Cam upgrade

[Scgreen620]

Is there a website where they sell a kit with everything in the kit ? .... Meaning cam, rocker arms, and what ever needs to upgrade the cam?

[G-Duax]

Maybe Kameari in Japan.......

http://www.kameariengineworks.co.jp/

 

Hope you have a big bank account.

[datzenmike]

Maybe Kameari in Japan.......

http://www.kameariengineworks.co.jp/

 

Hope you own a big bank.

[Stoffregen Motorsports]

Datsun parts, in kit form? That would just make too much sense.

 

Seriously though, there are too many variables to deal with on a 40 year old cylinder head to have a one-size-fits-all package.

[Scgreen620]

Maybe Kameari in Japan.......

http://www.kameariengineworks.co.jp/

 

Hope you have a big bank account.

 

Shit I don't speaky Japanese lol

[datzenmike]

$  is all you need to know.

[distributorguy]

I bought the last cam blank Schneider had a year or so ago, and they had to dig to find it.  

 

When you regrind a cam, most of the time they end up cutting into the base circle - where there is no lift.  However much they cut off the base circle, minus how much the valves are sunk during a valve job, is what you need to add to the lash pads.  Nismo has a good selection as well.  Since the rockers are adjustable, this is just done to keep the rocker arm geometry in the right range.  .010" won't be a big deal but .050" would need to be re-shimmed.  

 

As for a cam, you'll need to build a little more cylinder pressure to get the air flow velocity you need with the DCOE carbs.  That means you DO NOT want a higher duration cam, rather a relatively low duration cam with a little more lift.  You stock head will likely only be good for .425" lift before turbulence kills off airflow.  

 

I have a valve grinder with a rocker arm machining adapter.  Today I will experiment with my rocker arms because they need to be reground.  I may have to make an adapter for them.  If I do, I might offer up the regrinding service here.  Its easy.  Cleaning them up afterward takes more time than the grinding process.  Its typically 20 seconds per rocker.  The trick is to simply keep the rocker perfectly square to the stone.  

[flatcat19]

I bought the last cam blank Schneider had a year or so ago, and they had to dig to find it.  

 

When you regrind a cam, most of the time they end up cutting into the base circle - where there is no lift.  However much they cut off the base circle, minus how much the valves are sunk during a valve job, is what you need to add to the lash pads.  Nismo has a good selection as well.  Since the rockers are adjustable, this is just done to keep the rocker arm geometry in the right range.  .010" won't be a big deal but .050" would need to be re-shimmed.  

 

As for a cam, you'll need to build a little more cylinder pressure to get the air flow velocity you need with the DCOE carbs.  That means you DO NOT want a higher duration cam, rather a relatively low duration cam with a little more lift.  You stock head will likely only be good for .425" lift before turbulence kills off airflow.  

 

I have a valve grinder with a rocker arm machining adapter.  Today I will experiment with my rocker arms because they need to be reground.  I may have to make an adapter for them.  If I do, I might offer up the regrinding service here.  Its easy.  Cleaning them up afterward takes more time than the grinding process.  Its typically 20 seconds per rocker.  The trick is to simply keep the rocker perfectly square to the stone.

 

I have a set or two I'd trade to get a set machined.

 

Use it as your CORE stock. Maybe?

[Xnke]

I don't use any aftermarket cam cores except the ones I machine and send out for hardening and grinding. If it's not a roller conversion, I use the stock core and have it reground, and I send the rockers in to get reground at the same time. The Schneider cam cores were CWC brand, and they were trash. Every single time I used one they all lost cam lobes within a few months, unless we sent a cam in for them to regrind. It was just an issue with their supplier's metallurgy. Now that they don't have anymore of those junk cores, that problem should go away. The lobe profiles from schneider are pretty good, though! That was the killer, great grinds, but crap cores.

 

The rockers are the same as any other flat tappet rocker-you MUST use a fresh rocker face on a fresh cam lobe-if the rockers have been run in with a different cam, there WILL be damage! It can happen today, or tommorow, or next week-but it'll happen. In one of my engines it took two years-even though we only ran the rockers for an hour on the dyno with one cam, then ran them with the other cam and they lasted two years before they gave up.

 

I had delta cams do a five gallon bucket of rocker arms for me three years ago and haven't even come close to using them all up yet, but they charged me 3.00 a rocker to do the bucket. I would assume the price is probably 5 or 6 bucks per rocker if you're only doing 8 or 16. After regrinding I sat down and matched sets for ratio and weight, as even the factory ones don't all have *exactly* the same rocker ratio or thickness...let alone the aftermarket stuff that may be out there.

 

Also, your engine oil has a big effect on the lifespan of your cam and rockers. You want an oil with an API rating of SL or earlier. Don't run SM or SN grade oils! SG, SH, or SL are all still available and are appropriate for the type of valvetrain in the L-series engines. Castrol "Go!" is a conventional dino 4T bike oil that is perfectly suitable for the L-series engines, and it's still widely available in appropriate engine weights. I also use Valvoline VR-1 Synthetic that does NOT say "NSL" on the bottle with no issues, but the valvoline white-bottle conventional and synthetics are SN grade and and do not have the additives for a flat tappet cam-don't run them. Don't run the VR-1 "NSL" oils in anything but a race car-they do not have the detergent package and will sludge in a street engine.

 

Distributorguy, the rockers have a specific radius ground in them, make sure you maintain the radius-don't increase or decrease it or you will end up with rockers that will chew themselves up just as fast as un-reground ones. I *believe* it's a 2.5" radius, but I would have to check my notes to be sure. (I experimented with changing the radius to get more rocker ratio out of them, things did not go so well.) The rocker arm adapters work pretty OK as long as you make sure to set up all your rockers exactly the same, so you can keep the all the rockers in the set at the same rocker ratio. If you bump the rocker one way or the other you can adjust the ratio a slight bit to match them up.

 

As for lift/duration numbers, the stock L6 heads are pretty much done at 0.430" lift, but you still see gains up to about 0.460" or so. L4 heads are *probably* similar enough, but the default street cam that I sell here for stock and mildly ported heads is: 280* seat duration, 232* duration at 0.050" valve lift, and 0.455" maximum valve lift, ground on a 107* LSA, and degreed in so that the intake valve closes 68* after bottom dead center on the intake. You may want to adjust the intake closing point from 68* ABDC to as much as 72* ABDC depending on your desired torque band. I get Delta Cams to cut this one, it's one of their older shelf grinds. They also have some of the Racer Brown profiles as well, but they don't have the really good one for mild unported heads and mild turbo cars-that was 252* seat duration, at 0.450" lift. Basically stock as far as duration, but the profile was VERY different, more duration at 0.050" lift and more total lift. Was a great cam when you could still get it done-It's *possible* Megacycle Cams still has that profile, but I haven't called lately to ask. If they can still do it it would be my go-to choice for a stock head!

[flatcat19]

I don't use any aftermarket cam cores except the ones I machine and send out for hardening and grinding. If it's not a roller conversion, I use the stock core and have it reground, and I send the rockers in to get reground at the same time. The Schneider cam cores were CWC brand, and they were trash. Every single time I used one they all lost cam lobes within a few months, unless we sent a cam in for them to regrind. It was just an issue with their supplier's metallurgy. Now that they don't have anymore of those junk cores, that problem should go away. The lobe profiles from schneider are pretty good, though! That was the killer, great grinds, but crap cores.

 

The rockers are the same as any other flat tappet rocker-you MUST use a fresh rocker face on a fresh cam lobe-if the rockers have been run in with a different cam, there WILL be damage! It can happen today, or tommorow, or next week-but it'll happen. In one of my engines it took two years-even though we only ran the rockers for an hour on the dyno with one cam, then ran them with the other cam and they lasted two years before they gave up.

 

I had delta cams do a five gallon bucket of rocker arms for me three years ago and haven't even come close to using them all up yet, but they charged me 3.00 a rocker to do the bucket. I would assume the price is probably 5 or 6 bucks per rocker if you're only doing 8 or 16. After regrinding I sat down and matched sets for ratio and weight, as even the factory ones don't all have *exactly* the same rocker ratio or thickness...let alone the aftermarket stuff that may be out there.

 

Also, your engine oil has a big effect on the lifespan of your cam and rockers. You want an oil with an API rating of SL or earlier. Don't run SM or SN grade oils! SG, SH, or SL are all still available and are appropriate for the type of valvetrain in the L-series engines. Castrol "Go!" is a conventional dino 4T bike oil that is perfectly suitable for the L-series engines, and it's still widely available in appropriate engine weights. I also use Valvoline VR-1 Synthetic that does NOT say "NSL" on the bottle with no issues, but the valvoline white-bottle conventional and synthetics are SN grade and and do not have the additives for a flat tappet cam-don't run them. Don't run the VR-1 "NSL" oils in anything but a race car-they do not have the detergent package and will sludge in a street engine.

 

Distributorguy, the rockers have a specific radius ground in them, make sure you maintain the radius-don't increase or decrease it or you will end up with rockers that will chew themselves up just as fast as un-reground ones. I *believe* it's a 2.5" radius, but I would have to check my notes to be sure. (I experimented with changing the radius to get more rocker ratio out of them, things did not go so well.) The rocker arm adapters work pretty OK as long as you make sure to set up all your rockers exactly the same, so you can keep the all the rockers in the set at the same rocker ratio. If you bump the rocker one way or the other you can adjust the ratio a slight bit to match them up.

 

As for lift/duration numbers, the stock L6 heads are pretty much done at 0.430" lift, but you still see gains up to about 0.460" or so. L4 heads are *probably* similar enough, but the default street cam that I sell here for stock and mildly ported heads is: 280* seat duration, 232* duration at 0.050" valve lift, and 0.455" maximum valve lift, ground on a 107* LSA, and degreed in so that the intake valve closes 68* after bottom dead center on the intake. You may want to adjust the intake closing point from 68* ABDC to as much as 72* ABDC depending on your desired torque band. I get Delta Cams to cut this one, it's one of their older shelf grinds. They also have some of the Racer Brown profiles as well, but they don't have the really good one for mild unported heads and mild turbo cars-that was 252* seat duration, at 0.450" lift. Basically stock as far as duration, but the profile was VERY different, more duration at 0.050" lift and more total lift. Was a great cam when you could still get it done-It's *possible* Megacycle Cams still has that profile, but I haven't called lately to ask. If they can still do it it would be my go-to choice for a stock head!

Wow. Awesome info.

[datzenmike]

Nissan says 248 degree duration on all their L20B cams but I doubt this is at the 0.050" lift everyone else uses for comparison. Any idea what the Nissan duration really is?

[Xnke]

Yes, but it depends on the letter stamped in the back of the cam.

 

I only have the L6 cams in the shop to measure, don't have an L4 cam to measure anymore.

 

But, for the L-6 cams: (measured from NOS cams)

 

"A" stamp is 248* seat duration, 222* at 0.050", 0.413" lift

"B" stamp is 240* seat duration, 218* at 0.050", 0.413" lift

"C" stamp is 256* seat duration 229* at 0.050", 0.434" lift

All of the above are on a 109* LSA

 

"J" is same as "B", but on 110* LSA

"M" is same as "J", but only 0.400" lift

"E" is same as "B" but on 106* LSA

"K" is 238* duration, 214* at 0.050", 0.424" lift, 107* LSA

 

That's all the detailed stock cam data I have.

 

For the L-4's, I have basic data but I didn't measure the duration at 0.050", at the time I didn't consider it important...also didn't mark down the letter for the grind.

 

These were all junkyard cams, I wrote what engine and the vehicle but that's all I got...I bet these are pretty much the same grinds as the L6 but they have a bit of nose wear...the L16 grind looks really close to the "A" stamp grind, but worn over the nose..and the L18/L20B look really close to the "C" stamp grind.

 

L16, 510: 0.402" lift, 248* seat duration

L18, pickup: 0.425" lift, 256* seat duration

L20B, pickup: 0.425" lift, 256* seat duration

 

Don't have more detail on those, but looks like there's an L16 car cam, and an L20B truck cam, or maybe it's just the "car" and the "truck" cam. Dunno. All the stock cams are tiny, but solid.

[distributorguy]

I could figure that out in several weeks when we pull the practice motor out of our truck and install the race motor.  It has a stock L20b truck cam in it with only 1200 miles on it.  Zero wear.  It would only take maybe 20 minutes to map it out.  I thought I had already done that, but I guess I didn't enter it into my cam data bank.  My guess is that its close to a 260 "advertised" duration at .050". 

 

The cam core I got from Schneider was one they bought from Howard's - the original Howard's.  This one has the original oiling holes in the lobes.  There were only 4 of these in their inventory, ever.  I believe it to be OEM, and it appears to be nitrided.  

[Xnke]

Yeah, those old Howards cores were actually Nissan Motorsport cores-I wish those were still available!

 

There is a source out there-there are new cores coming out of Japan that are as good as the original Nissan, they have a hexagon wrench lug but I can't find a way to buy them yet.

 

Note that the durations I gave for the stock cams..."seat" duration is equal to "advertised" duration by an aftermarket company. The duration at 0.050" lift is almost NEVER listed...as it makes the cam look much smaller!

 

If your "stock" L20B cam really has a 260* duration at 0.050" lift...it's not stock, because that would work out to be around 320* "seat" duration...which, just going based on the cams I have for the L6, would be likely close to 0.590" lift or so...

 

I would expect when you measure the cam to get something close to 0.430" lift, 256* seat duration, and I would expect to find 225*-232* duration at 0.050" lift. Let us know when you measure it!

[G-Duax]

Guess this would be a good of place as any to post this:

 

JUN (Japan) L-series cams (if you ever stumble across any) had a 2 digit number stamped on the back of them.

 

 

Specifications (unit: mm)
 #  Duration   Lift    LSA VC        P/N

 

66    (264)      8.3   110              31   1004M-N011 discontinued

68    (272)      8.6   109              31   1004M-N012 discontinued

70    (280)      8.4   103              31   1004M-N013 discontinued

74    (296)      8.4   106              29   1004M-N014 discontinued

75    (300)      8.5   105              29   1004M-N015 discontinued

78    (312)      8.9   105              28   1004M-N016 discontinued

 "         "          9.0   105              28   1004M-N017 discontinued

79    (316)      9.3   102              28   1004M-N018 discontinued

[datzenmike]

I thought all after market duration were listed at 0.050" lift??????? Yes they would look less but at least apples to apples.

 

All my FSMs for car and truck L20B cams say 0.413" valve lift (0.276 lobe lift)  and 248 duration.

[Xnke]

Nah, "advertised" duration is the seat duration. You usually have to ask specifically for duration at 0.050", and a lot of hydraulic cams have the duration at 0.004" lift as the "advertised" duration.

 

Also, the bigger the engine displacement, the calmer the cam will be at idle. So an L16 with a 290* duration, 0.490" lift cam will be a little grumpier than an L20B, which will be pretty sedate at idle, really.

 

My L28 in the Z currently has a 292*, 0.500" lift cam and I daily it in town-the supercharger uses too much gas to really want to take it out of town much anymore. The Turbo ZX runs the Delta Cams 280*, 0.455" lift cam and still gets 24MPG, and lays down 280HP at the rear tires on 12PSI.

[distributorguy]

Cam manufacturers don't want you to be able to compare apples to apples.  Its a lot like testing cylinder heads on flow benches.  To disguise numbers, you use a different baseline setting of 28", 25", or whatever level of vacuum you want so comparisons cannot be made from one shop to another.  

 

Overhearing top fuel dragster teams talking about cams, you may hear a discussion of how they "dial it in" like never before.  They'll pick an abstract point like .350" down the back ramp as their point to set cam timing.  Talk about a good way to keep a secret!  

 

My understanding of displacement and duration is that the larger the bore, the lower the effect on cylinder pressure when you change duration.  An L20b at 11:1 compression and a 300 duration cam may land you at 150 psi cranking compression as opposed to a 10:1 motor with a 270 cam which could land at 190 psi cranking compression.  The results are more extreme the smaller the displacement.  

[banzai510(hainz)]

I have a Schneider and it hasn't worn down yet in over 100k miles. Its a CWC core. also Webcams uses the same core and I think another brand that's sold on Partsgeek(comp cams.

 

I have bought Delta but find out they are not per spec listed. also heard from a part supplier that someone says they wear down also .

 

I have been satisfied with them(schnieder)

[datzenmike]

Here's the Schneider cam http://schneidercams.com/260F_datsun4.aspx

and Crane... http://www.cranecams.com/282-283.pdf

 

 

I took at random for the L series and a Toyota R22 and duration is posted @ 0.050" so what am I missing here.

[Stoffregen Motorsports]

 

My understanding of displacement and duration is that the larger the bore, the lower the effect on cylinder pressure when you change duration.  An L20b at 11:1 compression and a 300 duration cam may land you at 150 psi cranking compression as opposed to a 10:1 motor with a 270 cam which could land at 190 psi cranking compression.  The results are more extreme the smaller the displacement.  

Right. A big cam in a 2300 is a huge cam in a 1600.

 

You need larger cam numbers to use up the cylinder pressure of added displacement.

[Xnke]

Hainz, you probably didn't look at the rocker ratio they list at at Delta cams...the rocker ratio they list at is a 1.6 ratio...the real ratio is 1.48. When buying a Delta Camshaft profile, you have to ask them to fix that-if you order the racer brown profiles they have for the Datsun stuff they are correctly listed.

 

Also there are some old kinetic/Sunbelt profiles out there that I have been trying to locate, I believe they were also purchased by Megacycle.

 

Other than the silliness about rocker ratio, I have never had a complaint to Delta Camshaft in the 40 or so cams I have had them cut. With the Schneider cams I have used and sold, I have never had a single one last more than 25k miles, that I didn't send in my Nissan core. If customers come asking for a cam but don't have a core, I do not order one...they need to bring a core or buy a core for me to send out. Just way too many failures on break-in and low milage with the CWC cores.

[banzai510(hainz)]

Xnke

Its a mute point now but I measure the cam in 90 deg sections even  so if they use a 1.6 ratio thats cheating to get the so called lift they advertised. and I don't think it was still near the 450 or 460 on the ones I bought.

All I think they did is ground down the top of lobe to get more duration out of it. Well anyway I got rid of them. Maybe have 1 as I use it to line up the cam towers.

 

 

Im satisfied with the cam I have and I do have another Delta cam in another but didn't actually measure it.

[willz]

I wish I understood any this enough to make a smart decision on purchasing a cam for my L20b. Never had any issues running a 276 in any of my 12v vr6 motors.

 

Let's say my valve train is in perfect stock condition, running a single 45dcoe on a L20b with a w58 head and a 2" free flowing exhaust. What would a good grind be for that application?

[distributorguy]

Willz, in order for anyone to give advice on which cam to pick, you'll need to know your compression ratio (if different from stock) and do a compression test to see where cylinder pressures currently lie.  You want to pick a cam that gives good air velocity for the Weber to work properly, in conjunction with the compression ratio and the cylinder pressures that would work well for you (160-180+ for street use with that carb.)  If you go up in duration, cylinder pressures drop and cause turbulence in the intake at lower revs (under 3000).  A low duration cam with more lift helps to reduce issues on a stock motor.  You also need more timing at idle.  That's where the advance curve in a Matchbox distributor helps, so you can run 16+ degrees BTDC at idle.  Which W58 head?  Small or big chamber?