Okay, the purpose of this write up is to provide a free solution to a 150 dollar problem. JWT offers these gears for that price, and while they are useful, few people actually find 150 dollars of horsepower here. However, if you want to use a 248 cam on your intake side, you're going to be retarding that cam 1.7 degrees. This puts the intake opening event .7 degrees before TDC, which is certainly not helping your top end (which is why you have a 248 in there in the first place). So to correctly install a 248 on the intake side you would have to use a 2.5 degree advance, this would make you only .8 degrees advanced over stock. For this write-up i have taken my goals one step further, and i only redrill the gear for a 5 degree advance.

similarly, you could drill all eight holes, or bring your gears to a maching shop and have them do it with the included template. But if youre like me and all you want is to properly install a 248 on the intake side, then all you need is to drill for 2.5 degrees advance. On the diagram/template 2.5 degrees of advance is the number 2, while stock is number 1. all the other holes can either be found on the JWT cam gear instructions form the site, or on one of my pictures.

For this write-up, i will be finishing with 248/248 with +5 degrees of advance on the intake side. i wouldnt recommend 248/248 to anyone unless they either do +2.5 or +5.

First things first: you must print out this template. i brought it to a 1:1 scale for you, but it only works in photoshop, so you may have to re-size and print to get it to fit. Either way, it is correct, and it fits the gear perfectly.



Now, as for the template you only need to cut out the inner ring. for this picture ive cut both the template and the inner ring. the template is good to have as a check of placement.



Now, place the inner ring into the cam gear, it should fit EXACTLY.



This picture shows your magic formulas for advance and retard. i'll be using hole number 3 for 5 degrees of advance. Now get out your centerpunch. Put iit exactly in the middle of the "hole" on the template and give it a whack. if you didnt get it in the center, dont even bother continuing. grab another gear if you must.



This photo shows me placing the template back on over the gear. if you look closely you can see my centerpunch dimple in the exact middle. On the outside of the gear i also hit the number three witht he center punch as the becomes the new alignment dimple (the dot you align the chain to)



This is a photo of the new dimple and the hole im about to drill



The size of the hole is about 1/4 but all you need to do to find the right size drill bit is try out different bits in the slot already cut in the gear. 1/4 is actually a tad large, but it works nice for our purposes.



Does it fit? you bet it does.



Now to install this gear you need to follow the JWT instructions, but it should be self explanitory at this point. here is a pic of a correctly installed 248+5 cam.



And this shows the lobes in the correct position.



There you have it, i just saved you 150 dollars.

As for first impressions, im blown away. When i went to 248/248 a year and half ago i thought it was okay, but when i switched to 248/232 i thought it was absolute crap. the mid range was WAY better with 248/232, but then i tried 240/232. 240/232 has a little less top end, but is amazing for midrange.

However, with this revised 248/248 and my other top end power adders im more satisfied with this set up. So get out there and try 248 (plus 2.5)/232 and 248(+5)/248.

awesome, man! i have a few extra sets of cams/gears laying around...

ow, my head........ to advanced for mah blood, but i do understand it, and that says alot coming from me.....Good job

i bet you dollars to donuts you could have both gears drilled for all 8 holes if you brought the template to a machine shop. and it would only cost you like 30 dollars. they would even have the numbers to stamp them i imagine.

i used to be worried about the structural integrity of the gear with drilling it for all 8 additonal holes, but the material down there is a quarter inch thick, so it should be straight.

if you were worried you could always have it heat treated. but comeon, if you got extras, this is practically free

EDIT: trust me its not THAT complicated. pick a hole (#2 or 3) and then whack it with a punch, then drill it out with a 1/4in bit.)

indeed. this is something im definitely going to be playing with in the near future. thanks again!

man great write up im going to add to favs!

Great Writup, time to do a 248/248 cam swap on my altima.

Any idea which is better 5 deg or 2.5 deg?

****!!! i wanna try this.. but it seems to hard for me. : (

is it a really big notice?

Just the Mod I was looking for! Good idea. Whats the Powerband with the 248(+5)/248.

is jwt gonna sue you now?

Nope, i dont know which is better. However, with a 248 cam rotated to work on the intake side you get this:

2.5 degrees: advance is really only .8 degrees of advance.5.0 degrees: 3.3 degrees of advance.

this is because a 248 rotated with the four teeth method is 1.7 degrees retarded from the centerline, so its a total of 2.5 degrees (if you add both sides of TDC)advance it 2.5 degrees from 1.7 degrees retarded, and you end up .8 degrees after TDC. And according to Tloof, almost all current nissan engines (including our stock set ups) open the intake valve 1 degree after TDC.

the reason 248 on the intake side is worse than a 240 is just this reason. although the 248 has more duration (alot more than 8 degrees over 240 we're coming to learn) it is retarded before tdc, which is wasting its duration. retarding that intake cam helps make mid range, which is not something you were trying to accomplish by swapping in the 248 cam. try em out and you'll learn 240/232 has a better midrange over 248/232 for this reason alone.

so with 3.3 degrees of actual advance, im really only 2.3 more degrees ahead of the stock timing. So you can see how small the 5 degree change really is. i think the next thing i'll try is 7 degree of advance, but that'll be when i get my second intake manifold finished.

yes, the hour it took to complete this task was more than worth it. 3.3 degrees (AKA 5+) isn't a HUGE change over stock, so i can feel confident about it with out going to a Dyno.

i dont think they'll sue me. I'm not selling this, but i am aware of laws....

besides, companies still sell this, although ive heard JWT no longer produces the item, so they're probably working on a better design.

Plus, im just giving a template and instructions, there's no telling why its so easy to get a 1:1 scale machine drawing in some instructions available to everyone....

MikeD. the power band is 2K-7K. with 248/232 (which i loved) i had some stupid dips, now the powerband is much more linear, and the top end is greatly improved. Granted, i have a DC sports header and the 3in N1 duals with no cat, i've been building for top end. I would have to say the gains are great for stock ECU.

EDIT: i just wanted to add that this mod is not jsut for 248/248. i would HIGHLY recommend 248(+2.5)/232. i have yet to try it, but i'm really looking forward to see what that combo can do with the proper intake opening event.
Modified by DjPantsSpecR at 4:27 PM 9/25/2006

article-worthy anyone?

anyone.... damn.

thank you man.. so much come next friday im doing this and preping my altima cam or gettin another one..

suggestion i know the altima cam is closer to beign stock setup so maybe the timing changes would have more effect on it.....

since i have an altima cam i think i will try the 2.5 setting first , but ill have to reread your and tloofs post before i make up my mind...

oh and im saving this just incase some bs happends..

shoot me your paypal and ill give u 5$ for doing this work ma...

u dont even know

lol im not gonna take your 5 bucks. maybe you'll buy my intake manifold when it comes out....

and ive read-and re-read tloofs posts as well as my own and this is where ive got my info from. ive read tons adn tons and i can conclude from other forums that the 1.7 degrees before the centerline for the intake opening event is correct.

now as for the altima cam, yeah definately re-read tloof's cam specifications post. But lemme know how it goes on friday friend. i got two tests before then....

i hate to ask, but i'm slightly confused. you saidHowever, with this revised 248/248 and my other top end power adders im more satisfied with this set up. So get out there and try 248 (plus 2.5)/232 and 248(+5)/248so did you do this to 248/248 or 232/248?

this is 248/248. but it actually is set up decently because i used the 5 degrees of advance setting, which gives an actual advance of 3.3 degrees which is only 2.3 degrees over stock

EDIT: i hope everyone still realizes you have to use the four teeth counter-clockwise method to get an exhaust cam to work on hte intake side, thats why i showed pictures of it set up correctly.
Modified by DjPantsSpecR at 7:13 AM 9/26/2006

this has been an article since i read it yesterday, sorry i forgot to tell you i converted it for you. as the articles are switched in file type to .pdf they will be available in final draft format for everyone to read/enjoy!

thanks DJPants, your knowledge is priceless.

DjPantsSpecR wrote:EDIT: i hope everyone still realizes you have to use the four teeth counter-clockwise method to get an exhaust cam to work on hte intake side, thats why i showed pictures of it set up correctly.

so even after drilling the hole, we still install the cam 4 teeth CCW from the timing dot we put in the gear?

yes sir, you need to still do the four teeth method.

the cam gears jsut correct the error associated with using a 248 on the intake side.

and as far as progress goes, i ripped everything apart today and checked the condition of everything adn its all good. My idle is nice and loopy before 900rpm, and it still goes like hell.

Now someone do this with 248/232 and lemme know the deal.

+1 article for Chase....

Ohhh mannn!! i have to drill a hole??!!!!! Can you do mine for me??!? I CAN"T DO THIS!!!!!!!!!!!

Good info, and good job!!! thanks for sharing to us!! I will definately try this on my motor. I would LOVE to see a dyno of stock --> 248/248 --> 248+5/248 import gay mag style somebody get on this please

Dj, great article, definately sticky worthy. Quick questions for you- What year motor are you running?

What year motor dou you get the 248 or 232 cams from?

And lastly, looks like you did not drill all the way through the cam gear, or did you?

Thanks,Kevin

its not stickied, its an actual article in the articles section.

yeah, maybe this is a sticky for the KA section. i didnt post it there obviously, but i tried to make it available specifically for some people wanting more out of their KAs.

My KA is a 93. My 248 cam is from my 93, but my 232 is from my 95 motor. So the 248 is an s13 exhaust cam, and the 232 is an s14 exhaust cam. to clairify, i'm using a 92 exhaust cam on the exhaust and the 93 on the intake side.

it doesnt really matter, however.

it only matters if you get an altima cam from 93-95 (not 96) then you dont even really need to do this, but i have someone in the KA section about to try an altima 248 plus 2.5 degrees

i definately had to drill all the way through the cam gear. you are drilling a hole for the pin on the cam to sit in, as opposed to the slot cut in the stock location.

in the words of mmm240 i believe, "do i get any custom title love?"

hey chase, what if you combined your cam threads into a singular writeup, one that you can add to as you go along, and we sticky that in the ka forum?

also you have email regarding emissions removal.

Thanks Dj, you a bad mothafocker.

i think thats a very good idea. i would lvoe to make a revised version of my post "my comments on 248/240 s13 cam swap"

that thread has SO much useful info in it, but its practically unsearchable.

i sent you an e-mail back, as i believe my emissions removal is more thorough than the article.

i really like that idea, as the post i wrote has been up in the KA section for weeks. its four pages long,a nd it really has nothing to do with anything anymore. So i have a test in calculus tomorrow, adn then another in electrical engineering the next day. But i will come up with something good, as it will clear up and knock down a few posts.

Awesome! lemme know!

DjPantsSpecR wrote:in the words of mmm240 i believe, "do i get any custom title love?"

i think you confused me with kenrik. so insulting! j/kbut you do deserve a custom title!