Cam Pulley question

[whrdnsx]

Anyone know if any other Honda Cam Pulley or other manufacturer is the same Diameter/tooth count as the NSX?

I know the centre may be different, just looking at maybe adapting another adjustable cam pulley to suit the NSX.

thanks

 

[Zoom]

Toda make adjustable cam pulleys for the NSX:
https://www.toda-racing.co.jp/en/product/cam/c30pully.html

 

[whrdnsx]

Thanks, but I know what is available, Toda & Comptech, But they are expensive, Every other pulley for other makes are a lot cheaper.
I can machine up a centre I'm looking for the outer gear in Aluminium.

Not sure if B series are the same or another Honda.

 

[MotorMouth93]

Toda and Comptech are the only options (there was a guy in Australia who made and sold a few sets years ago but last time I talked to him a few months ago he no longer had a machinist who could make them), other Honda pulleys have different tooth counts.

The USD-JPY exchange rate ($1.00 ~ ¥135!) has tipped such that a set of Toda pulleys is quite a bit more affordable than usual.

Toda actually modifies the OEM gears by boring out the middle and adding an adjustable center part, and you don't actually want an aluminum outer part, the timing gears are weighted for a reason.

 

[RYU]

in terms of the outer gear, i'd be concerned by using a non-reputable brand, not that we have many options to begin with, for fear of the gear teeth eating through the timing belt over time. I've seen this happen with lesser machined cam gears. I went with Comptech due to the lockability design of it. It's not on a compression/sandwich pinch bolt setup like the Toda. However, I don't believe Comptech makes these anymore? (Ask Shad) so i'd be fine with using the Todas.

 

[BBVNSX]

timing gears are weighted for a reason.

I’m using CT cam pulleys too, but would like to hear a bit more on this [MENTION=33247]MotorMouth93[/MENTION]

 

[Honcho]

in terms of the outer gear, i'd be concerned by using a non-reputable brand, not that we have many options to begin with, for fear of the gear teeth eating through the timing belt over time. I've seen this happen with lesser machined cam gears. I went with Comptech due to the lockability design of it. It's not on a compression/sandwich pinch bolt setup like the Toda. However, I don't believe Comptech makes these anymore? (Ask Shad) so i'd be fine with using the Todas.

Shad ran a new set, so they are available again. I agree that the OEM design is weighted for a reason. Look at the rear EXH gear specifically.

 

[BBVNSX]

... I agree that the OEM design is weighted for a reason. Look at the rear EXH gear specifically.

Yes true EXH is heavier! but I was curious to know if anyone knows the technical reason for this...?

 

[Honcho]

Yes true EXH is heavier! but I was curious to know if anyone knows the technical reason for this...?

Basically, harmonics and timing belt tension at high RPMs. The original engine redlined at 7,200 rpm and was SOHC. When they went to 8,300 rpm and added the VTEC late in the development cycle, testing revealed troubling timing belt tension issues at certain rpm points- it would start flopping around. They narrowed the cause down to harmonics, so they added a weighted rear EXH cam gear to tame the vibrations and preserve belt tension. I read this on some translated JDM NSX racing blog many years ago.

The NSX timing belt system by design forces all loose tension between the rear EXH and the tensioner- you can feel it and see it when you tension the timing belt. Thus, it makes sense that they wanted to tame any vibrations on that cam gear, since it would end up loosening the entire belt.

 

[whrdnsx]

Toda and Comptech are the only options (there was a guy in Australia who made and sold a few sets years ago but last time I talked to him a few months ago he no longer had a machinist who could make them), other Honda pulleys have different tooth counts.

The USD-JPY exchange rate ($1.00 ~ ¥135!) has tipped such that a set of Toda pulleys is quite a bit more affordable than usual.

Toda actually modifies the OEM gears by boring out the middle and adding an adjustable center part, and you don't actually want an aluminum outer part, the timing gears are weighted for a reason.

It was me that made the Adjustable Cam pulleys previously but i had the centres CNC'd and prices have tripled since the last batch.

I actually have a set of Mugen lightweight adjustable cam pulleys on my NSX Track Car.

The Toda pulleys are different on the GT engines to what they sell to the Public.

 

[whrdnsx]

Mugen Cam Pulleys??

 

[RYU]

It was me that made the Adjustable Cam pulleys previously but i had the centres CNC'd and prices have tripled since the last batch.

I actually have a set of Mugen lightweight adjustable cam pulleys on my NSX Track Car.

The Toda pulleys are different on the GT engines to what they sell to the Public.

Hi Wayne,

Yours use the OEM outer rings, right?

 

[whrdnsx]

Hi Wayne,

Yours use the OEM outer rings, right?

Correct

 

[whrdnsx]

I’m using CT cam pulleys too, but would like to hear a bit more on this [MENTION=33247]MotorMouth93[/MENTION]

The Comptech pulleys are half the weight of OEM

Haven’t heard of any belt related problems.