CA77 Cam Lift Specification?

[GeorgeP1111]

I'm starting to disassemble my CA77 (CA77E-1023944) for a "Refresh". After I pulled the head I removed the rocker arms and decided to measure the Cam Lift with my Dial Indicator before disassembling further to replace noisy bearings.

I get:
Left Intake - 0.224 Right Intake - 0.222
Left Exhaust - 0.222 Right Exhaust - 0.223

I have the Bill Silvers CD, and in the DreamRestore2010.pdf specs it says the Cam Lift Intake is 5.69mm (.222) and the Exhaust is 4.56mm (.178). His ShopManualHonda250-305(1973).pdf shows the spec for the CB77 (it has the specs for the CA72 but not the 77) as Intake is .118 and Exhaust is .179.

My Intake is Ok with my first spec source, but my Exhaust does not match either of my spec sources. I did read all I could find in his books on the cams and I did do a "Cam" search here, but I can't find anything that might explain why I have a different Exhaust reading than his Dream Restore spec calls for.

Did I miss something?

tnx
George

[jensen]

Hi,

What about the right cam, same measurements ?
Spec from the C72 and C77 (CA72 / CA77) are the same.
Because your intake measurement is within spec, I assume you measured the right way.

I can check the spec according to my manual and measure a NOS cam but that would be in the afternoon.

Maybe the exhaust cam is worn, how does it look like ?

Jensen

[GeorgeP1111]

What about the right cam, same measurements ?
- I listed both the Right & Left cams above, but Yes the measurements are the same (or close enough). -

Spec from the C72 and C77 (CA72 / CA77) are the same.
- Yup.... I got that -

Because your intake measurement is within spec, I assume you measured the right way.
- I put the Dial Indicator on the head with pointy part down on top of the cam, zeroed when it was at it's minimum, rotated cam to max lift and recorded readings, rechecked numerous times. -

Maybe the exhaust cam is worn, how does it look like ?
- All 4 cam (Intake & Exhaust) lobes look alike. If the Exhaust cam was worn wouldn't it have less left? Both of mine have 0.222 & 0.223 lift (5.63mm & 5.66mm) and the two specs I listed say it should be 0.178 (4.52mm) or 0.179 (4.54mm)

So I guess it comes down to both Exhaust specification listings I have from Bill's cd are wrong, or I have some very strange cams. Quite a difference between my 0.222 Exhaust lift and the 0.178 spec.

Thanks for your help.

George

[GeorgeP1111]

I should add that I did not see a Cam Lift specification in the C72 section (there is no C77 section) of the ShopManualHonda250-305.pdf as there is in the CB72/77 section.

Also, I did grab my digital micrometer and measured the total max diameter of the cams. I don't know if this is the same as the "Cam (Bearing Part) Height" specification in the ShopManualHonda250-305.pdf CB72/77 section but I measured:
Left Intake - 1.246
Right Intake - 1.246
Left Exhaust - 1.247
Right Exhaust - 1.244
My Intake measurement matches the spec's numbers, but just as with my Lift measurement the Exhaust measurement is too much. Again, it appears that all cams are the same.

My measurements could be a hair off, but they are probably within the tolerances of the inexpensive measuring devices I'm using.

George

[jensen]

Hi,

CB72 :

cam lift in : 5.69 (0.118)
cam lift ex : 4.56 (0.179)

For the C72 only the cam height is given, and that is 26.98 - 27.02 (1.062 - 1.063)

Jensen

[GeorgeP1111]

Hi,
CB72 :
cam lift in : 5.69 (0.118)
cam lift ex : 4.56 (0.179)
For the C72 only the cam height is given, and that is 26.98 - 27.02 (1.062 - 1.063)
Jensen

Yup, that is the same numbers I found for the C72. So the mystery continues on the measurements I took on my CA77.... all cam lobes the same: Height = 1.246 Lift = 0.223

Still Hav'in Fun tho !! :-)

tnx
George

[G-Man]

Jensen

The CB72 numbers are clearly a typo. 5.69mm is not 0.118inch, actually 0.224.

G