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Can S1 Cams Be Swapped Into A Neo Head

meet07

By meet07,
in Engines & Forced Induction

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meet07 Enthusiast

meet07

Posted
Posted

I have or had a series 1 rb25det in my 240sx. I have s-tec manifold, borg warner s366 turbo with all the basic supporting mods like intake manifold, AEM EMS and exhaust. I messed the motor up and now I'm searching for a replacement.

The NEO rb25's are getting pretty cheap over here in the states so I am considering converting over. I read on SAU about the neo motor being an all around better foundation than the basic rb25det. Having the solid lifters, rb26 rods and vct makes me want to upgrade this go around. Everything I have will swap right over including the wiring harness. I'm using GM coil packs and the sensors that are required for the AEM like the IAT and MAP.

If you are using the AEM EMS then it is required to swap out the CAS oem disk with the new one that AEM sells. This disk works only with the series 1 CAS. I've been doing tons of research and I can't find anyone that has used the AEM ems with a rb25det series 2 or neo with the black plastic CAS.

So I was thinking if need be I could install the neo RB25det engine and just convert the neo cams with the series 1 cams in order to use the series 1 cas.

-Is this possible??

-Will the AEM EMS work with the NEO CAS?

kitto Mentor

kitto

Posted
Posted

No cant swap cams. Hydraulic cams in solid lifter valve train = no.

If AEM says the disc will not work with a NEO then it probably wont work.

Change to a crank trigger system or get a CAS disc custom laser cut.

meet07 Enthusiast

meet07

Posted
  • Author
Posted

Besides mega squirt what other stand alones are out there that uses the crank trigger system?

If I don't convert my standalone then I guess I have to stay with the series 1 huh??

kitto Mentor

kitto

Posted
Posted

Err most aftermarket ECUs will happily read a hall effect or VR sensor from a crank trigger.

If the AEM cant then its not a very good ECU.

Link, adaptronic, motec, haltech, megasquirt, autronic, vipec etc etc can read a simple hall effect input. Although I believe the megasquirt prefers a VR sensor.

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discopotato03 Grand Master

discopotato03

Posted
Posted (edited)

Is it possible to use an R32/33 RB26 exhaust cam in a Neo head and and retime it ? Solid cam so to speak with the right CAS drive ?

It may pay to research the base circle diameters of RB26 and RB25 Neo exhaust cams .

Just a thought cheers Adrian .

Edited by discopotato03
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Neo cams have higher lift so good to keep. For most cars swapping the CAS type just involves reversing the wiring so I would have thought it possible to make it work even with your aftermarket ecu.

meet07 Enthusiast

meet07

Posted
  • Author
Posted

I always knew that the lift and duration are different on all cams but what matters is the gap between the cams and the lifters right?? I've heard about people installing rb26 cams into an rb20 and swapping the s1 cams with the s2 cams.

Neo cams have higher lift so good to keep. For most cars swapping the CAS type just involves reversing the wiring so I would have thought it possible to make it work even with your aftermarket ecu.

I know I could do that. I would hope that what ever flaw that the s1 CAS has might be corrected in the NEO cas....

meet07 Enthusiast

meet07

Posted
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Posted

Wouldn't it just be easier to do what you have to do to fit the right CAS onto the cam? You could manufacture an adaptor, or you could weld the end of the cam and remachine it with the right drive. The options are bound to be more plentiful.

There is a local machine shop that has been around for years. I'm sure it would take some sort of computer program and nifty machinery to get this done. Might not be worth it doe.....

GTSBoy Grand Master

GTSBoy

Posted
Posted

A good machinist could do pretty much anything with a lathe, a mill and a pair of verniers.

I wasn't suggesting it as the big solution, just offering up some alternatives. Interfacing one rotating assembly with another rotating assembly is something that car modifiers have been doing since forever. Used to get done with various distributors in order to get electronic ignition onto older engines (as an example).

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