720World

Little Trucks, Big World

I have an '83 2wd 720 with 5 speed manual trans, and I'm already running Pacesetter headers, a Weber 32/36 DGEV carb, Magnaflow high flow CatCon and Magnaflow SS muffler, and all that has worked out very well, but the midrange power still seems like it could use some improvement. So I'm thinking of adding a high performance cam to the motor. In doing research on line for Z24 cams, apparently the only thing available these days are a couple of Comp Cams grinds. They offer two grinds, the 252S and the 260S. The 252S looks like it's an RV type cam with most of the power curve on the bottom end, but the 260S looks like it's probably about what I'm looking for. The 260S cam  has 214 degrees duration @ 0.050", and .420" lift, with 110 degrees lobe separation angle.

 

My question is: Have any of you guys out there put a Comp Cams 260S in your 720, and if so, how do you like it? And if you used a different performance cam, what brand and what specs for duration and lift was the cam you used?

Views: 615

Reply to This

Replies to This Discussion

I put the 252 in a few years ago when I put bigger tires on thinking I needed more low end. It helped but I'd rather have the power at freeway speeds, these do have a nice bit of grunt after all (fir what they are at least). Probably gonna swap it with the 260. I also run a header (Doug thorley), 2" exhaust with a spintech muffler and resonator instead of cat and a weber outlaw 38. I'd go with the higher rpm cam if you do much freeway driving. Let us know how it works out for you.

a 2wd 5 speed with a weber will respond best with the Comp 260 cam. the 260 peaks out around 4500rpm on a stock engine which is perfect because a stock z24 wont offer you much past that anyway. 

 Keep in mind a GOOD tuneup is key before and after adding a cam.

I turn 35" tires with only 4.36 gears. the 260 works well but 3rd gear is mandatory for hills and brisk acceleration. 

Here is the PN#

Quick question, how will the 252 can run with a stock setup? Only thing I have done is the thorley header and 2" exhaust. Still running stock Cali. Carb...in Cali so changing that really isn't an option, I was thinking the cam would be easier, and maybe be able to slip it through smog? But I was curious if I'll run into any carbeuration issues? Oh yeah, 84 4x4 manual trans Cali truck, thorley header, 2" exhaust and 31" tires...
You can pass with a cam but you better make sure your truck is on tip top shape for passing the test. Passing can be more difficult. My 1980 toyota 4x4 ran a 32/36 weber, semi aggressive cam, 10.5 compression and a thorely tri Y header in Cali and barely passed the test... So it can be done.

I live in Idaho, and since the 720 is over 30 years old, I have it registered as a Classic, so there is no smog test. And even before I re-registered it, it was passing smog with no problem. 

Yeah California used to have that 30 year old deal, but they cut it off at model year 1976, everything else still get smogged (if you are in a smog controlled area) so every other year it's gettin the deed done...but as for tip-top shape, the head is new-ish maybe 6-8 thousand miles (I commute about 1000 a month) the engine is currently in the machine shop getting a .020 over bore, turning the crank .010 under and balance, so a complete bottom-end rebuild. I was going to hold off a few oil changes before putting the cam in. Figured it would be best to let the bottom end break in before doing anything to it...but i would imagine it being in tip-top shape by the time it's back in for smog next year.
I'd go with the 260 for performance (no idea about the smog aspect though). Maybe the 252 if all of your driving is stop and go/low rpm. I run 265/somethin R16 which are just a hair taller then 31's and a hair thinner. With the 252 I noticed a bit more pop off the line up to about ~2500 rpm then it flattens out pretty quick, don't expect to see a difference up to 4500 like they claim. Again, can't speak to the smog junk, Steve's the man for that.

Thanks for the responses, guys. What you said is about what I thought about how the cam would perform. I ordered one of the Comp Cams 260S cams this afternoon, so I should have it by the end of the week. Once I get it in the motor, I'll post a review here. I also did a search on just about all of the major cam builders websites, and Comp Cams is the only one who makes a performance cam for the NAPS-Z engine.

Update: I ordered the cam from Summit Racing at the first of August, and it showed up a few days later. I found a shop that specializes in import engines, but when I went over and talked to them, they really didn't give me the feeling that they really knew their way around the NAPS-Z engines. So the cam is still in be box and I'm still looking for a shop that is good with 720 2.4L engines. A cam change shouldn't be that big a job, unless the cam chain tensioner pops out, but if a shop doesn't know about that, it turns a sort of simple job into a major undertaking.

So does anybody know a shop or mechanic in the Boise, ID area that's good with 720 motors? Even a shop within 100 miles would be OK.

I'd think if they're familiar with overhead cams they should be able to handle it. A couple bungies from the chain to the hood or a wedge inside the chain will hold the tensioner in. I think Datsun specialists are far and few between these days. I remember seeing one in Seattle a few years ago but don't know if they're any good or if they're still in business.

Well, it's taken a couple of years, but I finally got the cam installed last week. The first time I drove the truck, I was kind of disappointed. Performance didn't really seem all that much different from the stock cam. But I remembered chatting with the guy in Vegas who runs High Impact Motorsports, and he said that would happen unless I advanced the timing a few degrees. So I did that, and it really woke the cam up. The truck is much more drivable now, and I'm tempted to advance the timing a couple degrees more and see what happens. By the way, anybody around Boise, the place I had the work done is Dr. Floyd's Garage over in Garden City. The guy is really good, and definitely knows what he's doing.

RSS

© 2019   Created by TigerRacing.   Powered by

Badges  |  Report an Issue  |  Privacy Policy  |  Terms of Service