Total advance question

-

buck351

Well-Known Member
Joined
Apr 22, 2010
Messages
427
Reaction score
37
Location
Campton Hills, IL
I was curious and checked the total advance on my 67 383 that has the mopar electronic ignition conversion kit that was installed many years ago. At no load and 2400 rpms it was 55 degrees. I'm using one of those tapes you install on the damper. Also what engine damage results from too much advance?
 
Detonation give me the engine year, carb and trans auto or manual I can look it up.
 
Correction: 1967 4 barrel with manual or auto trans without clean air package. According to 1967 service manual vacuum is 8.25-11 degrees and mechanical is 7-9 degrees @ 2400rpm. Old points distributor. Initial timing spec is 12.5. Total looked high. Something wrong with distributer advance?
 
Last edited:
Is it detonating (knocking) under load? The reason I ask is because there are many factors when it comes to initial/total timing. 65'
 
Any chance you have the number can be one of three.
 
I was curious and checked the total advance on my 67 383 that has the mopar electronic ignition conversion kit that was installed many years ago. At no load and 2400 rpms it was 55 degrees. I'm using one of those tapes you install on the damper. Also what engine damage results from too much advance?
Was your check done with the vacuum advance hooked up or plugged?
 
1967 4 barrel with manual trans. According to 1967 service manual vaccum is 12 degrees and mechanical is 19 degrees. Initial timing spec is 12.5. Total looked high. Something wrong with distributer advance?
I think you may have hinted at the answer to my question here ^

The service manual specs in the back of the electrical section are for distributor advance. Distributor degrees moved at specified distributor rpm; and distributor degrees moved for an amount of applied vacuum.
To know what the timing on the engine should be, double the distributor degrees and double the rpm. Add the advance degrees to the initial. This will now be the timing on the engine at the specified rpms.

To check vacuum advance on the engine, you must first establish the timing without vacuum advance.

If you post the full specs from the service manual, or the details of the car, we can be specific. They had different curves for 2bbl and 4bbl, stick shift vs auto, and Hi-perf package. Also sometimes theres minor differences between Plymouth and Dodge. Thats why Halifaxhops asked if you have the number on the distributor.
 
Last edited:
Thats why Halifaxhops asked if you have the number on the distributor.
If the distributor came with the MP full kit, the metal tag the number is stamped on will probably be green. The curve will not be stock but similar. Can walk you through that one too.
 
I haven't heard any knocking while driving. I did check the total advance with the vacuum attached. Service manual mechanical advance spec for 1967 Dodge 383 four barrel stick was @ 2400 rpm.

On the distributor top number is 22 4 and the long bottom number on the tag is 3690431. Metal tag was non painted metal.
 
I haven't heard any knocking while driving. I did check the total advance with the vacuum attached. Service manual mechanical advance spec for 1967 Dodge 383 four barrel stick was @ 2400 rpm.

On the distributor top number is 22 4 and the long bottom number on the tag is 3690431. Metal tag was non painted metal.
That looks like it might be a parts replacement distributor cast the 22nd week of 1974
 
timing distributor advance from manual.JPG
 
That looks like it might be a parts replacement distributor cast the 22nd week of 1974
Sounds about right. Parts manager friend suggested the upgrade kit
not too many years after I got the car when it was 1.5 years old. Had to replace the module a number of years ago but distributor is the same. Pretty old maybe need a replacement?
 
Regardless of specs (and they ARE distributor degrees) the total WITHOUT vacuum should be no where near what you are showing:

Unhook vacuum!!!!

Should be no more than 40max depending on "build" and that is likely high nowadays

If dist. is an exchange / rebuild it could have more modern BS smog advance and will have a long slow mechanical advance.

If you light is a "dial up" deal SUSPECT the timing light. I've run across those that are wrong. Find a "plain" non delay timing light to check
 
Regardless of specs (and they ARE distributor degrees) the total WITHOUT vacuum should be no where near what you are showing:

Unhook vacuum!!!!

Should be no more than 40max depending on "build" and that is likely high nowadays

If dist. is an exchange / rebuild it could have more modern BS smog advance and will have a long slow mechanical advance.

If you light is a "dial up" deal SUSPECT the timing light. I've run across those that are wrong. Find a "plain" non delay timing light to check

Distributor was new when installed many years ago. I used an old style induction connection light. I should also have one that connects to #1.
 
Regardless of specs (and they ARE distributor degrees) the total WITHOUT vacuum should be no where near what you are showing:

Unhook vacuum!!!!

Should be no more than 40max depending on "build" and that is likely high nowadays

If dist. is an exchange / rebuild it could have more modern BS smog advance and will have a long slow mechanical advance.

If you light is a "dial up" deal SUSPECT the timing light. I've run across those that are wrong. Find a "plain" non delay timing light to check

Ok I unhooked the vacuum and got the engine up to 2300rpm and I was reading 38 degrees advance. Wonder what the specs are on this distributor for mechanical and vacuum advance since it's not the stock one.
 
Ok I unhooked the vacuum and got the engine up to 2300rpm and I was reading 38 degrees advance. Wonder what the specs are on this distributor for mechanical and vacuum advance since it's not the stock one.
That's more like it. A golf tee is a handy way to plug the hose while the advance is disconnected so there is no vacuum leak.
My edition of the DC/MP Engine book doesn't specifically include that distributor, but I think that's just a part of the poor copying and editing when the book was put together from the Direct Connection bulletins. It probably has a curve similar to the other MP vacuum advance equiped distributors of the time.

If you have a chance, measure the timing around 1000, 1600, 2000 and 2800 rpm. Then you'll have a better sense of the curve. It's a two stage curve. The second stage slows the advance - more so on engines that pick up efficiency in the higher rpm ranges.
The MP instructions from my kit (mid 80s) suggest timing of 38* between 2600 and 2800 rpm for B/RB engines.
Then the suggest adjusting the vacuum advance so at steady cruise, the timing with vacuum advance hooked up is around 56* BTDC for a B/RB.
 
Last edited:
Matt your DC book have that one in it? I actually have no MP specs can use them.
 
Matt your DC book have that one in it? I actually have no MP specs can use them.
It has a general graph for the vacuum advance distributors, althought it doesn't actually list the 383 distributor number. Careless goof, or what? Who knows? The green lines here.
(Ehrenberg claims the B engine MP distributors he sells copy the 440 curve but doesn't say which one. )

P3690430-advance.jpg
 
I have a bunch of them just document the curves. Any specs on them you are aware of like the sun cards?
 
Just the graph I copied the green lines from. I'll take a picture later.
Maybe there was something better in the original typed bulletin.
 
Also what engine damage results from too much advance?
Detonation under load - you'll hear the engine pinging. If you hear it at wide open throttle, back off immediately.
If you hear it at light part throttle acceleration, not so bad, although you still would want to correct the situation.
Too much timing at steady cruising speedy and the engine may buck a little - some people call it trailer hitching or fish biting.

If you are concerned about detonation, you can check the spark plug porcelain for shiny specks of aluminum.
 
Detonation under load - you'll hear the engine pinging. If you hear it at wide open throttle, back off immediately.
If you hear it at light part throttle acceleration, not so bad, although you still would want to correct the situation.
Too much timing at steady cruising speedy and the engine may buck a little - some people call it trailer hitching or fish biting.

If you are concerned about detonation, you can check the spark plug porcelain for shiny specks of aluminum.

Only noise I have heard started in the past few days and only at idle after the engine starts to warm up not when cold. A strange high frequency noise that very short in duration but regular and goes away when you increase rpms above idle. Noise comes out the breather cap. If you cover up the breather cap with your hands you don't hear it. Can't hear it with a screw driver on valve cover, block on that side, exhaust on that side or intake. Haven't heard a ping in years would think it wouldn't be this high.

Doing some research on noise sounds like a lifter. Starts when oil starts to warm up and going away when increase rpm which increases oil flow. Too high pitched for rockers.
 
Last edited:
That's where3 I would start. If you know any one with a scope it might point you in the right direction.
 
-
Back
Top