!!! LET Motorsports Pulley Failure !!!
Re: !!! LET Motorsports Pulley Failure !!!
Mike R
I did a posting on the belts, the 114.5 and 115.3 are the same belt, the dimensions are the inner and outer measurments. THis is according to gates and their catalog. I got interested and tried to get a looser one and found this out. Sorry bout that, the next micro v belt larger and smaller are about 2" different in length.
Woody
I did a posting on the belts, the 114.5 and 115.3 are the same belt, the dimensions are the inner and outer measurments. THis is according to gates and their catalog. I got interested and tried to get a looser one and found this out. Sorry bout that, the next micro v belt larger and smaller are about 2" different in length.
Woody
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by RMADERMAN
AS LONG AS IT IS THE UPDATED WATER PUMP PULLEY YOU SHOULDN'T HAVE ANY PROBLEM.
I have been driving w/ mine for 5K and I generally drive hard and have been going to the drag strip once every three weeks or so. Last Wednesday I made 10 runs in an hour and only stopped once for 10-15 min. Before the last run of the evening.
I have been driving w/ mine for 5K and I generally drive hard and have been going to the drag strip once every three weeks or so. Last Wednesday I made 10 runs in an hour and only stopped once for 10-15 min. Before the last run of the evening.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by BrianBrave
Same thing happed to Lotus F1 and his ASP idler pulley - I wonder if they use the same bearing?
https://www.crossfireforum.org/forum...3&postcount=66
I tried to look at mine but can get the number off it..I'll pull it this weekend to see.
Lotus and your pullies are some damn rusty parts..
** EDIT **
Could someone with a ASP setup confirm the part number on the idler bearing - I'll look up the specs on the bearing supplied with mine and see what the duty cycle and max RPM are.
Perhaps a bearing upgrade is possible; if a better one is availible. Not much to press fit it in.
https://www.crossfireforum.org/forum...3&postcount=66
I tried to look at mine but can get the number off it..I'll pull it this weekend to see.
Lotus and your pullies are some damn rusty parts..
** EDIT **
Could someone with a ASP setup confirm the part number on the idler bearing - I'll look up the specs on the bearing supplied with mine and see what the duty cycle and max RPM are.
Perhaps a bearing upgrade is possible; if a better one is availible. Not much to press fit it in.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by 70GT6
Very strange..I just had the same problem.
Last night my idler pully bearing seized. Upon a quick inspection I did mot notice any major damage. Looks like the bearing seized and the bolt holding the idler backed out, idler dropped on the pan and threw the belt.
Left a message for Jerry earlier today, waiting to hear back, maybe on here is better.
*Edit - mine was not rusty looking at all - just completely locked up.
Also when an checked the factory idler - same basic part number but different manufacturer, factory was a Timken.
Last night my idler pully bearing seized. Upon a quick inspection I did mot notice any major damage. Looks like the bearing seized and the bolt holding the idler backed out, idler dropped on the pan and threw the belt.
Left a message for Jerry earlier today, waiting to hear back, maybe on here is better.
*Edit - mine was not rusty looking at all - just completely locked up.
Also when an checked the factory idler - same basic part number but different manufacturer, factory was a Timken.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by BrianBrave
Interesting - I'm looking at my stock idler pulley and the bearing is marked with a "6303 C3" and the green seals are stamped with "6303 RDD" but with a different type of seal then the bearings used on the LET or ASP (they look impervious to debris)
Now - if "speed limit" is 15,000 RPM - then we have a problem Houston!!
The stock idler pulley is approx 90mm
(178 / 90) = 1.978 * 6,000 engine RPM = 11,667 idler bearing RPM
(181 / 90) = 2.011 * 6,000 engine RPM = 12,067 idler bearing RPM
(185 / 90) = 2.056 * 6,000 engine RPM = 12,336 idler bearing RPM - No problem here.
The LET idler pulley is approx 60mm (and if the ASP idler is the same size):
(178) / 60) = 2.967 * 6,000 Engine RPM = 17,800 idler bearing rpm
(181) / 60) = 3.017 * 6,000 Engine RPM = 18,100 idler bearing rpm
(185) / 60) = 3.083 * 6,000 Engine RPM = 18,498 idler bearing rpm
Can someone verify the ASP idler pulley size and bearing used?
Looks like someone didn't do any math and just copied the OEM bearing part number...
Now - if "speed limit" is 15,000 RPM - then we have a problem Houston!!
The stock idler pulley is approx 90mm
(178 / 90) = 1.978 * 6,000 engine RPM = 11,667 idler bearing RPM
(181 / 90) = 2.011 * 6,000 engine RPM = 12,067 idler bearing RPM
(185 / 90) = 2.056 * 6,000 engine RPM = 12,336 idler bearing RPM - No problem here.
The LET idler pulley is approx 60mm (and if the ASP idler is the same size):
(178) / 60) = 2.967 * 6,000 Engine RPM = 17,800 idler bearing rpm
(181) / 60) = 3.017 * 6,000 Engine RPM = 18,100 idler bearing rpm
(185) / 60) = 3.083 * 6,000 Engine RPM = 18,498 idler bearing rpm
Can someone verify the ASP idler pulley size and bearing used?
Looks like someone didn't do any math and just copied the OEM bearing part number...
Re: !!! LET Motorsports Pulley Failure !!!
I have called the idler pulley manufacturer and they have confirmed the 15,000 RPM speed limit. He is looking to find a 20k+ rpm bearing that is a direct replacement that we can use. There are a number of options for us, so give him a little time to find the replacement.
One of the NSK 6301's is showing a grease RPM limit of 20,000.
One of the NSK 6301's is showing a grease RPM limit of 20,000.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by tighed1
Except for the Code3 pulley.
155 / 65 = (2.38) * 6K = 14,280 SC RPM
155 / 65 = (2.38) * 6K = 14,280 SC RPM
The answer is correct because the Code3 pulley approach is independent of this issue, as it maintains the stock crank pulley, stock idler pullies, etc. So, if you have the C3P S/C pulley and have your stock idler fail, presumably it would've failed anyway.
From BrianBrave's math and Jerry's post, sounds like this is a bearing issue - the bearing spec'd by LET and others isn't rated to handle the rpms; a higher-rpm compliant bearing needs to be spec'd.
Re: !!! LET Motorsports Pulley Failure !!!
OP - LET will replace the failed pulley and the damaged crank pulley (when we spoke you didn't mention the crank pulley was damaged).
I'm still not 100% sure that the bearing was at fault due to over spinning.
Over torqued idlers have been seizing for many, many years.
I have personally put 30,000 miles on my C32 with the same bearing that you had fail with no issues at all. Others have done the same...
Now, take a simple Google search for "Seized idler pulley" and you get tons (7,090) of listings where idlers have seized.
Google Search
There is even MBWorld listings for C32's without our product installed that have had a seized idler.
Link to listing on MBWorld
I understand your frustration and I did everything I could to help get the car on the road. I have taken proper measures and offered to replace the LET parts on the car.
I'm still not 100% sure that the bearing was at fault due to over spinning.
Over torqued idlers have been seizing for many, many years.
I have personally put 30,000 miles on my C32 with the same bearing that you had fail with no issues at all. Others have done the same...
Now, take a simple Google search for "Seized idler pulley" and you get tons (7,090) of listings where idlers have seized.
Google Search
There is even MBWorld listings for C32's without our product installed that have had a seized idler.
Link to listing on MBWorld
I understand your frustration and I did everything I could to help get the car on the road. I have taken proper measures and offered to replace the LET parts on the car.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by amg-jerry
OP - LET will replace the failed pulley and the damaged crank pulley (when we spoke you didn't mention the crank pulley was damaged).
I'm still not 100% sure that the bearing was at fault due to over spinning.
Over torqued idlers have been seizing for many, many years.
I have personally put 30,000 miles on my C32 with the same bearing that you had fail with no issues at all. Others have done the same...
Now, take a simple Google search for "Seized idler pulley" and you get tons (7,090) of listings where idlers have seized.
Google Search
There is even MBWorld listings for C32's without our product installed that have had a seized idler.
Link to listing on MBWorld
I understand your frustration and I did everything I could to help get the car on the road. I have taken proper measures and offered to replace the LET parts on the car.
I'm still not 100% sure that the bearing was at fault due to over spinning.
Over torqued idlers have been seizing for many, many years.
I have personally put 30,000 miles on my C32 with the same bearing that you had fail with no issues at all. Others have done the same...
Now, take a simple Google search for "Seized idler pulley" and you get tons (7,090) of listings where idlers have seized.
Google Search
There is even MBWorld listings for C32's without our product installed that have had a seized idler.
Link to listing on MBWorld
I understand your frustration and I did everything I could to help get the car on the road. I have taken proper measures and offered to replace the LET parts on the car.
If a bearing is rated to 15K max rpm, and is intermittently subjected to 18K+ rpm over the span of several months and thousands of miles (8+), isn't the logical conclusion for premature failure that the bearing couldn't handle the application? If 20K bearings are available in this application, why were those not initially spec'd for the LET Motorsports idler pulley?
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Re: !!! LET Motorsports Pulley Failure !!!
Woody,
I am going to disagree with you on the belt lengths. According to the chart from your earlier post the 4081150 is 114.5/115.3 and the 4081153 is 115.3/116.1. (I am doing this from memory so dont flame me too bad if I got a number wrong)
I took everything apart last night to install the 115.3 Gatorback and then couldnt find the sucker. I hate it when I try to get organized. I put everything back to gether and then while cleaning up and putting things away, I literally bumped into the belt hanging on a rack(that I looked a 4 time for the belt). I wasnt in the mood to tear it all down again so I will do it today. I will get the measurements of both the factory and the 1153 belt and pics of the position of the tensioner pulley.
It sounds like we may have found the culprit with the rating of the bearing though. Both NSK and Timkin are very good bearings. But if we are operating them outside of the rated spec, we are going to have failures. It's just a matter of when.
Jerry,
When you find a higher rated bearing, could/will you be offering the ideler pulley as a 'high speed' option pulley? I would like to swap mine out for a higher rated bearing pulley before I have issues.
MikeR
Edit: data from Woody's Goodyear link.
PART NUMBER METRIC PART NO. NO RIBS EFFECTIVE LENGTH OUTSIDE LENGTH
4081145 8PK2910 8 114.5 115.25
4081153 8PK2930 8 115.35 116.05
I am going to disagree with you on the belt lengths. According to the chart from your earlier post the 4081150 is 114.5/115.3 and the 4081153 is 115.3/116.1. (I am doing this from memory so dont flame me too bad if I got a number wrong)
I took everything apart last night to install the 115.3 Gatorback and then couldnt find the sucker. I hate it when I try to get organized. I put everything back to gether and then while cleaning up and putting things away, I literally bumped into the belt hanging on a rack(that I looked a 4 time for the belt). I wasnt in the mood to tear it all down again so I will do it today. I will get the measurements of both the factory and the 1153 belt and pics of the position of the tensioner pulley.
It sounds like we may have found the culprit with the rating of the bearing though. Both NSK and Timkin are very good bearings. But if we are operating them outside of the rated spec, we are going to have failures. It's just a matter of when.
Jerry,
When you find a higher rated bearing, could/will you be offering the ideler pulley as a 'high speed' option pulley? I would like to swap mine out for a higher rated bearing pulley before I have issues.
MikeR
Edit: data from Woody's Goodyear link.
PART NUMBER METRIC PART NO. NO RIBS EFFECTIVE LENGTH OUTSIDE LENGTH
4081145 8PK2910 8 114.5 115.25
4081153 8PK2930 8 115.35 116.05
Last edited by MikeR; 11-11-2008 at 09:39 AM.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by MikeR
Jerry,
When you find a higher rated bearing, could/will you be offering the ideler pulley as a 'high speed' option pulley? I would like to swap mine out for a higher rated bearing pulley before I have issues.
MikeR
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Re: !!! LET Motorsports Pulley Failure !!!
Just the last couple of mornings I have had a "sqeek" under the hood while warming up. I have not been able to find the source but I am now quite concerned the source has been identified. I may be able to come up with the correct bearing but if I have to replace it I expect a refund from LET. As my forum history shows LETs' 185mm pulley set up has all ready cost me $600.00 out of pocket, for tow and belt replacement costs. I don't think I should have to invest anymore in their product.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by BrianBrave
I would be content with just replacing the bearing in the idler pulley - but with a replacement rated at 25,000 RPM.
We should also use 6250 as the RPM, not 6000. The 70mm idler will be good with a 17k bearing at 6250 rpm on a 185mm setup.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by Montana Crossfire
Just the last couple of mornings I have had a "sqeek" under the hood while warming up. I have not been able to find the source but I am now quite concerned the source has been identified. I may be able to come up with the correct bearing but if I have to replace it I expect a refund from LET. As my forum history shows LETs' 185mm pulley set up has all ready cost me $600.00 out of pocket, for tow and belt replacement costs. I don't think I should have to invest anymore in their product.
Please wait until we find the bearing and we will ship it to you.
Re: !!! LET Motorsports Pulley Failure !!!
Sorry about the misfortune Brett! That caused a crazy amout of damage! This is scary scary stuff guys!! I have to be honest, I am now afraid to drive my car the way it stands now. It all makes sense to me about the bearing not being able to handle the increased RPM's and it seems like this is happening to a lot of you guys.......I really hope someone comes up with a quick solution!
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by distantpulse
Sorry about the misfortune Brett! That caused a crazy amout of damage! This is scary scary stuff guys!! I have to be honest, I am now afraid to drive my car the way it stands now. It all makes sense to me about the bearing not being able to handle the increased RPM's and it seems like this is happening to a lot of you guys.......I really hope someone comes up with a quick solution!