[lucky1]

I want to check my timing curve.
Any advise on how to control the throttle without a helper ?

Thanks. In advance.

[i82much]

it’s not too hard with a dialback. say you want 30 degrees at 3000 RPM. just set the dialback for 30 degrees, rev it up to 3000 RPM, and the timing marks should line up at zero on the tab.

[lucky1]

Yes, Santa brought a dial back with a tach. Light.
I don’t like standing in front of the car at 3000 rpm’s

I was wondering if the throttle could be controlled with a clamp or something.
Tks.

[STEELCITYFIREBIRD]

Use the curb idle screw and the tip of wire tie between it and the carb body.

[Navy Horn 16]

Make a friend, or a baby. My 5 year old can hold the throttle steady.

[i82much]

Originally Posted by lucky1

Yes, Santa brought a dial back with a tach. Light.
I don’t like standing in front of the car at 3000 rpm’s

I was wondering if the throttle could be controlled with a clamp or something.
Tks.

i set the parking brake, chock two sets of wheels, and lean over the fender from the side. they make those fender protective covers for this sort of thing if you are worried about the paint.

[ta man]

Just take your time and do it in steps. Don't worry about "the curve" as much as making sure at idle the timing is rock steady and at whatever rpm you want the mechanical "all in" at is close (eg. 3000rpm)...and doesn't creep up at higher rpms. Then if you make adjustments with different weights or springs...always double check the idle and full advance again.

[lust4speed]

If you are just checking total timing all you have to do is pull the weights and as soon as you start the engine up it will be at full advance at idle. The best thing about this is some distributors sneak in additional timing above 4,500 RPM with the weights riding up on the center cam, and the no-spring test will tell you what max timing really is.

As far as graphing the timing curve, you are condemned to lean into the engine compartment while plotting the advance with springs in place.

[Kenth]

I think Mick ment to pull the springs from the weights, the weight needs to be in place.
But first you need to put a 1/4" bushing on the centrifugal advance stop pin underneith the cam.
Then start engine, set the advance on lamp to 30°-32° or whatever you think you´ll need at idle speed. Check for mark on damper to 0 on scale.
Put back the springs and check initial which now should be around 10°.
Put back the vacuum advance hose.
Jobs done!

[Formulajones]

I just stand next to the car, wing the throttle up myself until the curve stops advancing, use my mouth to move the dial back and put the timing pointer on zero, and then check how much advance I have on the light.

Do it by myself all the time, it's not hard to do at all.


If I want to know what the rpm is when it stops advancing, I put the dial indicator where I know the total is, I rev the engine slowly until the timing marks line up with zero and I ask my son to peak in the car and tell me what the rpm is.

[Half-Inch Stud]

Plain 1980s Craftsman Light on Balancer.
I have ZERO, 30 and 34 lined: Use Sharpie anymore because Paint lines are not crisp.

1980s craftsman Dwell meter to observe RPM. Good toe Check Dwell Expansion for Suspect HEI Modules (7* to 23* dwell expansion ought be seen).

You are going to set Total ADV: i use 34* by 2800, with vac ADV hose opened.
Then paper and pencil jot advance at idle, and some RPMs. Draw a curve and study it to decide on re-tune or done.

Idle ADV from 10-17* is good for a 455. 400-350 are more particular for a proper idle ADV, Vac ADV opened. I dunno what the smaller engines prefer for idle ADV. Factory setting is a good guide, then just a little more IDLE ADV would be fun.


PMD HEI Centerplate and Advance Weights are "numbers down" for proper operation.

Total - Idle ought be 18-24. Vac Can ought be 20 . For not knowing anything about the CIDs or Cam combos. HIS

And remember "Ported Vacuum is just Manifolf Vac turned off at idle." - Shurkey

[lucky1]

Originally Posted by Half-Inch Stud

Plain 1980s Craftsman Light on Balancer.
I have ZERO, 30 and 34 lined: Use Sharpie anymore because Paint lines are not crisp.

1980s craftsman Dwell meter to observe RPM. Good toe Check Dwell Expansion for Suspect HEI Modules (7* to 23* dwell expansion ought be seen).

You are going to set Total ADV: i use 34* by 2800, with vac ADV hose opened.
Then paper and pencil jot advance at idle, and some RPMs. Draw a curve and study it to decide on re-tune or done.

Idle ADV from 10-17* is good for a 455. 400-350 are more particular for a proper idle ADV, Vac ADV opened. I dunno what the smaller engines prefer for idle ADV. Factory setting is a good guide, then just a little more IDLE ADV would be fun.


PMD HEI Centerplate and Advance Weights are "numbers down" for proper operation.

Total - Idle ought be 18-24. Vac Can ought be 20 . For not knowing anything about the CIDs or Cam combos. HIS

And remember "Ported Vacuum is just Manifolf Vac turned off at idle." - Shurkey

Can you elaborate on what you mean “advance hose opened” Tks.

[lust4speed]

Originally Posted by Kenth

I think Mick ment to pull the springs from the weights, the weight needs to be in place...

Yep, I put fingers in gear before engaging brain.

[Cliff R]

I recommend marking the balancer by computing advance based in inches. A magic marker as mentioned above is good enough and easy to see with a timing light.

I typically mark them at 36 degrees. As you rev up the engine when it finally quits advancing and 36 is lined up with zero that's where it's at for total mechanical advance.

Be aware here that a stock HEI distributor does NOT have a positive stop for the advance. They rely on the "flats" of the center can and weights to stop the advance when they all line up. The problem with that deal is that folks purchase these "goofy" spring/weight kits and don't realize that IF you put light springs in place it will allow more timing to come in at high RPM's as the weights will roll-out past the flats on the center cam.

The cheap POS center cam/weights in those kits aren't worth two squirts of duck poop so I'd avoid that junk all together. Even the springs are piss-poor quality and will go "soft" in long term service.

For those reasons I would NEVER rely on any particular center cam and weight combination to stop my advance curve. Take the time to weld in a positive stop and sleep better at night.

Determining how much timing the vacuum advance adds is really easy, just hook it up to a manifold vacuum source at idle and see how far the timing mark moves. If it's adding more than you want, simply modify the travel of the unit to get it where you want to be....pics attached......

[Half-Inch Stud]

"advance hose open" is the act of pulling the vacuum advance rubber line off the carb or dizzy.

Cliff: nice touch. We ought to have a hooby-fleet of well-timed Pontiacs across the lands.

Fuel mixtures not so much.

[lucky1]

Thank you Cliff.

[70GS455]

Reads 50 with the weights relaxed so 10 deg of distributor advance. Have since put screws in the vacant holes next to the top plate for a positive stop

Sent from my SM-G973U using Tapatalk

[amcmike]

I remove the air cleaner to access the throttle, put the timing clamp on #6 (it'll time same as putting it on #1), then stand on the passenger side. This way, I can reach over the carb to work the throttle and check timing with the dialback.