There isn't a practical way to check alignment to the millimeter level, between the idler and the crank.

My thoughts.

the belt is clearly being eating away. This can be caused by misalignment (prime suspect). You have found an offset.

Suspects are all new things and things you took apart. Maybe you can shim the old pulley to align to the new tensioner by shifting the shims. But isn’t the root cause in the new tensioner? Can you make measurements comparing it with the original?

in the end the belt has to be guided straight and with the right tension (belt lenght).

Adam

Not an unreasonable suggestion, and I've spent most of the morning trying to measure and check alignment.

Some things I have now verified.

The lower tensioner does have a shim on both sides. You can see the front on in this picture from EuroAMP.


Also confirmed I have the correct, updated tensioner assembly, which is needed for the VAP updated tensioner.

Confirmed that the lower idler does line up with the crank pulley better when there is a shim front and back, rather than two back.

Trying to measure the tensioner alignment is quite difficult. Reference surfaces are hard to come by and every setup seemed to be unrepeatable. The VAP tensioner may be about 1mm taller, but I wouldn't stand by that measurement. And... I don't think it matters much. Yes, alignment matters, but I was comparing the lower idler puller alignment to the tensioner pulley alignment, but the belt doesn't go from one to the other.



The blue arrows are the direction the belt moves. The path from the bottom of the crank pulley to the tensioner and from the tensioner to the upper idler are the two longest sections of belt. The longer the run, the less a 1mm difference in height would make. Yes, it will always make some difference, but 1mm over 200mm is 0.29deg. 1mm over 75mm is 0.76deg. The latter is going to cause more issues. Further, the yellow circle is where the squeak is coming from. That's the very short run from the lower idler to the top of the crank pulley.

Right now, the theory that makes the most sense to me is that the belt is bedding in on the GripTec pulley, which will wear away some of the rib material. Some of that rubber debris is staying on the belt and getting compacted by the trip around the crank pulley and that's where the squeak is coming from. I'm not happy with the explanation, but its the only thing I have right now.

So, for now, I'm going to go install the correct drive belt, get the supercharger belt back on and get it started and running and see what things look and sound like.

If trying different size belts doesn't fix it, I would consider re-installing the original tensioner as a last resort test...

So I put it all back together, started it up, and... after about 30 seconds, it started to squeak again. Congrats to @JagCode3 for getting the probably cause.

There it is, staring me in the face.



I have no idea how I missed that, all this time. The tensioner is at, or past, max extension because the belt is to long. I got shipped the 1480 belt, however, since I did the upper pulley too, I need the 1470 belt. Before anyone jumps on VAP, I take full responsibility for the fact that I totally missed the very well marked guide on the tensioner, in all my investigation. So yeah, wrong belt got shipped. I should have caught it at install and instead burned three-four days (cumulative) chasing a squeak that probably gets fixed by dropping in the correct belt.

As annoyed as I am at the time I wasted, I'm also thrilled to have found the likely problem. It also explains the significant motion I saw in the tensioner arm, when the engine was running -- the belt isn't actually under much tension.

As discussed via email, we have already sent a 1470 belt to you via DHL. Not sure if you have even seen the messages yet. The upgraded tensioner pulley is slightly smaller diameter than OEM. With just the upper and lower pulley, you would use our 1485 belt, however moving to the upgraded tensioner, we'd recommend the 1470 (which is on the way).

Thanks for the background. Yeah, I saw you emails and the shipping notice. Thanks for the quick turn around. It will be a race to see if it gets here before I leave on my next business trip. Luckily I have lots of practice in swapping the supercharger belt and can probably do the whole swap in less than an hour now. Assuming things arrive before I leave, I'll update everyone shortly after the belt gets here.

I obviously haven't posted an update on this in a while, but I've been working on it a lot. I was hoping to be able to come back with an update that covered my trials and tribulations, with a final resolution. However, that is not currently the case. I have managed to get the squeak to go away..... by going back to the stock lower pulley. Nothing else made a difference. I'd love thoughts from any of the actual JLR techs following this thread, or that come across it. I'd be happy with input from anyone -- with one big caveat: please read this post in full before you chime in with something to check or a comment about your tangentially related problem. Chances are really good that I've already tried it, or ruled it out.

For reference, this post has video that show the squeaks: https://www.jaguarforums.com/forum/f...pgrades-294025
That video is from very early in the investigation, but the squeaks haven't changed substantially along the way.

Belts: both the VAP 1470 and 1485 belts have been tried. The 1470 is the correct length for my actual setup. Also, I have double and triple confirmed that it is the belt causing the squeak. It is not bearings anywhere. Deodorant on the belt causing the squeak to stop for a bit (it's an "old timer trick"). Wetting the belt (generic blue windshield fluid) also causing the squeak to stop, but only if you wet the side that goes against the crank pulley. So it's definitely the belt and definitely the belt against the crank pulley.

More belt tension: With the 1470 belt on, increasing tension (wrench on the tensioner arm) did not make the squeak stop. It did make the pitch go up a bit.
Less belt tension: With the 1470 belt on, decreasing tension (wrench on the tensioner arm) makes the squeak quieter, but never made it go away.
Lower idler -- I put in a new lower idler, just to ensure there wasn't bearing play in my original that might be causing issues. No change.
Stock tensioner -- I put the stock tensioner back in, no change -- still squeaks.
Belt alignment is good. There is no sign of edge wear or unusual twists or other symptoms of miss alignment.

I confirmed that there wasn't anything between the two crank pulleys, or the rear pulley and the hub that would be causing alignment issues. Torque has been to 48lb-ft on the bolts.

So far as I can tell, VAP is the only one that has 8 rib, double sided micro-v belts in the correct length (or even close) -- at least for general purchase. Gates doesn't sell one, for example.

So right now, I'm running with stock lower, stock tensioner, new lower idler, and a Gates 8DPK1430 belts. No squeaks.
The CEL is on since the tune expect VAP lower and upper and I'm running stock lower. Otherwise, all good.

The VAP pulley looks just fine.





That's after I pulled it off this last time, when I went back to the stock pulley.

No we get into what I've been chasing. I took some "slow motion" video of the crank pulley -- both with the VAP and stock pulleys. In the videos, you can see what looks like runout, or a wobble in the pulleys.


In the last one, you can see the crank bolt head, which also appears to be slightly off center. Note: bolt heads are not reference surfaces and I've seen plenty that were just slightly off center, so that by itself doesn't mean anything.

I still have motion in the tensioner as well, even with the stock pulley:
So I had the thought -- maybe the harmonic dampener wasn't quite square to the crank shaft. If the mounting hole were drilled at a slight angle, or slightly off center, that would cause the whole assembly to wobble some. Now, there are problems with this theory. First, the accessory belt tensioner doesn't move at all. It's possible that the increased belt length, and the fact that the accessory drive pulley goes back towards the engine, putting it behind the surface of the the mounting hub, means that the geometry just doesn't make it move near are much. Now, the bigger problem. Today, I put a dial indicator on the stock crank pulley.

Radial runout was less that 0.3mm and axial less than 0.2mm. Now, it's cramped in there and pretty hard to setup the gauge on the pulley, so getting a few tenths of a millimeter doesn't seem horrible. Measurements were taken at the outer front edge of the pulley -- where it should have the largest amount of movement. 0.3mm doesn't seem like something that would readily show up in visual inspection, even in slowed down video.

So now I'm stuck. The video, to my eye, definitely shows a wobble in the crank pulley. Actual measurement shows some variation, but it doesn't seem like enough to account for the video. I did think that maybe it was engine vibration interacting with the video frame rate causing it to look like it was wobbling, but if you look at other parts of the engine in the video, there is not visible movement (this is all at idle, BTW).

Before I put the dial indicator on the pulley, my theory was that the wobble, combined with the shortened distance between the crank pulley and the lower idler, was just enough that the belt couldn't align with the crank pulley enough and was squeaking as it settled in, going around the pulley. It was a bit of a stretch theory, but all I had. In case anyone asks, I did measure the VAP pulley, on the bench. I don't have a setup that will let me do the radial measurement, but axial was less than 0.05mm on all front an back surfaces. It's not bent or otherwise out of true.

So, this is what I know:

There isn't anything wrong the the VAP pulley. There isn't anything wrong with the lower idler. It's definitely belt squeak. There is nothing obviously wrong with the belt oath and alignment. It's not a lack of tension. Video shows something that looks like runout or wobble in the crank pulleys. Measurement show some, but not much.

This has been a slog as I've been changing one thing at a time and, of course, changing something requires taking the belt off. With the VAP pulley in place, this also requires at least loosening the lower idler to get the belt off. So it's slow going. Unfortunately, do to being unable to find another double sided belt, the last change was a "two-fer" -- belt and crank pulley.

This is where I currently sit. I am open to any and all suggestions, but if you suggest something that I called out in this post already.... well, I shall mercilessly shame you for opening your mouth before actually reading the thing you are commenting on. I'll be nicer if you suggest something that is a number of posts back, but only a little nicer...

Also, I want to publicly say thanks to @Scott_VelocityAP . I've been chasing this without posting here, but I've been in contact with Scott and his help and patience have problem been a significant part of me keeping my sanity. At this point I'm pretty confident this isn't a problem with the VAP pulley, per-se. Something about my car isn't playing well with tighter belt path.

I have sent DMs to @Life And Projects By Austin YOUTUBE and @Gasman2 to see if they can help.

Just to confirm, the wobble is the same for both VAP and OEM lowers?

I was going to suggest getting a new VAP lower from a different manufacture date batch, but since it seems you have the same observed wobble with both the OEM and VAP lowers it may not make any difference.

Would reinstalling all the new VAP gear and determining if the belt squeak went away after a bit of driving make sense - since you have ruled out misalignment?

And I was concerned about replacing the door puddle lights on my own! You guys are mechanically blessed.

Yes, I see wobble in video of both the VAP and stock pulleys.

I have considered the "let it wear in route". I know others have gone that route without problems. However, it shouldn't be squeaking from the beginning, so that means something isn't right. Now whether the fact, that something is slightly off matters, or not, depends on what it is. I can't make the determination on whether letting it "wear in" is going to cause short of long term issues until I know what is wrong.

I race this car, so having an unknown problem with the supercharger belt that "fixed" itself, because the belt wore down some, would be a bit stress inducing. It's already inducing enough stress as I leave for the Big Bend Open Road Race in four weeks.

Or cursed, depending on how you look at it. I was expecting the suspension work to be the problem child, when I started the larger project. It's only real problem was parts availability and the fact that I couldn't tell ahead of time that I needed to order a few things.

I was not expecting the pulley to be the PIA.

Hi
not sure my setup is any help
i have the 2300 so the upper pulley is a little different but I have the vap crank and the upgraded tensioner
squeaks are always a bugger to trace reason
Belt/tensioner/pulley are external but also tolerances
its something that a jaguar tech needs to trace source of squeek

Ah... I should also note that I have followed the belt path. as much as I can get to, with an automotive stethoscope. The squeak is isolated to the area around the lower idler and crank pulley and loudest where the belt hits the top of the crank pulley. All other rotating points in the path have been checked, including with the bearing probe, where possible, without any other sign of unexpected noises.

I'mm 99% positive I know where they squeak is coming from, I just don't know why. Without the why, any attempt to fix is just a shot in the dark.

I am pretty confident in the alignment of the upper pulley. The hub is flush with the end of the supercharger shaft. Even if it were off just a bit, but not enough to cause belt issues between the upper idler and the upper pulley, I'd be hard pressed to figure out how that would cause the belt to squeak at the top of the lower pulley.

I did, however, come across this post today: https://www.jaguarforums.com/forum/f...6/#post2431005

I have the exact same problem that @Slowcat had -- the belt will not fit between the VAP crank pulley and the lower idler. I had be pondering the possibility of swapping the lower and upper idlers, but hadn't yet confirmed the were interchangable from a mounting perspective. So now that I know that swap is entirely doable, I think that will be my next step. I was thinking about it for two reasons. First, it would mean that I wouldn't have to loosen the lower idler to get the belt off/on. Second, it would also slightly lengthen the path between the lower idler and the crank pulley. This would bring that part of the belt path closer in length to the stock setup. Perhaps that makes a difference. So yeah, something of a shot in the dark, but I can do the full pulley swap in about 90 minutes now. This will be the fourth time I've had the pulley off, so I'm well practiced.

Hello,

Apologies for the inconvenience. Please send me an email concerning the issue to tuning@velocityap.com. If you already have a case open, no worries simply reply to that email and I will help track down what is going on.

Have you tried to use a caliper, and mesure from the front Timing cover, to the last rib groove in the stock bottom pulley, then do the same on the VAP pulley? IF, for some reason the machining is off on the VAP one, pushing the belt more to the front or rear, That could be your noise.... You have been looking for up and down differences I'm thinking more in and out misalignment of the bottom pulley grooves, as if the lathe started cutting early or late, making the belt have to ride too hard on the front or rear of the grooves. If that turns out to be the case, a fix would be small shim washers between the bottom pulleys bolt holes, or machine a few thousands off the back of the pulley, depending what direction you need to go.

I have been looking at front to back as well, though more in the context of unexpected runout. I've got a line laser arriving tomorrow, to help confirm overall pulley alignment through the system.

Best of luck....I'm about to install a VAP tensioner and belt on my car, This weekend, actually), and am a bit worried after everything I have been reading! I am following this, so please keep us updated! Oh amd a quick way to see if it's an alignment issue on the bottom pulley would be to loosen the bolts on that lower pulley about one turn, allowing the pulley to "float"...if you noise goes away, your grooves were cut too close to the rear, if the pulley never tries to "walk forward, and stays hard against the accessory pulley, they were cut to the front too much.