G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Post by **Gort400** » Mon Apr 11, 2022 9:31 am

Hello! Quick question.... Yesterday morning and this morning I had a belt squeal when starting. It quickly quieted down each day and did not squeal anymore for the days, even with multiple start-stops. Is this a loose belt? or a Tight belt. When I installed all three belts I tightened them to where I could press down with a little force about 1/4 inch or so. Not too tight not too loose. Is there a good way to find which one is squealing or do I just slowly tighten each one. Thanks...

Post by **Q451990** » Mon Apr 11, 2022 9:46 am

I would invest in a tension gauge and torque them to the specs in the factory service manual. I used to try all of the shade tree techniques, and had the same issues you're having. Over tightening is dangerous too, because you can damage bearings.

If you set the tension correctly, and still have startup squeal, the bearings on your tensioner pulley may be failing.

This is the tension gauge I bought.

Gates 91132 Krikit V-Ribbed Belt Tension Gauge, Black https://www.amazon.com/dp/B000CRDLZM/re ... UTF8&psc=1

Post by **Gort400** » Mon Apr 11, 2022 1:19 pm

Q451990,
Thank You. I will look into this. All the tensioner pulleys seemed to be smooth when I took the belts off. I specifically checked them with my hands and rotated to see if there was any rough movement. I will look in the service manual for the specs. JG

Post by **dna9656** » Mon Apr 11, 2022 9:51 pm

Using a torque wrench as a ratchet makes for bad karma. Invest in a breaker bar or long handled ratchet and maintain the calibration of your torque wrench. Also a piece of pipe makes a wonderful ratchet handle extension....

Post by **Gort400** » Tue Apr 19, 2022 12:36 pm

Q451990, I plan to buy the Krickit gauge. Question? I looked in the 1995 FSM and it only shows Belt Deflection in mm. Do you know how that equate's to Lbs on the Krikit gauge?
https://drive.google.com/file/d/15Adrz2 ... sp=sharing

Post by **dna9656** » Tue Apr 19, 2022 12:45 pm

No, I'm sorry I don't, I doubt you'll find a conversion chart for that. I would look for (or fabricate) a gauge to measure the deflection. I would call the local dealer and see what the mechanics use there. I imagine it's a "by the feel of it" way to determine if it's tight enough. That's most most mechs do. This spec removes ANY subjective-ness to the measurement of belt tension. This mush will be true: if it squeals you know it's not tight enough.

Post by **VStar650CL** » Tue Apr 19, 2022 2:14 pm

Gort400 wrote: ↑
Tue Apr 19, 2022 12:36 pm
Q451990, I plan to buy the Krickit gauge. Question? I looked in the 1995 FSM and it only shows Belt Deflection in mm. Do you know how that equate's to Lbs on the Krikit gauge?
https://drive.google.com/file/d/15Adrz2 ... sp=sharing

Applied force is 22 lbs for all your belts. It's at the bottom of the deflection table, easy to miss. That figure is pretty standard for all Nissan belts. When using the gauge, it always goes center span on the longest unsupported span. There are little arrows on the belt diagram to show the right spots.

Post by **Q451990** » Tue Apr 19, 2022 4:33 pm

Gort400 wrote: ↑
Tue Apr 19, 2022 12:36 pm
Q451990, I plan to buy the Krickit gauge. Question? I looked in the 1995 FSM and it only shows Belt Deflection in mm. Do you know how that equate's to Lbs on the Krikit gauge?
https://drive.google.com/file/d/15Adrz2 ... sp=sharing

Ugg, that's frustrating. It looks like I may have not done this job on the Q since I got the gauge. The FSM for my truck shows specs for both Deflection and Tension. The Q only shows Tension. I'll do some more looking later tonight to see if there's a conversion.

Post by **VStar650CL** » Tue Apr 19, 2022 5:09 pm

No, it's in the '95 FSM on MA-10. Look at the very bottom of the tension table:
https://www.nicoclub.com/service-manual ... 5%2Fma.pdf

Post by **Gort400** » Tue Apr 19, 2022 5:57 pm

VStar650CL wrote: ↑
Tue Apr 19, 2022 5:09 pm
No, it's in the '95 FSM on MA-10. Look at the very bottom of the tension table:
https://www.nicoclub.com/service-manual ... 5%2Fma.pdf

The way I read MA-10 is.... you apply 20 lbs of force down on the belt for a deflection of 7.5-8.5mm for a new alternator belt. just my thoughts.

Post by **VStar650CL** » Tue Apr 19, 2022 6:25 pm

Gort400 wrote: ↑
Tue Apr 19, 2022 5:57 pm
The way I read MA-10 is.... you apply 20 lbs of force down on the belt for a deflection of 7.5-8.5mm for a new alternator belt. just my thoughts.

Correct, 22 but 20 will be close enough. The checkpoint will be center on the belt between the crank and alternator pulleys, there's a little arrow for "check point" in the diagram above the chart. You run it a bit and then re-check, it should be 9~10 after it seats and gets comfy. If it doesn't seat then check for crap in the bottoms of the pulley grooves, that can happen if the old belt was hydroplaning (don't ask me why they call it that, they just do. I guess beltoplaning would be awkward).

Post by **Q451990** » Tue Apr 19, 2022 9:02 pm

VStar650CL - do you have any ideas on how to convert the deflection specs given for the Q45 to tension specs? In other Nissan FSMs (e.g. 2005 G35, 2004 Nissan Frontier) they give both specs - which lets me use the Krikit style gauge.

Post by **VStar650CL** » Wed Apr 20, 2022 4:23 am

Q451990 wrote: ↑
Tue Apr 19, 2022 9:02 pm
VStar650CL - do you have any ideas on how to convert the deflection specs given for the Q45 to tension specs? In other Nissan FSMs (e.g. 2005 G35, 2004 Nissan Frontier) they give both specs - which lets me use the Krikit style gauge.

The info is all there. This is from the '05 Q45 FSM. It's 22 lbs (10 Kg) on the Krickit for all 3 belts. The 10 Kg is pretty standard for just about everything Nissan:

: 05 Q45 Belt.jpg (31.53 KiB) Viewed 684 times

Post by **Gort400** » Wed Apr 20, 2022 6:11 am

VStar650CL wrote: ↑
Wed Apr 20, 2022 4:23 am

Q451990 wrote: ↑
Tue Apr 19, 2022 9:02 pm
VStar650CL - do you have any ideas on how to convert the deflection specs given for the Q45 to tension specs? In other Nissan FSMs (e.g. 2005 G35, 2004 Nissan Frontier) they give both specs - which lets me use the Krikit style gauge.
The info is all there. This is from the '05 Q45 FSM. It's 22 lbs (10 Kg) on the Krickit for all 3 belts. The 10 Kg is pretty standard for just about everything Nissan:

05 Q45 Belt.jpg

The Krikit gauge starts at 100lbs.....now im confused??????

https://www.amazon.com/dp/B000CRDLZM/re ... UTF8&psc=1

Post by **VStar650CL** » Wed Apr 20, 2022 9:02 am

Then you need a different gauge. I know Gates makes several different types of belt gauges, I'd imagine you have the one for the big industrial belts. This is the right one, it's what our shop has in the toolroom:
https://www.amazon.com/Gates-7401-0076- ... GXK6&psc=1

Post by **Q451990** » Wed Apr 20, 2022 9:26 am

I see the 22lb spec. It appears that there are two ways used to measure belt tightness. Deflection and Tension. In other service manuals, Nissan gave us both specs. In the Q45 we only have deflection. Check out the attached chart from the 2005 G35 Sedan. The right half of the chart shows tension specs that would correspond to the Krikit style of tool that I have. What I'm hoping is that there's some way to calculate the tension number. I guess I could order the other style of deflection tester, but I think there's still some math involved there, since the "applied pushing force" isn't going to be 22lb. Maybe I don't understand how that tool works.

Post by **Q451990** » Wed Apr 20, 2022 9:27 am

Gort400 wrote: ↑
Wed Apr 20, 2022 6:11 am
The Krikit gauge starts at 100lbs.....now im confused??????

I'd hold off on the Krikit gauge. We don't have the correct specs to use it.

Post by **Gort400** » Wed Apr 20, 2022 10:17 am

Q451990,

Thanks. In holding pattern for the tool.

JG

Post by **VStar650CL** » Wed Apr 20, 2022 10:48 am

Q451990 wrote: ↑
Wed Apr 20, 2022 9:26 am
It appears that there are two ways used to measure belt tightness. Deflection and Tension. In other service manuals, Nissan gave us both specs.

No, you're confusing yourself. Both specs must be used, not one or the other. Deflection is useless without knowing how much force to apply, knowing the force is useless without measuring how much the belt deflects. Belt tension is how much the belt deflects with the specified force applied.

Post by **Gort400** » Wed Apr 20, 2022 11:02 am

VStar650CL,

Thanks.

JG

Post by **Q451990** » Wed Apr 20, 2022 1:26 pm

VStar650CL wrote: ↑
Wed Apr 20, 2022 10:48 am

Q451990 wrote: ↑
Wed Apr 20, 2022 9:26 am
It appears that there are two ways used to measure belt tightness. Deflection and Tension. In other service manuals, Nissan gave us both specs.
No, you're confusing yourself. Both specs must be used, not one or the other. Deflection is useless without knowing how much force to apply, knowing the force is useless without measuring how much the belt deflects. Belt tension is how much the belt deflects with the specified force applied.

By all means, you know more about this than I ever will. I think I'm not doing a good job explaining myself. I completely understand that you need to know the force you're applying to the belt to measure deflection - 22lbs. That 22lb force doesn't appear to apply when you're measuring tension. I believe the Krikit device works like a clicker torque wrench, so when it "pops" you've used the correct amount of force for it to measure tension in lb or kg. What's missing from the Q45 chart, that Nissan provided on other cars, is the area I circled in red.

Post by **VStar650CL** » Wed Apr 20, 2022 2:25 pm

Okay, now I see what you mean. I never used a gauge like that, but it's working sort of like a slide rule, producing an integral of deflection and force using a mechanical motion. Gates looks to have a calculator you can use to get the right figure for any given belt type if the manufacturer doesn't provide it:
https://www.gates.com/us/en/knowledge-c ... lator.html

Post by **Q451990** » Thu May 11, 2023 10:12 pm

So I used the Gates calculator today. It said to set the tension on new 4 rib belts (like the AC and PS belts) to 120 lbs, when new - or 90 lbs for a used belt. The acceptable range after the belt has been run for 5 minutes is 60-80 lbs. For 6 Rib belts (like the alternator) they say to set a new belt to 187.5 lbs, and a used belt to 135 lbs. The acceptable tension range for this belt after running it for 5 minutes is 90-125 lbs. I'll post up here if these values give me any trouble with being too loose and squealing.

As a side note, on a standard Q (no active pump) the Bando part numbers that I found to work are:

Compressor - 4PK970 - (Replaces factory 11920-66US1VW) That one was actually marked 4PK971 but Bando no longer makes that belt
Fan/PS - 4PK1285 - (Replaces factory 11720-60US1VW)
Alternator- 6PK960 - (Replaces factory 11950-60US4VW)

These part numbers were printed on the Nissan belts I bought in 2003, so I think they are the closest thing to the real correct part numbers available. I believe Bando made the belts for Nissan, and they are not available from Nissan anymore, so this is the closest match to factory that I could find. Two of the three belts in Bando's catalog do not match this list - but I have found their catalog to be riddled with errors. I had 2 of 3 belts on my Frontier that were too small.

Post by **Q451990** » Thu May 11, 2023 10:20 pm

Note - since the thread about alternators turned in to a discussion about belts, I split the thread out into a second topic to make it more searchable.

Post by **Ryantzer** » Fri May 12, 2023 7:17 am

Keep in mind that if a belt is old, worn, or glazed, setting the correct tension may not stop it from squealing at times. A can of belt dressing is handy to have around for diagnostic work - if an application of belt dressing stops the squealing and the belts are properly tensioned, you know it’s time for new belts in the near future.

Post by **Q451990** » Fri May 12, 2023 12:13 pm

Oh my old belts absolutely needed to be replaced, but they weren't squealing. I'm embarrassed to say I ran them for about 70,000 miles over two decades. Coming from a guy who used to change his oil early, just because it was fun and "what could it hurt?" it's tough to see that I'm not the car guy that I used to be.

Maybe it's age, maybe it's a wife and children, but hopefully someday I'll get back in to it like I used to be.

Post by **Q451990** » Fri May 12, 2023 12:39 pm

The interesting thing was watching the new belts stretch and their tension reading drop just minutes after installing them. This was before ever even running the belt. I guess that's why the ranges are so broad.

Post by **Ryantzer** » Fri May 12, 2023 12:53 pm

Q451990 wrote: ↑
Fri May 12, 2023 12:13 pm
I'm embarrassed to say I ran them for about 70,000 miles over two decades.

I've run plenty of belts more than 120k miles - it was the age that killed your belts, not so much the mileage.

Post by **VStar650CL** » Fri May 12, 2023 2:41 pm

Ryantzer wrote: ↑
Fri May 12, 2023 12:53 pm
I've run plenty of belts more than 120k miles - it was the age that killed your belts, not so much the mileage.

+1. The serp on the wife's Altie made 110K before it showed any cracks. That's the main thing, replace at the first sign of cracking. Even small cracks mean the rubber is deteriorating. That exposes the cording, which will rapidly weaken in turn until the belt fails.

Post by **Gort400** » Fri May 12, 2023 5:00 pm

I don't have a good answer for you. What happened to me was that my alternator worked for 20 days. Then it failed with the exact same problem. I don have the capability to take the alternator out ad re do everything again right now. I also suspect a wiring problem. Two alternators with the EXACT problem and both testing on the bench perfect??? I also have a belt squealing at start up. It does quiet down. None of the belts are loose. I plan to slowly tighten the alternator belt to see if the squealing stops. Im not much help. PS Running on battery! Spare battery in the trunk, when needed.

G50 Q45 Belt Tension and Deflection, Belt Part Numbers

G50 Q45 Belt Tension and Deflection, Belt Part Numbers

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Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

Re: G50 Q45 Belt Tension and Deflection, Belt Part Numbers

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