BRAAP

The “cam degreeing how to” is up in P-1 currently. If response is good enough, I may change some of the details for privacy reasons, and repost it here in the L-6 forum…

LMAO!!!! I am at this very moment writing a "how to" with detailed pics on degreeing a cam on an L-series for the PINKs boys. In this article it shows my steel plate for the mag base. It will be posted in the next hour or so… Timing... LOL

Ok Phred, We also have an Electramotive cam that we need the specs for. We are building a mild street L-28 with one of our custom MN-47 heads for a local customer who lives on the west side. The customer supplied the cam but does not have a cam card for it and we would like verify proper cam timing when we install the cam this week. Below is a pic, hopefully you have the specs for it? BTW, you seem well versed in extreme L-series, you are located so close to us, (we live in Sandy right on Roslyn Lake), yet I don’t think we have ever met… Do you run a Datsun shop? Paul (BRAAP) Ruschman

Where do the 2.93 gears come from? Any chance of taller gears, say around 2.5?

Justin, The 5 cylinder set up looks great, nice work…. Hmmmm I think we should invite you over to the Rusch Motorsports Shop on the East side, in Sandy on Roslyn Lake, some weekend for a BBQ lunch/dinner and some Z car bench racing…

Thanks for the the quick response. Keep us informed on your progress...

Are you utilizing the Relay board? I’m wanting to use the F-idle relay on my relay board to be the power source for either the fan or the EDIS module. This is a race car so there is no fast idle but and want to make use of the fast idle relay. Is it easy? .

If you are going to buy a bandmzcars radiator, (looks like a nice radiator for sure), do yourself a favor and purchase the hoses as well. As a dealer of custom radiators ourselves, (we “currently” don’t offer matching hoses for our radiators), if you have ever purchased a custom radiator and had to take the time to measure up/mock up radiator hoses and then spend the time in the local auto parts store comparing what they have hanging on their walls to what you have measured/mocked up, (both procedures can take several hours each or more), you are money ahead buying the hoses that are known to fit already. Bryan is doing you guys a “HUGE” favor by only charging what he charges for those hoses. BTW, Bryan, The radiator looks nice, good work.

Hmmm…. Never really though about that. I promise that by the end of this weekend I will actually try that scenario out on one of the P-90’s or P-79s that are currently in process of customization. Yes, this would allow more valve choices for sure.. I’ll report back by the beginning of next week….

True indeed. Altering the cam timing will alter the relationship between the piston and valve as they chase each other. Even if the head was severely warped and then shaved flat on both top and bottom, the valve stem tips of the middle cylinders would be closer the cam lobes as compared to the outer valve stems, (stem heights would shorter in the center vs the ends). By using thicker lash pads on the outer cylinders, the rockers will remain at the same angle in relation to each other, and it is that angle of the rockers that will alter the valve event timing from one valve to the next. If the same thickness lash pads were used on all valves in this scenario, then there would be an issue of differing vale event timing as the rockers would be at differing angles and the wiping patterns could even be off the rocker pad, which is very bad. By varying the thickness of the lash pads bringing the wiping pattern to the same location on the all the rockers, the valve event timing would not change from one valve to the other. Another approach as mentioned previously is to tip the valve stems which would achieve the same results as using varying thickness lash pads. The end result would be consistent valve event timing. With this same warped head, there is a very minor issue of the outer valve stems being angled, not perpendicular to the bores anymore. It takes more warpage than we typically see with these heads for that to actually become an issue in regards to valve stem to rocker/cam geometry…… I’d like to stay and chat with you guys more on this topic, but the rest of this week I need to devote to our customers. . Good night guys…

As for piston to valve clearance, you probably will be fine, especially if you are using a P-79 or P-90 head, though don’t take my word for it. The clearance should actually be checked. To know for sure, you really need to mock up one cylinder of the engine long block with the cam to be used and soft springs on the valves of the #1 cylinder and valve lash set on the tight side. This means the crank, piston and rod, no rings, preferably a used head gasket that is the same as you plan to run, and with a small blob of Silly Putty on top of the piston where the valve would contact the piston if such as thing would happen, (Yes, the same silly putty you played with as kid, every good engine builder has an egg or two of Silly Putty in his tool box), “carefully” rotate the mocked up cylinder through 2 complete crank revolutions. If you feel any resistance, don’t force it. That could be the piston and valves crashing into each other and you don’t’ want to bend the valves. If you were able to rotate the engine through 2 full revolutions, then you can remove the head and you will see 2 valve head imprints in the Silly Putty left from the valves as the piston passed near TDC. You can then use a steel rule or calipers to measure just how thick the Silly Putty is at the thinnest point. That will be your actual piston to valve clearance. As for ported vs non ported heads. A bone stock L-series running a stock cam, stock induction and stock exhaust might realize a couple/few HP running a ported head vs a non ported head. On a full tilt road race engine with triple Webbers, huge headers, .600” lift cam, the difference between a ported and non ported head could easily be 30 HP or considerably more depending on several variables. Just remember, the more radical the power plant, the more power a ported head will unleash vs its non ported variant.

Sorry to hear about your Ron Davis experience. We hope your new vendor will build a radiator that is everything you hope it to be. Everyone that I know that has used Ron Davis radiators has said nothing but praise, your experience is unfortunate to say the least. Being as the current production RD radiators are 100% aluminum and if you’d like to give Ron Davis a 2nd chance, let us know what you need for the custom radiator and we’ll see if we can get one built for less than $800 and possibly done in a shorter time frame. Again, sorry that your Ron Davis experience was a negative one. Paul

We are a Ron Davis distributor and since 1997, all of the Ron Davis radiators that we have either used on our personal project Z cars or sold for V-8 and L-6 powered Z cars have been 100% welded and none have leaked, (or none of the customers have reported back to us with any leaking issues). I took one of the radiators out of our inventory that fits the ‘74 ½+ Z car with SBC, and took a few pics. It is hard to make out, but looking through the filler neck and both the inlet and outlet, these radiators use no epoxy and are indeed 100% welded. To our knowledge, Ron Davis has always been 100% welded, no epoxy, but that isn’t to say ALL Ron Davis radiators are this way, only the ones we have sold to customers and used our selves. As a side note, $800 seems pretty high for a Ron Davis radiator. Custom Radiators from Ron Davis made to our specifications for L-6 powered Z cars with specific inlet and outlets sizes, inlets and outlets angled to our specifications and with mounting tabs and another tab for mounting an aftermarket coolant recovery tank is less than $500. Is there a chance your radiator is a Be-cool or some other brand or is it just a “very” custom Ron Davis? As for mounting ANY radiator in a Z car that has had the chassis upgraded for improved handling and/or the car is driven aggressively, YES, the radiator should be mounted in such a manner as to be “free floating”. Z cars are flexi-flyers and with aggressive chassis mods coupled with spirited driving, any radiator mounted as the OE intended will eventually get torn up, or at least have the mounting tabs ripped off. If you mount the radiator with two bolts at the top, that will allow it sway side to side as the core support racks back and forth, but that is only acceptable if there is ample room for the radiator to say without hitting the frame rails, which usually is not the case. We don’t offer “floating” radiator mounts, (though we may some time in the future), we leave mounting the radiator up to the individual customer. We do offer the radiators with the optional mounting tabs welded on the radiator tanks for mounting it to the OE core support, (as mentioned above), though we don’t recommend “solid” mounting to the core support , but to isolate or rubber mount it in some way, even using rubber grommets is better than solid mounting especially in Z cars that will experience heavy cornering or torsional loads. Here are some pics that sort of show the floating mounts I built for the Ron Davis radiator in my personal L-28 powered race Z. I machined some aluminum extrusion to accept rubber pads and then “captured” the radiator in those padded mounts so that it essentiality floats allowing the radiator core support to rack and flex all it wants without also trying flex and shred the radiator.

Your question is a great question, thanks for asking, and it was not taken as being critical at all. If you’ve read any of my other posts regarding L-series cylinder heads, you will note that I have a tendency to write novels about rather simple topics. I just prefer to mention all the details that are applicable and could be pertinent to the topic in an effort to answer any other possible questions that may arise. It is just my nature to be “very wordy”, as my lovely wife puts it. Installing “this” cam would be no different than installing any other aftermarket cam, other than it doesn’t come with a recommendation for lash pad thickness. Anyone with good basic mechanical aptitude can do this though, he/she just needs to be sure to check the cam wiping pattern. Most of the time with milder aftermarket cams, the supplied, or recommended lash pads will be just fine, but not all the time. This is especially true if any custom head work has been done, such as extensive surface decking, extensive seat cutting/grinding, new seats installed, larger valves installed, new valves installed, etc. My opinion on the topic of swapping in an aftermarket cam is the cam wipe pattern should “always” be checked no matter what, never just trust the manufactures recommendations for lash pads they either recommend or supplied with that particular cam. I have seen on more than one project where the supplied lash pads allowed the cam to run off the end of the rocker wiping surface, and in those instances, if the cam would’ve been run with those lash pads, the cam would’ve wiped itself out in very short order. In fact, this was true with one of the custom N-42 heads we did for a Hybrid member recently. His cam kit came with lash pads and we couldn’t use any of them as they didn’t work after all the custom work that performed, so we ordered the appropriate lash pads, double checked wiping pattern before we shipped it. If you haven’t already seen the thread linked below, it covers some of the details that goes into building a custom cylinder head and covers cam wipe patterns as well including pictures of the parts and tools used in the process as we built that custom N-42 head mentioned above. http://forums.hybridz.org/showthread.php?t=108398 BTW, thanks for the "heads up", via PM earlier, I owe you one… Sorry if I got too far off topic here guys... Paul Ruschman

Well, it depends on how deep we sink the valves, how much we kiss the valve stem tips. Also, just how much we shave from the head deck surfaces, both top and bottom, and also how thick the head gasket to be used is, will dictate how many, if any, tower shims we need. Then, we will mock up the head with the valves, retainers and keepers to be used, using soft springs and using lash pads from our in house lash pad inventory, (every lash pad thickness available from Nissan), on each and every cam lobe to verify the cam wipe pattern is where it is supposed to be, or where we want it to be on the rocker arm, which is typically cheated to the back side of the rocker with approx .030"-.050” untouched margin. We will then order and install the appropriate lash pads. The head that will receive this cam may undergo some chamber welding in an effort to gain some more compression, so right now, we don’t know what lash pad thickness we will need, suffice to say, it will be thicker than average and the Schneider retainers do have adequately deep lash pad retention lips to retain the required lash pads.

Rusch Motorsports offers a REBELLO ground cam with .520” lift. The Schneider springs are the recommend springs for this cam, and either IR EFI or Triple carbs complement this cam quite nicely for the racers and the “extreme” hot street enthusiast. It Definitely wont fall on its face below 7000 RPM. Here is a pic of that .520” lift cam prior to installation in a Hybrid Members custom stroker 3.1 that we are building a custom P-79 for. He also plans to run a nice shot of N2O on this combo as well. Should be VERY potent at the strip and on the street. The combustion chambers for that P-79 head will kook just like these chambers on a P-90 that we recently shipped.

Pete, Nope, haven’t heard of him. Is he a Wolf dealer/tuner? If so, Ron T. may know of him. I’m not savvy to the Wolf system other than it seems like a very powerful system and quite stable, (void of the “programming” issues, if you know what I mean), and there is a good chance I will be running it in the future on one of my cars whether it by the race car or the V-8 Z.

Not sure what it would take for MS to run C.O.P., but WOLF EMS does. Good friend Ron Tyler, of Prime EMS, is currently setting up this custom built L-28 that we built a custom P-79 for, utilizing Wolf 3D controlling 6 GM LS-X coils. FWIW, my personal L-28 race powered 240-Z car running flat tops with one of our custom MN-47 heads will be running MSnS-E sparking EDIS, (wasted spark Distributor-less ign). Our MSnS-E project can be seen at these two locations… http://forums.hybridz.org/showthread.php?t=103781 http://www.msefi.com/viewtopic.php?t=15436

Contact us via E-mail at ruschmotorsports@hotmail.com and we can work up a quote for building a custom cylinder head to fit your needs perfectly. Our web site, http://www.ruschmotorsports.com, is ALMOST finished, (boy is web design expensive, but when it is quality work like our web designer does, it is worth every penny).

Hello fellas. I inadvertently stumbled on this post and noticed “olderthanme” made mention of our cylinder head work, (Thanks for the compliments, I’m sure it is worth at least a Rusch Motorsports sticker… ) Any how, if it helps save searching through the archives, here are a few threads with details and pictures of some of our work. http://forums.hybridz.org/showthread.php?t=108398 http://forums.hybridz.org/showthread.php?t=107624 http://forums.hybridz.org/showthread.php?t=104420 http://forums.hybridz.org/showthread.php?t=110269 Custom EFI intake.. http://forums.hybridz.org/showthread.php?t=108389

The answer to your question is a nice warmed over budget Chevy V-8 swap. (I know most of you think I’m strictly an L-series guy with all the custom L-series heads we build here, but deep down, if it goes fast, I really don’t’ care what’s under the hood, and bang for he buck, the SBC swap is pretty hard to beat). For example, for my personal daily driver back in the late ‘90’s, I personally built a 280 Z that ran very consistent 12.3 @ 113 MPH at Woodburn drag strip in northern Oregon, using a VERY mild Chev 355, (cast pistons, Edlebrock performer intake, hooker shorty headers, 041 casting iron heads with 1.94/1.50 valves, cam was a s 216/228 @.050” on 112 LC, 468/480 lift). Running on some real cheesy 195 60 HR 14” all season tires, Yokohama Y-388 to be exact. Trans was a Borg Warner W/C T-5 five speed trans from a ’91 Firebird. The engine idled glass smooth at 750 RPM,, no lope whatsoever, got 20 MPG on the freeway with a Holley 650 double pumper, and if the throttle was used judiciously, the car was as docile to drive around town as a stock L-28 powered Z car. My wife regularly drove the car around the greater Portland area with no problems of it being a beast. Good luck

Pete, Thanks for the update. Looking forward to your next… Moby, Also looking forward to your EDIS-8 update as well. If we can help out in any way, let us know.

WOOPS!! My bad. You are absolutely correct. I wasn’t paying attention to the details within this thread, (I just lightly skimmed through it), and I just assumed he was asking about how/why just the act of shaving a head would need to have the valve springs shimmed…. DOH!!! Sorry fellas. Please forget my previous post. Paul

Shaving the head has no affect on valve springs, (unless you shave into the vale spring pockets which would be impossible). You can shave the head as much as you want and the valve spring pressure with the valve on its seat and over the nose of the cam wont change, so there is no need to “shim” the spring just because of surfacing. You shim the springs for other reasons such as sinking the valves deeper into the head, etc. or for any other reason that the installed spring height isn’t where it is supposed to be for that particular spring. Now you will need to shim the cam towers if you shave al to of material off of the head to keep cam timing within the range of the factory adjustments on the cam sprocket. Spring shims and cam tower shims were mentioned and pictures shown as well in this thread about what is involved in building a custom L-series cylinder head. http://forums.hybridz.org/showthread.php?t=108398