Cam shaft ?? with 756 on the gear end

[dave t]

The card states IN:28_72 LIFT .350 CLEARANCE .012 .... EX:62_22 LIFT .330 CLEARANCE .014 any idea what I have? I will assume it is on 108 L.C. just wondering about the duration I will take the lift as .350 at the cam so 1.1 arms = .385 Cam is stamped 756 on the end.

[Steve Arndt]

Any stampings on the drive end of the cam?

[Marc]

Anything on the card which implies that the cam is designed for higher-ratio rockers or hydraulic lifters? .350/.330" sounds pretty tame.

[dave t]

I will have to check the end of the cam. I was thinking the same thing about Hydro, but the cam card states. Make sure to use chilled iron lifters. check spring pressure and clearance. Paint shaft with WHITE LEAD when installing. I was on this site . http://www.actionimport.com/Tech_Files/ ... mation.htm . and found the Hydro specs but also a ratio rocker But??? Who knows. Thanks Dave T

[woodsbuggy1]

DRD sells cams that use Chilled Iron lifters, might check with him.
Kenric

[dave t]

Thanks, this is probably a 20+ year old grind. So the specs are a mystery. The end does have a stamp of 756

[Marc]

DRD sells cams that use Chilled Iron lifters, might check with him.
Kenric

Weber had some dual-profile grinds that were in this ballpark too, perhaps Web-Cam has something in their archives...

[Dougy Dee]

Using your posted advertised duration numbers puts intake duration at 280. Exhaust at 264. Pretty mild.

[dave t]

Hey Dougy Dee Thank you and how did you figure that out. Mild is o.k. Strange if this is a Hydro cam that they would have a dual lobe pattern?? If this turns out to be a Hydro cam could it be used without using hydro lifters? I tried calling Web-Cam on 1-30-15 and the phone said could not complete as dialed. So I did not find out if they had an "archive" of old cam specs. The cam grinder is ... Cleveland Hone & MFG. Co. with a lift of .350 int and stock 1.1 arms the valve lift isn't to bad at .385 . But the specs sure do look like the Weber Cam

Cams for use with hydraulic lifters (lift at cam)
529-521H 274º 0.350" 8.89 Dual lobe street cam
...............268º 0.330" 8.38

[Marc]

Intake opens as the piston is approaching TDC, and closes well after it reaches BDC. In the case of this cam (using the specified checking clearance) the numbers are 28° BTDC and 72°ABDC. Add those, plus another 180 for the trip from TDC to BDC and you get 28+72+180=280.
Exhaust opens before the piston gets to BDC, and closes after TDC...62+180+22=264.

These would be the "advertised" duration numbers, which often vary between manufacturers (due to the fact that they can change the number by fiddling with the "checking" clearance). In the USA, the "effective" duration is generally accepted to be the number achieved when using .050" clearance, so it'll be much less - but at least when you use the effective number you stand a halfway-decent chance of comparing cams from different grinders.

Hydraulic lobe profiles, as a rule, won't have the gentle "take-up" ramps that "solid" cams have to cushion the lash, so running them with solid lifters is risky as regards valvetrain life expectancy. Hydro grinds typically open quickly to make up for some of the "bleed-down" that's normal with hydro lifters, and some close more slowly to reduce valvetrain noise. I wouldn't expect any of these considerations to be a huge problem on such a mild cam (especially if you stick with stock-ratio rockers), but it's still worth thinking about - and why you shouldn't use this cam with solids until you've determined for certain that it is NOT a hydraulic grind.

http://www.hotrodders.com/forum/solid-l ... 92466.html