dist. vacuum advance question

Reply Subscribe

Thread Tools

Search this Thread

Apr 10, 2009 | 02:44 PM

nutsy

Thread Starter

Melting Slicks

Joined: Sep 2007

Posts: 2,387

Likes: 123

From: CA.

dist. vacuum advance question

after putting a new distributor vacuum advance on do i need to adjust anything? thanks.

Apr 10, 2009 | 04:39 PM

S489

Burning Brakes

Joined: Feb 2006

Posts: 1,024

Likes: 1

From: AL

short answer: no
IF you replaced the correct advance "in kind" on an otherwise well tuned engine . . . (this assumes you checked the timing after replacement)

Apr 10, 2009 | 06:24 PM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

Likes: 3,113

From: Crossville TN

Only that it really works! {Lots of 'new' parts don't, anymore.} I would put the timing light on it just to check.

Apr 11, 2009 | 06:47 PM

cardo0

Le Mans Master

Joined: Oct 2002

Posts: 7,098

Likes: 378

From: Las Vegas - Just stop perpetuating myths please.

U mean u replaced the vac can?

Quote:

Originally Posted by nutsy

after putting a new distributor vacuum advance on do i need to adjust anything? thanks.

All the vac cans are rated for certain vac. Like some have full adv at 18" Hg and some at 22" Hg. U can find out what your eng needs by using a vac gauge (most fuel press gauges are vac too or use a mighty vac brake bleeder gauge). Connect the vac gauge to the intake and measure vac at your normal eng idle (450-900 rpm). Next rev the eng untill the secondaries open. *Warning don't WOT the eng without a load on eng and overrev it* - u will destroy the vlv springs. Just rev to 4000rpm max and measure eng vac.
Now u know your eng idle vac and WOT (next best thing) vac. U need a vac can that has no adv at WOT and full adv at your normal idle rpm. U can check any installed vac can by taking off the dist cap and connecting a "Mighty Vac" brake bleeder and watch where the can starts to pull in (WOT) and and where full adv (idle) is on the "Mighty Vac" gauge.

That's as easy as i can make it for u. Now u can shop for the right vac can yourself.

Hope this helps,
cardo0

Apr 11, 2009 | 07:12 PM

Roarinbear

Instructor

Joined: Oct 2008

Posts: 121

Likes: 0

From: Hooksett NH

Not to hi-jack this thread, but, can an adjustable vacuum canister be used?

Apr 11, 2009 | 07:25 PM

cardo0

Le Mans Master

Joined: Oct 2002

Posts: 7,098

Likes: 378

From: Las Vegas - Just stop perpetuating myths please.

Quote:

Originally Posted by Roarinbear

Not to hi-jack this thread, but, can an adjustable vacuum canister be used?

I can't see from here in California how your adj vac can works in NH.

But u can test it and set it just like how i just described.

cardo0

Apr 11, 2009 | 07:35 PM

Roarinbear

Instructor

Joined: Oct 2008

Posts: 121

Likes: 0

From: Hooksett NH

Thanks. Didn't know if it would be easier, or better.

Apr 11, 2009 | 09:15 PM

FB007

Burning Brakes

Joined: Dec 2007

Posts: 952

Likes: 0

Quote:

Originally Posted by Roarinbear

Not to hi-jack this thread, but, can an adjustable vacuum canister be used?

I wouldn't. They are inconsistant POS's.

Corvette Stories

The Best of Corvette for Corvette Enthusiasts

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Michael S. Palmer

10 Revolutionary 'Corvette Firsts' Most People Don't Know

Joe Kucinski

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Michael S. Palmer

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Joe Kucinski

10 Most Common Corvette Problems of the Last 20 Years!

Joe Kucinski

5 MOST and 5 LEAST Popular Corvette Model Years in History!

Joe Kucinski

2027 Corvette Buyer's Guide: Everything You Need to Know!

Joe Kucinski

10 Things C8 Corvette Owners Hate (But Won't Tell You)

Joe Kucinski

10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

Brett Foote

Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

Joe Kucinski

Apr 11, 2009 | 09:16 PM

FB007

Burning Brakes

Joined: Dec 2007

Posts: 952

Likes: 0

Quote:

Originally Posted by cardo0

Next rev the eng untill the secondaries open. *Warning don't WOT the eng without a load on eng and overrev it* - u will destroy the vlv springs. Just rev to 4000rpm max and measure eng vac.
Now u know your eng idle vac and WOT (next best thing) vac.

There is no manifold vacuum at WOT.

Apr 11, 2009 | 10:18 PM

#10

baxsom

Le Mans Master

Joined: Jun 2008

Posts: 5,284

Likes: 235

From: Rockledge FL

Quote:

Originally Posted by cardo0

Connect the vac gauge to the intake and measure vac at your normal eng idle (450-900 rpm). Next rev the eng untill the secondaries open.

i didnt think that the secondaries would open in park

Apr 12, 2009 | 12:30 PM

#11

Reggie Dunlop

Drifting

Joined: Aug 2008

Posts: 1,381

Likes: 11

Adjustable cans are like anything else - just buy a good name brand unit. I have used several and have never had a problem. I have the Accel on my '79. It's been there for about a year on a car that I drive 60 miles everyday. I have the Crane unit on a '77 Pontiac 400 - it's been there since '03 and has over 50,000 miles on it and still works just fine - and I have the Proform (came on the dist) on a '72 Chev K20 - again no problems in over 3 years of occasional use.

Apr 12, 2009 | 09:35 PM

#12

cardo0

Le Mans Master

Joined: Oct 2002

Posts: 7,098

Likes: 378

From: Las Vegas - Just stop perpetuating myths please.

Quote:

Originally Posted by FB007

There is no manifold vacuum at WOT.

Really? Then how does air (and fuel) move through the carburetor and into the combustion cylinder? Just PFM?

Quote:

Originally Posted by baxsom

i didnt think that the secondaries would open in park

Someone or more than one here needs to go out and measure thier eng vac with the secoundaries open.

cardo0

This thread isn't just hijacked its trashed. Too many posting info they need to prove to them selfves instead of expecting others explain the very basics to them.

Reply Subscribe