C2 advance adjustment

[John P.]

Hello folks,

I seem to have my idle issue solved on my 1965 convertible 327/350- Appears that the throttle return spring needed changing.

Simple fixes are nice.

Now on to the advance curve mod- As was mentioned on this forum, I have the B26 vacuum can in place. I just received a weight and spring kit-a Moroso, correct for this application. # 72310

My questions are: Any need to remove the distributor? Any reason not to use the replacement weights in the kit? I have no way to check their weight but appear to be exact size and gross weight as the OEMs. Can we confirm that the gold springs are the ones to use-they appear to be the lightest in pull. Is it necessary to use the brass bushing? I would have to research how to do that a bit.

Thanks as always for input.

[John P.]

Re: C2 advance adjustment

Actually the vacuum can is B28

[David H.]

Re: C2 advance adjustment

... My questions are: Any need to remove the distributor? ....

John

I imagine Duke Williams will weigh in here, but ...

There are multiple pdf sources re timing in the "sticky" Database of Restoration Documents section of this Tech Board. Articles by Duke Williams, John Hinckley, and Lars Grimsrud. Link below

Duke's San Diego presentation has a section on tools you will need.

Dave

https://www.forums.ncrs.org/showthread.php?117966-Database-of-Restoration-Documents

[Gary B.]

Re: C2 advance adjustment

… Can we confirm that the gold springs are the ones to use-they appear to be the lightest in pull...

Fir the Mr. Gasket spring kit, there is confusion in the DB archives about whether the gold springs or the black ones have the lower stiffness. I think the more recent postings say the black ones are the lightest.

Gary

[Duke W.]

Re: C2 advance adjustment

The 8" B28 is equivalent to the more aggressive than necessary 236 16 which was OE, but since typical L-79 idle behavior is 14" @ 750 the 12" B26 is a better fit. The least aggressive VAC that passes the Two-Inch Rule is best.

Use the OE weights. Test all three spring sets for the start and stop points, then road test the lightest for detonation. Use a dial back timing light and set at 38-39 (VAC hose disconnected and plugged with a golf tee) a few hundred revs above the engine speed that yields max centrifugal advance.

To change springs you only need to remove the cap and rotor. The distributor does not need to be removed, but most could use an overhaul.

Read my tuning seminar and distributor blueprint overhaul article. They're probably easier to find on the Corvette Forum than here. Do an advanced search for threads started by SWCDuke and go down the list. There aren't that many.

Tell us the results of your testing.

Duke

[John P.]

Re: C2 advance adjustment

I am searching for B26. Any idea for a current source? Thanks for input

[Jeff S.]

Re: C2 advance adjustment

John
A B20 has same specs as 26, if you want to expand your search. (I may have one in my stash o' vac cans).
Jeff

[Leif A.]

Re: C2 advance adjustment

I am searching for B26. Any idea for a current source? Thanks for input

NAPA auto parts. Echlin VC1765.

https://www.napaonline.com/en/p/ECHVC1765?impressionRank=1

[John P.]

Re: C2 advance adjustment

Well perhaps need to start a new thread-but....

I removed cap and rotor, changed springs, removed and lubricated the weights. I put a small amount of spray Kroil on the posts of the weights and on the distributor cam. The car was running well prior to my invasion. Now-NO Start.

Ever since I did that-cranks but won't start. I was very careful with plug wires, double checked them. I then returned previous springs to the original weights. I never removed the distributor. Checked for fuel at carb-plenty flowing in after cranking. Spark plugs are 3 months old. Charged the Optima, jumped the battery-cranks but won't start. I have changed the points, gapped them per standard procedure. I did not change condenser, though it is less than 1 year old. I just put a new coil in. All wiring seems just I it was before my tinkering started.

STILL will crank but not start. What could be different now after I tinkered? Cap and rotor appears to be fine, plug wires are less than 6 months old.

Any ideas on this one?

[Leif A.]

Re: C2 advance adjustment

Possible Kroil on the points.

[John P.]

Re: C2 advance adjustment

would the Kroil around the distributor be an issue? Would like to avoid distributor if possible. Advice?

[Owen L.]

Re: C2 advance adjustment

Make sure the wire connecting the coil to center distributor tower is fully engaged on each end – plus the connections at the coil. If it's not something simple like that:

You're going to have to check for spark at the points. Remove the cap, make sure the coil and condenser wires are connected securely, and spray electronics cleaner on the points while open. Then rotate the rotor back and forth to see if the points open and close. If they don't, you may have to bump the engine over to get into a position so that happens. Then, with the key on, there should be a visible spark or at least an electronic snapping sound when you move the rotor back and forth. That will tell you if there's power from the coil and through the points.

[John P.]

Re: C2 advance adjustment

no snap or spark there. Battery seems very low after a short bit of cranking. Perhaps a battery issue? Only 1 year old Optima, but will replace and see.

[Duke W.]

Re: C2 advance adjustment

I'm not familiar with Kroil, but never put anything on the weights other than wiping them down with WD-40, and that's for corrosion protection. All those parts are hardened steel and lightly loaded with low relative velocity. Any kind of oil or grease will gum up the works. They just need to be clean.

It's always a good idea to replace the condenser when you replace points. Maybe you got that oil on the contacts.

Duke

[David H.]

Re: C2 advance adjustment

John

Any chance key was left on?

If so, suspect points and/or coil.

Dave