RB26 GTR R33 Timing Belt Tensioner

[proline]

After having a new timing belt kit installed by someone else, I experienced belt whine which drove me nuts for 800 miles. I assumed the belt was too tight and eventually got around to loosening it myself but it made no difference. I then noticed the timing belt tensioner was markedly different to the old one that was taken out. I installed a timing belt with the 'correct' tensioner and am now noise free again.

The tensioners have different product numbers :

13070-5L300 which is supposedly for RB25 & RB20
13070-42L00 for the RB26/GTR

The product codes seem to have now changed according to amayama :

AY460NS010 for RB25
AY460NS013 for RB26

I'm assuming these parts are not interchangeable - certainly the RB25 tensioner didn't pivot smoothly when I was re-tensioning the belt. Pictures across the net show RB25 and RB26 engines with different tensioners. I am wondering whether the 'incorrect' tensioner was causing the belt whine? I'm also wondering what is the potential impact of using the 'wrong' tensioner - the RB26 tensioner seems to be much beefier that the RB25 version. I've searched across the usual forums and spoken to a supplier but there seems to be a lack of clarity on the subject. Can anyone here shed any light?

[niZmO_Man]

Perhaps the noisy tensioner is just plain shit?

[Andy Tomm]

I looked into tensioner and idler part numbers last year. Mostly I wanted to identify the NSK bearing part numbers to avoid paying extra for the same parts in a Nissan branded box.

Tensioner RB20 and RB25:

• Nissan: 13070-5L300 or 13070-73L00 or AY460-NS010 (Pitwork)
• NSK: 60TB0683
• GMB: GT90600

Tensioner RB26:

• Nissan: 13070-42L00 or AY460-NS013 (Pitwork)
• NSK: 60TB0732A
• GMB: GT80340

The parts fit interchangeably. I installed the RB26 NSK part (60TB0732A) on my R33 RB25DET. The GMB catalog lists almost identical dimensions between their part numbers. They differ only in overall height by 0.5mm. The catalog also mentions that their RB25 tensioner weighs 390g and is a "single row" bearing type. The RB26 tensioner weighs 505g and is "double row". Perhaps someone more knowledgeable about bearings can comment on whether single vs double row implies a significant difference in durability?

For completeness, following are the idler part numbers. Unlike the tensioner, RB26 has the same Nissan part number as RB20 and RB25. I installed the NSK part (56TB2801B01) on my R33 RB25DET.

Idler RB20, RB25, and RB26:

• Nissan: 13074-58S00 or AY660-NS001 (Pitwork)
• NSK: 56TB2801B01
• GMB: No listing (that I could find)