!!! LET Motorsports Pulley Failure !!!
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Re: !!! LET Motorsports Pulley Failure !!!
The true question now is what will you torque the SRT6 Idler pulley bolt to?
The Crossfire manual gives you two choices:
One setting in the Cooling - Engine - Water Pump - Installation SRT section (10 N-m - 89 in. lbs. - 7.4 ft. lbs.)
Another setting in the Cooling - Accessory Drive - Idler Pulley - Installation Idler Pulley SRT section (20 N-m - 15 ft. lbs.)
The Crossfire manual gives you two choices:
One setting in the Cooling - Engine - Water Pump - Installation SRT section (10 N-m - 89 in. lbs. - 7.4 ft. lbs.)
Another setting in the Cooling - Accessory Drive - Idler Pulley - Installation Idler Pulley SRT section (20 N-m - 15 ft. lbs.)
Last edited by BrianBrave; 11-13-2008 at 08:18 AM.
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...
THE 178MM ASP KIT THAT I PURCHASED FROM ROB AT NW'S. I RECIEVED IT APROX. 10/16/08 ( NOT INSTALLED YET ). THERE ARE NO OTHER MARKING ON THE IDLER PULLEY OR BEARING. THE IDLER PULLEY HAS A SNAP RING ON IT TO REMOVE THE BEARING. ILLCYA
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by PA/XFIRE
BRIAN HERES THE # ON THE IDLER PULLEY BEARING 6303Z, THIS WAS WITH
THE 178MM ASP KIT THAT I PURCHASED FROM ROB AT NW'S. I RECIEVED IT APROX. 10/16/08 ( NOT INSTALLED YET ). THERE ARE NO OTHER MARKING ON THE IDLER PULLEY OR BEARING. THE IDLER PULLEY HAS A SNAP RING ON IT TO REMOVE THE BEARING. ILLCYA
THE 178MM ASP KIT THAT I PURCHASED FROM ROB AT NW'S. I RECIEVED IT APROX. 10/16/08 ( NOT INSTALLED YET ). THERE ARE NO OTHER MARKING ON THE IDLER PULLEY OR BEARING. THE IDLER PULLEY HAS A SNAP RING ON IT TO REMOVE THE BEARING. ILLCYA
<--- Huge Horsepower
Re: !!! LET Motorsports Pulley Failure !!!
I've been researching and inquiring about a replacement bearing - If we want a sealed bearing (like the OEM idler and tensioner bearing) then LET may need to have a special lot run where they use a special High temp PTFE grease.
They have a bearing that's sealed on one side (VS shielded) and rated to 22,000 rpm. This may work- but would still need to be replaced after time as the grease will escape and debris will contaminate the bearing. They also make bearing that's sealed on both sides but it's only rated to 17,000 rpm but using the PTFE grease - it would be rated to 25,000 rpm. I'm trying to find out the minimum lot order.
If not - I plan on re-installing the stock idler pulley and sourcing a bigger belt.
You could always get an unsealed bearing and re-pack grease by hand every 6-12 months. Do you remember your mom showing you how to re-pack bearings by hand? I still remember my first truck - back in those days we didn't have sealed bearings.
I imagine some of you kids are too young and probably spend your youth sitting on the couch playing video games and eating junk food.....
They have a bearing that's sealed on one side (VS shielded) and rated to 22,000 rpm. This may work- but would still need to be replaced after time as the grease will escape and debris will contaminate the bearing. They also make bearing that's sealed on both sides but it's only rated to 17,000 rpm but using the PTFE grease - it would be rated to 25,000 rpm. I'm trying to find out the minimum lot order.
If not - I plan on re-installing the stock idler pulley and sourcing a bigger belt.
You could always get an unsealed bearing and re-pack grease by hand every 6-12 months. Do you remember your mom showing you how to re-pack bearings by hand? I still remember my first truck - back in those days we didn't have sealed bearings.
I imagine some of you kids are too young and probably spend your youth sitting on the couch playing video games and eating junk food.....
Last edited by BrianBrave; 11-13-2008 at 05:17 PM.
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Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by BrianBrave
I've been researching and inquiring about a replacement bearing - If we want a sealed bearing (like the OEM idler and tensioner bearing) then LET may need to have a special lot run where they use a special High temp PTFE grease.
They have a bearing that's sealed on one side (VS shielded) and rated to 22,000 rpm. This may work- but would still need to be replaced after time as the grease will escape and debris will contaminate the bearing. They also make bearing that's sealed on both sides but it's only rated to 17,000 rpm but using the PTFE grease - it would be rated to 25,000 rpm. I'm trying to find out the minimum lot order.
If not - I plan on re-installing the stock idler pulley and sourcing a bigger belt.
You could always get an unsealed bearing and re-pack grease by hand every 6-12 months. Do you remember your mom showing you how to re-pack bearings by hand? I still remember my first truck - back in those days we didn't have sealed bearings.
I imagine some of you kids are too young and probably spend your youth sitting on the couch playing video games and eating junk food.....
They have a bearing that's sealed on one side (VS shielded) and rated to 22,000 rpm. This may work- but would still need to be replaced after time as the grease will escape and debris will contaminate the bearing. They also make bearing that's sealed on both sides but it's only rated to 17,000 rpm but using the PTFE grease - it would be rated to 25,000 rpm. I'm trying to find out the minimum lot order.
If not - I plan on re-installing the stock idler pulley and sourcing a bigger belt.
You could always get an unsealed bearing and re-pack grease by hand every 6-12 months. Do you remember your mom showing you how to re-pack bearings by hand? I still remember my first truck - back in those days we didn't have sealed bearings.
I imagine some of you kids are too young and probably spend your youth sitting on the couch playing video games and eating junk food.....
<--- Huge Horsepower
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by MD SRT6
If you put your stock idler back on wouldn't your boost take a big loss over putting back both stock idler and crank pulley? If Stock is approx 14,500 and 185+ stock idler is 12,336? I'm not questioning, just trying to follow all this info as I'm not a math guy, and I'm worried about breaking down too. Thanks for all the homework on this, and I'll try to follow along.
I imagine they decided on a smaller idler pulley so to keep the stock belt. (probable some marketing idea)
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by BrianBrave
Just re-installing the stock idler pulley and keeping the 185mm and the smaller WP pulley. This would keep the ratio's for all the other accessories the same (including the supercharger) just reducing the ratio (and thus RPM) of the idler pulley to within the bearing range.
I imagine they decided on a smaller idler pulley so to keep the stock belt. (probable some marketing idea)
I imagine they decided on a smaller idler pulley so to keep the stock belt. (probable some marketing idea)
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Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by BrianBrave
Just re-installing the stock idler pulley and keeping the 185mm and the smaller WP pulley. This would keep the ratio's for all the other accessories the same (including the supercharger) just reducing the ratio (and thus RPM) of the idler pulley to within the bearing range.
I imagine they decided on a smaller idler pulley so to keep the stock belt. (probable some marketing idea)
I imagine they decided on a smaller idler pulley so to keep the stock belt. (probable some marketing idea)
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Re: !!! LET Motorsports Pulley Failure !!!
I just looked at my factory Ideler and it has an NTN 6303LHA bearing. Yellow seals on both sides. Intersting how they took two stamped cups and stuck them back to back withthe bearing trapped in the middle and then riveted it together. Much cheaper than machining a pulley, but not easy to fix. It's a throw away part.
My LET bearing still feels like it is in excellent condition. But I dont have a ton of miles on it either. So I will put it back in and use it until Jerry comes up with the replacement. I just got a new 115.3" gatorback but that wont handle the factory idler. I got it to give a little less tension on the tensioner.
MikeR
My LET bearing still feels like it is in excellent condition. But I dont have a ton of miles on it either. So I will put it back in and use it until Jerry comes up with the replacement. I just got a new 115.3" gatorback but that wont handle the factory idler. I got it to give a little less tension on the tensioner.
MikeR
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by c32AMG-DTM
PA/XFIRE - I believe it's been confirmed that the ASP and LET idlers are identically sized, similar design and material specs, and use identical bearings. If you look at post #2, 3rd picture down - does your bearing look like this? I'm guessing it's identical, since it's the exact same P/N.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by PA/XFIRE
I JUST HAVE 6303Z ON IT. IT DOES NOT SAY NST OR JAPAN. ILLCYA
But the 6303Z really is not the part number for the bearing. It is a designation of size. The real specs of the bearing are the numbers & letters following the size number.
And worse, there is not a universal system- each manufacturer has there own system. And just when you thought it was bad, the complete part number may not even be printed on the bearing, just the size....6303Z
There are non-, single, & double: sealed (several materials) or sheilded bearings. Different bearing angles, greases and oils which all effect durability and rpm range...
You have got to find a detailed spec page to get the real story on a specific bearing.
Who would have known....
Last edited by 70GT6; 11-14-2008 at 12:05 PM.
Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by 70GT6
I am learning more than I need to know about bearings....
But the 6303Z really is not the part number for the bearing. It is a designation of size. The real specs of the bearing are the numbers & letters following the size number.
And worse, there is not a universal system- each manufacturer has there own system. And just when you thought it was bad, the complete part number may not even be printed on the bearing, just the size....6303Z
There are non-, single, & double: sealed (several materials) or sheilded bearings. Different bearing angles, greases and oils which all effect durability and rpm range...
You have got to find a detailed spec page to get the real story on a specific bearing.
Who would have known....
But the 6303Z really is not the part number for the bearing. It is a designation of size. The real specs of the bearing are the numbers & letters following the size number.
And worse, there is not a universal system- each manufacturer has there own system. And just when you thought it was bad, the complete part number may not even be printed on the bearing, just the size....6303Z
There are non-, single, & double: sealed (several materials) or sheilded bearings. Different bearing angles, greases and oils which all effect durability and rpm range...
You have got to find a detailed spec page to get the real story on a specific bearing.
Who would have known....
Re: !!! LET Motorsports Pulley Failure !!!
I have plans of purchasing the 185 pulley this March with tax return. So as for now, have we definately concluded we need to keep the stock 90MM idler pully to keep the bearing RPM's safely under the max spin? Are there any other pulleys (other than super charger)with this 185 set up spinning any faster than the origional factory setup? With 35,000 miles I don't have any problems with purchasing a longer new belt. I realise it may still be in testing,but has anyone mached up the ultimate supercharger pulley to bring out the NeedsWings manifolds full performance potential? Thanks... Don