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Choosing a cam


tjyak50

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Rebuilding the engine in my 240z and the insane amount of choices on a cam is paralyzing.

 

 

Engine to be;

L28 F54 flattop block Total Seal rings with N42 head. I have tower shims and a spring kit already. Running Triple Webers and Headers.

 

I drive this car maybe 3 times a month and it has a race-car interior so stock is long gone.

 

I want a cam that has a lumpy idle capable of frightening children. I want it to pull to 7000 or so.

 

 

Options:

New billett or Regrind my L28 cam at Delta or Isky or Webcam?

* Webcam recommended their 155a: .488 lift and 240 duration at .050 and 109.5 LSA

* Delta recommended his 270-2: .464 lift with 225 @.050 and 108 LSA

* Isky guy didn't seem to want to talk about it.

* MSA new Stage 3 is 460 lift with 270 / 280 advertised duration.

 

 

 

Lift between .460 and .490 range seems pretty easy to choose, but duration numbers are all over the place.

 

Any input is appreciated.

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Intake reversion is what causes the "lumpy cam sound" or "lope". If you want the cam to perform well at higher RPM's and want that lumpy sound without lowered timing and throttle, you will want a longer duration on the intake valves. Keep in mind, there are consequences to running too large of a camshaft, but this doesn't sound like much of a daily driver.

 

Lope is caused by the intake charge being pushed back up through the intake due to a late intake valve closing. The lope is the sound of the motor being inefficient until you reach higher RPM's and backing air up through the intake and carburetor/carburetors as the piston starts the upstroke before the intake valve fully closes. The lope that you can hear is usually from the sound imbalance of air both entering and exiting the intake manifold as each cylinders intake valve opens and closes slightly late.

 

Technically, you can have a higher lift cam and not have the "lope"...and a cam should be matched to the motor if you are after performance, if you just want the lope and don't care about a few horsepower lost or gained, and driveability/tuning isn't a concern, grab a really big cam and toss it in there. If you are concerned about how well the engine runs, get a cam that matches your motor, and if the lope isn't enough for you, back the timing off a degree or two and idle 100 or so RPM lower...normally lower idle or a degree of timing retard is not a bad thing when looking for high RPM horsepower...I would rather have a matching cam with a little less throttle response at low RPM than an unmatched camshaft that won't do the engine justice.

 

As far as where to buy the cam, I have heard pro's and cons for all those companies...I would pick a place that has a local outlet that members here know and trust...local franchises are sometimes easier to deal with if there is a problem, especially if you know several people that can vouch for a specific outlet.

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We've run 2 different grinds, offered by WebCam, in the L18 racing motor that we're messing with (just trying things), and to be honest, neither impressed me too much - although they were both very smooth with their power delivery. We tried different diff ratio's and tyres to suit to try and maximise them too.

We then switched to a grind by Schnieder, and it performs noticably better.

 

From the grinds and few details you've listed, I would favour the WebCam grind. Mainly due to the increase of duration without a massive loss of lift. However, I wouldn't consider any of those to be really aggressive. They might be strong performing street grinds, but they are far from a big performing competition grind.

 

Take a look at "zcars", "kameari" and a few other sites that specialise in the z cars/L motors. I doubt they will have their own grinds, they will just offer other manufacturer's grinds that they have found to work well.

 

I'm pretty sure Crower also has some grinds for the L6 motors. Here in Australia there is also Crow Cams, Waggot & Ivan Tighe Engineering that offer grinds for those motors.

 

 

 

 

 

Just looking through my Crow catalogue, they list this as a Medium Street Performance camshaft;

 

#58721 Valve Timing - In 39/73 Ex 75/37

 

Duration - In 292 Ex 292

 

Duration @ 0.075" - In 225 Ex 225

 

Lobe Centre - 108

 

Valve Lift - In 0.495" Ex 0.495"

 

Power - 3000-6500rpm

 

 

 

& this is listed as a Mild Cam For Use In Stock or Near Stock Engines;

 

#58640 Valve Timing - In 40/76 Ex 77/41

 

Duration - In 296 Ex 298

 

Duration @ 0.075" - In 214 Ex 216

 

Lobe Centre - 108

 

Valve Lift - In 0.485" Ex 0.495"

 

Power - 2200-6200rpm

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Valve Overlap formula method?

(Intake + Exhaust Duration / 4) - LSA then times 2 = Overlap.

More overlap = more reversion and a lumpier idle

 

Annoying that specs and terms listed by vendors are not very standardized. Advertised duration vs .050 duration or .075 duration. Some don't list LSA at all.

 

The E88 head in the L24 I was running had some CWC cam with lift of 460+ unknown any other specs. It idled like a Buick so I never suspected it was in there. But I always felt the powerband was narrow and low (3500 - 4800 if I recall)

 

I think I need to determine the most RPM my DCOE40 carbs can flow and use that as a limiting factor. I suspect it will want a lot of fuel up top.

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PocketRocket

What web cams you have ? the specs?My personal opinion is go at aleast 460lift to the 475lift range otherwise dont waist your time on and money on a cam swap.

 

I have a Schneider also in my Daily driver as I like the Asymetric profile Fast open slower closing (ezer on the seats and springs). The webcam look like a Isky in that its symetric.

 

What I read on OZDAT alot of people dont like Crow cams.

 

 

tjyak50

I have bought 3 Delta cams and each were not per spec. I gave 2 away!!!!!!!! the other I drilled out and use it to launch bottle rockets from it

 

I have one in one car(supposed to be a 475lift/275dur It seems good but dont know if really per spec and it really dont know if my match porting and sidedrafts that make most of the power.But those pull good. so at least maybe they got the duration longer

Delta seems not to make the Lift per spec but it is a longer duration.

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Was just a info for you.

 

So Delta was 60$ with a core or not?

Regrinds use bigger lashpads most likely.

Nothing wrong with a regrind but hard to deal with the company once you got it shipped to ur house and find out its not per spec and our shipping it back.

crap maybe all are not per spec.

 

Isky makes a (475 /275) and webcam are new cores.

My Schneider was a new core

What I seen they have a CWC cast on them. I wonder if that isnt the caster marks from the same company then sent to Scheider, Webcam for grinding.

 

Isky I dont know never got one from them.

I do like Scheider but no longer NEW ones

 

 

Personally you want a cam to put power down fast. Datsun ignitions barely can handle abouve 6500 before the slop in the system gets varible in the timming. Least get a eleltronic ignition. thats why they go crank fire or really get there distributor worked.

 

Read Sealicks 720 cam build up.PLEASE READ IT

the machinst plays a big rol in this

http://community.ratsun.net/topic/25497-sealiks-shit/

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I will read that article. Have read about 10.000 posts in the last month.

 

I have an XR3000 ignition now.

 

The CWC grind cam I pulled out showed some lobe wear so I am making it into a peace-pipe.

 

These things are not really all that expensive and if the vendors are under-delivering I will over-buy and probably be happy either way. Or just replace.

 

Sorry for the relatively Noob cam discussion.

Tj

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Lobe wear.

My Delta 475/275 regrind I can tell there is lobe wear across all lobes but using both nissan motorsport springs. I cant confirn this they might be made by Isky. As motorsport sell Isky cams.If I did a 475lift cam again I would use one motorsport spring and one stock one. Long as they dont coil bind.

 

MY Scheider 46o I used a stock outer and a Motorsport inner. Figure it was a daily driver and longivity was a big factor. No need to over pound the seats. However one lobe seems scrarred slightly. Dont know from dirt or what but seems still ok.

 

 

Gude in Californa had some cams also but dont know much about them.

 

I dont go super huge as I dont want to run a cam spray bar either.

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PocketRocket

What web cams you have ? the specs?My personal opinion is go at aleast 460lift to the 475lift range otherwise dont waist your time on and money on a cam swap.

 

I have a Schneider also in my Daily driver as I like the Asymetric profile Fast open slower closing (ezer on the seats and springs). The webcam look like a Isky in that its symetric.

 

What I read on OZDAT alot of people dont like Crow cams.

 

 

 

We used WebCams grind #'s 87 & 84

 

Schneider thats in it at the moment I think is #311F from memory

 

Note that its not a street car! it is a race car only

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FWIW, we've used Crow stuff in alot of motors we've built.

 

Their chev V8 stuff, IMO is nothing but a copy of profiles from Comp Cams from about 15 years ago - but, I guess, why try to re-invent the wheel. If it worked reasonably well back then, it will still work reasonably well now.

 

 

Has anybody any experience with the stuff from Paeco?

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Finished tearing the bottom end down tonight and still have the tranny to rebuild so no decision made yet.

 

SHOCKED at the stuff I found in the water jacket. How dow water flow through the engine if the passages are plugged.

No wonder the Head Gasket was yucked.

 

For the record, an LD28 crank would be handy right now...

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Paeco?

No never tried there stuff.

 

 

Webcams 87&84 I see those are full out race cams.

 

Bryron510 had some Canadian cams from Colt I believe and he put a bigger one in and came out less HP he told me so I guess its part learning experience also

 

tjyak50

I would go with the Isky 475/275 myself

the 490 might be on the long side for dailly driving around town

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Did I mention that now would be a great time to find an LD28 crank?

 

Doing everything ourselves with the delightful cooperation of my buddies machine shop. Nice to have friends that have heavy equipment.

 

Its a learning and bonding experience. I think they call it a double entendre'if I said that having a big crank would make me a better person.

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??Well it isnt going to happen with that cheap ass Delta camshft your looking at.

 

 

I am not looking at a Delta Cam. I called them for details but not going that way.

 

 

Thanks for the link to the L24 with Triples - a setup I already have. The goal is 28 or better and the pleasure of knowing I did it or blew it up myself.

 

I agree that ISKY seems like a decent route.

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Paeco?

No never tried there stuff.

 

 

Webcams 87&84 I see those are full out race cams.

 

Bryron510 had some Canadian cams from Colt I believe and he put a bigger one in and came out less HP he told me so I guess its part learning experience also

 

tjyak50

I would go with the Isky 475/275 myself

the 490 might be on the long side for dailly driving around town

 

 

 

Yeah thats right, this is a racing car, not a street car. The Schneider cam we've got in there now is bigger than both the WebCams we tried and makes noticably more power. The WebCams should have both produced more midrange torque, but the car was a slug with both of them.

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