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How do I know if I have a flat lobe?

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Old 05-12-2001, 04:58 PM
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How do I know if I have a flat lobe?

My engine is coughing through the carb and a guy told me that I had a flat lobe on my cam. Does anyone have any experience with this? What were your symptoms? Thanks for the info.

Chad

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85 SC,previously a 2.8 now 355 ci, Crane 216/216 .454/.454 @ .50, Weiand Stealth intake, Holley 750 vac., Mallory Unilight Distibuter, Blaster2 coil, Accel wires, K&N open element, Hedman Hedders, gutted cat, Flowmaster exhaust.

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Old 05-12-2001, 06:30 PM
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Yea that sounds like a flat cam. You really cant tell which lobe is gone until the cam is removed. A good indication of the problem area would be a gas fouled plug. But the cam definatly has to be pulled to be sure.
Other than that, the timing could be way off a very bad vac leak, bad plug wires. But if the car started to decline in small increments its most likely the cam.
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Old 05-12-2001, 06:30 PM
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Car: 82 camaro SC
Engine: 350
Transmission: 700r4
Pull the valve covers off and see if a rocker arm doesn't move up and down with the engine running.

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Old 05-13-2001, 12:18 AM
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Just as a sidelight, when I pulled the original cam out of My first SBC, it had 2 flat intake lobes.


Car ran pretty good considering, I still ahve the cam, haha )



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Old 05-13-2001, 09:44 AM
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Clindt,

The best way to be certain is to use a dial indicator on the push rod end of the rocker arms. Travel should be very close to the OEM lobe lift specs. If the lift is considerably less than the spec, the cam is already beginning to wear and will wear quickly in the future.

On the bright side, if you do find a worn lobe, it's a great excuse to install a much better cam.

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Old 05-13-2001, 01:16 PM
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Thanks for the replys. I really didn't want to tear into the engine again. I guess its a good opportunity to put in a roller cam.
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