B_Something

I have read and searched. If you can't help me please don't reply, just let the post pass by and forget about it.

Anyways, I was curious to those that have experience with CRVTEC's; is there a piston that can be installed in the B20 short block so that the valve reliefs do not have to be modified?

I have a 94' Sir-II top end, and am contemplating on getting a local B20Z. This will be mated with the trans that came off the same Sir-II. This will be my first complete tear down and rebuild type swap. I really just want to make it easy as possible.

Thanks for any possible help.

JDMotive

Aftermarket pistons are your only option.

africanqueen

I think Arias pistons make some for the B20. I am going to have to get some too very soon.

B_Something

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by africanqueen &raquo;</TD></TR><TR><TD CLASS="quote">I think Arias pistons make some for the B20. I am going to have to get some too very soon. </TD></TR></TABLE>

So do you have valve clearance issues? From all that I have read the OEM B20 valve reliefs on the pistons are not large enough for the valves from a VTEC to clear during engine operation. I just thought maybe the powers that be would have given us rookies a quick answer.

How do you like the CRVTEC?

africanqueen

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

So do you have valve clearance issues? From all that I have read the OEM B20 valve reliefs on the pistons are not large enough for the valves from a VTEC to clear during engine operation. I just thought maybe the powers that be would have given us rookies a quick answer.

How do you like the CRVTEC?</TD></TR></TABLE>

I think the clearance is fine. No problems whatso-ever. I use my car as a daily driver and I love it. If the swap is done correctly and you notch the pistons, everything will run smoothe. I would recommend this swap to everyone.

B_Something

Yeah I have had various swaps, not that on yet. I think I would like a little shot of torque! Did you perform the swap or have it done? What ecu are you runnng?

Veris

The B20B/Z intake valves are 31mm.
Vtec valves are 33mm.

So the the vtec vales will not clear the valve pockets in the stock pistons.
On mild cams this isn't an issue. Cams with greater lift cause a problem.

FYI If you deck the block or mill the head the problem is further exaggerated.

JDMotive

Just modify the valve reliefs and youll be fine.Its alot easier and cheaper than buying a new set of pistons.

B_Something

Any writeups on that?

Veris

It involves taking a dremel to the valve seats and opening them up a couple mm. I've never seen a how to article done on it.

If you do it you want to keep the valve openings symetrical and smooth as possible. Note this work will slightly reduce compression as you are decreasing the volume of the piston.

Personally I wouldn't do this mod, but if you are running high lift cams and stock B20Z pistons you'll need to.

B_Something

Yeah I'm not real interested in grinding away at my pistons. That's why I am looking for a proven drop-in replacement.

importimage

Arias and JE make B20B/Z Pistons for sure. I know this because I have them in my car and they work like a charm!

africanqueen

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B_Something &raquo;</TD></TR><TR><TD CLASS="quote">Yeah I have had various swaps, not that on yet. I think I would like a little shot of torque! Did you perform the swap or have it done? What ecu are you runnng?</TD></TR></TABLE>

Rage Performance did the swap. I thank them for doing a swell job on my car. Everything runs Perfect. As for the ECU, I am running the JDM GSR.

92eg-pa

importbuilders make pistons for the b20 vtec check out there site importbuilders.com

irev210

hey whats up man, I just wanted to pass along my dyno of my old b20vtec setup



b20z bottom, I opened up the valve releifs (though you DONT need to with ITR cams and stock cam timing)
B16 head
ITR cams(stock valvetrain)
ITR intake manafold
ITR throttle body
untuned stock OBD1 b16 ECU
adj FPR to add the needed fuel

Was a lot of fun to drive, still runs great today even though I sold the motor to a friend.

Not a bad daily driver

let me know what other questions you have

give me a call on monday, ill walk you through all your b20vtec questions

B_Something

Cool, thanks again.

JDMorgan

topline p30's?

irev210

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KraZEtEggIE &raquo;</TD></TR><TR><TD CLASS="quote">topline p30's?</TD></TR></TABLE>

84mm bore yo

jlsmi2

bump.

B_Something

What are topline P30's?

Propulsion

If you are changing the pistons, you don't need the b20z, b20b's are cheaper.

JDMorgan

sorry bout that. i thought camp 1320 had a batch made but i went back and looked and i guess every1 flaked out or something. find 99 more people and u can have a set made.
https://honda-tech.com/zerothread?id=631970

irev210

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KraZEtEggIE &raquo;</TD></TR><TR><TD CLASS="quote">sorry bout that. i thought camp 1320 had a batch made but i went back and looked and i guess every1 flaked out or something. find 99 more people and u can have a set made.
https://honda-tech.com/zerothread?id=631970</TD></TR></TABLE>

yah you need a lot more people