[Fot] Cam timing mystery

[John Styduhar]

Assuming this is a symmetrical cam profile, set your cam timing so that TDC
shows max lift for both the intake and exhaust lobes. This should be
dot-to-dot. Then use a degree wheel and a dial indicator to plot the cam
profile and check the cam grinder's specifications at .050 lift.  Advance
the cam timing 4 degrees in your final build.

On Mon, Dec 12, 2016 at 4:14 PM, Bud R via Fot <fot at autox.team.net> wrote:

> List,
>
> I have an inherited cam (came with the car) that has no markings
> whatsoever so I don’t know what brand it is exactly (although it’s close to
> an Elgin 7708-12 grind for 5500-7500 rpm road race cam @ 12:1 CR). I had it
> ground and nitrided and the cam grinder told me the duration was 256
> degrees at 0.050 inches, and the cam lift is 0.350. The lobe separation
> angle is 108.5 degrees. I’m going to use 1.55 rockers.
>
> I did not and probably cannot get a cam card from the grinder, it’s a long
> story.  So I’m trying to figure out what the cam timing should be since he
> never told me what it should be.
>
> Any one running a similar cam that could tell me at least a ballpark for
> timing this cam? I don’t have access to a Computer Doctor setup to figure
> it out, the grinder supposedly had one but either didn’t use it or didn’t
> tell me.
>
> If there’s a plus/minus range of 6 degrees retard/advance for cam timing
> from TDC can I start somewhere in the middle to see what works best? Once
> the engines done it will go on a dynamometer for break in and tuning, but
> I’d like to get it dialed in better before that. Where to start?
>
> Thanks
> Bud
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