my comments on 248/240 s13 cam swap

Information on the naturally-aspirated KA24E and KA24DE engines.
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guyaverage
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I'm one of the (apparently few) 240/232 people. I got my 232 cam off eBay for $.01 and $8 shipping. Best one penny I ever spent. I think the stigma is so against the 232 cams people rule them out as 'too restrictive' without taking into account timing, overlap, etc. so few people ever try it. 248/232 idles great and runs smooth, but 240/232 definitely has a noticeably better low end, and doesnt seem to sacrifice anything in the mid and upper range.


tloof
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OK, I went back and carefully looked at and measured all the cams I have and determined the following:

1) All of the 19 tooth driven sprockets from the '91-'97 models are double row chain types, and have the drive pin oriented directly between two of the teeth in line with a chain roller, and are the exact same sprocket whether used on an int or exh cam. 2) Just for reference, all of the 19 tooth driven sprockets from the '98-'04 models are single row chain types, and also have the drive pin oriented directly between two of the teeth in line with a chain roller. When using the cams from any '98 up engines in the earlier ones, all that has to be done on the intake side is advance the pin location forward clockwise by 75.8 deg (or 4 teeth on the sprocket) since the drive pin was relocated on them by that amount from the factory. The exh cams on the '98 up versions still have the drive pin located in the same location as the earlier models, so no timing change is required to use them in an earlier engine. 3) The centerline of the 1st cam lobe on the '91-'93 240SX (S13) 248 deg exh cam is directly in line with one of the chain rollers in between two of the teeth on the driven 19 tooth sprocket and has the drive pin oriented 75.8 deg counterclockwise from the centerline of that 1st lobe in line with a chain roller (this is exactly 4 teeth behind the cam lobe centerline).4) The centerline of the 1st cam lobe on the '95-'97 240SX (S14) 232 deg int cam is 4.75 deg advanced forward of the chain roller centerline in between two of the teeth on the driven 19 tooth sprocket and it has the drive pin oriented 4.75 deg counterclockwise from the centerline of that 1st lobe (in otherwords, the drive pin is still directly in line with a chain roller, but the cam lobe centerline is not).5) The centerline of the 1st cam lobe on the '95-'97 240SX (S14) 232 deg exh cam is 4 deg retarded behind the chain roller centerline in between two of the teeth on the driven 19 tooth sprocket and it has the drive pin oriented 71.8 deg counterclockwise from the centerline of that 1st lobe (or 75.8 deg counterclockwise from the centerline of the chain roller).

Now, if a 248 deg S13 exh cam is used as an int cam in the S14 (or even in the '91-'93 S13 with stock 248 deg exh cam), it will result in the timing being retarded 1.5 deg behind the stock 232 deg int cam (it will open at 0.5 deg before TDC and close at 67.5 deg after BDC giving 4.5 deg of overlap when used with the S14's stock 232 deg exh cam). Previously it was stated that using the 248 deg cam would result in a 1.7 deg retarded timing, but from my measurements it appears to actually be 1.5 deg...the reason for this is that EVERY cam combination Nissan uses runs a 1 deg after TDC opening for the int cam. Since a 248 deg cam has a lobe centerline located at 124 deg (the halfway point of 248 deg) and a 232 deg cam has a lobe centerline located at 116 deg, then the longer duration 248 deg cam would have to have the lobe centerline retarded 8 crankshaft deg (or 4 camshaft deg) in order for the opening point to start exactly 1 deg after TDC. Since the cam lobe centerline of the S14 232 deg int cam is actually advanced 4.75 cam deg when compared to the S13 248 deg exh cam, then when installing the 248 deg exh cam into the int position using the 4 tooth counter clockwise rotation method of the drive pin on the driven sprocket will result in the cam being retarded 4.75 deg instead of the 4 deg that is required based on the difference in duration time alone. The difference between the two values is 0.75 deg (4.75 - 4), which results in a total of 1.5 deg of retarded timing at the crankshaft. Generally it isn't a good idea to open the intake valve before TDC on these motors, so using the 248 deg exh cam for an int cam may not give any advantage over the use of a stock 240 deg S13 intake cam. Now, using the S14 232 deg exh cam in place of the S13's 248 deg exh cam does seem to help the low to mid range dramatically since it opens 16 deg later (while still closing at the same exact time) thus allowing a longer burn time and still giving the optimum 3 deg overlap period when used with a 240 deg int cam. The 248 deg cam produces a longer overlap period of 4.5 deg (which is of no help when the int cam opens before TDC...if anything that would cause flow reversal potentially hurting performance) and also destroys the longer burn time potentially resulting in reduced torque overall. This is probably why Nissan seems to favor using shorter duration cams on the exh side in all of the later engines.

Someone previously asked whether it might be better to use an S14 232 deg int cam as an exh cam, and in my opinion the answer is NO. The 232 deg int cam has the lobe centerline advanced forward 4.75 deg vs the 4 deg retarded lobe centerline of the 232 exh cam. Installing the 232 int cam on the exh side using the 4 tooth rotation method will result in a cam timing that is advanced 8.75 deg (4 + 4.75) which in turn will cause a 17.5 deg advanced crankshaft timing such that the cam will open at 65.5 deg before BDC and close at 13.5 deg before TDC giving NO valve overlap at all(since the int cam won't open until 1 deg after TDC). This will destroy the performance of this engine and won't make for a good combination at all. If the 232 deg int cam were to be repinned to match the 232 deg exh cam, then it would work just fine!

The other mentioned combo was 248/248 + 5 deg. That would effectively advance the int timing such that it will open at 4.5 deg after TDC (isn't that defeating the purpose of early cyl filling) and close at 72.5 deg after BDC. Since a stock 248 deg exh cam closes at 4 deg after TDC, then this combination will give NO overlap either, and it closes way to late to be effective (in fact it will probably result in dropping the cyl pressure a bit...maybe that might help you guys trying to run 11.6:1 comp race engines on the street by using SOHC pistons in these DOHC engines! Ha) so I don't see how this could possibly be worth doing!!

From all of the above, my best choice for a cam combo in the KA24DE is the 240 int cam with 232 deg exh cam!!

Just my 2 cents!

tloof
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I didn't cover one other cam combo that a few of you might be considering, and that is the 240/240 combo (S13 240 deg int cam used as an exh cam).

The centerline of the 1st cam lobe on the '91-'94 240SX (S13) 240 deg int cam is 2.75 deg advanced forward of the chain roller centerline in between two of the teeth on the driven 19 tooth sprocket and it has the drive pin oriented 2.75 deg counterclockwise from the centerline of that 1st lobe (in otherwords, the drive pin is still directly in line with a chain roller, but the cam lobe centerline is not).

Now, assuming a 240 deg S13 int cam is used on the exh side (in conjunction with a stock S13 240 deg int cam on the int side), then the 240 deg int cam has the lobe centerline advanced 2.75 deg forward of the drive pin location on the cam which is 2 deg retarded in relation to the lobe centerline of a 232 deg S14 int cam (remember, both intake cams will close at 1 deg after TDC during operation, thus the 2 deg difference). Ideally all of the exhaust cams should close at 4 deg after TDC (both the 248 deg S13 exh cam & the 232 deg S14 exh cam do so), so that would imply that a 240 deg cam used on the exh side should also do the same, thus the centerline of the cam lobe itself would need to be advanced 2 deg on the 240 deg cam in relation to a 232 deg exh cam. Installing the 240 int cam on the exh side using the 4 tooth rotation method will result in a cam timing that is advanced 4.75 deg (2 + 2.75) which in turn will cause a 9.5 deg advanced crankshaft timing such that the cam will now open at 57.5 deg before BDC and close at 2.5 deg after TDC giving only 1.5 deg of valve overlap (since the int cam won't open until 1 deg after TDC). This is probably no better overall than what you get when using the 248/232 combo that is recommended by many others on this site, but at least it does have an int cam that opens 1 deg after TDC (the stock 240 deg int cam), so it might be slightly better on the high end than the 248/232 combo (I bet they are both virtually the same in that regard), but it is doubtful that it will produce as much torque in the low to mid range as the 248/232 combo.

Still, my best choice for a cam combo in the KA24DE is the 240 deg S13 int cam (the same int cam is used in the '93-'97 Altima) with a 232 deg S14 exh cam!! This combo should have the best of both worlds (good high end power combined with good low to mid range torque). As a side note, this is the exact same combo that is used from the factory on the '97 Altima (and the '96 Ca version Altima).

Just my 2 cents!!

zero_gripS13
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what about the 248/248 with the 3 teeth method isntead of 4.. ive been hearing about it more and more can u use your mighty cam profile figuring out stuff for this swap and let us know what going on when u use this setup/./

thanks

tloof
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Yeah that's easy,

If you only use a three tooth counterclockwise rotation method during installation of a 248 deg exh cam for use as an intake cam, then it will be advanced 18.95 cam degs or 37.9 crankshaft degs in the duration cycle in relation to its installation using the four tooth method. What that means is that the intake valve would then open 37.4 deg after TDC and close at 105.4 deg after BDC (which is only 74.6 deg away from TDC during the compression stroke). Using that method will absolutely DESTROY the performance of this engine (and it probably won't idle or run worth a s*** if you know what I mean) since it won't even begin to start getting any intake charge until the piston has already travelled 36.4 deg PAST where Nissan normally opens the intake valve on EVERY cam combo it uses!!! Also there is my previously pointed out issue of when it closes which will severely drop the cylinder pressure during the compression stroke because of the fact that the intake valve is left open so long as the piston is trying to compress the incoming charge (this will actually cause reverse flow and push a good deal of the intake charge the engine has finally gotten after the late opening back into the intake manifold).

Suffice it to say that using a three tooth rotation method ifor installation of the 248 deg exh cam in place of the int cam is NOT a good way to go!!!! Don't do it...


zero_gripS13
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thanks alot... so why do u thin people are saying that the 3 tooth method creats so much more power except after 5500>???


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DjPantsSpecR
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i dont think anyone ever said that.

anyone who has actually accidentally installed a 248 with a three tooth method will agree that it idles like ***, and doesnt have nearly as much power as it should

the three teeth method, which ive never actually heard of, because i dont believe it exists, is just one step closer to bending your valves.... this can only be considered a mistake, and you would notice something very very wrong after you fired up there car. perhaps you just misread?

struckinc
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how would an altima exhaust cam as intake cam work? it is the same 248 specs except it opens at 60 deg before bdc and closes at 8 deg before tdc so an overall 4 deg sooner than s13. how would that affect the difference in timing with a stock exhaust cam?

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DjPantsSpecR
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i'll add to my first post later just for reference of people who will only be reading that post, but here goes...

240/232 this swap is initially the "wtf, i want my 248 back" swap. the car actually idled when it was cold without shaking the **** out of everything. But like i said the first impression isnt a good one.

the car is warm but not up to temp yet and already it feels better in the low end. the power from 1k to 3k has got to be better with this swap, but the top end just doesnt feel right

up to temp, the low end still feels the same if not a little better. There is a certain hesitation with 248/232. with 248/232 you floor it at 2k and there is a jolt of power and then a slight hesitation until 3k where it builds into more power and by 5k you start feeling more and more all the way to 7k.

therein lies the contrast with 240/232. the power is great from 1k all the way to 3k (i only say in compareson with 248/232) then its greater until about 5k. this is where it sharply contrasts with 248/232. 248/232 even sounds louder and pulls noticably harder at this range all the way to redline. i was very disapointed with 240/232...

but the car is faster. i havent done any proving or anything but the gain in low end is enough to outweigh the loss in top end. shifting from 2 to 3 give more consistent chirps thanks to a fully stripped car and an xtd stage 3 clutch.

the only proof i have is a certain turn i take at the limit, and then accelerate to the first right turn, where you must brake in a sufficient amount of time. i do this often and always when i ahve changed something to see the result. 240/232 was faster than 248/232 at the same turn an hour earlier

tloof
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Struckinc,

That's a good question about what difference the Altima 248 deg exh cam would make if used as an int cam in the 240SX.

First of all I should point out that only the '93-'95 Altima and the '94 240SX has the 248 deg exh cam that opens at 60 deg before BDC & closes at 8 deg after aTDC. The '96 Altima (non Ca version) changed to the use of the same 248 deg exh cam specs as was used on the '91-'93 240SX (that being opening at 64 deg before BDC & closing at 4 deg after TDC). The '97 & up Altima's (and the '96 Ca Altima version) did away with the 248 deg exh cams using a variation of different durations (see my "KA24DE Cam Specifications" post).

Now, since the centerline of the 248 deg lobe on the '93-'95 Altima & '94 240SX is retarded 2 deg (which results in 4 deg at the crank) in relation to the '91-'94 240SX 248 deg cam, then the valve timing of this cam will be shifted 4 deg later regarless of whether it is used as an int cam or an exh cam. I previously determined that if the normal '91-'93 240SX 248 deg cam were to be used for an int cam using the 4 tooth rotation method that it would open at 0.5 deg before TDC and close at 67.5 deg after BDC. However, using the '93-'95 Altima 248 deg exh cam will net an opening at 1.5 deg after TDC and a closing of 69.5 deg after BDC which has a 2.5 deg overlap when used in conjunction with a 232 deg exh cam. This cam is only 0.5 deg away from the ideal specs that Nissan normally uses for opening any of the int cams on this engine, so this may be the most ideal 248 deg cam to use for an int cam swap. If an adjustable drive sprocket were to be used on this cam it would be easy to adjust back 0.5 deg to match the same 1 deg after TDC timing that the stock cams use!


tloof
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DjPantsSpecR,

I want to know more about the true performance of the 240/232 vs the 248/232 since the 240/232 is what I installed in the KA24DE that I'm swapping into my 720 pickup (in place of the KA24E I already have in it).

Did you use the proper S14 232 deg exh cam with the S13 240 deg int cam, or did you try to use a 232 int cam as an exh cam? When you tried the 248 deg exh cam as an int was it from an '91-'93 S13 or the '93-'95 Altima? (which by the way has the same specs as the '94 S13). I assume you used a S13 248 exh cam for the int and a S14 232 exh cam for the exh in your 248/232 combo, and if so you might want to consider trying the '93-'95 Altima 248 deg exh cam for use as an int cam as I detailed in my post just before this one (it moves the int cam timing forward 2 deg in relation to the S13 248 exh cam). It might be a good setup!

I was hoping that the 240/232 combo would be the best combination for my truck where I wanted a bit more low to mid range power over the 248/232 combo, but I am surprised that it doesn't idle as well from what you indicate. Granted you are saying that it pulls better from 1K to 5K RPM and thus is slightly quicker in acceleration, but is the 5K to 7K pull that much better on the 248/232 combo in comparison with the 240/232 combo? Also, what about a straight 232/232 combo comparison in the 1K to 5K range with the 240/232 combo? Perhaps the 232/232 combo would be the best in a truck anyway if it has superior low to mid range over any other cam combo?

Let me know...

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DjPantsSpecR
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i drove this ****er for two and a half hours today... i am using an 240 intake and a 232 exh. i gave away one of my 232 intakes in exchange for a 240 intake...

this altima swap i still dont know entirely about.... ive read some thigns that say you can do it because the altima cam runs the dist and blah blah blah, but ive also read other posts of people claiming to have done it. Ive read more posts on these boards calling the altima cam in a 240 KA a myth...

I dont know if its true or not, but im not going to mess with that, im more than liekly going to get my gears drilled at a machine shop, if i decide not to do it on my press

i think you may have misread, or i miswrote, but earlier i said that 240/232 idles better when the motor is cold than 248/232. however, after 2 and a half hours with about a hour being rush hour, it started to shake like a mofo. This car has a purposefully plugged IACV and PAIR. so this is reasonable. idle quality is great with both swaps, but may be better with 240/232

i think for your truck you still want to use 240/232, as you probably wont be ringing it out to 7k several times a day every day. I havent decided if im going back to 248/232 yet. i actually wanna try 232 (int)/ 248. it sounds jsut plain stupid, but then again so was 248/240 and 240/240, so why not try everything

the problem with any tests is that they are done on the butt dyno. The car appears to pull harder in the top end for 248/232, however, they could actualyl haven identical horsepower numbers and one could have more torque gain which would make the car feel as if it fell off.

an example is to pull off the connector to your coolant temp sensor. the motor is a dog everywhere until it hits 5500 rpm. then it takes off and you assume youve got butt loads of top end. youre wrong though, it still has 10 hp less than stock at this peak. it seems like it has more power becasue it losses up to 30whp down lower....

maybe 248/232 really doesnt have more top end, maybe it does. we are only dealing with horspower gains with a max of 4 whp, so i would try everything adn choose whatever. some dyno time would be nice, but chirping third gear on an otherwise stock car is fine for me....

i urge you to try 232/232, and i hope to eventually too. i also wanna retry 240/248. However i think you will be most satisfied with 240/232.

its so hard to compare these swaps but i still think that my order of favorites goes 248/232 > 240/232 > 248/248 > 240/240 and then all the other crap...

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guyaverage
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Dj, my 240/232 idles absolutely smooth as silk hot or cold. I will say when the throttle body and/or IACV gets the least bit dirty, that story changes in a big hurry. They both seem to build up a lot of carbon, and quick. Every 3-4 months they both need to come off and thoroughly cleaned with a rag, toothbrush, and a can of gumout. Makes a huge difference.

I seem to remember 248/232 idled good too, and if I remember right 248/232 idled about 100 rpm higher and I had to adjust it down (from where it was with 240/248) when I first installed it.

tloof
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DJ,

Thanks for that info, I think I will stick with the 240/232 combo like you suggest for my initial installation, and then later try the 232/232 combo as a comparison in my truck. I take it from what you are saying that your idle quality is bad because you have no functional IACV, whereas Guyaverage does have a functional IACV and thus has a decent idle, correct? I too have deactivated the PAIRC system, and also the EGR system, but that actually helps out to avoid carboning up the intake internals including the IACV.

As for the Altima cams, all those myth claims are a bunch of bull**** concerning whether they will fit in a 240SX or not!!! I have an example of each and every cam that has been made for the DE engine (be it 240SX, Altima, or Frontier), and I have measured them all to see if they match the Factory service manual specs. I can tell you for CERTAIN that the Altima cams will fit in ANY DE head (240SX or Frontier), and that includes the exh cam. All you have to do to get the Altima exh cam to work is to cut off the 5/16" slotted end so that it will clear the rubber seal at the back of the valve cover (in reality it would probably would still work OK even if you didn't cut the slotted end off since it just barely touches the rubber seal, and would likely just wear in some clearance to it). The '93-'95 Altima and the '94 240SX has the 248 deg exh cam that is retarded the extra 4 deg compared to the '91-'93 S13 exh cam, so that cam is the better choice to use as an int cam when installing via the 4 tooth rotation method because it results in a cam timing that is only 0.5 degree retarded in comparison to a stock int cam. Just food for thought!

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guyaverage
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Tloof, just as an FYI my EGR vacuum tube is disconnected and capped, and my PAIRC is connected but sealed off from the intake with a clamped metal slug plugging the hose.

I think you'll like the 240/232.

tloof
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Hey DJ,

Another cam combo you might want to consider trying is the use of the 224 deg int/ 240 deg exh cam combo that comes in the '00-'01 Altima's. Nissan upped the power rating from 150 hp to 155 hp in those models using that cam combo. They went just the opposite of the long duration int with shorter duration exhaust like you have been experimenting with in the 248/232 & 240/232 combos, and they also increased the overlap from the normal 3 deg that they had been previously using to 6 deg on that combo. Apparently it upped the torque in the mid range while still increasing the overall power rating up to 155 hp (I guess they did that since the Altima was getting so much heavier than the previous models, and almost all of them used an automatic tranny). Maybe we have it all wrong with the combinations we have been trying?

As a side note, Nissan also changed from the 232/216 cam combo they had previously used on the '98-'00 Frontier to a 224/224 combo in the '01-'04 Frontier's. Once again that change must have been made for a torque gain over the earlier model that had more duration on the int than the exhaust and less overlap! (no doubt for the heavier trucks in those later year models?).


Bigvinnie
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I think I'll just go with these bad boys and some adjustable sprockets!!!!These are meant for DOHC trucks but they are affordable compared to jim wolf with more duration ( TRUE 275).http://www.4x4parts.com/public...228aa

tloof
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If they truely are 275 deg duration cams then they will absolutely KILL the low to mid range torque that the stock cam combos discussed above provide. They might be advertising total duration at zero beginning & ending lift vs the normal accepted duration at .05" lift like most cams, and are thus actually less in duration. Normally a 275 deg cam set will be a top end race only cam, which isn't worth a damn in a NA relatively stock KA24DE. Even the Nissan Motorsports 248/248 cam set is only any good above 6500 RPM at the expense of the low to mid range power that the lesser duration cam combos give. Regardless, all of these cam combos are only good for a difference of between 4-6 hp or so, thus the stronger low to mid range cams seem to work much better for street use!!

Bigvinnie
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Agreed but I feel it is more to the effect of where the overlap is set, not necessarilly the duration of the cam it self. That is to also say that no one on these boards to date have even properly set the exhaust 248 on to INT. There is no real significant proof, Data, or dyno results. Again this is more about overlap than it is the duration of the cam(s) itself, there are many combinations that can still be made.Besides I'm not to concerned with what ever torque variables are supposedly lost using these cams, the KA is a born stroker that makes torque with it's massive stroke anyways. I care more about Idle and it's throttle responce above 3000RPM, I would rather see some accelerated growth and HP than Torque to tell you the truth.The innevetable speaks for itself though if you use moderate cams you only get moderate margins in power. Yes they are fun to toy with as far as moving power around in the power band, but the fact still remains that none of these cams significantly increase horse power. The engine is only as aspirated to the lobe that it is given, creating the proper overlap seems to be the majority of the problem.I've looked at cams for years and can say from my personal knowledge cam lobes aren't the problem with the KA, the bottom end of the engine is.If you want to decipher engines with similar characteristics we can use the CA engine which in comparison uses pretty close to the same Rod/Stroke ratio, same bucket head design, and the same style loby cams.The CA itself has far surpassed 280 duration cams, and the bottom end is significanly built to resist harmonic distubances. If the bottom end is disturbed and deals with any ill type of viabration it actually causes a loss in power, or preventing power from moving upward in the power band.When I install the 275 duration cams I already had in mind to make corrections to the bottom assembly to accept high rev a bit better than stock.
Modified by Bigvinnie at 9:22 AM 5/2/2006

Silvia_Freak
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Okay lets see how im going to put this...Im alittle confused at this whole cam thing...A friend of mine said for free hp its a good swap.I will list what I want to know....Thanks in advance..

I would like to know what exact models the cams come in and what the numbers are...

I have a 1992 nissan 240sx with the twin cam motor. It is my daily driver. I will be buying a header for it soon and asp pulleys but I do have an intake an exhaust. I hear from you guys a 248/248 is bad so I dont want that...What I do want to go with is what will give me low rpm power where it counts on daily drivers and just little more up top...So should I go with 240/240 and where do I get these cams or should I go with the 248/232 cam? I do drift my car and do rodeo drifts and when I do that Im usually close to hitting redline... So what do you guys recommend? And how to single cam pistons benifit? Do I buy used ones? or new ones?With that do I have to bore out my block?

Im also building a turbo motor so what cam swap should be good for this?

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DjPantsSpecR
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alright, ill handle this as im pretty sure im the fool who started this thread. and actually ive been swapping cams alot and even today. i'll tell you my exact impressions as of now.

i'm going to be trying 248/248 again soon. this is only because im going to redrill a cam gear similar to the discontinued JWT gears. i also have changed alot on this car since some of my earlier cam impressions and this car has become much more of a top end breather. my high end power producers include 3in SSAC n1 dual, soon to be a DC sports header, cams and gears obviously, and most importantly a homemade intake manifold and intake ram. the manifold plenum is tuned for peak torque at 6K, while the runners are tuned for peak torque at 7k. the intake ram is tuned for around 4-5k. the only thing im missing is an ecu to keep me from going so lean below 4500.

so now that i made you read all that, thats honestly the only reason i would even try 248/248 again. its probably not for you.

i can tell you, and im sure Ajax can support my claims, but the new intake manifold ive made hauls ***. this is using a 248/232 setup. i am and always have been a firm believer in 248/232 ever since i had 248/248 originally.

248 is from 91-most 94s and it is an exhaust cam. this needs to be rotated 4 teeth counterclockwise to get it to work on the intake side232 refers to both s14 cams from 95-97. in this situation i am refering to the exhaust cam. so the setup has an s13 exhaust cam on the intake side and an s14 exhaust cam on the exhaust side.

i have installed a 248/232 setup using an s14 intake cam rotated four teeth clockwise to work on the exhasut side. i didnt drive the car, so i cant give you my impressions, but it shouldnt be too different, although logic would say it wouldnt be quite as strong. however logic isnt always truth.

dont do 240/240 its lamer than 248/232(intake)

i use 240/232 in my automatic car. i just swapped to this today actually because i didnt like 248/232 in it. i love 248/232 in my modifed 240 (like yours) but i dont like it in my near stock automatic. 240/232 is right up my alley for this car. it gives much more low end and midrange. however this is power usually only seen at part-throttle. its great for daily-drivability, but not for WOT performance. its not necessarily bad in the high RPMS, and it might even be better, but 248/232 builds in such a way that at least makes it seem faster if it isnt...

also, i alot of turbo guys were using 248/232 before i even heard about it. its a great swap for turbos because its stock lift, with great low and midrange until full boost.

single cam pistons will raise compression significantly to between 11.2-11.7. i know there are a lot of problems with actually getting the earlier pistons to work which yield the higher CR, so get the pistons from a 90.

you wont turbo your car with 11.2:1 compression

you could buy new ones and get them in a 1mm overbore if you wanted to bore out your block, or if its out of round. this will raise your displacement to like 2458ccs or something of the like, which isnt all that significant but it helps and will lower the compression a little.

just try 248/232. you only need to buy one s14 exhaust cam which will only cost you from free-25 bucks. then youc an try 240/232 when youre a pro at swapping cams. and keep saving up for turbo parts, even though you bought that header. leave this N/A stuff to the big boys... just kidding

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Ajax
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I concur, DJ's new setup hauls. And thank goodness he finally has some tires with grip to put the power down.I'm not a big fan of the lopey idle he's got, as I've had too many cars with bad idle problems (240 included), and I was always thinking it was going to bog and die. Once the engine hit 3.5-4 grand, though, it just sang.Stripped 240 with mild work kept up pretty well with heavy 350Zs with exhausts and big wheels.Now If only I could get my car running right...

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InsanityInc
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Needs more dyno with the intake manifold. I'm happy to see that someone is likely going to finally prove the "KAs can't make top-end power" thing wrong.

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Ajax
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DJ and I are going to try to do an article this winter on the manifold thing. I'll be getting the Xcessive unit for my car, and we'll do some guinea pig dyno testing. I'll borrow a camera so we can take lots o' pictures.I'm hoping to do this in February or so- fingers crossed.

*Sorry, that's kind of a tangent. Please resume your regularly scheduled camshaft discussion*
Modified by Ajax at 5:19 PM 8/30/2006

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DjPantsSpecR
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Holy top end Batman!

it's true. i ripped it apart from this weekend and i re-glued the flange on to the runners. there is still some unwanted movement during WOT, but i know why its happening, and this is jsut an experiemental manifold.

i can honestly say, however, that my manifold will make more top end and throttle responce than the xcessive unit. it alos has a whole hell of a lot mroe problems, but it will ultimately make more power, because i sized my plenum accordingly. the xcessive unit is designed for forced induction, because its volume is about the same or slightly larger than the KAs displacement of 2.4 liters.

N/A manifold volume should be about 60% of the motors displacement to make peak torque at around 7k. you decrease this volume to raise peak torque rpm, or raise the volume to decrease peak torque rpm.

i wish someone had told me that before i designed my FSAE style manifold at 3.6 liters. this thing was a dog everywhere. it was total poop. but in FSAE we need to breath through a 20mm restrictor, so you want all the volume you can get inside that plenum. when your motor revs to 12 grand and its only 600ccs the large plenum actually builds pressure due to the harmonic waves in the runners. its slight, but it is an advantage. however, its no go for our cars. my current manifold design is about 67% of 2.4 liters.

i actually noticed adn started researching that my manifold was crap when i saw a skunk2 b16a2 manifold. the plenum was so tiny, but i knew skunk2 knew what they were doing, so obviously i didnt. stupid hondas....

anywho, i do love, love, love this thing. i cant believe how long people have driven KAs hard without these. the throttle response is actually BETTER than the stock unit, and it feels like there is more torque at around 3k. after that though, its a done *** deal, and i remember me and Ajax doing a 3rd gear pull up a ramp catching an sti spitting black smoke. keeping up with 350z's with two people in the car? i almost **** myself.

its gonna happen insanity, it really is. lets put this ***** to rest.

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InsanityInc
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Too bad my 240 was so cursed. Maybe someday I'll get another one.

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DjPantsSpecR
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i feel bad for anyone who reads all the way through this thread looking for sweet cam info now.... 2 damn pages long?

and with the extra research tloof has provided, and what ive heard about the actual durations of the cams....

this thread is still about the seat of the pants feel of these cam swaps. i cant tell you which one makes the cars faster but i can give you my honest impressions. so in light of this info i will do everyone a favor, and modify my original post to include all the info i wanted ot originally.

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Vkoslak
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Since this thread has been reserected, I thought I would update that my engine rebuild is almost done using 90 SOHC pistons with a 92 head and block. New bearings all around. The cams are being installed next. I will be using a 98 exhaust cam (232) on the exhaust side, and a 92 exhaust cam (248) on the intake side. 93 octane from now on. lol

I will have some extras though: a 98 intake cam (232), and a set of cams from a 91.

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InsanityInc
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Vkoslak wrote:Since this thread has been reserected, I thought I would update that my engine rebuild is almost done using 90 SOHC pistons with a 92 head and block. New bearings all around. The cams are being installed next. I will be using a 98 exhaust cam (232) on the exhaust side, and a 92 exhaust cam (248) on the intake side. 93 octane from now on. lol

I will have some extras though: a 98 intake cam (232), and a set of cams from a 91.
While your dynamic compression will probably be a bit higher at certain RPMs, I seriously doubt it's enough to warrant 93 octane.

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Vkoslak
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even with 11.1:1 compression ratio?


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