Dwell changes
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Good point- my original TI distributor, the lower bushing was shaped like a football. It's a wonder that the upper bushing was still fairly good.
Thread Starter
Safety Car
Joined: Sep 2005
Posts: 4,222
Likes: 643
From: Orange County Ca
I rebuilt the dist. about 25k miles ago. I replaced the lower bushing. The top was good. I did shim the gear to get the correct clearence. Guess I'll have to check everything again.
Racer
Joined: Jan 2014
Posts: 425
Likes: 3
From: Jefferson City Missouri
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
One test that is long forgotten by new mechanics, in regards to dealing with the old school distributors. How to check the distributor for bushing/shaft wear.... and that test is to attach a dwell meter to the distributor and bring up the RPM's. If the dwell increases the distributor needs to come out.
Last edited by Willcox Corvette; Mar 16, 2014 at 01:31 PM.
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
It's normal for dwell to decrease slightly as rpm comes up - it's one of the drawbacks of single point ignition systems. A 3-4 degree change may be excessive at 2000 rpm, but it's perfectly normal for dwell to decrease from 30.5 degrees at idle to around 29 at elevated rpm.
If I were you, I'd first install a good set of points. If your points spring is inadequate, is will decrease dwell at elevated rpm. Try a set of NAPA CS786.
Normally, if you have bushing wear or things "flopping around" from wear, you will see fluctuating dwell at any rpm - not just an overall steady decrease as rpm comes up.
Lars
If I were you, I'd first install a good set of points. If your points spring is inadequate, is will decrease dwell at elevated rpm. Try a set of NAPA CS786.
Normally, if you have bushing wear or things "flopping around" from wear, you will see fluctuating dwell at any rpm - not just an overall steady decrease as rpm comes up.
Lars
