CNC L Series Rocker Arms

Engine, Transmission and related drivetrain.
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Byron510
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CNC L Series Rocker Arms

Post by Byron510 » 11 Jan 2015 10:05

I felt this thread needed to be out of the Ebay finds thread as discussion is encouraged;



SPECS:

*Full CAD 1-Piece design

*CNC Machined, 2 stage cutting and finish.

*Heat treated .020” Case @ 62-63 HRC / Core: 57-58 HRC

*Weight: ~2.00 oz. each ( +/- 0.030 oz )

(O.E. Rocker Weight Vary between 2.70 ~ 2.75 oz.)


OK, the case hardness is good, but the core hardness is near that of tool steel..

Let's be clear - I'm not flaming here, nor am I hating - this is discussion and please keep this thread to discussion.
The OEM arms are forged units, with brazed on wear pads on both the cam and lash pad contact surfaces. The forged arm give great strength, and the ductility of steel core in a low frequency application. The wear pads brazed on (admittedly may vary as per sellers comment - that l have no doubt) have specific wear properties to run directly against a cast iron cam and a hardened steel lash pad – both requiring different material ideally.

The rocker arms and specified are a one piece design, one material type and surface hardened consistently throughout with only a slightly less hard core.
Up front I do question the full hard arm. Having seen rockers break on other OHC engines BMW (E30), MB, Toyota of similar design - I know there is an incredible strain on this component at hi RPM - a consistent hammering strain especially when combined with the mostly non asymmetrical camshafts we use, stiffer springs and the fact that there is no hydraulic connection to dampen this action or the inherent frequency in which the material will start to react to.

I'd really want to see some test data and extremely conclusive product information before I would venture into use of this product.



Additionally, for anyone actually using these in a performance application, there is no way there are "ready to run". Every one of those fancy CNC lines is a stress riser - not good in any situation. These rocker would have to be polished smooth and balanced no different than balancing a rod end for end and not just overall weight.

On the flip side, it is nice that people are coming up with options for our old L motors. That is very cool.

Let’s get a little more knowledge on this product – azcarbum used to frequent this site - if this seller is able to join us – that would be great.

I have attached the Ebay ad for future reference.


Byron
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New L series rockers 1.jpg
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New L series rockers 2.jpg
New L series rockers 2.jpg (237.75 KiB) Viewed 2793 times
New L series rockers 3.jpg
New L series rockers 3.jpg (64.97 KiB) Viewed 2793 times
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bertvorgon
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Re: CNC L Series Rocker Arms

Post by bertvorgon » 11 Jan 2015 10:11

I looked at that, and I'm with you.

At 8,000 RPM, the cam is spinning at 4,000 RPM, and with all those little stress risers...makes me wonder..over TIME...

I too would like to see a test motor run with these, under extreme conditions, with some cams like we run.
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Re: CNC L Series Rocker Arms

Post by datzenmike » 11 Jan 2015 10:32

Image

Even Nissan was smart enough to support that suspension bridge. This has to be weaker than stock. Someone buy one and push down on the cam wear pad.
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McWicked
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Re: CNC L Series Rocker Arms

Post by McWicked » 12 Jan 2015 01:55

datzenmike wrote:Even Nissan was smart enough to support that suspension bridge.
Yeah "I" beams tend not to work as well when you cut the "I" out of them. There's also not much in this design that would prevent torsional deflection. Nor is there anything to dampen resonance in the thinner unsupported center section. That last part may or may not be an issue, depending on engine harmonics and the exact alloy used.

Unfortunately, we'll have to see a good number of builds utilizing these rockers before any sort of pattern emerges.

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zKars
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Re: CNC L Series Rocker Arms

Post by zKars » 12 Jan 2015 07:15

Brian has had those available for several years. My gut is that he isn't selling many, so decided to see if some other L engine nuts might be interested, hence his appearance here. I'm sure he would be willing to share his experiences, he's a pretty decent guy. Maybe send him a quick note and invite him to comment directly. zccjdm.com or azcarbum@msn.com

Note that he also has custom lash pads in many thicknesses available. These are getting hard to find.

From the Z forums side, I've never heard the use of these even barely discussed, other than in the context of general rocker arm issues where someone points out these are available, but at least there have been zero reports of failures of any kind with them. I'd suspect it mainly some pretty serious engine builders who have included these in their builds which is somehow comforting...
Last edited by zKars on 12 Jan 2015 09:37, edited 1 time in total.

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Re: CNC L Series Rocker Arms

Post by 510wizard » 12 Jan 2015 07:32

The cutter step over on these are pretty bad, (if it is step over, maybe its intentional ) I wouldn't put my name on them. The cam interface appears to be ground, by the way the mill marks end at that surface. The only advantage that I can see on these, beccause they are milled, is the lift ratio is consistent. I think that the Malvern racing roller rockers where a lot better design ( but from my reading needed more R&D) and would require a different grind of the cam.

http://www.angelfire.com/extreme/280zxt ... rocker.jpg

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Re: CNC L Series Rocker Arms

Post by Mattndew76 » 12 Jan 2015 08:58

We have enough people on here to come up with a group sourced design.

For the sake of the new, we could build a test motor to make these viable.

Monte I don't like the finish either, seems they made them fast with a cob mill and bad step overs. Could be since it is non wear surfaces it doesn't matter to them. I have been asked to make these before, and my reason for not attempting it is I don't want my name attached should a failure occur. I stand by my work, but R&D has to be done for these.
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Re: CNC L Series Rocker Arms

Post by john510 » 12 Jan 2015 16:05

700 bucks ? are the reground factory rocker arms any good ? and what would NOS rocker arms be worth ?

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Re: CNC L Series Rocker Arms

Post by bertvorgon » 12 Jan 2015 17:50

That is the problem,,no testing....having been a round many, many race 510 motors over the years, when a rocker/valve train fails...it is usually catastrophic damage.

It would behoove them to maybe get someone to set these up on a race type motor, and test the things. As we all needs these over time, for our engines...yet..is there enough market now for the L series? seems like everyone is either going to Sr20 or Ka, so what is the incentive to do the real testing?
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

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1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
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SpudWhitman
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Re: CNC L Series Rocker Arms

Post by SpudWhitman » 28 Jan 2015 08:48

From the additional images here http://www.zccjdm.com/catalog.php/azcar ... MS_#IMAGES, the I beam appears intact.

I quote; "These rockers have been tested in race application around the world, with great success!!" By whom?
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Re: CNC L Series Rocker Arms

Post by Mattndew76 » 28 Jan 2015 09:44

I would like to know the material. I see he listed the Case harden specs, but not the alloy.
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Re: CNC L Series Rocker Arms

Post by Byron510 » 28 Jan 2015 10:46

zKars wrote:Brian has had those available for several years.... I'm sure he would be willing to share his experiences, he's a pretty decent guy. Maybe send him a quick note and invite him to comment directly. zccjdm.com or azcarbum@msn.com

Jim - do you know, or have had regular contact with this guy? Can you invite him to join the conversation?

Coming from me wouldn't say much. I helped this guy with some of my previous engineering ideas about 10 years ago here on the realm, and then he turned around and made a commercial product out of it....once bitten, twice shy.

But maybe an invitation from yourself how has had some more regular (and positive) contact would have more effect.

If he has a worthy product to sell, then it's only a good thing for us all. This is good for the comunity as a whole.

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Re: CNC L Series Rocker Arms

Post by zKars » 28 Jan 2015 11:12

Byron, sounds like a great idea. I'll invite him, see what he says.

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Re: CNC L Series Rocker Arms

Post by azcarbum » 28 Jan 2015 12:09

Hi everyone…. I was invited to chime in, and answer questions for you all.
I appreciate your invite, and am always open to ideas for advancing my products.


Let me start by saying the photo of the design on those rockers is actually an incorrect photo. I didn't realize I had used that one. That design was one we played with, but as you a few of you mentioned, It did not support the rocker enough, so said 'NO" to that one. I've attached a photo of the new design.
FullSizeRender-24.jpg
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The new arms are made of 8620 Tooling steel. This material is by far the best choice for applications of stress, and can be heat treated to get the appropriate case hardness required to take the abuse of the cam. Now when I say "by far" please keep in mind for small production runs and for the general majority of people and use…. which means cost effective. Of coarse there are other materials that can be used, but for machine quality ( with out destroying your tooling ), and for end result, this is hard to beat.

The photos I have attached can show in better detail the small things you can't tell in the Ebay photos. The lash pad and nose have been belted smooth, and can be polished fairly easily. Note where the machine tracing stops before the lash area, and it disappears just before the pad. This is the belted smooth area.
FullSizeRender-25.jpg
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FullSizeRender-26.jpg
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As for customer… I've sold 4-5 L6 sets, and 2-3 L4 sets to customer around the world to include Japan ( LMAO )… Not a huge market, but I knew that most would't want to spend the money for this, unless more along the racing scene. Lets face it, the cost it takes to make, heat treat, and then charge to customer for such a customized part, is not one most will pay for. Im a realist on this fact, and in my 25+ years as a Datsun enthusiast, I've learned that we are some of the most frugal car people you will deal with. If your thinking your going to come up with some awesome part, and make a living off of it with Datsun enthusiasts, your kidding yourself.

Anyway, love to chat it up….. Look forward to hearing from you.

Brian - ZCCJDM
www.ZCCJDM.com
Your Source for KAMEARI Performance, JDM Products.
P.O. Box #213
Terrebonne, OR. 97760
541-913-6530
azcarbum@msn.com

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Re: CNC L Series Rocker Arms

Post by azcarbum » 28 Jan 2015 12:17

The reason I do these parts, is basically because no one else does….. Kameari did have rocker arms at one time, but like I said, It wasn't enough to carry it with large stock. Needless to say, they no longer make them!

In the sets I've sold, most of whom were to be used on race cars, I've never heard or received any feedback of broken, or failing rockers. My machinist is a bit of a ANAL #*&^%*#, and he himself made sure to put in his 2Cents in how these were to be designed and made. He doesn't want a failure, as much as anyone.

So what are your questions, and what ideas may you have?….
www.ZCCJDM.com
Your Source for KAMEARI Performance, JDM Products.
P.O. Box #213
Terrebonne, OR. 97760
541-913-6530
azcarbum@msn.com

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