Valve lift measurements

[ncdogdoc]

What are the stock valve lift numbers (mm's or inches) for both cam profiles. I have dug around in my service manual and the site and can find lobe measurements, and valve sizes, but not the actual amount they open into the cylinder head.

I need both intake and exhaust. Thanks.

p.s. If anyone has the numbers on the Comptech cams, that would be great too!

 

[Eddy]

Honda 5 speed camshafts
(source: HyperRev NSX)
intake
10.2mm valve lift (middle lobe)
exhaust
9mm valve lift (middle lobe)

Comptech camshafts
(source: Speed World Challenge GT NSX approved spec)
intake
12.446mm valve lift (middle lobe)
exhaust
11.938mm valve life (middle lobe)

Eddy

 

[NA1 #2853]

Another Addition To Eddy's Comment

(Speed World Challenge Approved Spec Sheet)

Rocker Arm Ratio = 1.55

Maybe that, combined with Eddy's Specs will help you determine the actual protrusion of the valves into the combustion chamber.

-Ray

 

[Eddy]

Actually.. the numbers I posted are the actual valve lift numbers.. if you are looking for the cam lobe height.. then you need to use the 1.55 ratio to find the lobe height.. you can also use that along with the service manual numbers to find the base circle of the cam lobes.

Eddy

 

[NA1 #2853]

next time i should crack my manual open before i open my mouth...

LOL!

Thank for the clarification

-Ray

 

[ncdogdoc]

Thanks guys. I never thought to look in HyperRev.

The WC figure may not be correct, as RealTime info is what led the the destruction of a FI engine last month, when an intake valve kissed the piston.

 

[NA1 #2853]

Well the best was is to mock assemble, lock the VTEC on, clay, then rotate the engine over.

I do it on every cam install i do on a B-series motor.

Granted that it much more of a pain in the arse on the NSX motor.

Its surpising how many cams i have installed that with stock pistons, and head and block that have not been milled, the clearances are less than the minimum acceptable amounts. Especially on the exahust valves.

i usually like 80 thou on the exhaust, and 50 thou on the intake, minimum.

I would be scared to sell these things to kids, who would just to a 20 minute "swap-em-out" install. The first time they would go into vtec, they would get a brrrrrrrr-BOOM, instaead of the pleasant brrrrrrr-BAHHHHHHHHHH sound.

Oh geez, take in to account Cam Gears, that can really mess things up if you are boarder line with the clearances.

-Ray