Question about stabbing a distributor

[Gaz64]

If the distributor is static timed at 10BTDC on the balancer, it should show up as 10BTDC on a timing light.

Ignition timing is always quoted in crankshaft degrees. Distributor degrees is half, but irrelevant.

What timing light are you using?

What camshaft is in the engine?

By the sound of it, you have 16 degrees of mechanical advance, what distributor is this?

[Ohio Ken]

Originally Posted by Gaz64

If the distributor is static timed at 10BTDC on the balancer, it should show up as 10BTDC on a timing light.

Ignition timing is always quoted in crankshaft degrees. Distributor degrees is half, but irrelevant.

What timing light are you using?

What camshaft is in the engine?

By the sound of it, you have 16 degrees of mechanical advance, what distributor is this?

Well I guess that blows my theory for being at 20 degrees

Using an older Sun timing light dial less
Bought car used so I do not know cam, but it does not sound real Lopey
Dist is Mallory Unlite for 351w. (Note, inset says it has 24 degree advance) however like I said at base of 20, fully advanced I am reading 34-36.
Windsor has alum SVO heads with rollers.
Only other notable issue, is my manifold vacuum is low at idle at approx 10". If I set timing at 10 degrees, vac drops to about 7"

[Dwight]

I always find top dead center on number one cylinder and move the timing marker to "O" on the damper.

If someone installed the timing marker, do you know that it is correct???? I think this is the one thing most guys miss on setting their timing.

Next I install the distributor with the number one plug in a convenient location. I make sure I can turn the distributor clockwise and counterclockwise, to adjust the timing. I install the dist. and line up the rotor with the number one plug.

Now with the timing light hooked up I start the motor and adjust the distributor till I have my base timing (10 degrees) lined up on the timing mark / damper.

If you have vacuum advance, you need to disconnect it and plug the hose. Vacuum will give you 20 degrees on top of the base timing.

If you have mechanical advance, (it should give you 20 degrees on top of the base) just adjust the distributor for total timing at what every rpm you want all your timing to come it. Say 34 degrees at 3,000 rpms.

Then there are springs and bushing in the distributor to fine tune your timing.

Dwight

[ame]https://www.youtube.com/watch?v=UYGU7mTwsZc[/ame]

Set your timing - for more performance!

I would buy a new timing light

[Ohio Ken]

[quote=Dwight;1342518]I always find top dead center on number one cylinder and move the timing marker to "O" on the damper.

If someone installed the timing marker, do you know that it is correct???? I think this is the one thing most guys miss on setting their timing.

Next I install the distributor with the number one plug in a convenient location. I make sure I can turn the distributor clockwise and counterclockwise, to adjust the timing. I install the dist. and line up the rotor with the number one plug.

Now with the timing light hooked up I start the motor and adjust the distributor till I have my base timing (10 degrees) lined up on the timing mark / damper.

If you have vacuum advance, you need to disconnect it and plug the hose. Vacuum will give you 20 degrees on top of the base timing.

If you have mechanical advance, (it should give you 20 degrees on top of the base) just adjust the distributor for total timing at what every rpm you want all your timing to come it. Say 34 degrees at 3,000 rpms.

Then there are springs and bushing in the distributor to fine tune your timing.

Dwight

thanks Dwight
Being that it is a mechanical advance, it must be affecting my idle timing . As I said in first post. I did verify that at full advance at 3000RPM is around 34. And she starts great and revs great. So I should be good to go. I just didn't understand why I am pointing at 20 (makes sense that the mechanical advance may be why.
Thanks to all for your input
Ken

[olddog]

No vacuum advance will make your engine do exactly what you describe if you set it at 10 BTDC. It needs the vacuum advance to run properly at anything other than WOT. There will be people who disagree. Racers don't want vacuum because it is one less variable, and they only intend to run the engine flat out. People think it's better cause racers do it. They are wrong!

Bottom line:
Watch the timing as you rev the engine and find out where maximum mechanical is at. Then set the timing to 35 give or take when the mechanical is fully advanced. Then see what you have at idle. My guess is that it will be somewhere approaching 20. That is a typical trick to try to get some reasonable drive-ability on the street without vacuum advance. It is critical that the timing be right at full throttle, because that is when the engine can be destroyed if you get it wrong. The best way to find out what your engine needs is to run it on a dyno.

If you want it to run the best it can on the street, put a vacuum advance distributor in it.

[olddog]

Originally Posted by Ohio Ken

Being that it is a mechanical advance, it must be affecting my idle timing . As I said in first post. I did verify that at full advance at 3000RPM is around 34. And she starts great and revs great. So I should be good to go. I just didn't understand why I am pointing at 20 (makes sense that the mechanical advance may be why.
Thanks to all for your input
Ken

On a typical vacuum advance set up you set the initial at 10, with vacuum disconnected. The vacuum pulls in ~15-20 deg. The mechanical pulls in ~20-25 deg. At WOT the vacuum does nothing and the mechanical controls the WOT timing. At light loads, the vacuum pulls in the extra timing needed. With the vacuum connected (before the ported vacuum abomination to meet emissions) 25-30 deg at idle was typically what the engine needed.

A street engine will run like crap, if you set initial timing at 10, with no vacuum advance. So what they did was set the initial at 20. Then they set the mechanical to advance 14. 20+14=34. This is robbing Peter to pay Paul, but it half ass works. The problem is if you open the throttle below ~2000 rpm you will have too much timing, and the engine may well go into detonation, destroying it. So do not go WOT at low rpm with this distributor! Additionally you do not have enough timing at light loads. Your engine runs hotter, makes less power, and wastes fuel. The emissions suck, too. So you have an engine that only runs well at WOT and higher rpms. Everyplace else is a half ass compromise, but it's cool cause racers do it!

[Gaz64]

All very good info lads.

As others have pointed out the OP needs to check the balancer ring has not shifted by verifying TRUE TDC.

[Gaz64]

Originally Posted by Gaz64

All very good info lads.

As others have pointed out the OP needs to check the balancer ring has not shifted by verifying TRUE TDC.

Ken, have you verified TRUE TDC using the positive stop method?