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Discussion Starter #1
I've had some noise that's been slowly getting worse since I installed the bigger blower, and lately it's gotten so it's very noticeable. I suspect some of the reason it's more noticeable is the cooler winter weather because the noise isn't as pronounced once the engine has warmed up. After a cold start this morning (40* +) the noise was very pronounced. It's not like a bearing squeal. It's more like a weird grinding noise. I tried isolating with my stethoscope, and about all I determined was the noise seemed to come from lower on the front end around the water pump. However, after I got a long wooden handle (24"), I started the car back up to try and isolate by touching the dowel to different parts. Touching the blower snout, it sounded similar to the noise, but it wasn't nearly loud enough. Then I was able to touch the water pump housing, and that was ok. Then it was the tensioner's turn (hard to get at), and it was making some noise yet not exactly the same. Then, wouldn't you know it but the sound stopped! So I took video of that too and posted both videos on YouTube that captures the difference between noise and no noise. The other cool thing I caught was at the 5 second mark in the no-noise video, whatever was making the noise gave a quick blip of the noise before going away again. Thoughts? I know it's hard to tell, but maybe someone has heard this before to give me some insight. I figure I will need to remove the blower belt to start with. Then I'll start it cold to see if the noise goes away, which would make the tensioner, blower, and other pulleys on that route suspect. Obviously if the noise remains, I've eliminated a number of causes. I've not run the car without the blower belt so that should be interesting.

Video with the noise:

Video without noise:
 

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Moderator/Admin Dude!
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I don’t hear much difference between the 2 Mike, but I know some sounds are lost during recording and playback. I have used your technique for locating sound sources... I’ve also had good luck using a hollow PVC pipe held up to my ear. This allows me to move the other end around without touching it on components to hear different areas. Of course as soon as you touch against something, you hear all sorts of stuff.

Other than the hollow pipe technique, I agree it’s a good idea to remove the blower belt to confirm which pulley system is the culprit. Unfortunately you have to pull the accessory belt off to get to the blower belt.
 

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Discussion Starter #3
Well, maybe somebody else might hear it and have experienced it. I just played the imbedded videos from my post, and since I know the noise it’s very prominent. Listen to the two videos one after another, and the video with the noise has a louder and continuous background noise that’s kind of like a mild grinding. The 2nd video is much quieter as far as background noise, and at the 5 second spot a momentary sound of the noise pops up just for a split second.

Hey @Catmonkey, are you there? And don’t ask me for my car info! :)
 

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Hmm, sure it's not the supercharger itself? Since that's the new part - was it filled with enough oil?

Keep us posted!
 

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I'd pop the supercharger belt off to rule out which set of drive pulleys it might be. If it is the supercharger side, look at the tensioner idler. Are you running an auxiliary idler?
 

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Discussion Starter #6
Hmm, sure it's not the supercharger itself? Since that's the new part - was it filled with enough oil?

Keep us posted!
I’m not at a point where I could rule out the SC. However, the stethoscope I use has just the open hose end on it so I can probe around for noises and isolate them very well. The loud noise doesn’t get loud in the stethoscope when I probe around it’s snout with the open hose end. I did verify it was full of oil when I installed it. Also know the SC wasn’t recently installed. That was done about a year ago. Thanks for the response!
 

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Discussion Starter #7
I'd pop the supercharger belt off to rule out which set of drive pulleys it might be. If it is the supercharger side, look at the tensioner idler. Are you running an auxiliary idler?
Hi John! Thanks for jumping in here. I am still running the stock tension idler, and I am running the VMP 90mm idler pulley that I installed back when I took my Eaton pulley down to 2.5". Looks like I'll move the car out into the shop tomorrow so I can pull off the SC belt, but I'll first see if I can try to isolate the noise again in the morning during a cold start. Then in the time that it'll take me to remove belts and reinstall the aux belt, but car should cool down enough for another cold start with the SC belt removed.
 

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Discussion Starter #8
I don’t hear much difference between the 2 Mike, but I know some sounds are lost during recording and playback. I have used your technique for locating sound sources... I’ve also had good luck using a hollow PVC pipe held up to my ear. This allows me to move the other end around without touching it on components to hear different areas. Of course as soon as you touch against something, you hear all sorts of stuff.

Other than the hollow pipe technique, I agree it’s a good idea to remove the blower belt to confirm which pulley system is the culprit. Unfortunately you have to pull the accessory belt off to get to the blower belt.
You know, if you donated your 2020 GT500 to me with its noise cancelling technology, I wouldn't hear these irritating noises from the engine compartment. Of course, that also might mean the darn thing would blow up because I wouldn't hear that there is a problem!
 

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I had an accessory pulley bearing start to take a dump and found it very quickly with a stethoscope.

Take both belts off, and just spin them by hand... you might be able to hear it without a stethoscope... I could on mine.

With a stethoscope the sound is dramatically different.
 

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Discussion Starter #10
Today I was able to look at this more, and after I took the SC belt loose, I checked all the pulleys on that leg. All felt smooth with no slop except for one. It's the grooved idler pulley that is bolted to the passenger side head. It's located right above the tensioner. When I spun it, I didn't feel a problem, but then I grabbed it by the pulley's outer ridges to see if the bearing had any slop and it did. I removed it, cleaned and checked it, and then reinstalled it with the correct torque (thank you @Catmonkey). No difference. Check out this video.


Then I found out how hard it may be getting to find parts for our cars. I'll save you all the details, but this idler pulley wasn't at most Ford parts counters. I have ordered it from Tasca.com, and they confirmed on the phone with me that it was at their supplier.

I may still remove the SC belt tomorrow and start the car just to be sure the noise is gone since I have at least a week before I will see the pulley. I'd hate to wait that long only to find the noise is still there, but this pulley sure seems sloppy compared to all the others!
 

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Today I was able to look at this more, and after I took the SC belt loose, I checked all the pulleys on that leg. All felt smooth with no slop except for one. It's the grooved idler pulley that is bolted to the passenger side head. It's located right above the tensioner. When I spun it, I didn't feel a problem, but then I grabbed it by the pulley's outer ridges to see if the bearing had any slop and it did. I removed it, cleaned and checked it, and then reinstalled it with the correct torque (thank you @Catmonkey). No difference. Check out this video.


Then I found out how hard it may be getting to find parts for our cars. I'll save you all the details, but this idler pulley wasn't at most Ford parts counters. I have ordered it from Tasca.com, and they confirmed on the phone with me that it was at their supplier.

I may still remove the SC belt tomorrow and start the car just to be sure the noise is gone since I have at least a week before I will see the pulley. I'd hate to wait that long only to find the noise is still there, but this pulley sure seems sloppy compared to all the others!
Hopefully that’s it and about to be rectified Mike!
 

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Discussion Starter #12
Hopefully that’s it and about to be rectified Mike!
I hope so! Relatively speaking, this would be a pretty easy fix.
 

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Discussion Starter #13
Hopefully that’s it and about to be rectified Mike!
Tim, interestingly, you actually commented on a thread over on SVT a few years ago when a guy posted this same pulley having the same problem on his car. He even took a video of the loose pulley, and that's what you commented about. He said he ordered a replacement, but he never came back and reported the fix. I hate to find threads like that which are left incomplete. These forums and threads that document problems and subsequent fixes aren't as helpful if the story isn't completely told.
 

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These forums and threads that document problems and subsequent fixes aren't as helpful if the story isn't completely told.
YES! Many people go to forums to solve their problems, but never feel compelled to “give back.” Letting everyone know how a problem was resolved is an easy way to give back. All of these threads become historical data for these cars. Current and future owners will be researching these issues for a long, long time.
 

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Discussion Starter #15 (Edited by Moderator)
Another update: Removed the blower belt and no noise when I run the car without the blower belt! I removed the tensioner when removing the blower belt, and upon closer inspection, the pulley on the tensioner has some wiggle slop too. It's about half as bad as the other, but I'm not putting it back in. I'm going to reuse the tensioner despite its age. I'll be the first to tell you the spring is still very strong, and to date (knock on wood) I haven't had any belt slippage. I have a spare blower belt that I will install, and I'll put my used belt in the trunk as an emergency spare. I ordered a replacement tensioner pulley from BPS, and I ordered the grooved idler pulley from them too. I missed the grooved idler pulley when I looked at their website yesterday because it was labeled as an a/c pulley. Well, duh, the a/c is on the blower belt path too, and in their idler pulley description they take out any guesswork by saying it is a direct replacement for the stock pulley pn:4G7Z6C348AA

I cancelled my Tasca order since it was looking like I wouldn't see the part for 2 weeks.

Here are the links for the tensioner pulley:


And the grooved a/c idler pulley:

 

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Discussion Starter #16
Another update, and I'll need @fletchffletch or @Goose17 to modify my last post because I can't. I get this pop-up when I click on edit, "You may not edit more than 10 different post(s) within 7 days". I ordered the wrong smooth pulley for my tensioner, and this is the correct link for the tensioner pulley, Automotive performance Parts.

The first link in my previous post is to a smaller pulley designed for an aftermarket thump tensioner. The description says it's a "stock sized replacement for a steel GT500 thump tensioner pulley". The catch there is "thump" tensioner, and there isn't a stock "thump" tensioner for my car. As such, the pulley is too small, but BPS was true to form and shipped me the correct sized pulley, 76mm, and they included a return shipping label in the box.

Unfortunately, replacing both pulleys did not get rid of the noise I am hearing! There just isn't much else driven by the blower pulley that could make the noise. I raised the car back up on the lift while it was running so I could double check the air conditioner compressor, and it's perfectly quiet. I still can't isolate exactly where the noise is generated, but at this point I'm going to swap blowers. Standing in front of the car, the noise sounds like it's coming from the center of the engine compartment, and I need to establish whether the blower is the culprit. I'm sure I could continue running this since it's not a noise that's indicative of a terrible failure looming, but I can't stand hearing the noise that I know isn't right. The noise does still tend to stop once the engine temp gauge just touches the normal range. Fortunately, swapping the Eaton blower back onto the engine isn't a big deal since I'm leaving the fuel rails and injectors alone.

So since I still have the car on the lift, I'll kill two birds with one stone. I'll put my Eaton back on just to see if the noise disappears with a different blower. I don't have a tune for the Eaton with the BAP and bigger injectors, but I'm just going to start the car and see if the noise is still present at idle. Then I'll know if it's the Gen 2 blower or another pulley on the blower belt route that's causing the noise. Then the 2nd bird that I'll kill is I'll remove the EGR hard pipe so I can bend it a little to make it fit the Gen 2 blower more easily.
 

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Mike, do a copy/paste/edit of your post that you want edited and send it to me in a PM. Please mention what # the post is and I’ll swap all of the text out for you. An alternative is to wait and do it later. Apparently you reached the max edits per allotted time limit (forum limit).
 

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Discussion Starter #18
The noise is in the VMP Gen 2 blower. After swapping out blowers, I started the car with the Eaton blower on it...no noise. I ran into some other things I had to do today, and by the time I did the Eaton test, it was about 10 minutes after BJ and VMP closed. I want to see if this is something either has seen before and based on their experience I'll decide where I go from here. Hopefully I can text them my 8 and 7 second videos.
 

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Glad you finally found the culprit at least.
 

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Discussion Starter #20
The problem is in the snout. Having talked with BJ and doing some email exchanges with VMP, they both felt like the problem was in the blower. Talking with BJ yielded a lot more details than with VMP. With VMP I was buffered from Justin and some of the mechanics. In both cases, sending the Gen 2 out for a rebuild was suggested.

I decided to change oil in the snout as a relatively cheap test. I got the SC oil from the local Chevy dealership (AC Delco 4oz bottle 10-4041). Then things got interesting. Since the Gen 2 was off the car, I decided to pour the oil out the fill hole in the snout of the SC. I used a cleaned milk jug with the top cut off to collect the oil, and I tipped the blower all different directions as I poured the oil to make sure I got it all. Unfortunately, I only recovered 1 ounce of oil when I should have gotten around 4 to 4.5 ounces! My checking for the presence of oil in the hole after I bought the blower wasn't good enough. Never did I imagine the blower would be low like this after seeing there was oil inside. Most people never even check the oil in their superchargers! The previous owner had never popped the plug, and the snout with the rotor packs was kept in his possession while the case was sent out for porting. So there was never a 3rd party that could have inadvertently let some oil out of the blower. Adding to this, I was the first to break the paint dot on the plug that's put there to establish whether the blower plug had ever been removed. The ounce of oil that I got out was amber in color, but it didn't smell or look burnt. When I refilled with new oil, I got almost all of one 4 oz bottle into it. I installed the blower, and when started, the noise was still there (of course) but it was intermittent and not continuous like it had been before during a cold start. Prior to starting the car, I unplugged the HE fans to reduce the background noise, and between doing this and the noise being intermittent I was able to hear the noise when I put a small pvc pipe on the blower snout and up to my ear. Finally what I feel was conclusive evidence, and it made sense given the low volume of oil found in the snout.

The problem is I now have a blower with a total of 2500 miles on it with a snout that was under-lubricated. How that happened I won't know because there has been no sign of oil leaking behind the pulley, and the rotors are dry too. Was the blower short filled when it was made? No way to know, but now I own the results of the deficiency. There were three supercharger rebuild companies that came up in various conversations. They are Superchargersonline.com, which is the one Eaton endorsed business around. Then there is Jokerz Performance and Steigemeier. Unfortunately the one I am leaning towards, superchargersonline, is the most expensive, and Jokerz is about half as expensive. So I will ponder and decide soon. Maybe I can sell my services for installing and removing blowers. I've gotten a lot better and faster after five iterations of either installing or removing the Gen 2 and M122 blowers as I troubleshot this problem.
 
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