100mm Idler Rubbing

stangin

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Anyone ever have a 100mm idler rub on the Metco lower? The same day I installed them it started making a grinding noise and sure enough after removing each 100mm idler one by one the lower idler on the drivers side was rubbing on the Metco bracket somewhere.. it is in the upper position as Dana suggested.
 

stangin

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Originally posted by Bosko
Hmm... Maybe the 100mm wont fit with the 8lb lower.... ?

It fits ok, no interference from the 8lb lower, it seems to be something directly behind the lower drivers side idller. I cant see down there to look, must be a bolt head for the bracket.. I cant remeber what was down there. I guess I will have to take the idler off again and have a look. The stock idlers are hollow behind so there is no interference.
 

AMB

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I beleive you may have it on backwards. Mine has a different offset on each side. I had the same problem with my upper idler.

AMB
 

stevenscamaross

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??

I little off the topic, why are people with heavy mods running the 6 lb lower instead of the 8 lb lower for more power? :idea:
 

stangin

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The lowers help with belt slip so you dont have to run such a small upper, less surface area.. more slip.
 
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stangin

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Originally posted by AMB
I beleive you may have it on backwards. Mine has a different offset on each side. I had the same problem with my upper idler.

AMB

I checked that, the BF idler has the holding bolts forward and it rubbed on the back side. I think my Cobra is just a freak.. the alternator pulley rubbed on the alt housing as well, had to grind a little off the shoulder of the alt.
 

stevenscamaross

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??

Ok.. so 2.8 upper + idlers + 6 lb lower = lots of hp/tq
2.8 upper + idlers + 8 lb lower = lots more hp/tq?
 

stangin

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Re: ??

Originally posted by stevenscamaross
Ok.. so 2.8 upper + idlers + 6 lb lower = lots of hp/tq
2.8 upper + idlers + 8 lb lower = lots more hp/tq?

2.8 usually means Eaton, but some run the 2.8 with the Eaton and the 6 lb lower which is 20 or 21 lbs boost on the Eaton 500rwhp and 540rwtq usually or there abouts.

The KB I run 3.25 upper and 8 lb lower, 23 lbs boost which should yeild 600 + rwhp and 600 + rwtq if the tune is right.

There are many pulley combinations inbetween that yield different amounts of boost.
 

Dana

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stangin,
The pulley may be rubbing on the stud (mount) provided by Metco. It may not accept the different style inside of the BF idler, although I just mounted a 92 mm on my lower with no problems. The inner edge of the BF may just be wide/deep enough to contact the Metco pulley stud. You shoud be able to grind or file one of them down enough to create enough clearance. Or try switching with one of the 92mm pulleys if you have one and see what happens. When I installed mine, I also put a thin washer over the Metco stud to move the pulley out a little, but not for that reason and this may be why I did not have an interference problem. You should be able to use a 1/2 inch washer or something similar.

Dana
 

AMB

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ALT CASES

I understand that there are two different alt. cases, and you need different alt pulley/spacers!!

AMB
 

JB

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Re: ALT CASES

Originally posted by AMB
I understand that there are two different alt. cases, and you need different alt pulley/spacers!!

AMB

the spacers are different because of the change in drivers side head design that they began installing on Nov 4th, 2002, although the two may actually be related... (new head, new case)
 
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stangin

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Re: ALT CASES

Originally posted by AMB
I understand that there are two different alt. cases, and you need different alt pulley/spacers!!

AMB


I had both spacers, came with the alt pulley to cover both designs. Neither one worked. The shoulder of the alternator just came out too far and rested on the pulley so no spin. I just nicely filed down the shoulder and used the spacer per the instructions. Pulley placement was perfect.. worked out well.
 
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stangin

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Originally posted by Dana
stangin,
The pulley may be rubbing on the stud (mount) provided by Metco. It may not accept the different style inside of the BF idler, although I just mounted a 92 mm on my lower with no problems. The inner edge of the BF may just be wide/deep enough to contact the Metco pulley stud. You shoud be able to grind or file one of them down enough to create enough clearance. Or try switching with one of the 92mm pulleys if you have one and see what happens. When I installed mine, I also put a thin washer over the Metco stud to move the pulley out a little, but not for that reason and this may be why I did not have an interference problem. You should be able to use a 1/2 inch washer or something similar.

Dana

Yes, I agree.. it just barely rubs. I would probably have to take a 1/4" or so off of the back of it. Guess I missed the memo, no 100mm idlers with metco lower adjusted in up position :) Thanks for the awsume write up as well Dana, helped a lot!
 

stangin

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Originally posted by 98kobra
overspin the alt with the 8lbs lower

Supposedly not with the 3.5" alt pulley I have on the alt, guess we will see. Not much of a difference with 6 vs 8 lb lower that I can tell.
 

Dana

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stangin, just try the thin washer. I doubt that you will need more than 1/16 inch thickness. The stud is about 1/2 inch O.D., so a 1/2" washer should fit. I would do that first, before grinding anything down. There should still be plenty of room on the pulley for the belt to ride on. As long as it is narrower than the Metco stud and also the I.D. of the BF hub, it should do the trick.

The 3.5 inch alt pulley is as close as you are going to get. It brings the alternator reasonably close to the stock crank to alt ratio.

Dana
 

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