Been trying to get as much info as possibly on my probable B20/VTEC set up, and I came across this information from Hybrid Garage. http://hybrid2.honda-perf.org/....html It basically said that the intake valve reliefs on BOTH the B20B and B20Z are not sufficient for a VTEC head. If this is the case, what is done to resolve it? Im guessing a thicker head gasket but Im going to be boosting and I dont want the gasket to become a week point. I dont see how this is valid though since I was currently using CTR pistons and they have way bigger domes than the B20 pistons. Maybe I am misunderstanding something here.

 

LS (b18a/b, B20b/z) valves are smaller then Vtec valve, in turn you have problems with valve to pistons contact (more with B20z then b20b).

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2 &raquo;</TD></TR><TR><TD CLASS="quote">what is done to resolve it?</TD></TR></TABLE>

IF you want to reuse the B20 pistons (it is better if you just upgrade because you are going to boost the motor anyway), take them to a machine shop and the can shave the valve reliefs bigger to run your vtec head.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2 &raquo;</TD></TR><TR><TD CLASS="quote">I dont see how this is valid though since I was currently using CTR pistons and they have way bigger domes than the B20 pistons. </TD></TR></TABLE>

They are Vtec pistons, so they have bigger (diameter) then non-vtec pistons. It is not the dome (in this case) that is the problem, it is the actually size of the valve relief.

 

gotcha

I was hoping to run the stock B20 bottom end for now as a temporary fix to my blown 1.8 bottom end until fall so I can tear it down and begin the buildup. Thanks for the info

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2 &raquo;</TD></TR><TR><TD CLASS="quote">gotcha

I was hoping to run the stock B20 bottom end for now as a temporary fix to my blown 1.8 bottom end until fall so I can tear it down and begin the buildup. Thanks for the info </TD></TR></TABLE>

IF that is the case, run a B20b. It has lower compression, in turn, more piston to valve clearance. B20 sleeves (they are just bored out B18b blocks) are not the best for boost, what set-up you going to run?

 

B20B or Z, doesnt matter since its gonna be fully built. stock 84mm, fully sleeved by either AEBS or Benson, forged internals, the whole deal. That is the winter project anyway. But for now I was hoping to run the stock B20 with my ITR head until the Fall. Guess thats not gonna happen since the reliefs wont work with my head without some kind of modification or different pistons. I dont want to go through all that.

 

You can run that block, you just have to mindful of the cam lift, milling the head, head gasket thickness, intake cam advance:

https://honda-tech.com/zerothread?id=737766