Timing and vacum advance???

Topic: Timing and vacum advance???

in Forum: C3 Engines

Already a Member? Click Here to Login

Not yet a Member? Click Here to Register for Free!

Forum List New Topic

Search Hide Signatures

Posted: 7/29/03 7:31pm Message 1 of 6

Quote

Owen

Lifetime Member

Send PM

HOUSTON, TX - USA

Joined: 11/15/2002

Posts: 296

Vette(s): 1976 L-48 coupe

Howdy from Texas all!
Please help me understand something... I run an HEI distributor and holley carb. Where is the correct place to attach the advance vac line to the carb/intake? What is 'ported' vacum?

Next question... When I adjusted the timing, I disconnected the advance vac, pluged the line and adjusted for about 8 deg btdc. With the vac reattached, the timing was about 12 deg btdc at idle. Does this sound correct? The motor seems to run pretty strong and the idle is as smooth as expected with the cam.

Save the Wave! |wavey|

SPONSOR AD:: (Our Sponsors help support C3VR)

Timing and vacum advance???

Posted: 7/30/03 7:15am Message 2 of 6

Quote

glenns

Former Member

Send PM

DOWNINGTOWN, PA - USA

Joined: 11/24/2001

Posts: 962

Vette(s): 1969 Monza Red Black Conv / Black Vinal hardtop 454/480 Tremec 5 Speed 308 Posi.Black Leather Interior, PS, PW, Air cond., tilt/tele,AM/FM Cass.-5 Pack CD, Hurst Shifter, side pipes 2004 Yellow convertible with black top and black interior

Mine is hooked up right behing the front bowl and just ahead of the choke. You should have a decal somwhere telling you how much initial timing to set. Mine is 4 btdc. I think full advance comes in somewhere are 34 degrees, but not sure.
Good luck.

Timing and vacum advance???

Posted: 7/30/03 8:26am Message 3 of 6

Quote

joe73vette

Former Member

Send PM

Eastern part of, CT - USA

Joined: 1/29/2002

Posts: 319

Vette(s): White 73 convertible - 350/auto, A/C PS, PB, PW, leather, t/t, two tops Also had a 69 t-top 20 years ago

I would shoot for about 10-12 degrees without the vacuum advance hooked up. Also, only 4 degrees of vacuum advance is very low. They are usually in the 10-20 range. You can find a ported vacuum connection by unhooking them one at a time at idle and feeling if any air is drawn in. Newer carbs seem to have more ported connections than manifold connections. Joe

Timing and vacum advance???

Posted: 7/30/03 9:12am Message 4 of 6

Quote

After Shark

Former Member

Send PM

Portland, TN - USA

Joined: 4/29/2003

Posts: 805

Vette(s): 1972 Coupe Anything, but Stock and more mods to come! SSBC Force 10 Brakes, 3.73, TH350, 355 CID, Rack and Pinion, Vette Brakes suspension front and rear.

Your hookup for vacuum advance is on the metering block on the choke side just behind the fuel bowl. Single vacuum tube coming out of the side.