Idler pulley, is it necessary? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Nima · 06-01-2022, 11:36 PM

Hi there:
Since I don't have PS, my belt routing is a little different. As you can see in the picture, the belt rubs against itself routing around the idler pulley. I am thinking about just have a tensioner with no idler. Is that a no no?!

ls1nova71 · 06-02-2022, 04:51 AM

If you don't have that idler pulley, the belt will go through where your air intake will be on the throttle body. You might try going from the bottom of the crank pulley, to the alternator, then down under the waterpump pulley then to the tensioner. Not sure if that will have enough wrap on the crank, but its worth a shot.

**mongocanfly** · 06-02-2022, 02:17 PM

Could you make a bracket and mount another idler pulley in the general are of where the ps pump used to be?

Nima · 06-03-2022, 12:56 AM

Thanks guys.
I guess I'll try rerouting the belt to see if that works. If not, I guess I need to come up with some sort of relocation bracket.

**bhap** · 06-03-2022, 08:47 AM

Power steering delete pulley..

**kwmech** · 06-03-2022, 02:00 PM

That is a whole lotta belt just to run the alt.

LS short box · 06-03-2022, 04:37 PM

Check with the folks at ICT. They make all kinds of LS brackets.

**Accelo** · 06-03-2022, 06:18 PM

Are both idlers the same diameter? If one is slightly smaller switch them out.
I'm betting you could find a smaller diameter pulley, if you were able to look at a few pulleys, at the auto parts store.

**mongocanfly** · 06-03-2022, 06:31 PM

Accelo, theres only one idler on it...the upper left is the tensioner

Nima · 06-03-2022, 09:50 PM

Yes, the left one is the tensioner, which is needed. I actually had a smaller idler which I tried but it didn't make much difference.

**Accelo** · 06-03-2022, 10:45 PM

LS short box suggested ITC.
Below is an example manufactured by ITC..
Maybe this bracket set up would work if you have room for the low alternator?

e015475 · 06-07-2022, 10:57 PM

This is a truck accessory drive with an ICT idler relocation kit installed

But I don't think you need one- the idler or the relocation kit

I think you need to reroute your belt to be like the one in the picture above. The way you've got it routed, the tensioner is never going to work

**mongocanfly** · 06-07-2022, 11:36 PM

Nice setup that e0 showed above..

Nima · 06-10-2022, 02:20 PM

Well, I just rerouted the belt as was suggested by LS1Nova and it seems it should work, we'll see when I fire it up!

06-01-2022, 11:36 PM	#1
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Idler pulley, is it necessary? Hi there: Since I don't have PS, my belt routing is a little different. As you can see in the picture, the belt rubs against itself routing around the idler pulley. I am thinking about just have a tensioner with no idler. Is that a no no?! Attached Images __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

06-02-2022, 04:51 AM	#2
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,119	Re: Idler pulley, is it necessary? If you don't have that idler pulley, the belt will go through where your air intake will be on the throttle body. You might try going from the bottom of the crank pulley, to the alternator, then down under the waterpump pulley then to the tensioner. Not sure if that will have enough wrap on the crank, but its worth a shot. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html Last edited by ls1nova71; 06-02-2022 at 04:56 AM.

06-02-2022, 02:17 PM	#3
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: Idler pulley, is it necessary? Could you make a bracket and mount another idler pulley in the general are of where the ps pump used to be? __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

06-03-2022, 12:56 AM	#4
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Re: Idler pulley, is it necessary? Thanks guys. I guess I'll try rerouting the belt to see if that works. If not, I guess I need to come up with some sort of relocation bracket. __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

06-03-2022, 08:47 AM	#5
bhap Senior Member Join Date: Mar 2006 Location: Pittsburgh, PA Posts: 264	Re: Idler pulley, is it necessary? Power steering delete pulley..

06-03-2022, 02:00 PM	#6
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,634	Re: Idler pulley, is it necessary? That is a whole lotta belt just to run the alt.

06-03-2022, 04:37 PM	#7
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,132	Re: Idler pulley, is it necessary? Check with the folks at ICT. They make all kinds of LS brackets.

06-03-2022, 06:18 PM	#8
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,296	Re: Idler pulley, is it necessary? Are both idlers the same diameter? If one is slightly smaller switch them out. I'm betting you could find a smaller diameter pulley, if you were able to look at a few pulleys, at the auto parts store.

06-03-2022, 06:31 PM	#9
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: Idler pulley, is it necessary? Accelo, theres only one idler on it...the upper left is the tensioner __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

06-03-2022, 09:50 PM	#10
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Re: Idler pulley, is it necessary? Yes, the left one is the tensioner, which is needed. I actually had a smaller idler which I tried but it didn't make much difference. __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

06-03-2022, 10:45 PM	#11
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,296	Re: Idler pulley, is it necessary? LS short box suggested ITC. Below is an example manufactured by ITC.. Maybe this bracket set up would work if you have room for the low alternator? Attached Images

06-07-2022, 10:57 PM	#12
e015475 Registered User Join Date: Nov 2013 Location: Show Low, Arizona Posts: 778	Re: Idler pulley, is it necessary? This is a truck accessory drive with an ICT idler relocation kit installed But I don't think you need one- the idler or the relocation kit I think you need to reroute your belt to be like the one in the picture above. The way you've got it routed, the tensioner is never going to work

06-07-2022, 11:36 PM	#13
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: Idler pulley, is it necessary? Nice setup that e0 showed above.. __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

06-10-2022, 02:20 PM	#14
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Re: Idler pulley, is it necessary? Well, I just rerouted the belt as was suggested by LS1Nova and it seems it should work, we'll see when I fire it up! Attached Images __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

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