cam help.

[Silent]

i know this has been beat to death. but search has helped me none thus far.

 

my set up is this

3.1 stroker n42 block

su carbs w/sm needles

msd 6al

blaster 2 coil

carter fuel pump, holley fpr.

 

compression is believe is around 10:2.1 right now. did a comp test and it came out 165 across the board. so i could be way off.

 

im getting ready to have the head ported and polished {an e88}.

 

putting bigger valves in it, and the whole 9 yards.

 

 

what i want to do is this, it has to be some what streetable, i cruize around town at 3k rpms. i don't plan on running webbers on the car {i like easy tuning} but i do plan on boring the su's out to 50 mm

 

so my guess would be an rpm range of 2500 to 7k? the bottom end has been balanced.

 

the cam is what im trying to figure out. i haven't found anything yet that falls into this range or is close to it

 

in the end im looking for about 10:5.1 c/r. id like to see above 230 to the wheels

 

any help would be apprecitated!!!!

 

[johnc]

You'll most likely be limited to 6,500 rpm max with the SUs and you won't need to go any higher anyway. The Nissan Motorsports L7 cam would be my choice if you do all that you say you're going to do to the engine. It has .475" lift and a 270 duration and you can use the stock valve springs if you keep to a 6,500 rpm limit.

[DAW]

If your compression test is 165lbs. warm, and a stock cam, you either don't have 10.0:1 c.r. or you have holes in the pistons. DAW

[Silent]

If your compression test is 165lbs. warm, and a stock cam, you either don't have 10.0:1 c.r. or you have holes in the pistons. DAW

 

it's not a stock cam right now. im looking for something bigger.

 

me personally, i was thinking of the msa/schnider cam 480 lift jobby. still half ass streetable and such.

[JMortensen]

Both these guys are right. With a stock cam and 10.2:1 you'd be running on the ragged edge of pinging. With a stock cam and 165 lbs, I'd guess you're running about 8:1. Could it be that the engine already has an aftermarket cam in it though...you didn't say. Do you know what head/pistons are in it? You can figure the compression out that way.

 

IIRC the FSM for the 280Z says compression tests should show about 180 and they were 8.3:1, but that's pure years old recollection, so hopefully someone will back that statement up.

 

If you're serious about getting 230 to the wheels, talk to Dan Baldwin. He tried SU's, then Jag SU's, then finally went to triples and got 255whp out of his 3.1. I don't recall what he was able to get out of the various SU setups he has, but I do remember him agreeing with me that switching from SU's to triples is like flipping on a 40 hp light switch.

 

I've never dynoed mine but I'm sure that I'm right in the area you want to be. I struggled with SU's for years because I was scared of the triples. Everyone said that they were such a PITA, and while they were right and it did take me a while to dial them in, they make a HUGE difference. If you like top end power, get triples. If you like low end, then bore your SU's and be happy with your flat torque curve and the idea that you may not hit 230 and it might not like to rev past 6K, but it will be a lot more driveable on the street.

[Silent]

the cam in the car isn't stock its power band runs from about 2200 to 6k.

 

knowing the person who got the cam its a crane from victoria british. thats my best guess, i want a cam in the car that i know what it is.

 

the motor in the car had 250miles on it when i got it. so as far as finding out true c/r right now. im at a loss as to it. it does have an n47 head on it.

 

 

OH something else. where could i get some bigger valves at?

 

if im going to build it, im going to build it once.

 

no comment on the 480 lift cam?