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How-to: VTEC Cams on NON-VTEC Head

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197K views 231 replies 106 participants last post by  LotusElise  
#1 · (Edited by Moderator)
Here is the how I got the K20a2 cams to work on the K20a3 head. You need the K20a2 cams (or type-r, tsx, crower...), K20a2 rockers and pins, and k20a2 rocker shafts. The pins in this picture are how they come in the A2 head
Image

You have to switch the pins in the left and middle rocker like this picture
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This locks the left and middle rocker together so that the middle rocker will not bounce around due to the cylinder head not having the lost motion spring.
Image


Image


Image

This makes the left valve always ride on the vtec lobe and the right valve rides on the non-vtec lobe. When vtec is engaged by the solenoid it locks all three rockers together the same way the factory does and you have a regular working vtec.

Edit by Signalpuke:
More info on Rockers here http://k20a.org/forum/showthread.php?t=88770
 
R
#15 ·
Re: How to get A2 cams to work in an A3 Head

riptrsxs said:
very cool!!! now i can put my k24A1 heads to good use... i'll try and do the same technique on a K24A1 head and I'll append to this thread as I'm sure a lot of people would be wondering about that too.
Click to expand...
Rock on brother... Ill wait patiently.. :rolleyes:
 
#17 ·
Re: How to get A2 cams to work in an A3 Head

Hey Riptrsxs keep me posted cause I have a k24a1 in my ep3 now. If it works I'll be right behind you. I already have k100 so I'm half way there.


Just curious about this set up and forced induction. What do you guys think cause I plan on going turbo before the year is out.
 
#22 ·
Re: How to get A2 cams to work in an A3 Head

RSX_import_Ricer said:
I still wish someone would let me know what I should buy those rockers/rocker pins and shit for used...
Click to expand...
You wouldnt wanna buy these new!!! These are approx $200 a set and there are 8 of them.

So based on Jeremy's genius, I tried the same technique on a K24A1 head to see if it applies to the K24A1 head as well. So here you go....

K24A1 head
Image


K24A1 Vs K20A2 Exhaust rocker shafts
***Notice that the K24A1 exhaust rocker shaft is a bit longer than the K20A2
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K20A2 rocker arms installed!
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PROBLEM:
The 1st set of exhaust rocker arms (closest to the sprocket) are very tight and had very little play. It did not allow for full motion of the rocker arms.
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POSSIBLE SOLUTION:
Mill the cam shaft holder on the number 2 cap to allow for motion.
Image


I initially installed the rocker arms using both K20A2 rocker shafts but when I discovered the issue with clearance, I swapped out the k20A2 shaft for the K24A1 thinking that the length difference might have a factor but the issue was still there so, I'm gonna shave the shaft holder slightly to allow for movement.
 
#23 ·
Re: How to get A2 cams to work in an A3 Head

Would this be the same problem with the k24a4 head? I'm going to do this, Btw i purchased k20a2 cams for 100.00 and whole rocker assembly w/ shafts and cam caps/holders for 175.00. So if it works it'll be sweet and cheap.
 
R
#25 ·
Re: How to get A2 cams to work in an A3 Head

dc2gsr95 said:
Would this be the same problem with the k24a4 head? I'm going to do this, Btw i purchased k20a2 cams for 100.00 and whole rocker assembly w/ shafts and cam caps/holders for 175.00. So if it works it'll be sweet and cheap.
Click to expand...
PM me if you still have more hooks ups on that shit... lol
 
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