How does old school Honda CVCC work?

Mr. M · **Posted:** Wed Jun 03, 2009 8:40 pm

Hello everyone in JNC land!

I have read that Honda patented the CVCC technology when it origionally came out. I know it was used to increase the mpg of Honda Civics back in the day. I recently read an article in Grassroots motorsports where a Hondaphile had made a special CVCC style cam for his early '90s racer. The CVCC cam is supposed to create a better swirl of the air-fuel mixture by varying the opening and closing of the intake valves.

Does anyone know a good website that explains CVCC or could explain it on this forum? Could a CVCC style cam be designed to improve the performance of any engine if you understood how and why it works?

colhogen · **Posted:** Thu Jun 04, 2009 2:55 pm

More can be found here. http://www.1stgencivic.org/

*BTW, I deleted your poll because it had nothing to do with this thread, kinda confusing.

john · **Posted:** Thu Jun 04, 2009 4:35 pm

Mr. M wrote:

Could a CVCC style cam be designed to improve the performance of any engine if you understood how and why it works?

Sounds like the answer is no.

Never seen it explained before, that's kinda kooky. I'm also the kind of guy that thinks "if it was really that awesome, Honda wouldn't have given up on it"... :tu:

Stationwagonguy · **Posted:** Thu Jun 04, 2009 5:30 pm

Yeah, it was based around an extra small combustion chamber, kind of like a diesel.

From what I had heard, there were issues of these small combustion chambers coming loose with time and just falling into the cylinder. But I have no idea. I have seen articles about people who had them on the road still and were quite fond of them as well. :shrug:

kev · **Posted:** Thu Jun 04, 2009 5:35 pm

I think the gun racing mod for these 1st gen engines was the JDM-spec RS head, which didn't have CVCC and had bigger ports.

jacbo · **Posted:** Thu Jun 04, 2009 5:36 pm

Sounds kinda like the "MCA jet" deal mitsubishi did in the eighties. The G54b in my challenger has a MCA jet head with the third valve and I really don't think it makes much of a difference, especially on an older car line mine with a million little unhooked/ blocked off/ leaking vacuum lines and emissions mijigers. :lol:

bajasoobnut · **Posted:** Thu Jun 04, 2009 10:38 pm

datsunfreak wrote:

I'm also the kind of guy that thinks "if it was really that awesome, Honda wouldn't have given up on it"... :tu:

Main reason why they did is due to the NOx emissions are through the roof with that setup due to running so lean

GT-R380 · **Posted:** Fri Jun 05, 2009 1:19 am

This reminded me of a brief article I have somewhere around here, about Honda building a set of heads for a small block chev ~350 I think. If it's in the publication (Japanese, english print) I think it was 1973 some time. It was a one of for a show (SEMA?) I'll see if I can find it. Anyone else heard of this?

How does old school Honda CVCC work?

Who is online