Developing your own cam specs for the KA24de!

[BigVinnie]

I thought I would make a thread to up some rep points for myself since I have been a jack ass lately. Mostly due to my own lame temper (I'll get over it).
So now I am kicking down info on how to make better cam specs for the KA than JWT or PDM racing.
First off this will take the use of your original cams for regrinds.
Secondly this will need the actual cams from a CA18DE, CA16DE, or a KA20DE found only in few markets from Japan and the U.K.
How do we know these cam specs will work?????
First off ignition timing amongst these engines werent to far off from each other.
Secondly they all ran on the EXACT same bucket style hydraulic assembly's, using the same shimming for correct valve lift.
Third they are all derived from the nissan parts bin which has been around since the 1960's.( Nissan/Datsun really hasn't changed there parts inventory until the creation of the SR). All these engines used the same geometry known as the 4 cylinder stroker principle. Where the rod/stroke ratio were all pretty consistent to it's stroke. If you do not know what R:S ratio is then SEARCH..
So to find out if the lift and duration specs are compatible from one of these engines to the other we need the R:S ratio's. Which I happen to collect for data for the last couple of years.

CA16DE 1.75:1 rod/stroke ratio
CA18E/CA18de 1.59:1 rod/stroke ratio
Z24/KA24e/KA24de 1.71:1 rod/stroke ratio
L16 1.80:1 rod/stroke ratio
L18/z18ET 1.62:1 rod/stroke ratio
L20b/Z20e/Z20s/KA20de 1.76:9 rod/stroke ratio
Z22e/Z22s 1.59:1 rod/stroke ratio
FJ20E/FJ20ET 1.75:1 rod/stroke ratio
FJ24 1.59:1 rod/stroke ratio


Technically the engine with the larger ratio will have the better duration. Not always true do to rules with smog emissions on USDM's, but in the case of using CA16de cams on the CA18de this lies true.
http://www.nissansilvia.com/forums/i...0&#entry319569
Second question in the ask Sarah Column.
http://www.nissanperformancemag.com/april04/ask_sarah/

Technically if you think about it, if there were more specs available for the CA16 the KA would have many more options to chose from today being that there rod stroke ratio wasn't to different from each other. Butthat still doesn;'t mean you can't use specs from the CA18de or DET (Hint for you KADET guy's)
As an example: the KA's 242 intake duration VS. the CA16's 248 intake duration which also included a slightly larger lift for using smaller valves for it's engine. Kind of makes you think of swapping the KA's exhaust cam over of 248 duration on to the intake, doesn't it? All relative sence, all to the same spec comparisons.
So I had to think about this for awhile.... Why haven't shops caught onto specs from these similar engines? Tomei, Greddy, and HKS all make specs for the CA18de. Already R&D'd specs for a fraction of the cost of JWT or even PDM. I mean in all reality if a shop owned the cam with the specs they could relatively charge regrinds for atleast under $110, and then they would be true 270 duration cams or larger unlike JWT which actually fall's short.
To sum up this post you can use cam specs from any of these engines, it's just up to people how they chose to use this information to there advantage to building a better KA.

Also all SOHC engines that are listed in the R:S ratio that I listed can as well use the advantages of using other specs from one engine or the other( as long as that engine was a SOHC using either lifter or a rocker arm assembly).

All I wanted to do with this post is diversify cams and pricing to prove that the KA market isn't just singled out to using expensive PDM or JWT cams. I think after this post alot of shops will catch on (well maybe). Maybe some all ready have......