cams

[freaky510]

as some of you know I am trying to build a head.I have a U67 head with larger valves in it it has been port matched to my intake polished pretty much everything. I really dont want to put as stock cam in it.To honest the whole # thing dont mean sh#% to me.I just do under stand the whole # so if

 

1) if some could explian this to (remember idiot :unsure:) me.

 

2) just tell me what cam lope to buy.:o

 

Now i know that it hard to tell a guy what he wants for the preformance of his car and if you havent driven it it would be hard to say what i need.so i will list what i can about the car and whats been done

 

280zx 5speed, running gear swap:p

moog plates

l20 b stock motor:(

weber 32/36 thinking about s/u's have a set:confused:

big yellow coil:eek:

 

I plan to build a good autocross motor.The events I run in are smaller and I seem to be hanging out at about 4-5000 rpm in 2nd gear :rolleyes: and the power doesnt start untill 3500 i would like to try to drop it to a lower power pull point.Also Iam running the R200 and 195/55z/14. I would like to make more power before i start changing gear ratios. I dont know if any of this makes since and iam kind ofgeussing on the rpm levels but i do know unless i had a power serge or the motor can hit 9500

 

thanks freaky

[DISLEXICDIME]

i have a cam question also. what is the biggest cam you can run in an l20 with out a spray bar?

[freaky510]

i also have a post under wtb head parts that covers some of this.hanzi recommends the turbo oil pump. Bt if you building a high rpm motor i dont think it would hurt also i would give a guy confindince that his cam is wet.http://forum.ratsun.net/showthread.php?t=594&highlight=cams check this out doing research

[datzenmike]

Very basically, to increase power you need to increase RPM while at the same time opening the valves sooner and closing them later. This gives more time for the fuel/air to get in and the exhaust to get out. More fuel in, X more times = more power. This also means that the intake valve is open longer before closing and the exhaust is opening sooner and there is an increased time when both valves are open at the same time. Called overlap, and while this works to the engine's advantage a very high RPMs, at low speeds, both valves open longer, destroys intake manifold vacuum and ruins throttle response and power. So, you can have top end power (and poor bottom end), or good low speed power, torque and idle but no top end. Or anywhere in between. There's no way around this, well there is, but not on a single cam motor.

 

If you have a stock cam, going to more duration will raise the RPMs where power is made while robbing lower speed torque. A rule of thumb is that for every 10 degrees of duration increase the power band is raised by about 500 RPMs. So going, (for example) from a 230 duration to a 270 degree cam, will raise everything by 2,000 RPMs. Totally out of your 4-5,000 range in second gear. This you do not want to do with the gearing you have.

 

There's an old saying that the cheapest way to increase power is to change the rear end gears. This allows the engine to rev in a higher range at the same speed in each gear. What is the ratio for your R-200... 3.70 or 3.90? A 4.11 would really help.

 

What year is your 280zx tranny? A look at the ratios below will show that the older '78-'79 has lower 1st and 2nd gears, more useful for auto-Xing

 

1st....2nd....3rd....4th...5th

3.321 2.077 1.308 1 0.864 '78-'79 280zx tranny

3.062 1.858 1.308 1 0.773 '79-'80 280zx tranny

 

Tires. A slight overall lowering of final gearing can be gotten, by running a smaller diameter tire. Easy to switch back to regular street tires after the race too.

 

Edit:

 

The hi volume pump can be found on KA24E RWD motors, Z24i (throttle body) motors, 280zx turbo and LD28 diesel motors (810/Maxima) rumored to be on the Z18ET JDM motor too. I put a $10 wrecker Z24i pump on my 300,000 km L20B and the hot idle oil pressure went from 17 to 28 lbs! Worth it.

[datsunfish]

My 2 cents as usual.From what I know a spray bar is for a new cam that does not have oil ports drilled in it.The highest lift you can use with stock springs is .460.The tallest lash pad in a stock retainer is .170.I have a .450 with .160 lash pads in my 521 with rebuilt l16 and open chamber ported a87,edelbrock mani and DGV.I love the way it goes but the initial throttle response does suffer.I plan to put it all in a larger valve peanut a87 on l20b with twin mikuni phh.

Suppose you want max power possible and want to use a .490 cam you would have to get nismo racing springs and have the step around valve guide machined off for the inner spring.Lash pad thickness at this point is anybodys guess.You cannot allow the cam lobe to run off the rocker surface.You would have to have new rockers.$$$$You can get them resurfaced through a cam shop for less than new.You will have to do this with a regrind too.

With a z 5 speed a 4.11 would be your best bet to get through those gears easy since your initial throttle response will suffer.

I would recommend the .460 .170 combo and call it good.I would suspect a very large cam profile would be better for drag strip rather than autoX.More time to rev it up before taking off.You wouldnt want to stumble to hard on a corner and lose all the time you gained with max power on the straight.

Basically a ton of variables to get you confused and broke.

You would probably be over $400 for a new cam setup.A regrind you could do for around $200

Everyone who wants to mod their L series 6 or 4 needs to own the book "how to modify your nissan/datsun ohc engine" by Frank Honsowetz.Priceless info.

[banzai510(hainz)]

Are you positive you have a R200 in there???????R200 need Mustache bar Modified right? If it bolted right in then its not a R200

 

From what vehicle? a Z car? Those rear diff ratios SUCK in a 4 cyl.

 

Most are like 3.55 or something like that unless there was a change.

 

Now cams cost money to do correctly

these are general prices that I incontered and may have rising as of late

Cam 160$

rockers 13 $ apc x 8

springs 80$

retainers 4-8$ apc x8

lash pads 3-4$apc X8

timming set 60-80$

plus head work or install of some of these parts

also the lash pads you have to give a best guess on size.

I have a asoortment at home from 150-200.

valves seats all measure close to the same in seat depth/valve stem end also so you dont need different size lash pads also

 

If running a used cam one should have the old rockers that were on the corresponding lobes of the old cam(dont mix them up)

 

Im going to try to save you money! maybe find a R160 with the stock gear ratio and get rid of the R200 if it is a 3.55 GR and run stock motor with a pair of SUs bolted to it or a set of 40mm sidedraft if you could find a set for cheap(unlikely but never know) or WEBER 38dges DOUBLE OPENER.

 

If the gear ratio is from a stock Z car its killing your power

Maybe scam a R180 from front of a 4x4 720 and change to 4 bolt Flange

Spiff is supposed to put it on GUBA.com on how to do this(Jeff Hino)

[datzenmike]

Good stuff hainz. Here's the R-200s and where they come from:

 

Datsun R-200 list (not R180)

 

* '75-79 280Z(X)s had a 3.54

* '81-83 turbo ZX's had a 3.54

* '81-83 non-turbo ZX's had a 3.90

* the '85-86 200SX turbo had a 4.11

* the '87-89 LSD was a 3.70

 

The '80-'85 720 truck R-180 front differential was a 4.375 (nice!)

[freaky510]

yes it a 200 i built the bar myself it came out of a 79 280zx.I went to the 200 after i broke the 160 then the 180 i cant belive that the u joints didnt break so yes its the 200

[banzai510(hainz)]

I think your autox performance can improve if a different gear ratio. If its truely a 3.5 gear ratio

[RacnJsn95]

Was the 79 280zx your R200 came out of a 2+2? If so then you have a 3.70 ratio R200... I have one stashed away.

[datzenmike]

Raise one rear wheel, trans in neutral and put a mark on the driveshaft. Have a friend turn the wheel 10 times while you count the number of driveshaft turns. Divide the driveshaft turns by 10 and you have the rear ratio. Example: 35 1/2 driveshaft turns would be a 3.55 ratio.

[freaky510]

why yes it was a 2+2 79 280zx

[freaky510]

RacnJsn95 Was the 79 280zx your R200 came out of a 2+2? If so then you have a 3.70 ratio R200... I have one stashed away.

 

SO WITH a 3.70 ratio iam on the right track?By building hp

[pl521sss]

I was considering Isky cam and their stage 1 (270

[banzai510(hainz)]

Isky stage 1 or 2 would be fine. for the streetI run a 475 /275 (regrind)im my beater.

Schneider 460 or 480 lift

webcamshaft 488

 

The Damb cam is very BIG!!!!! and uses a special retainer system to use the stock lash pads if I remeber right. ask some body else on this one

Maybe ask someone on the 510realm

My cheat sheet I wrote Damb Cam

.520 lift 280dur

.540 lift 278dur

why i have 2 #s I dont know.

 

the 219(SSS) is just close to a L20b grind on the cam.My Nissan motorsport book list is as 434lift 248dur for a true SSS cam grind. might be slight variations .410 is what i seen in other books for L20s and stock L16/18 .390lift

 

all these Cams work best with more carburation. like sidedrafts 1.5 in intake with matching 1.5 manifold.

cannon sidedrafts manifolds are only 1.25 runners ,just to let you know.So getting a SSS head with this manifold defeats the purpose.

[pl521sss]

I also have these cam sprocket.

It's adjustable but don't know what the range is.

Let alone how to use it.

Didn't come with manual.

 

[hang_510]

^ the sproket is for adjusting the cam timing w/o removing it from the cam.

 

i have the ISKY stage II, for a similiar U67 setup, but dont have it running yet :cursing:

[hang_510]

http://cgi.ebay.com/ebaymotors/Datsun-L-Series-4-Cylinder-Camshaft-Performance-Grind_W0QQcmdZViewItemQQcategoryZ33614QQihZ005QQitemZ150209486904QQrdZ1QQsspagenameZWDVW

[freaky510]

so i finnaly got a cam and now i need springs and retainers really do like the idea for 200 for the set so if anyone hass some comp springs that are good and would like to sell please hook a guy up:)

 

the cam i got i belive it is a 490 it came down the ratsun chain i think it was hangs first :lol:

[Jason]

Brian, for springs, retainers and lash pads, Specialty Engineering here carries them in stock, new from NISMO, but, they are quite expensive. Call them at 604-521-9232. You'll also need to either have your rocker arms refinished or new ones as Hainz has suggested. I'm running a .507 lift cam right now without a spray bar, but, I keep the revs down to the 6000rpm range or so.

[banzai510(hainz)]

Freaky

I thought you was going KA motor and gave up on the L motors

 

490 Isky I think what HANG is talking about is usually the 490/290 duration cam .

I think it would be a little long with a 3.7 gear ratio

 

 

MY L16 with duals and 475 cam 2nd gear would be about right. 3rd gear pulls are best for me on the freeway(also very long pull the get the HP out of it)

 

 

I really think you should start with a 4.375,4.11 or 3.90 hgear ratio

[hang_510]

I think what HANG is talking about is usually the 490/290 duration cam .

not an ISKY cam.

.490 is the calculated lift off the measurements i did, stamped NORRIS on the rear. no clue as to the duration...

 

i woulda used it if i hadnt already purchased the isky :mellow:

[Phlebmaster]

not an ISKY cam.

.490 is the calculated lift off the measurements i did, stamped NORRIS on the rear. no clue as to the duration...

 

i woulda used it if i hadnt already purchased the isky :mellow:

 

341 SRA is what is stamped on the end.....from what I have gathered from another Norris cam I saw in Canby at the show, this means the duration and SRA means the profile ID.

 

I gave Freaky510 the phone # for Norris cams to check on that. :cool:

[banzai510(hainz)]

If the duration is shorter that cam might be fine but 3.70 is not a good autox gear ratio.

Plus with any aftermarket cam you really need dual carbs like Mikunis/Weber DCOEs to make the cam come alive. Otherwise just bolt some Dual carbs on first for a more noticable improvement.

[freaky510]

yea i got some s/u's and as for a ka it is still in the works. and i traded my cam so here i am. i have a head that i had done and i want to get some springs to finish it then i will put it on the block thats going in soon i dropped it off he just needs to take it in. as for gears i have been looking for a gear set but right no the wife is home for the summer with the kids so the gears have been on the back of the list :lol: