Belt size for 2.8/4 pc idler combo...

[SCT2003]

I just picked up a 4 pc BF idler set to go with my upper JDM 2.8 pulley.

I'm trying to figure out the correct belt size for my particular application.

When I first put the 2.8 on last year, I threw on a Gates K080740 and had no problems with slip. I actually made 466 RWHP at a peak of 14 lbs. After a year (15-20Kmiles), the belt started to stretch and slip. My last dyno numbers started to fall off to the 450 ish range. She is now only hittin' 12 lbs boost and droppin' to 9 lbs through the top of the pulls.

:dw:

I finally decided to pull the trigger on a 4 pc idler set and get all my boost back. The Cobra Bob chart says I need a K080745 or K080750 in the Gates version or 4080745 or 4080750 in the Gatorback version.

When I originally installed my 2.8, I picked up an extra Gates K080740...would this 74" inch belt be too small for the 2.8/4 pc idler combo I intend to use???

The chart says use a 74.5" or 75" belt...can I get away with using the 74" belt??? Do I need to guy buy a 74.5" or 75" belt???

Has anybody out there used a 74" belt with a 2.8/4 pc combo???

:??:

BTW, I've knotched the tension idler already.

Thanks...

:beer:

Later...Dave

 

[mixxer]

74.5 or 75.1

 

[SCT2003]

74.5 or 75.1

75.1" is the stock size, maybe I got the original still lying around???

Thanks...

:beer:

Later...Dave

 

[SCT2003]

Just found my stock belt...looks like it's in real good shape...part# is Motorcraft 2R3V-8620-BC...wonder if it's the 75.1"???

I'll let you guys know how it works with the BF 4 pc kit...

:beer:

Later...Dave

 

[Jomo1994z71]

I have the stock motocraft with my 2.76 pulley setup...no slippage

 

[SCT2003]

I have the stock motocraft with my 2.76 pulley setup...no slippage

A 2.76 with a BF 4 pc idler set up???

Is it the same Motorcraft # I mentioned above???

Later...Dave

 

[Jomo1994z71]

A 2.76 with a BF 4 pc idler set up???

Is it the same Motorcraft # I mentioned above???

Later...Dave

Not sure...car is covered up and the number is hard to get to because it spins so fast haha, but for sure it is the Stock Motorcraft belt...

 

[SCT2003]

Got the pullies today...questions???

The kit comes with hardware just for the aux idler bracket/pulley. The 3 other pullies need to use the stock OEM hardware but the OEM washers look like they're too wide(diameter)??? Should I go and buy some new washers that match the washer that's supplied with the idler bracket. That washer looks correct (thickness and diameter).

Also, where does the smaller pulley of the 4 pc set go...I'm runnin' a 2.8 upper if that makes a difference.

Lastly, what's the easiest way to get the serp belt off...haven't looked at it yet!!! Wrench, socket or pry bar???

Oh yeah, do we need to torque these down to a certain spec or just snug???

Any lock tite or grease needed for the install???

These parts don't come with instructions...only negative so far!!!

Thanks...

Later...Dave

 

[Jomo1994z71]

go to billetflows website...it will tell you where they all go...I believe the smaller of the 4 goes right under the tensioner...best way to get the belt off is to get a big 1/2 drive and put another wrench over it to pry it down...be careful not to let go of the tension too fast...I was amazed how easy it was to get the stock idlers off...I just tightened them pretty snug and rechecked them after 500 miles...regarding the washers...I reused the stock stuff...everything went in great, no problems...good luck
Here's the link
http://www.billetflow.com/IdlerBracket.htm

 

[SCT2003]

go to billetflows website...it will tell you where they all go...I believe the smaller of the 4 goes right under the tensioner...best way to get the belt off is to get a big 1/2 drive and put another wrench over it to pry it down...be careful not to let go of the tension too fast...I was amazed how easy it was to get the stock idlers off...I just tightened them pretty snug and rechecked them after 500 miles...regarding the washers...I reused the stock stuff...everything went in great, no problems...good luck
Here's the link
http://www.billetflow.com/IdlerBracket.htm

OK...I'm clear on the belt removal...that's easy!!!

I can't tell with those BF pictures...did you put the smaller 92 mm pulley under the tensioner???

Stock hardware works...that's good!!!

No lock tite or grease needed???

Thanks...

Later...Dave

 

[Ex President]

I wouldn't put loctite on them personally... Just check them every so often.

Here's where they go... http://www.billetflow.com/where-they-go.jpg

 

[SCT2003]

I wouldn't put loctite on them personally... Just check them every so often.

Here's where they go... http://www.billetflow.com/where-they-go.jpg

Thanks for the link, that helps out alot!!! OK...no lock tite...92 mm pulley is located under the under the Eaton pulley...now how about applying some grease on the inside of the bearings before you install it???

Again, no instructions, should I grease her up???

:shrug:

Later...Dave

 

[Ex President]

It's a sealed bearing... Don't think it would do any good. :dw: :banana:

 

[SCT2003]

It's a sealed bearing... Don't think it would do any good. :dw: :banana:

You misunderstood what I meant or maybe I asked the question wrong. Yep, I know it's sealed. If you look at the pulley, the inside diameter of the bearing will actually sit against something when it's installed (the pulley shaft). I'm talking about coating the inside diameter before installing them on the shafts. Know what I mean Vern???

:dw:

Later...Dave

 

[03cobra#694]

You misunderstood what I meant or maybe I asked the question wrong. Yep, I know it's sealed. If you look at the pulley, the inside diameter of the bearing will actually sit agaist something when it's installed. I'm talking about coating the inside diameter before installing them. Know what I mean Vern???

:dw:

Later...Dave

No GreaseJust put them on!

 

[Ex President]

Pretty sure that whatever part of it that touches doesn't actually spin. Maybe someone could chime in on this just to be sure, but I think the inner part of the bearing is locked down by the bolt and just the outside spins. :shrug:

 

[SCT2003]

No GreaseJust put them on!

Cool...

Already installed this afternoon. Thank Gawd for a 1/2" breaker and all the right tools. Haven't taken her for a ride yet but she sure is louder(Belt)!!!

Looks bitchin'...BF has some quality parts and Lethal did a great job of getting them here on time!!!

Thanks Jared and thanks to all of you that helped with the advice...I appreciate it!!!

I'll let you all know how the belt works out and if there's any slip on the dyno.

:beer:

Later...Dave

 

[SCT2003]

Pretty sure that whatever part of it that touches doesn't actually spin. Maybe someone could chime in on this just to be sure, but I think the inner part of the bearing is locked down by the bolt and just the outside spins. :shrug:

After installing it, I agree that the part in question doesn't spin. However, from the looks of the shafts the pullies sit on, I had to clean up a lot of rust once I pulled the stock pullies off. The bottom pulley was the worst. If anything, some grease or lubricant could keep the shafts rust free.

Just an idea.

Later...Dave

 

[Ex President]

FWIW: I'm using a stock length Gatorback on my 2.76/4 idlers setup.

Put down 473 on the dyno and runs 94.5 mph in the 1/8th. So far so good! :banana:

 

[SCT2003]

FWIW: I'm using a stock length Gatorback on my 2.76/4 idlers setup.

Put down 473 on the dyno and runs 94.5 mph in the 1/8th. So far so good! :banana:

Sweet...she's goin' back on the dyno Saturday. Don't know when she hit the track again!!!

Hopefully I can crack 470/480 but everything will have to be perfect!!!

Thanks for the help bro!!!

:beer:

Later...Dave