Post by
tloof »
https://forums.nicoclub.com/tloof-u11109.html
Wed Apr 12, 2006 3:16 pm
I thought I would clear up a lot of confusion on several of the Nissan websites concerning which KADE models have what cam specs in them, and which cams can be retrofitted into any KA24DE (be it a 240SX, Altima, or Frontier truck variant). Also, this will dispel all the myths about whether the Altima cams can be used in S13 or S14 240SX engines. All of the specs I list below come directly from the Nissan factory service manuals for each of the years, and I have an actual example in hand of most of them that I carefully measured to verify that the specifications are correct.
Let me say here & now that ANY Altima cam (both intake & exhaust) will fit into any of the other KA24DE variants, but in order to get the exhaust cam to fit in them 5/16” has to be cut off of the slotted distributor drive end in order to clear the rear valve cover seal…that is all that is required, end of story!
Also, another issue to point out is that ALL of the ’98 & up KA24DE’s changed to the use of a single driven chain sprocket from the previous double chain sprocket that was used on the ’91-’97 models (also the ’98 up intake cams had the dowel pin relocated to match the same 12 o’clock position as the exhaust cam has). Along with this change the rear most #6 cam bearing was also eliminated out of the head casting (I guess after 7 years Nissan finally decided it wasn’t necessary…that or they got cheaper on the whole design to save costs!!!). Even so, any of the early ’91-’97 cams will still fit into & work in the later ’98 up S14 & Frontier KA24DE’s (and they will also work for the intake cam in any ’98 up Altima KA24DE). On the flip side any of the later ’98 up cams will also fit into & work in the earlier ’91-’97 S13 & S14 KA24DE’s (and once again they will also work for the intake cam in any ’93-‘97 Altima KA24DE). For use as an exhaust cam in an Altima, the correct version Altima exhaust cam HAS to be used (this means a ’93-’97 Altima exhaust cam is required for a ’93-’97 Altima KA24DE, and a ’98 up Altima exhaust cam is required for a ’98 up Altima KA24DE) because the distributor drive bearing diameters are different between the two versions. MAJOR NOTE: if an earlier ’91-’97 cam is used in any ’98 up engine, then the rear oil plug in the cam will have to be punched in deeper past the oil feed hole that feeds the rear most #6 cam bearing in order to avoid spraying oil around in the valve cover area!!! (this is not necessary if a later ’98 up cam is used in the earlier ’91-’97 engines…but then why would anyone want to do that since the later cams have reduced duration specs & thus lower performance!).
Now for all the cam specifications:1) ’91-’93 240SX (S13) - Note: '94 exh specs are slightly different intake cam = 240 deg duration with a 1.6699”-1.6774” lobe height (intake opens 1 deg after TDC & closes 61 deg after BDC) exhaust cam = 248 deg duration with a 1.6699”-1.6931” lobe height (exhaust opens 64 deg before BDC & closes 4 deg after TDC)2) '94 240SX (S13) intake cam = 240 deg duration with a 1.6699”-1.6774” lobe height (intake opens 1 deg after TDC & closes 61 deg after BDC) exhaust cam = 248 deg duration with a 1.6699”-1.6931” lobe height (exhaust opens 60 deg before BDC & closes 8 deg after TDC)3) ’95-’98 240SX (S14) intake cam = 232 deg duration with a 1.6699”-1.6774” lobe height (intake opens 1 deg after TDC & closes 53 deg after BDC) exhaust cam = 232 deg duration with a 1.6699”-1.6774” lobe height (exhaust opens 48 deg before BDC & closes 4 deg after TDC)4) ’93-’95 Altima intake cam = 240 deg duration with a 1.6699”-1.6774” lobe height (intake opens 1 deg after TDC & closes 61 deg after BDC) exhaust cam = 248 deg duration with a 1.6699”-1.6931” lobe height (exhaust opens 60 deg before BDC & closes 8 deg after TDC)5) ’96 Altima intake cam = 240 deg duration with a 1.6699”-1.6774” lobe height (intake opens 1 deg after TDC & closes 61 deg after BDC) exhaust cam = 248 deg duration with a 1.6856”-1.6931” lobe height (exhaust opens 64 deg before BDC & closes 4 deg after TDC) (Note: Ca exh cam has 232 deg duration with a 1.6699”-1.6774” lobe height) (Note: Ca exhaust opens 48 deg before BDC & closes 4 deg after TDC)6) ’97 Altima intake cam = 240 deg duration with a 1.6699”-1.6774” lobe height (intake opens 1 deg after TDC & closes 61 deg after BDC) exhaust cam = 232 deg duration with a 1.6699”-1.6774” lobe height (exhaust opens 48 deg before BDC & closes 4 deg after TDC)7) ’98–’99 Altima intake cam = 232 deg duration with a 1.6734”-1.6809” lobe height (intake opens 1 deg after TDC & closes 53 deg after BDC) exhaust cam = 216 deg duration with a 1.6104”-1.6179” lobe height (exhaust opens 32 deg before BDC & closes 4 deg after TDC)8) ’00-’01 Altima intake cam = 224 deg duration with a 1.6551”-1.6626” lobe height (intake opens 1 deg after TDC & closes 45 deg after BDC) exhaust cam = 240 deg duration with a 1.6551”-1.6626” lobe height (exhaust opens 53 deg before BDC & closes 7 deg after TDC)9) ’98-’00 Frontier intake cam = 232 deg duration with a 1.673”-1.681” lobe height (intake opens 1 deg after TDC & closes 53 deg after BDC) exhaust cam = 216 deg duration with a 1.610”-1.618” lobe height (exhaust opens 32 deg before BDC & closes 4 deg after TDC)10) ’01-’04 Frontier intake cam = 224 deg duration with a 1.644”-1.651” lobe height (intake opens 1 deg after TDC & closes 45 deg after BDC) exhaust cam = 224 deg duration with a 1.646”-1.654” lobe height (exhaust opens 37 deg before BDC & closes 7 deg after TDC)
What’s interesting about all of the above cam specs is that both the S13 & S14 240SX’s are rated as having the same 155 hp output even though the cam specs are vastly different. Not only that, but all of the ’93-’99 Altima’s are rated as having a 150 hp output, whereas the ’00-’01 Altima’s were changed to claim a 155 hp output (the same as the 240SX). Once again that seems a bit strange considering that all of the cam specs are so different between the different Altima models. On top of all that, all of the Frontier versions are listed as a 143 hp output despite the difference in cam specs in the ’00 back models & the ’01 up models. What gives here? Perhaps Nissan is bull****ting us as to the actual power ratings, or can ECM programming account for all of these differences? Granted the comp ratio of both the Altima’s & Frontiers is 9.2:1 vs the 9.5:1 that the 240SX’s have, but that would only amount to about a 1.5 hp difference between them at the most. Also the intake manifold & runner diameter is smaller on the Frontier vs the Altima & 240SX, which could amount to up to about a 4.5 hp difference (this value is based on the fact that the better flowing SOHC KA24E manifold that was used on the Stanza only increased its power rating 4 hp over the smaller runner truck intake despite the 8.6:1 comp ratio & cam being identical). Thus if a Frontier engine were to have the 240SX intake manifold & 9.5:1 pistons retrofitted into it, you would probably experience an overall increase of about 6 hp or so bringing up the power rating to only 149 hp. This would imply that all the different cams are really only good for about a 5-6 hp difference between them all.
Just as an interesting comparison, ALL of the SOHC KA24E engines have the following specs:
10) ’89-’90 240SX, ’90-’97 Hardbody truck, & ’90-‘92 Stanza intake cam = 240 deg duration with a 1.7653”-1.7728” lobe height (intake opens 3 deg before TDC & closes 57 deg after BDC) exhaust cam = 248 deg duration with a 1.7653”-1.7728” lobe height (exhaust opens 56 deg before BDC & closes 12 deg after TDC)
The above specs for the SOHC KA24DE are close to being the same as the ’91-’94 240SX DOHC KA24DE engine, yet it only makes 140 hp vs the 155 hp that the DOHC version makes. But all is NOT the same here…it really isn’t a true apples to apples comparison since the SOHC 3 valve KA24E engine has smaller intake valve diameters that have only 86.8% of the open area that the DOHC motor has and only a single exhaust valve that has only 82.1% of the open area that the DOHC motor has. Basically if the hp were to be considered as a linear function in relation to the airflow (which is dependant on the valve area), then for all practical purposes you could expect a decrease in power of around 15% between the SOHC & DOHC engines when both have the same comp ratio & cam timing due to the valve diameters alone. This would suggest that the 155 hp would drop to somewhere close to 131 hp or so. In reality it should really be compared to the 150 hp ’93-’95 Altima engine since it has a 9.2:1 comp ratio vs the 9.1 that the early SOHC 240SX had, and both have similar cam timing. As we can see that only amounts to a 10 hp difference which is only about a 7% difference. This would imply that the SOHC KA24E engine would easily match the DOHC KA24DE engine in power if the intake valves were simply increased in size to match the DOHC intake valve sizes (36.6mm vs 34.1mm), and if the single exhaust valve were to be increased in size from 40.1mm to 44.2mm (this is about a 1.74” dia valve vs the stock SOHC’s 1.58” exhaust valve) to match the same valve area as the DOHC’s two exhaust valves. An interesting observation (courtesy of Adam Hutchison on the Fresh Alloy website) is that the stock SOHC intake flows 208 cfm vs 240 cfm for the DOHC engine (that is about a 14% difference...virtually the same as the valve open area difference). The stock SOHC exhaust flows 145 cfm vs 196 cfm for the DOHC engine (that is about a 26% difference...which is worse than would be expected in relation to the actual valve open area difference, so the exhaust port would probably require a little porting work as well to match the DOHC’s exhaust side). Adam also reported that with porting work on the SOHC head and still using the stock valve sizes that the intake flow increased to 240 cfm (the exact same as a stock DOHC intake port), and the exhaust increased to 181 cfm (which is only down about 7.5% to the stock DOHC exhaust port). My bet is that if the SOHC’s valve sizes were increased as I previously mentioned and some slight port work were to be done that the SOHC KA24E would more than be a match for the DOHC KA24DE even with its stock cam (never mind if the Nissan Motorsports R4 cam were to be installed, as that would push it way beyond the DOHC KA24DE!!!!
Sorry for the long read, but hey hopefully there is a lot of useful info here!!!!!!!!
Modified by tloof at 3:31 PM 4/18/2006
Modified by tloof at 3:39 PM 4/18/2006
Modified by tloof at 10:11 AM 5/1/2006