What Valves?

[MJTru]

As we speak im cleaning up the bowls in the new head. After im done I will try and up load some photos. Its not that hard. Im making sure that I dont remove material that not needed to be removed. As I do it, I'm think of the air coming in and just work on the transion that machines left behind. Im an advocate of velocity. Lol

The very most I would like to spin the motor is 9000 rpms. With these new springs. [email protected] total net lift is 16mm.

Now for valves im a little confused. Because my head shop over here cant even do a angle job. This is in the bahamas a place close to florida. If I get the valves I would need to send it all to miami florida to have it all installed.

As for what whats to use I was wondering is supertech ss valve would do tye trick.

Please keep in mind the car is only for drag.

If it was a old recon head then I would most likely go that way. I just want to know if these parts will work for my goal of 600hp. Max rpm 9000.

GTS Boy are you in florida???? Hope you are having a good time.

[Fat32gtr]

Interesting read, thanks for energy ones input. I just needed to ask because I don't trust my 20 year old head being ontop of my new bottom end, the valve guides look abit tired and one of them have a chip on it, engine builder told me it will be fine but this still doesn't sit we'll with me.

I was going to get new brass valve guides but I was told not to go down that path because even if it's seated properly that there's a chance they could fall out so I went with a brand new head.

A set of new oem nissan in and ex valves are just over $1000 but I can get the tomei ones for around $6-700. I was just wondering if it would be beneficial to go with the tomei or any other aftermarket valves as they look abit cheaper and if it will benefit the type of power I'm going for.

Would any of you recommend changing the valve springs if going 1mm valves?

[MJTru]

Well I would recommend getting new springs cause those set you got right now are straight up old and can be compromise a little. A fresh set would be good. Spring that is. I got new spring but im just like you. Im thinking of going with new valves.

[Fat32gtr]

Do you think going oem springs?

I've have these poncams ready to go in

Type 2- Duration: IN 260, EX 260 Lift: 9.15mm

[Fat32gtr]

So far it looks like the ferrea +1mm valves and the dual springs. Hopefully I get more gain from them

[MJTru]

In my most humblest opion which is based on not have proven to myselft through real live data. First I would think that 9.15 lift is to much for a stock spring to handle. Im basing this on the fact that a 2jz motor can only run 8.5mm the very most on stock springs. So I really cant say for sure on the stock springs, but I always side on being cautious. From what I know the stock spring can olny be crushed so much which works hand in hand with lift. So in short you can be able to google the maximum lift on the oem springs and then give yourself a margin of error for me its always 90%. So if max you can run is lets say 8.5mm lift on oem spring ill look at it at max being 8mm. Thats just off the top of my head.

As for the duration I would ask what you max rpm you are planning on running. Cause that will then affect the pressure of the spring. Or opting for lighter valves. Like titanium and so on. Its complicated stuff. But no one knows it all. So its always good to ask. This is why I use this site.

When I first joined this site people looked at me as a stranger and didnt help me at all. But tried to steer me a stray. But cause of my mechanic and technical background all I need is a few words and I can filter out who are just trolls and who knows what they are talking about.

I just wish that I can contest to have moded rb heads but I just smilpy have not. I have always recon heads and run them stock and made really good power. But now im forced to do so. So I turn to this same site for all my insight. Cause I would be an ignorant prick to think this site hasn't done nothing for me. Its so easy now more than ever that I know the mates on here by name. As to the ones that knows shit. At least to the point of a particular subject. I even notice that by using kwy words and the way I make my questions they then would answer. Lol. But they are always reading evwn though they are way past the subject at hand.

Sorry to get off topic here but I just needed to getwthis out. Wow.

Thanks mates.

[scotty nm35]

Gain?

They will take more energy to turn over in the engine, how much gain do you really expect from 1mm larger valves and dual springs?

[MJTru]

I would say not much. Lol. Why dual spring. If a single can do the job. From what I would imagine is the only reason for 2 spring is more seat or operating pressure. But to much isnt good. You should first need to know what it is you want, and then build around that. Just using the maximum seat preasure just simply overwhelming the valve train. As a guess would kill longevity.

[Fat32gtr]

Max rpm I would be chasing would be under 9k. It's just confusing what to do for reliability that's all. There was an interesting read I can't remember what page I found it on this forum. But basically if you go a valve made from a different material other than stock that it's no good for the valve guides as it causes more friction. Can someone clarify this?

[Fat32gtr]

Mjtru if I may ask what kind of turbos are you running?

[MJTru]

I have a PT 6262 and a gtx3582 and finally a PT GTS 75.

But for this motor im planning on using the PT6262.

As GTSBoy recommended.

You are right about the valve seats and not mixing the materials up.

But building a race motor and going or choicing to go titanium valve it would come naturally that the mating surface should be of adequate material as well. You are right. ??? You also mention the guide im interested to hear some other peoples ideas about the subject as well. Along with what has been tried to obtain a 9000k rpm limit safely. As I have yet to do so.

[GTSBoy]

Hi Marcus,

Not Florida sadly. Working near Philly for a few weeks.

[MJTru]

GTSBoy.

Damn. If you were in florida Iwould have invited and paid for your trip the freeport bahamas. Lol.

I do go to florida from time to time.

But never the less it nice to here that your over there.

I truly hope you have fun and remember not to work to hard. Lol

[KiwiRS4T]

Here's a quote from our local engine builder http://www.hytechengines.co.nz/p/sale.html :

Nissan RB Bronze Valve Guides

The factory RB26 valve guides will happily stand up to the factory hp levels as they’re only made from cast iron. Once you start to up the power levels & push the car beyond 7000rpm they begin to develop hair line cracks & will soon destroy themselves, along with your valve stems. Fitting a set of bronze valve guides will give engine reliability to levels 7000rpm & beyond.

Price: $480 NZD inc GST (set)

[MJTru]

This is funny. I can remember in 2010 I build an rb25 just to blow it up with all left over parts I had spin the motor to 9200 rpms everytime at 25 psi on pump gas. Lol. I know stupid. But it was fun. Finally after 6 months of street driving the oil pump failed (short ) collar crank. On tear down the head was all ok guilds and all. No cracks or chips. Nothing.

I just wish I could say the same for the bottom.

So after seeing this my conversation with redR racing ended as I wanted to convert to solid lifters. But its to expensive. It was easier to use a neo head and just change my intake. If my memory serves me right. Finally I just opted to go with a gtr motor.

I have never looked back since. I now have a r33 gtr 32. And a gts4 wish Im building a rb26 motor for just drag racing at the moment.

RedRracing had mentioned that I dont need to go with bronze guide thats for the old skyline heads that had oil lubrication issues and these newer heads are way better its not needed and they wear out faster. But the friction reduction is good I would guess.

From my experience I just dont see a need for them unless funds are no problem. If you are olanning on going all out and a car thats build for a specific purpose like drag. Expecting to rebuild in about a year. You can go with those. Other wise stocks are fine from my experience.

Edited November 4, 2013 by MJTru

[MJTru]

Well as an update I decided to go with the stock valve. I also mesure the cams and found that they are stock lift. 8.5 with 272 duration.