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RB25 + inlet cam gear

Skyrine-Dave
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lukevl Collaborator

lukevl

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If you buy Jap cams for the RB25VVT they will have a conservative inlet so it can run with the VVT. Buy cams to suit a non-VVT Rb25 or RB20 that way your HKS gears (I assume they are the same- 4 bolts and a pin) will bolt on and you will have no VVT.

Sydneykid Grand Master

Sydneykid

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I have used the Tomei Poncams (256 for RB25DET and 260 for RB25DET Neo) in a few engines and they work very well. I have tried an adjustable exhaust camshaft pulley on 2 of them and found no improvement. They appear to be very well timed standard.:cheers:

Skyrine-Dave Mentor

Skyrine-Dave

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Gary thats good info that has been repeated alot around here i have noticed, BUT

does the inlet cam have 4 bolts + locating pin or does i just have 1 big bolt to hold the VVT gear on?

What sort of cams would be suitable in an RB30DET situation.. Limited to 8.5mm lift due to rb25det head?

Reason why i have concerns with the Tomei cams is that they are made to work with the VVT, so therefore you would still bolt the stock cam gear on thus would have the incorrect bolt pattern for my HKS RB cam gear...

Sydneykid Grand Master

Sydneykid

Posted
Posted
Gary thats good info that has been repeated alot around here i have noticed, BUT

does the inlet cam have 4 bolts + locating pin or does i just have 1 big bolt to hold the VVT gear on?

What sort of cams would be suitable in an RB30DET situation.. Limited to 8.5mm lift due to rb25det head?

Reason why i have concerns with the Tomei cams is that they are made to work with the VVT, so therefore you would still bolt the stock cam gear on thus would have the incorrect bolt pattern for my HKS RB cam gear...

I am certainly not the only one that has found that the RB25DET Tomei Poncams don't need adj pulleys, Croydons have reported the same on a few cars as well.

The standard internals RB30 is not a big rever, so it doesn't really need big duration cams. The 256's should work VERY well. The 8.5 mm lift is not "limited by the RB25 head", I have used the Jun 256/9.3 mm in an RB25, but the valve springs needed to be changed.

As for camshaft selection, it was suggested to me that the RB20DET 256/8.5mm camshafts would work OK in an RB25DET cylinder head with adjustable camshaft pulleys. I have not personally tested this though, but the source is reputable.

Hope that is of some help:cheers:

Skyrine-Dave Mentor

Skyrine-Dave

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Gradenko: I'd be interested to know how they managed to put that cam gear on the inlet cam!

Does anyone know anyone with Tomei Poncams installed in an RB25DET head? I want to know what the profile is on the front of the cam to hold the cam gear on... Is it 4 bolts and a locating pin, or is it the same as stock with a single bolt??

  • 2 years later...
ovabooster Collaborator

ovabooster

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Posted

just checked my tome poncams 260 for my neo. the inlet has one bolt.....dat suxs coz i got a set of tomei adj cam gears to go aswell!!! Anyway of still installing it???? And if it could be done then the hud on the stock inlet could be removed?

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