my comments on 248/240 s13 cam swap

Information on the naturally-aspirated KA24E and KA24DE engines.
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DjPantsSpecR
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OH YEAH, i definately wont be selling the cam gear, you can have that done at your machine shop for probably less than 30 dollars with a stock gear.

or if you do it yourself you need this: first go to the jimwolf technology page. you can go to the instructions page. Then download the instructions. you'll quickly see exactly how JWT was doing this. you'll need a protractor and these instructions. I think JWT drills 7 holes for a total of 8. for our purposes we will only be drilling one to three. (im most comfotable with drilling only one hole, however). The only hole you'll be drilling is for the 2.5 degree retard, which is enough to make the 248 cam work like a stock intake cam.

so you pretty much use a protractor and mark the degrees off on the gear. then use a punch to mark the hole. its goign to have to be exact, i dont think i need to say that. if you're off by a little you might be 3.5 degrees retarded or 2 advanced.... then use a different punch to mark the new tooth that you'll be using to line up.

ive still been to scared to get this done, but i will let you know. as far as power goes.... i think its worth 1-2 horses max.... but mostly its for a good shift in the powerband.

do you think i should make a write-up of this? i think a lot of people with KAs want to use 248s on the intake side, and this is a free solution toa 150 dollar problem. it would be quick and easy for me to do. and IMO this a lot less crazy then redrilling yout own brake-rotors.... Thanks for the inquiry spank, i think this would be a good way for me to get a good write-up out there. there is no reason someone with a drill, and punch, and a protractor should pay for this.


zero_gripS13
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hmm quesition... can u post a pic of u taking a prtractor to the am gear showing how u would measure it... im ot exactly sure how u would measure 2.5* since ur dealign with a circular object and not a line..could u prived a more detailed explanation for measuring

thanks

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DjPantsSpecR
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yeah, i justr grabbed my cam gear, and im gonna do a write-up with pictures.

you cant measure out 2.5 degrees. However, the difference between the holes and the teeth creates the ability to advance or in 2.5 degree increments. so basically im going to be using JWT's idea to re-drill 8 holes, and then mark the teeth accordingly.

i'll do this write up soon enough.

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spank044
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Thanks alot for the writeup. Hope to see some pics and writeup soon.

zero_gripS13
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yes thank you... i really didnt want to have to buy jwt gears..

but i wasnt sure how to do this method so i appreciate all your work to come

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DjPantsSpecR
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its in the works, im going to drill it for 5 degrees of advance tomorrow.

If JWT didnt want us doing this, they shouldnt have given us a free scale template. you just need to increase the scale to fit a gear....

so i'll be including this template as well, and the method/pictures to get this done.

unfortunately when you go to google now and google jwt gears and KA24DE this is liek the first entry, so no one is going to be happy losing 150 dollars.... just for you NICO

zero_gripS13
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thansk alot...

its not liike alot of people are buying jwt anyways.... not alot of serious ka buuilders.. i was until i heard u saying this...

this is a great idea...

is there any dynos of 248/248 with intake retarded 2.5*???


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DjPantsSpecR
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i believe there are but i couldnt dig ANY up.

but you dont wanna retard it any more trust me, you want 2.5 degrees of advance to get the came back to a grand total of only .8 degrees advanced over the stock position (the four teeth method leaves the cam retarded by 2.5 degrees)

i just made this thread for you and yall, and i better get a custom title of rit damnit....

zerothread?id=199829

youll see that i only drill one hole for 5 degrees advance. but you could drill the number 2 hole instead, but if youre going 248/248 i gotta recommend this
Modified by DjPantsSpecR at 4:28 PM 9/25/2006

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InsanityInc
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Seems to me that if anything, you'd want the cam to be retarded 2.5 degrees to delay intake closing and decrease overlap, unless of course it would mess up intake opening somehow.

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spank044
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Djpants, what degree do you suggest for the 248/232 combo.and the link won't work for me.

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DjPantsSpecR
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oh... well dont go to that link, just go to the 240sx and silvia forum. or its been on 240sx.org homepage liek the whole day

anyway insanity, i cover somewhere in that post that a 5.0 degree advance on a 248 cam rotated to work on the intake side, is really only a 3.3 degree advance. which is only 2.3 degrees over stock.

so before when usinga 248 on the intake side using just the four teeth method, we were shooting ourselves in the foot. there was little to no reason why we werent using a 240 cam instead. since the cam was 1.7 degree retarded before tdc it was producing more low end power. but the intake valve opens before tdc, which i dont like at all. And from everything ive read retarding the intake cam is for making low end.

and since i was getting the cam to and the past where it should have been, it seems like any low end that was lost was not noticable.

with 248/232 i would definately use both. 2.5 degrees (.8 degrees of actual advance) will get that 248 cam back to stock position, and you should make all kinds of midrange with that 232. but when its this easy, try both

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Riubens
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hey djpantsspecR,,got a quik question ,,,I did the 248/232 swap on my zenki yesterday,,with the 4 teath method.my car runs good and is a little faster but for some reason it cant hold idle after a high reving runs,and the idle is very unstable, plus its looping or loobing really bad. what you think could of been the problem??

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DjPantsSpecR
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maybe you need to reset the ECU. I hear you can jsut pull off the battery cable and then cycle the key to on several times. i usually do it 15 times.

It all depends on what you removed when you did this swap, its possible you've accidently disconnected soemthing, or you messed with your ignition.

where is your idle at? i leave mine turned at about 900. maybe you want to increase it to around there and see if that helps you. otheriwse reset your ECU first adn then let me know whats up.

this reminds me i forgot to reset my ECU when i put in my gear and swapped exhaust cams today, the car wouldnt idle at all when i fired it back up. But it goes like hell.

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Riubens
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yea I switch to an auto ecu after the swap to see if that was the problem but still it came about.I checked every thing ,vacums and all , if it jumped a tooth would that cause that problem because after afew runs,I opened the valve cover and the mark I made on the cam gear was not in the same place even after I put at TDC,or is that normal because the car pulls hard but the Idle sucks.

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Riubens
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sorry for re posting,,but my idle is about 6 to 7 houndred like I said very unstable and to keap the car on I have to turn the A/C on.

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DjPantsSpecR
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yeah, that kinda loopy idle isnt all that uncommon. i havent had an IACV for at least a year or so, so i wouldnt really know how it behaves. I didnt have these problems on my automatic S13, and ive tried ALL of the cam swaps on these pages in that car, that car has a fresh rebuild and everything was gone through.

So the cams shouldnt be causing your problem, but maybe you should crank your idle up a little bit. If you were a tooth off you would have noticed a difference immediately. When the car is a tooth off you definately dont have much power.

Also, it takes a few hundred if not a thousand something rotations to get the marks on the chain to line up with the cam marks again. so you need't worry about that. as long as your cams look like the cams in the pictures, you arent a tooth off.

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Riubens
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so do you have any idea of what could be wrong with my car?? or any pointers?

thanks,and sorry for thread jacking.

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DjPantsSpecR
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This thread got jacked before it was even created. honestly the name of the thread is like 1/17 of its content....

i would look at the vac line between your two EGR components, as that could have failed and you'd never even know about it. Thats just a good general thing to check.

turn your idle up with the screw on the back on the intake manifold, turn it to 800 and see what thats like. my car with 248/232 was idling at 1k, but now with 248/248 it loops so much it idles at 8-900. i really doubt anything happened to your car as a result of the cam swap, especially ebcause the only thing you need ot do to swap cams is 1) pull plug wires 2) pull the valve cover 3) pull the bearing caps 4) swap cams and realign gear. i cant see anywhere where it could have gone wrong.

so turn that idle up and then lemme know if you still have a serious problem. Its also a long-shot but its possible you lost an injector in the process. so check the resistance across all of the injectors with a multi-meter (12 ohms) and then re-make sure you put all the plug wires back in the right place and they are properly seated.

if something is looping really bad that means you probably have a cylinder out. its weird and its a long shot, but it happens all the time.

struckinc
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hey dj-- i did the altima 248 swap with the s14 232 for exhaust--how difficult would it be to drill the gear to make up for the .5 degree advance? half of a degree is not alot at all. would you feel safe drilling a hole that close to the old slot? btw i really like the way the altima cam and the lower exhaust brought up the midrange--huge difference

also i had a hard time with my idle also-- check to see where you dist timing is set. mine was a little off--like 15-18 deg and it would barely idle--i reset my timing and adjusted the idle to about 8-900 and it idles fine--a little loping but that sounds really nice

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DjPantsSpecR
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i re-read me and Tloof's posts and there is a lot of conflicting arguements at first. However, we eventually straighten everything out, and if what he says about altima cams is correct then:

i wouldnt do anything. You are opening the intake valve 1.5 degrees after TDC. factory KA spec is 1 degree after. With a regular 248, you are opening .7 degrees BEFORE tdc. this is a problem. You have .5 degrees of advance, which is actually helping bump your curve up. However, .5 degree probably only shifts the power curve up a few hundred rpm if that.

So leave it alone. Definately dont drill for .5 degrees. That would require a completely different template, adn youre correct there is no way you could actually get something to wrok where you could do a .5 degree adjustment.

if you were really itchin to try this free mod, i would advance what you have an additional 2.5 degrees. or even throw your 248 in the exhaust side. I have, what was it? like 3.3 degrees of actual advance? you would have 4 degrees. Its fun, give it a whirl.

and i agree with checking dizzy timing, ive been using a lot of advance, but 92 octane is WAY cheap now, thank ****ing god.

struckinc
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since i had to use the 4 tooth method also to time it right..how difficult would it be to redrill so my timing marks matched AND correct for the .5? how do you mean correct it 2.5..and where would the 248 exhaust move the power...i kind of like the 232 but have the extra cams so i might try the dual 248. depending on where it shifted the peak.... i like the setup i have now...3k to 5500 has ALOT of power. my only complaint is 5th gear doesnt feel right for highway driving--80-85 mph in 5th is only turning about 3300rpm. 5th doesnt feel like it is pulling until about 90-100mph. my dist. timing is set dead at 20. but i have to run premium because of my compression. my next step will be a bikirom to make the a/f ratio and ign timing more linear and to optimize the motor

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DjPantsSpecR
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im saying that i dont think you can. there are 19 teeth on the gear and 9 total holes drilled for the adjustable gears.

you would have to take my template, then with the number 2 hole (thats 2.5 degrees of advance) you would have to drill that hole counter clockwise by 2 degrees. i'm pretty sure you wont be able to accurately mark for 2 degrees. Thats how you would do it, but im sure the more you think about it you wont do it. you're already luck enough to have the altima cam.

with your mod-list i really think you should try 248/248 (and advance it 2.5 degrees) and then throw some dizzy advance on there if you can handle it. im jealous of your biki-future, as i think im going to be reprograming the stock ECU.

i mean you can handle it, it will only take an hour of your time, so its worth trying. you can swap back and give everyone your impressions of the differences.

struckinc
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you mean adjust the intake cam 2.5 deg? that would mean that it opens at 1 deg. btdc. that is 2 deg from stock.. how would that help?

and i was going to start ecu reprogramming but by the time i bought a eeprom burner and everything and removing the chip i think it would be easier to buy a biki and just do the same thing from my laptop with the ecu in the car...with the data monitoring it seems like the easier of the 2 to tune on the fly. money is important but ease of use is more important

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DjPantsSpecR
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oh, well sell me your stuff for dirt cheap then eh?

and no, not 2.5 degrees retarde, i'm talking 2.5 degrees advanced. so after all is said and done you'll be sitting at a total of 4 degrees after TDC. if you retarded it to 1 degree BTDC you'd be sitting at a bad spot, just like a regular 248 rotated four teeth.

i have a total of 3.3 dgrees of advance with my +5 set up. you would have 4 degrees of advance (by adding 2.5 degrees of advance). thats why i was recommending that for 248/248. definately dont retard it.

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ORL240
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broke my exhaust cam last week after oil pump lost pressure and threw in a s14 exhaust cam.now i have s13 intake and s14 exhaust...240/240 if im not mistaken, but i want to kno for sureis that right dj?

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GlacierFreeze
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S14 had 232/232. You now have 240/232.

S13 had 240/248.

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ORL240
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GlacierFreeze wrote:S14 had 232/232. You now have 240/232.

S13 had 240/248.
thanx freeze

thought s14's were 232/240, guess not havent driven it yet with em on but ill let u all kno what theyre like.this is mostly out of neccesity since all i had layin around was a spare set of s14 cams. all ready got timing set up just waitin on new oil pump 2 get'r back on da road. will post my impressions of 240/232 and compare to 240/248 which i had b4.

now some one sell me a set of s13 cams please...

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KFL
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DjPantsSpecR wrote:from the looks of it, it meaning the jim wolf technology cam install page, it looks like to install the s13 exhaust cam as an intake cam in your 98 motor, you have to rotate the single row cam gear counterclockwise EIGHT total teeth.

now, this is going off the fact that the 98 intake cam has the dowel pin at 12 oclock when the first lobe is pointed away from the exhaust cam's lobe. Double row chains have the dowel pin rotated CCW 4 teeth when the 1st lobe is in the same position. So to get it to this "stock double row" position, you need to rotate the cam gear CCW four teeth first

the JWT guide will show you have to install a double row chain cam in your single row motor, but only the intake cam. to install a double row exhaust cam on the intake side of your motor you have to rotate the timing gear an ADDITIONAL 4 teeth CCW

so from your stock position, put the cam in the correct position, you will then need to rotate the cam gear counterclockwise 8 total teeth for the dowel pin to line up in the slot of the gear. Then torque it down.

be very careful, dont get in over your head, and dont blame me if you bend valves. Take a picture of your motor at TDC, and when you put everything back together, make sure the cam lobe positions look identical, then crank it over by hand, and you should be straight.
Well I'm working on my 98 and it is basically like any other s14. Intake pin is at 9ish opposed to 12o'clock and its double row. Question the 4 teeth ccw doesn't include the tooth its sitting at does it?think not cause I installed the s13 exhaust cam into intake side 4teeth including starting mark. Figure its off 1 tooth, car ran but all lumpy,shaky distrubutor/timing was fine. Finish that up tommorow.

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DjPantsSpecR
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your 98 240sx has a double row chain?

the four tooth method doesnt include the first mark, as soon as you move it one pin over you count one, then two then three then on four you stop. i have apic posted on my write up of what it should look like. its its off by a tooth its off by a lot and you would notice at TDC

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KFL
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Here is a pic of my ka it's identical to the one shown on JWT cam install.http://home.comcast.net/~kfl007/98ka.jpg

I decide for now to just run the 240/248 setup. So, I leave the intake gear alone and just rotate the exhaust gear 4teeth ccw. The position of the lobes should be around 10 and 2. Correct?My brain is having a hard time comprehending due to head cold.


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