Dialling In Hks Cams (rb25)

[33drifter]

well if your doing the work yourself, you may aswell put the stock ones in to see if it fixes it self up. youve only got your own time to lose, as opposed to a couple of grand for the other options

Edited June 18, 2008 by 33drifter

[PM-R33]

well if your doing the work yourself, you may aswell put the stock ones in to see if it fixes it self up. youve only got your own time to loose, as opposed to a couple of grand for the other options

Yeah true. There's two outcomes by putting the stock cams back in 1) It fixes the problem and goes back to the way it was and ill just need a quick retune so it wont cost me too much but then ill never know why the HKS ones did what they did and the whole thing would have been a wate of money and time or 2) The car still has the same problem back on the stock cams and therefore its going to be something in the head meaning i still have to rip the head apart. I suppose its the only choice i have unless some one can think of something else.

[33drifter]

for your sake i hope its outcome number 1, although im going to have to put my money on outcome 2. perhaps its been an underlying problem that has been exagerated by the new cams. Having said that i have an almost identicle setup to you modification wise, (give or take a few brand differences) and have a simillar power output to you. another thing to note is that on nengun if you search by car or engine type it actually gives a different part number - 2202-RN176

EDIT - i see you have already looked at nengun, my bad. Although it does still raise the question. which part is the correct one?

Edited June 18, 2008 by 33drifter

[PM-R33]

Part number should be the right one as the only difference on the RN175 and the RN176 is that the drive for the CAS is different, the later 97 model R33's have the CAS off of the R34, the plastic black one which is different to the R32 and the R33 one which has a half moon shaft thing.

So

1: Camshafts are 100% correct ones RN172 intake and RN175 exhaust

2: 100% Dialled in correctly at TDC (view pics on previous page)

3: Definetely not a boost/tune/spark/fuel issue as all of this has been checked over and over again

Could be due to

1: Something is wrong in the valve train, either springs or valves. Even though i havn't read about one person on SAU having dramas with this i could always be the first one

2: There is something physically wrong with the camshafts, bad casting or something, which in that case i am flying to Japan and kicking some ones head in at HKS

3: It's something completely different that no one i know has been able to think of

When we last tuned my car before the cams we could keep putting more and more timing in and the car just physically would not have any pinging, we than ran a bit less because it was in summer and we didnt want to risk it pinging on a hot day in traffic. It's now pretty cool and we cannot run any timing in it what so ever without it pinging hardcore, how on earth do bigger camshafts cause the engine to ping so easily and make crap power without even coming on strong?

Edited June 18, 2008 by PM-R33

[PM-R33]

My friend had a quick talk to the guys at Advan today and told them the situation. Without seeing the car its obviously hard for them but they dont think its a valve springs problem so it shouldnt be valve float, binding or a damaged valve but they are more thinking along the lines that maybe the valve clearances aren't correct and i should check them first and maybe have to shim or deshim the head.

Could this be the cause? Does any one know how to properly check valve clearances with a fealer gauge?

[WARLORD]

sorry to here your still having problems its a shit thing to go thru. mine was a straight swap no problems at all , i also changed valve springs.

[Smitizen]

sorry to here your still having problems its a shit thing to go thru. mine was a straight swap no problems at all , i also changed valve springs.

G'day mate,

Have been waiting to here PM-R33 results for HKS (256/264) cam install to see if i should go the same ones but obviously the poor barstard is doing it tuff with it all.

Reading above you also have the same model as he and i and have installed cams yourself, what sought?

All i really want to know is was it worth installing cams???

And how good are the driveability benefits???

Cheers,

Adam.

[PM-R33]

Warlord has the same cams as me 256/264, here's a link to his thread http://www.skylinesaustralia.com/forums/Mo...&hl=warlord

His dyno graph is amazing and i want the same thing out of mine lol. Just need to solve this f***ing problem first!

[Smitizen]

Warlord has the same cams as me 256/264, here's a link to his thread http://www.skylinesaustralia.com/forums/Mo...&hl=warlord

His dyno graph is amazing and i want the same thing out of mine lol. Just need to solve this f***ing problem first!

Thanks mate!!!

Good luck!!!

[Guilt-Toy]

I am going through similar issues. Down on power for NO reason at all.

I was on the dyno today for a few hours.. have changed a few things just now, going back on in the morning.

Good luck with it, i know how much of a pain in the ass it is.

[Martin HKS]

My friend had a quick talk to the guys at Advan today and told them the situation. Without seeing the car its obviously hard for them but they dont think its a valve springs problem so it shouldnt be valve float, binding or a damaged valve but they are more thinking along the lines that maybe the valve clearances aren't correct and i should check them first and maybe have to shim or deshim the head.

Could this be the cause? Does any one know how to properly check valve clearances with a fealer gauge?

RB25 uses hydraulic lifters so there is zero lash. Your combo should yeld 300kw at the wheels. It's the same combo I've seen before several times.

The camshafts should slip straight in without any other mods giving increase across the entire rev range. It doesn't sound like valve float because you cannot put any timing in anywhere. This all sounds too much like a timing issue - be it installation marks or computer base timing verse actual engine timing missalignment.

Good Luck and hope you sort it out.

Cheers

Marty

[rev210]

Since the CAS was farquared then you have to ask why.

Time to take a good look at the cams and check them for straightness, cracks and correct torque on retaining bolts. If the CAS is chewed up this could be due to something amiss. Have a look at the new CAS just in case there are some signs of metal shavings starting again.

The install of these cams I reckon is best done with new cam bearing retainer bolts and absolute care on torquing, old bolts aren't quite as accurate for torquing due to stretch and can break or crack (check them all). Snapped and bent cams can happen in the process, the RB cams are fairly long making them a little more prone.

While your at it checking all the individual valve clearences something funky may show up here before you get them out and help spot a problem like those above.

[PM-R33]

Ok last night we pulled it all apart. New CAS looks ok, no idea why the other one shat itself, maybe the bolts were tightened too much causing extra strain on it?? Cam clearances look fine as when the lobe is in the top position you can freely spin the buckets. Cam's aren't damaged in any way i can see. Tomorrow ill finish it all off by putting the standard cams back in and see what it does so i can atleast narrow it down a bit. This week ill also order some Performance Springs through work, part # PS251089-24, these ok? I did a bit of reading about them and they seem fine and i can get them cheap through work.

Atleast slowly we're narrowing it down.

[Cubes]

All though unlikely throw a timing light on it when you've got some decent rev's and boost on board and see what the crank marks are doing.

A mates rb had an issue where it was fine at lowish rpm; once in the higher rpm's the cas timing went to shiet. Cas looked fine; replaced it and power jumped 50rwkw.

[PM-R33]

Im waiting on the new valve springs to get here so we can replace them but still been thinking about this issue and reading a million threads on here, only similar problem i can find is people fitting RB26 cams to RB20's and having problems.

I've got the old cams and new cams sitting next to each other here and they definetely look the same just obviously the lobes are slightly different, it just doesn't make sense what the hell is going on. Fair enough i could understand if the car lost some top end power due to some problem, but for it to lose power all throughout the rev range and not like any advances timing just doesnt make sense. I keep thinking the cams aren't ment to be set at TDC on the standard cam gears but everyone else has done it like this.

I just hope some one will read this and go "your problem is .........." and just solve this drama lol. F***ing cars, why couldnt i have picked some other hobby.

[WARLORD]

Im waiting on the new valve springs to get here so we can replace them but still been thinking about this issue and reading a million threads on here, only similar problem i can find is people fitting RB26 cams to RB20's and having problems.

I've got the old cams and new cams sitting next to each other here and they definetely look the same just obviously the lobes are slightly different, it just doesn't make sense what the hell is going on. Fair enough i could understand if the car lost some top end power due to some problem, but for it to lose power all throughout the rev range and not like any advances timing just doesnt make sense. I keep thinking the cams aren't ment to be set at TDC on the standard cam gears but everyone else has done it like this.

I just hope some one will read this and go "your problem is .........." and just solve this drama lol. F***ing cars, why couldnt i have picked some other hobby.

pm sent....its too late to pick some other hobby your a addict like the rest of us now.....lol

[Cubes]

Could just be bad luck.

Some rb25det heads begin to float at 20psi with std cams others with 25psi+. Just luck of the draw.

Throw an aggressive ramp rate in to the equation and its all over.

I lucked out; my rb25de head had issues at 9-10psi+ over 4000rpm; others with the same heads its almost always 17+psi. Changed valve springs and its all good.

[Cubes]

Also.... There was recently another bloke with his RB30DET running a set of 282duration cams and gt42 turbo. The thing just didn't making power much like yours.

Speculated the ramp rate was too great for the hydraulic etc; he does run isky springs etc but yeah not sure if he did get to the bottom of it.

He runs on the same dyno as I so I will find out within a week or so when mines back on the dyno with a set of 264/264's if he did ever get to the bottom of it.

That thing spins to 8.5k :S Who said rb30's don't rev.

Out of curiosity what plugs are u running?

[PM-R33]

Interesting you should mention the plugs, normally i ran BKR6E on the standard cams with 17psi but after speaking to my tuner and reading a bit about it on here we moved onto a slightly colder plug, BKR7E....this was changed the day we did the cams. Surely that couldn't be causing this......could it?

Still hoping that the valve springs could be the cause here.

[R31Nismoid]

F***ing cars, why couldnt i have picked some other hobby.

lol i know the feeling

Should have stuck with the stock cams