valve springs for hks 264 cams

[legend01]

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

[Steve]

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.

[legend01]

Ummm spose i shoulda menchined tooo it for an rb20 :-/

[Steve]

not really, 9mm lift is only step one.

[legend01]

steve

hat cams r u running

Peter

[Clint32]

if you find some different valve springs let me know as i deffinately wont to upgrade mine. Also the rb26 ones are supposed to be a lot better and streight fit

[legend01]

Clint32

arnt u selling ur engine

[Clint32]

yeah selling rb20, building rb25

[legend01]

clint 32

what where the spec's on your old to4e just picked one up for my rb20 a/r 50 compressorand a/r 58 turbine houseing how's this rate to urs

Cheers Peter

[rev210]

using std springs with my 264 hks 9mm

[Steve]

legend, using 256/8.8mm inlet, 264/9mm exh HKS cams. Absolutely no probs to 7500rpm.

[B-Man]

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.....

[legend01]

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

[Sydneykid]

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.

[RBsileighty]

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?

[Merli]

Sydneykid:

I have Tomei 260/260 9.15mm lift cams for my RB26... Will I need to replace the valve springs and seats for this application?

[RBsileighty]

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?

[Warpspeed]

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.

[RBsileighty]

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?