Camshaft Specs. & Rocker Arm Ratio

[Doward]

Hey guys, wondering what the stock cam specs (carb and EFI) are. SAE duration/duration @ .050" and lift, please.

Looks like @ 1mm lift (.039" - close to .050, but not quite) - (for the KC - which is mine)
205º/215º ? I didn't fint anything about lift in there - and what ratio are the rocker arms?

wtf... looks like the automatics have a camshaft that is 5º more duration than the stick shifts.... that's almost always the other way around, with domestics!!
Also looks like the EFI camshaft is a *HAIR* higher lift... same duration, though.

What's the rocker arm ratio, in our motors?

FYI - Melling HSC-11 from Autozone ($106)
218º/225º @ .050" lift, and .267"/.262" lift AT THE CAM. MULTIPLY BY ROCKER RATIO TO DETERMINE ACTUAL VALVE LIFT.
So what's the rocker arm ratio?

That's fine... I'd really like to know the rocker arm ratio, though

Rocker Arm Ratio, anyone?

[A20A1]

I don't think anyone knows that, you'll have to remove the cam and make measurements. Or possibly make all the measurements with the cam on the head since the followers/rockers might change the values.

[smufguy]

the only specs i have are on my site http://www.accordproject.com/cylinderhead.htm just the runout lobe height.

[Strugglebucket]

try looking at page 2-5 of this document: http://www.pauldesign.ru/honda/shopmanual/62se310.pdf

sorry, don't know how to post pdf stuff as a pic

[A20A1]

Not sure, I merged your threads though, since the info is closely related to the same subject.

[A20A1]

I measured from the wear marking on the cam follower

• The Valve Adjustment Scew:
  - Radius = 3.450cm
  .
• The Cam Follower Inner Wear Mark:
  - Radius = 2.700cm
  .
• The Cam Follower Outer Wear Mark:
  - Radius = 3.650cm
  .
• The Cam Follower Wear Center:
  - Radius = 3.175cm

Am I doing this right?

Cam Lobe 1.05 : 1 Valve Screw (Outer Edge)
Cam Lobe 1.00 : 1 Valve Screw
Cam Lobe 0.92 : 1 Valve Screw (Center)
Cam Lobe 0.78 : 1 Valve Screw (Inner Edge)

It does fluctuate, but at some point it's 1:1, Oh and I guess it's backwards... you wanted the cam lobe to be "1" and the valve screw ratio so you could times it by the cam value. I think this is it the other way around

• 0.940 : 1
• 1.080 : 1
• 1.270 : 1
  .
• 1.096 : 1 Average
  __________
  __________
• 0.940 : 1
• 1.000 : 1
• 1.080 : 1
• 1.270 : 1
  .
• 1.075 : 1 Average
  __________
  __________
• 0.940 : 1
• 1.000 : 1
• 1.080 : 1
• 1.096 : 1
• 1.270 : 1
  .
• 1.077 : 1 Average
  ====================================
  ====================================
• 0.940 : 1
  ___0.250980"/0.246280" Lift
  _________________________________________
• 1.000 : 1
  ___0.267000"/0.262000" Lift
  _________________________________________
• 1.075 : 1
  ___0.287025"/0.281650" Lift
  _________________________________________
• 1.077 : 1
  ___0.287559"/0.282174" Lift
  _________________________________________
• 1.080 : 1
  ___0.288360"/0.282960" Lift
  _________________________________________
• 1.096 : 1
  ___0.292632"/0.287152" Lift
  _________________________________________
• 1.270 : 1
  ___0.339090"/0.332740" Lift
  _________________________________________

I still think I'm missing something.
.
.
.

[A20A1]

Only near the top of the lobe would the lobe be able to contact the outer or inner edge of the cam follower. Most of the time it's touching near the center of the follower. Which may be 1:1. So really I don't think you'll see the 1.27:1 ratio at the apex of the lobe, but rather as the lobe receeds, it's losing lift on the lobe but the ratio is closer to 1.27 making up for the decrease in lift... keeping the valve open more untill it finally drops off and closes.

Do you think the change in the ratio causes the valve to open and close at different rates? I think it does.
.
.
.

[Doward]

I think the easiest way to measure it, is going to be to take a measurement of the valve off the cam lobe, and one on top of the cam lobe - then divide by the actual cam lobe measurement.

I'll find out, as soon as I find a spare motor

[A20A1]

Anyone get any further with this... trying to turn the camshaft with everything installed is crazy... I may have to weld a pipe to a spare cam gear and then turn the gear... I don't trust my socket set, that or reinstall the head... but I prefer to have the head off of the motor.

[Oldblueaccord]

well I do the math way

if your lift at the cam is .200 and the final is whatever .400 the ratio would be 2 to 1 .


wp

[truetune]

umm, you need to rotate the cam using the crank just like you would for setting the timing with everything on it, it you want to measure it that way but the math way makes more sence due to the face that our old motors varry due to diffrent wear tollerances.

[A20A1]

The head is not installed... I'm doing this to an old head.

[stevenr816]

does anyone know the lift specs for the bs motor? cause i want to know how much bigger the lift is on the gude cam.
thanks,
steven

[smufguy]

I think its like 10 mm, not sure




http://www.accordproject.com/cylinderhead.htm

[A20A1]

hmm, it may be less. I think you need to measure the seat on the head side and the seat on the valve. or tear the distance that the valve protrudes from the surface of the combustion chamber then you can open the valve and measure to the base of the valve.

[stevenr816]

this doesnt really help me.............i want to see how much more lift the gude performance cam has compared to stock. so 10mm, what would that be in .---? the gude has in- .434 ex- .434 and a duration of 252 so, i just need the lift.

[A20A1]

Try this thread...
https://www.3geez.com/forum/showthread.php?t=45663


10 milimeters = 0.3937 inches

thats not out cylinder head though, our cam doesn't push down on the rocker arm directly, we have the follower.

[smufguy]

Try this thread...
[url]thats not out cylinder head though, our cam doesn't push down on the rocker arm directly, we have the follower.[/IMG]

It was for a B20A i suppose, i just got it off of Paul's website.

Best thing to do is just measure the lift on the cam itself.