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 Changing Cams On A Vvt Rb25 - how do you cancel vvt or dont i have to  

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lukey1
  • lukey1
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  • Joined: 28-September 10
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Post #1 post 7th November 2010 - 06:20 PM
i want to put some big cams in my rb25 im building but am having problems finding cams to suit vvt heads.
is it hard to cancel (can i just get a new cam gear with the new cam)
and what cams would you guys recomend im after about 500 to 550rwhp
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iamhappy46
Post #2

The RB25 NEO head uses different cam profiles due to the solid bucket style head. They are pretty much non-existent as far as aftermarket goes.

You cannot fit non NVCS cams to the NVCS head.

lukey1
Post #3

can you cancel the variable timming

iamhappy46
Post #4

Sure, you can cancel the VVT but you cant fit non variable timing cams to a variable cam timing head. Different design :o Besides, variable timing has some advantages in spooling the turbo quicker etc

49AZM
Post #5

you can buy cams to retain the vvt or you can buy cams that delete it, most common is to use rb20 cams and adjustable cam gears if you retain the vvt you will only be able to change the the exh side

pipster11
Post #6

^^^

vct (not vvt) controls the inlet cam


just get a set of tomei poncams and be done with it

there is also supposedly a small amount of adjustment on the stock cam gears but tomei ones are already dialled in spot on

lukey1
Post #7

am i able to just get my std cams reground or does it stuff the vct.
whats the most agressive i can go without going solid lifters.

49AZM
Post #8

QUOTE (pipster11 @ Nov 11 2010, 07:11 AM) *
^^^

vct (not vvt) controls the inlet cam


just get a set of tomei poncams and be done with it

there is also supposedly a small amount of adjustment on the stock cam gears but tomei ones are already dialled in spot on

my bad vct was cought up with others saying vvt>>>>>

if you want big lift you will need springs aswell you will also have to varify s1 or s2 as these are different if your chasing big hp you will need more than poncam

iamhappy46
Post #9

Variable Cam Timing and Variable Valve Timing are the same thing, just different lettering. It is the adjustabment of valve event timing in relation to the crankshaft :P

I assumed OP had the R34 head. In that case, Kelford cams do some really good cam grinds for the normal RB25 heads, fit some OS Giken cam gears and unplug the cam oil solenoid plug(no oil flow = no adjustment) and then dial in the cams to suit :) They also sell valvesprings to suit the cams :unsure: Aus dollar Vs the NZ dollar is good at the moment as well :(

pipster11
Post #10

poncams drop in, late model 33's use an r34 cas but have hydraulic lifters

someone on sau is selling some late model ones for sale for about $500 atm

tomei procams will need head work

or kelford cams or whatever

09ONE
Post #11

You cant go above 9.2mm of lift without going for solid lifters, depending on how much HP your chasing the hydraulic lifters are all good although valve lift is something that you can never really have enough of, within reason of course.

LaynLo
Post #12

im using kelford cams on my 25head, non vct, just removed the solanoid and blocked up the hole. got after market springs and gates adjustable cam gears(aparently they come outa the same factory as hks cam gears) my kelford cams have 9.5mm lift. contact will at JHH he will be able to help you out

lukey1
Post #13

im gunna get a set of 268dur and 9mm lift from cam tech in syd has anyone got pics of the solanoid i need to remove to cancel nvct or want to tell me how to do it

pipster11
Post #14

pretty sure you could still run it, its just like having a cam gear with 2 settings on

speak to your tuner first

09ONE
Post #15

Yeah thats it ^^

49AZM
Post #16

QUOTE (lukey1 @ Nov 15 2010, 12:37 PM) *
im gunna get a set of 268dur and 9mm lift from cam tech in syd has anyone got pics of the solanoid i need to remove to cancel nvct or want to tell me how to do it

it will depend on what cams you get as to weather or not you can remove or have to remove the vct to start with?

lukey1
Post #17

ive got advance duration 268 and 9mm lift and the inlet cam front has the four bolt holes the same as the ex cam so i have to cancel it

49AZM
Post #18

QUOTE (lukey1 @ Nov 18 2010, 06:55 PM) *
ive got advance duration 268 and 9mm lift and the inlet cam front has the four bolt holes the same as the ex cam so i have to cancel it

yes thats correct i assume you also have adj cam gears and valve springs to suit?

09ONE
Post #19

The VCT is controlled by oil pressure and a solenoid on the inlet cam GEAR.

49AZM
Post #20

QUOTE (09ONE @ Nov 22 2010, 06:49 AM) *
The VCT is controlled by oil pressure and a solenoid on the inlet cam GEAR.

yes thats correct but his cams will not allow for him to bolt the factory vct cam gear back on he will have to go adj or at worst case rb20 (not recomended)

lukey1
Post #21

ive got a set of tomei adj cam gears and a set of tomei rb26 type b springs with titanium retainers lined up.
so what else do i have to do apart form put that set up in (plug any oil holes or anything)

09ONE
Post #22

QUOTE (49AZM @ Nov 23 2010, 11:47 PM) *
yes thats correct but his cams will not allow for him to bolt the factory vct cam gear back on he will have to go adj or at worst case rb20 (not recomended)


As far as I can remember mine bolted straight up. VCT cam gear didnt make a difference.

49AZM
Post #23

QUOTE (09ONE @ Nov 26 2010, 06:50 AM) *
As far as I can remember mine bolted straight up. VCT cam gear didnt make a difference.

on all that i have done the vct cam gear has one bolt through the centre ? if you want to run adj cam gears you had to go a rb20 inl cam as adj cam gears and rb20 cams are both 4 bolt pattern. so if he has 4 bolt cams i cant see how he can use the vct cam gear .

09ONE
Post #24

Im pretty sure both my RB25's were series 1 if that makes a difference? Also I have always used the set of HKS cams that came out of a 2.65L RB25 from Japan and havent ever really bothered to suss them out cause they have always bolted up / worked with my VCT and now in my 25/30 without VCT.

49AZM
Post #25

QUOTE (09ONE @ Nov 28 2010, 11:32 AM) *
Im pretty sure both my RB25's were series 1 if that makes a difference? Also I have always used the set of HKS cams that came out of a 2.65L RB25 from Japan and havent ever really bothered to suss them out cause they have always bolted up / worked with my VCT and now in my 25/30 without VCT.

Which cam gears where you using? by the sounds i would assume standard at least on the inlet cam,its when you come to use aftermarket adj that you cannot use the stock cams.

09ONE
Post #26

Oh yeah of course! My inlet cam gear is stock and the exhaust cam gear is adjustable. Now Im on the same page as you lol.

You were confusing the fuck outtta me for a bit there.

49AZM
Post #27

sorry sometimes ive made a post but becuase im not a tech member it comes up after you have posted

MR2Mark
Post #28

QUOTE (49AZM @ Nov 30 2010, 08:45 PM) *
sorry sometimes ive made a post but becuase im not a tech member it comes up after you have posted

It may take a little while for a non-tech member post to be approved but once it is they will always appear in chronological order of when each user posted it (as far as I know).

mark

pipster11
Post #29

QUOTE (MR2Mark @ Dec 1 2010, 10:01 AM) *
It may take a little while for a non-tech member post to be approved but once it is they will always appear in chronological order of when each user posted it (as far as I know).

mark


yeah but sometimes you miss what a non-tech member has said because you are linked to the latest post and the non-tech post is above what your linked to (from an email eg)

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