tangent off another post I made...Unknown cam in my slant. Put it in a year ago and lost the cam card, so I chucked up a dial indicator and a timing wheel and got some numbers. Trouble is that these numbers dont jive with anything Ive seen for a slant. Using a wheel that has zones for intake and exhaust timing events, I was within 3 of the 4 zones and just a little out of the 4th. My cam events look like this (all numbers taken from TDC compression stroke) both Cam lobes had a .289 lift off a pushrod, as best as I could get them. That gives me a theoretical .433 valve lift at 1.5:1. Intake and exhaust events looked like this off the wheel from TDC:
Exhaust starts to open (.001) @ 98 and closes at 65. On the wheel this reads exhaust open 82 BBDC, and closes 65 ATDC.
Intake looks like it starts to open (.001) @315 and closes at 282. On the wheel it says opens at 45 BTDC and closes at 102 ADBC.
Plugging this into the calculator ( http://www.wallaceracing.com/camcalc.php) I get :

Intake Duration is 327.00 degrees.
Exhaust Duration is 327.00 degrees.
Installed Intake Centerline is 118.50 degrees ATDC.
Installed Exhaust Centerline is 98.50 degrees BTDC.
LSA is 108.5 degrees
Overlap is 110.00 degrees.

Is this a legit cam or am I messing up somewhere? IIRC it was a Comp 264 solid but cant remember. 327 duration seems off the chart for a street cam.

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I didn' t buy it, I built it.....

important factors - you have to measure lift at the lifter (not the rocker or valve). Most cam timing specs are at 0.050" lift (or 0.040"). so measuring at 0.001" lift will give you numbers that don't match up with anything. If you try to measure at the valve nothing will make sense.

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The .050" is at the tappet.........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

For a solid, try .015 and .020

For a hydraulic, .006

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

A .435 lift at 1.5 would be a comp cam 252.... they are typically a 110 LSA though... the only other cam with a lift close to that would be the Mopar Performance "RV" style of cam, or the OCG 818 at .431

Comp 264 has a .440 lift...

well, I did it again and used .050 and got something more believable: Intake Duration is 220.00 degrees.
Exhaust Duration is 219.00 degrees.
Installed Intake Centerline is 118.00 degrees ATDC.
Installed Exhaust Centerline is 101.50 degrees BTDC.
LSA is 109.8 degrees
Overlap is 0.00 degrees.

but that seems pretty tame for an aftermarket cam...I dont know what to measure at, .001 (huge), .050 (tame) or.xxx?

At .015 int and .020 exh (??) its:
Intake Duration is 260.00 degrees.
Exhaust Duration is 248.00 degrees.
Installed Intake Centerline is 118.00 degrees ATDC.
Installed Exhaust Centerline is 102.00 degrees BTDC.
LSA is 110.0 degrees
Overlap is 34.00 degrees.

That looks more like it but what is it, a 248 or a 260? not as easy at they make it look, but once you do it 7 times, its starting to make some sense if they only kept the measurements the same across cam makers.

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I didn' t buy it, I built it.....

on COMP site for the 252 cam they say measure at .006, that gets me:
Intake Duration is 288.00 degrees.
Exhaust Duration is 290.00 degrees.
Installed Intake Centerline is 119.00 degrees ATDC.
Installed Exhaust Centerline is 100.00 degrees BTDC.
LSA is 109.5 degrees
Overlap is 70.00 degrees.

I guess I can safely say my LSA is 110 and lift at valve is .433ish as that seems to be the only things that are repeatable with random duration numbers. All numbers taken off lobe using pushrod to dial indicator tip. Bad think is there are no springs involved except the weight of the dial indicator to push the lifter down so I was tapping the indicator end slightly to make sure it was pushing the lifter down, that seemed to work as I was getting no deflection more than about .001.

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I didn' t buy it, I built it.....

COMP 264 has a little larger lift but they say measure at .012...? WTF?
Intake Duration is 258.00 degrees.
Exhaust Duration is 263.00 degrees.
Installed Intake Centerline is 111.00 degrees ATDC.
Installed Exhaust Centerline is 100.50 degrees BTDC.
LSA is 105.8 degrees
Overlap is 49.00 degrees.

that seems off as my LSA change so perhaps there is an error somewhere. Seems COMP cams are measured at different

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I didn' t buy it, I built it.....

Looks like an OCG819 or comp cams 264

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

you have discovered the difference between advertised duration and .050 duration, use the .050 numbers and the .050 specs to find out what cam you have

Measuring at .050 matches nothing online but the COMP 264 looks pretty close even though the events are off. I'll just go with that as I seem to remember it may have been a 264 when I saw the ad. Thanks, educated now.

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I didn' t buy it, I built it.....

All aftermarket cams have their part number stamped or etched in the ends of them as part of the manufacturing process, just look and see what it says.

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There's no such thing as too much cam....only not enough engine!

If it weren't in the block, buttoned up and in the car, id do that.

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I didn' t buy it, I built it.....