vac gauge/ cam

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Jan 9, 2003 | 11:06 AM

johnsonacres

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From: south central

vac gauge/ cam

Hey Cam People:

I just added an edelbrock performer 4v carb/intake/cam. At idle (575 rpm) does this cam make the vacuum gauge jump a little. Its reading about 17 inches. At a higher idle the vac gauge needle is steady. Just wondering?

Thanks,
Keith

81' f-150 4x4 302, c6/np208

Jan 9, 2003 | 01:11 PM

grclark351

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From: chicago burbs

vac gauge/ cam

advanced ignition timing can cause a vac gauge needle to dance,where's your timing set?

Jan 9, 2003 | 01:36 PM

johnsonacres

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From: south central

vac gauge/ cam

Hello G.C.

Thanks, fot the reply. Its set at 15 btc.

Thanks,
Keith

Jan 9, 2003 | 03:18 PM

grclark351

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From: chicago burbs

vac gauge/ cam

just for kicks try backing it down and see what happens to the vac gauge. 15 doesn't sound like way to much but may be causing the dance step. any idea what your total advance is? this would be checked with the vac hooked up and reving to enough rpm to throw the mech weights inside the dist. slowly increase rpm until the timing light shows that all adv is in. you may need a timing tape to stick on the balancer to get a reading that far from TDC. or your balancer may be marked far enough. anyway most engines like 34-38 total

Jan 9, 2003 | 03:48 PM

johnsonacres

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From: south central

vac gauge/ cam

Hello G.C.

I'll try backing the timing down and see what happens. I don't know what the total advance is. Th balancer is marked to 30 Deg. I'll work with it and let you know.

Thanks,
Keith

Jan 10, 2003 | 08:35 PM

Taynton1

Mountain Pass

Joined: Jan 2002

Posts: 198

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From: Ft. Pierce Fl usa

vac gauge/ cam

Still working on my Edelbrock Manifold,carb, cam install in an 85 460. I have a clank in mine which I have not found but I did notice the vacuum gauge does bounce at idle where before the rebuild it did not. Timing is 15 degrees advance. BTW, when I did the Edelbrock thing to my 81 Jeep 360 the gauge jumped a bit but then again so did the Jeep and that was what I was looking for. 30% more power and 25% better gas mileage, what a win-win. Hope it works that great in the dually.
MT

Jan 13, 2003 | 02:03 PM

TorqueKing

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From: Atlanta, Georgia, USA

vac gauge/ cam

You're gage reading will be erratic like you said because your idle speed is too low. bump it up to about 900 when warm and in park, which should drop to around 650-700 when idling in gear. This will bring the vacuum signal steady. I'd say to check for vacuum leaks, but with 17" at that low RPM, I'm pretty sure you're all sealed up.

'77 F100, 100% Aftermarket 302 w/C4 cruisin' through 2.75's
John F. Daly III, E.I.T.
The TorqueKing