Jump to content
SAU Community

Recommended Posts

Hi guys

just trying to find some specs on me cams which are 264 hks items with 9mm lift

need to find out what valve springs are needed to be used on these cams as retailers need some specs to supply them also what if any advance or retard timing need to be applied to inlet and exhaust cams or do they set up as standard cams

Cheers Peter

Link to comment
https://www.sau.com.au/forums/topic/33567-valve-springs-for-hks-264-cams/
Share on other sites

You can use standard springs, bloody hope so anyways as I am sitll using my standard ones. This was the advice I was given and no probs yet, buy havent turned redline up past 7500 yet - no valve bounce.

Not totally sure about cam timing, so far I have not had them dialled in what I would call properly, but seemed to respond well to around 6 degrees of retard on the exhaust. Inlet I am still running VCT.

When the head guys did mine, with my Tomei 256/9 cams - they measured my valve spring rate and advised me that they were a little tired and stongly recomended new springs.

After researching new std springs, Tomei springs, and Isky Springs, we decided on the later.

Iskys were better than std but slightly more $$. Tomei were as good as Iskys but more $$ and long lead time for delivery.

So they fitted the Isky valve springs - No idea on the spec - those guys are the experts, so I trusted what they said.

They seem to be working well.....

B-man

I agre whith your head man im a fan of iski springs myself all i need is the rite info to get the rite springs for the cams though if i went for standard spring rate and went to the next rate up from that that should be enough any opinions on that ???????

Peter

Hi guys, RB's (being DOHC and 4 valves with cam on bucket actuation) don't need big psi valve springs. There are no rockers or (heaven forbid) push rods for the valve springs to move, just the valves themselves, the followers and the buckets. This is pretty light valve train gear. I have found quite a few heads with rediculous valve seat pressures and the damage it does to the valve seats is not pretty. Flattened seats really knock the edge of the performance as well as it upsets the airflow into and out of the combustion chamber.

So I would be very careful about increasing the valve spring tension much more than 20%. If you do, then hardened vlave seats are a must.

Hope that adds to this interesting thread.

Are there any valve seats available for the RB20? I was looking into running TOMEI's or JUN's VG30DETT valve spring set. My goal is to have a 8500 redline (why I want valve springs), and then match a turbo to make a longer power band. I do know it might be less to build a 25 and make more power, but that is not what I'm looking to do now. I am more in this for the engineering aspect.

Here are TOMEI's RB20,VG spring specs:

http://www.tomei-p.co.jp/_2003web-catalogu...4_v-spring.html

Would they need a stronger valve seat?

Hi guys, RB's (being DOHC and 4 valves with cam on bucket actuation) don't need big psi valve springs.  There are no rockers or (heaven forbid) push rods for the valve springs to move, just the valves themselves, the followers and the buckets.  This is pretty light valve train gear.  I have found quite a few heads with rediculous valve seat pressures and the damage it does to the valve seats is not pretty.  Flattened seats really knock the edge of the performance as well as it upsets the airflow into and out of the combustion chamber.

So I would be very careful about increasing the valve spring tension much more than 20%.  If you do, then hardened vlave seats are a must.

Hope that adds to this interesting thread.

How would you go about hardening the valve seats? Would I have to heat treat the whole head?

Sydneykid is spot on as always. If you are not actually valve bouncing, leave the damned springs alone. Fitting expensive heavy duty springs is not going to improve anything, it just increases the contact pressure of the already highly loaded cam face and follower. Everything is going to just wear out that much faster.

A lot of cam suppliers make cams in the 9.0 to 9.5mm lift range which will work fine with stock springs. If you are worried about coil bind at full lift, turn the cam until one valve is fully open right on the cam nose. See how much further you can push the follower down until the spring binds solid. 1mm extra is plenty. If you can move a 40 thou feeler around under the cam nose, you are o/k.

Really high lift cams DO need special springs to allow the extra lift. They might also might need relieving the head around the cam follower bores so there is enough clearance. Unless your head has been significantly ported, the extra lift is going to make almost zero difference and is a complete waste of time.

Very good information, thank you very much. I wasn't as worried about lift as much as I was rev capability. My reasoning for looking into them was that I figured respectible companies like TOMEI and JUN wouldn't make them if they weren't needed for a reason. I have not run across cams that have a higher lift than 9.5 for the 20, so I guess they really are only intended for the VG motors. Sounds like the stock springs will be fine for my purpose. Thanks again.

Any pointers Sydneykid or Warp (anyone who knows really) about the best way to prep my head for my power goals? I was planing on a mild 3-5 angle on the valves and DE cams. What porting/pollishing would be good/needed do you think?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Very nice - I also have a 92 GTST and hardly see any others around these days
    • When I need something else to edit, I use Movavi. A friend who does video editing on a daily basis recommended me) it's an easy video cutter to use for beginners
    • I need to edit some videos for work but I'm not good at all this. Which video editor can you recommend?
    • I think you're really missing the point. The spec is just the minimum spec that the fuel has to meet. The additive packages can, and do, go above that minimum if the fuel brand feels they need/want to. And so you get BP Ultimate or Shell Ultra (or whatever they call it) making promises to clean your engine better than the standard stuff....simply because they do actually put better additive packages in there. They do not waste special sauce on the plebian fuel if they can avoid it. I didn't say "energy density". I just said "density". That's right, the specific gravity (if you want to use a really shit old imperial description for mass per unit volume). The density being higher indicates a number of things, from reduces oxygen content, to increased numbers of double bonds or cyclic components. That then just happens to flow on to the calorific value on a volume basis being correspondingly higher. The calorific value on a mass basis barely changes, because almost all hydrocarbon materials have a very similar CV per kg. But whatever - the end result is that you do get a bit more energy per litre, which helps to offset some of the sting of the massive price bump over 91. I can go you one better than "I used to work at a fuel station". I had uni lecturers who worked at the Pt Stanvac refinery (at the time they were lecturing, as industry specialist lecturers) who were quite candid about the business. And granted, that was 30+ years ago, and you might note that I have stated above that I think the industry has since collected together near the bottom (quite like ISPs, when you think about it). Oh, did I mention that I am quite literally a combustion engineer? I'm designing (well, actually, trying to avoid designing and trying to make the junior engineer do it) a heavy fuel oil firing system for a cement plant in fricking Iraq, this week. Last week it was natural gas fired this-that. The week before it was LPG fired anode furnaces for a copper smelter (well, the burners for them, not the actual furnaces, which are just big dumb steel). I'm kinda all over fuels.
    • Well my freshly rebuilt RB25DET Neo went bang 1000kms in, completely fried big end bearing in cylinder 1 so bad my engine seized. No knocking or oil pressure issue prior to this happening, all happened within less than a second. Had Nitto oil pump, 8L baffled sump, head drain, oil restrictors, the lot put in to prevent me spinning a bearing like i did to need the rebuild. Mechanic that looked after the works has no idea what caused it. Reckoned it may have been bearing clearance wrong in cylinder 1 we have no idea. Machinist who did the work reckoned it was something on the mechanic. Anyway thats between them, i had no part in it, just paid the money Curiosity question, does the oil system on RB’s go sump > oil pump > filter > around engine? If so, if you had a leak on an oil filter relocation plate, say sump > oil pump > filter > LEAK > around engine would this cause a low oil pressure reading if the sensors was before the filter?   TIA
×
×
  • Create New...