Ls/vtec Ctr Pistons +juniii Cams

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no2psi

Senior Member
:unsure:
I have this combo in my garage. Ls/vtec with CTR pistons and JUN stage 3 cams. Has anyone out there run this combo? Did you have any clearance problems. I allready have the motor built and have concerns about valve piston contact. I dont have a honda vtec engagement tool to check clearance either.
Thanks
 
Well, when i built the motor it had stock cams. No clearance issues. But I got a sweet deal on Jun III's so I put them in there. Even if I had clay checked the motor it would'nt help without engaging vtec, to check the big lobes. So now I am wondering if anyone has done this, to know whether or not it works, without having to dissassemble.
 
I can't tell you if it will work, but the way I clayed my engine without the tool is I measured clearances on the small lobe. Then I measured the difference in height between the highest point on the big lobe and the highest point on the small lobe and I made wure I had at least that clearance.
 
if you have a helms it explains how to engage the vtec. all you really need is compressed air, put it into the service port and plug the hole with your finger (it kinda hurts, but tough it out :p)
 
Thanks, I will give it a try. I will post numbers when I get to a dyno. Or pictures if I blow it up. Knock on wood.
By the way " LS/VTEC" I saw your pictures...nice. What was the valve piston clearance? looks pretty f#$kin close.
 
I had to do it my way because I do not own a compressor. :(

I have all kinds of clearance in there, which is what I expected with ITR cams. I don't remember what the numbers came out to, I have it written down somewhere. If I find it I'll post the actual numbers.
 
you dont need a compressor for compressed air, you can buy the bottles of compressed air :)
 
Ok, I clay checked the motor. And it is crazy close. Adding the stock head gasket I get clearance of .030" I did the clay check and added 3mm for the vtec lobe and took into consideration of a .029" head gasket. Man this sucks.
Anyways if anyone ever asks if you can use CTR pistons in a Ls/vtec tell them to make sure that the block they are using and the head they are using dont have to be resurfaced. Now I have to cut more valve relief or use a bigger head gasket.
 
I've got CTR and JUNIII cams in my B16A even had 3 thos off the head, cams gear IN +2, ex-1. no clearance problem.
 
I'm using TODA valve springs i used to have Toda A, but everyone say you must run JUN springs otherwise the cams would snap, but i've seen people using JUN springs still snap the cams, I doubt is the quality of the cams not the matter of springs .
The head been milled 3thous approx =0.45mm.
 
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