Robert Lewis

Can anyone point me to the thread that referred to "jumping" the distributor i.e. moving it over one tooth in order to correctly align it? Mine has the advance can hard up against the coil; I need to move it in order to get the timing correct.

66jack

Try this one


Post #6

http://forums.corvetteforum.com/c1-a...djustment.html

Or This one...

http://forums.corvetteforum.com/c1-a...-terminal.html


Here is a whole list of others with the same problem.....

http://forums.corvetteforum.com/sear...rchid=41938608

Procrastination Racing

It is easier to keep it all straight if you have the cap off. Then you can see the rotor move and have reference for how far things are going and with direction.

Robert Lewis

Well guys, my worst fears have been realized on my '65 327/365.

I followed the CF counsel, s-l-o-w-l-y raised the rotor until it cleared the tooth and moved it one notch counter-clockwise. Had to bump the starter to get it to drop back in; so far, okay. Buttoned it all back up, wouldn't start. Bumped the starter until I could verify that the rotor was pointing at the number one spark plug lead on the cap when the mark was at 0* TDC. Finally got it started thanks to ether.

Now, after fussing a LOT with idle speed and moving the dirty around, I can get it to jump around 0* BTDC with the vacuum plugged, but 24* dial-back at 2750 RPMs? Forget it.

Dwell's at 30 as it should be. What should I try next? Put the rotor back where it was, with the can hard against the coil? At least now the "window" is just past facing the back of the carb....

JohnZ

What does that mean - you don't like that, or you can't achieve it?

Robert Lewis

Sorry I didn't make myself clear, John. The car should be 24* BTDC at 2750 RPMs on centrifugal advance alone, but I can't achieve it.

FWIW, manifold vacuum is 9-10", as it should be at idle.

JohnZ

Try a lighter spring (or two) until you get there.

Robert Lewis

I'll try the lighter springs, but right now I'm dealing with a really lumpy idle and detonation/run-on when I try to shut it off, even at very low RPMs: <400. I have to engage the clutch to stop it cold in order to prevent the dieseling.

toddalin

You did it wrong. You went two teeth instead of one.

You were supposed to pull the bolt on the manifold, remove the distributor, drive the roll pin out of the lower gear, turn the gear 180 degrees, replace the roll pin, replace the distributor, and replace the bolt.

DansYellow66

I'm not sure 9 - 10 inches vacuum is normal for a stock 327/365 engine? Is this a stock cam? Are the idle mixture screws responsive to adjustment? A lumpier than before idle sounds like not enough initial timing and run on at shut down sounds like too much timing or too high an idle speed. Possiibly you don't have enough initial timing in it (causing lumpy idle) and have compensated by raising the idle speed to where the primary throttle plates are open too far and above the idle transfer slots (causing run on). Even if you are pulling the idle down to 400 rpms by loading it with the clutch, the throttle plates are open far enough to allow it to syphon air and fuel in causing run on.

But, you have something funny going on there.

JohnZ

Yes, it is - that's the "30-30" solid-lifter cam, which was called back to active duty in the ''67-'69 Camaro Z/28; I've tuned lots of them, and I've never seen one that generated more than 9"-10" Hg. of vacuum at an 850-900 rpm idle.

Gary's '66

with toddalin. Sounds a like the same thing I was going through. Had to turn the distributor gear 180° to be able set it proper.

Robert Lewis

[QUOTE=DansYellow66;1587445458]
"I'm not sure 9 - 10 inches vacuum is normal for a stock 327/365 engine?" As noted, this is normal.
"Is this a stock cam?" Yes.
"Are the idle mixture screws responsive to adjustment?" Yes.
"A lumpier than before idle sounds like not enough initial timing" It's set at 0* per specs.
"...and run on at shut down sounds like too much timing or too high an idle speed." It's certainly not too high an idle speed.
"You did it wrong. You went two teeth instead of one." Possible, but I sure don't think so: I went VERY slowly.

"But, you have something funny going on there." No kidding.

How do I proceed from here? I can line up the rotor to the #1 spark wire when the dampener is at 0*. I could pull the distributor and check the dimple, but do I really need to do that?

Gary's '66

Let's back up a bit and see if we can make this less confusing.

This is the issue that I was having. Let us know if it sounds like the same scenario then maybe we can all be on the same page and go from there.

No matter which way I installed my distributor, either moving it back or forward, one tooth, could I get it to line up correctly.
No matter what I did the vacuum can would either be up against the coil or the intake but never in the center so that I could adjust advance/retard properly. Does this sound familiar?
If so, then read on:

In order to fix this anomaly I had to pull the distributor out, (and this is what toddlin was referring to) knock the pin out of the shaft, and rotate the gear 180°, then reinstall the distributor. I was then finally able to get the proper placement. My understanding is that I was always off by 1/2 a tooth and this was the only way to fix it. Hope this helps.

Gary

Robert Lewis

How do I make sure that I can return the distributor to its original, pre-removal position?

Mike Ward

Robert-

Can you achieve the desired initial (idle) timing without the dist. housing hitting anything?

Yes- your distributor does not need to be reoriented.

No- move 1/2 or 1 tooth as described above.

Once the above is OK, try the test at 2750 RPM again and report results. Do not turn the distributor.

Robert Lewis

I couldn't achieve the correct initial timing (12*) with the advance can against the coil, so I jumped a tooth counterclockwise. Now I can't move the advance past 0* without the idle increasing on its own.

FWIW, the distributor "window" is now past the centerline i.e. the window is slightly toward the driver side of the centerline.

Right now I can't set the initial timing at 12* because the idle keeps increasing all by itself.

Mike Ward

Ah! The idle speed change is perfectly normal and expected. Simply adjust the idle speed as required while setting the timing to the desired advance.

ghostrider20

You turn the dist counter- clockwise to advance it, clock-wise to retard it.

If you are hitting the coil, you are turning the dist the wrong way to advance it, you should be hitting the intake if you cannot get enough advance.

You need to pull your dist.

Take cap of dist, and rotate the engine via the crank snout bolt until the timing mark is lined up with the timing tab at 12 degrees (note, the crank rotates twice for every one revolution of the distributor). The rotor firing tab should be pointing towards the front of the car when the timing tab and balancer marks line up.

Now pull your dist out.

Now on the bench, install the cap (no need to lock down) and with a black marker, mark on the dist base where the number 1 cap tower plug terminal is located. This. Will be a reference mark for where the rotor tab should be pointing.

Next, look at the dist drive gear. There is a dimple on the gear casting above the gear, it should be in line with the rotor firing tab. If it is not, you need to knock the roll pin out of the gear, remove (don't loose the shims) and rotate it 180 degrees, then reinstall the roll pin.

Next, reinstall the dist in the engine. You want the dist to be installed so the rotor tab is aligned with the mark you made on the dist base. A long flat blade screw driver works,nut eye balling it will work as you can fine tune later. The vacuum advance can should be in the middle of the travel range between the coil bracket and the intake.

Since we set the balancer mark to the 12* mark on the timing tab (6 notches BTDC) your base timing should be very close. Also, as long as the vacuum can is not real close to hitting either the coil or the intake, you now have room to make adjustments to fine tune your timing.

Notes.
The number 1 cap tower is the first terminal to the left of the points window.

Each notch on the timing tab is 2*

You may need to use a long flat blade screw driver to orientate the dist oil pump drive shaft.

Using this method, I am seldom off by more then 1 or 2 degrees and the engine will fire off immediately.

Mark

MikeM

I think it's more accurate to say the rotor should be pointing to the R.S., inboard valve cover bolt unless you are talking HEI.

Many engines with aftermarket camshafts are known to not have the distributor gear teeth indexed properly and this throws the distributor out of proper orientation by a "half tooth". That's why the advice to rotate the gear 180*, wherever it may be currently.