Timing issues

[MO.RR]

Yesterday I was tuning on my carburetor and figured I would see where my timing was since I hadn't messed with it since I bought the car. I was pretty surprised to see it sitting at 35-36° at idle. Figured the damper had slipped alot and rolled the engine over both ways and sure enough it pretty much on plus or minus a degree or two. I hooked a vacuum gauge up and its pulling 16-17, it bounces between the two. Just to do some testing I dropped the timing down to 12° initial and took it out. Down on power, repeatedly backfired and barely idled. Checked for vacuum leaks and didn't find any, it did have a msd6 box with a converted distributor that I replaced with a msd 8387 that I dropped right in and ran the same as the other ignition. It's a lopo 77' 440 so I doubt it's got anything more than a factory RV cam in it.

Any ideas? I searched but didn't find anything on here.

 

[moparedtn]

First guess I'd have is a slipped harmonic balancer (indicated timing ain't the real timing).
Fetch a TDC "stop" tool for the #1 spark plug hole, then rotate the engine by hand each direction.
Mark the balancer where the piston stops against the tool in each direction; true TDC is exactly
halfway between the two marks.

In my example below, I discovered mine was dead on fortunately:

 

[MO.RR]

I didn’t use a piston stop but I did use a camera in the #1 and rolled it both ways. Marked the damper on movement and split the difference. Came up within a degree or two of groove.

 

[khryslerkid]

Make sure you're on number one plug wire. Simple mistake.

Make sure of your mark on the dampner.

Have the vacuum advance hose disconnected and carburetor vacuum port plugged off.

 

[WP29440SE]

you could have light springs in the distributor coupled with an elevated idle rpm that is letting it run at full mechanical advance. FWIW, mine idles at around 38* . it doesn't run very well with less than that. I chose to just leave it alone because it runs so good.

 

[MO.RR]

It’s blue and silver springs. Mine doesn’t run “good” but it does run, so I got that going at least. Just seemed odd that it was running that high. Still going to double and triple check everything.

 

[moparedtn]

It’s blue and silver springs. Mine doesn’t run “good” but it does run, so I got that going at least. Just seemed odd that it was running that high. Still going to double and triple check everything.

You are checking it with the vacuum advance hose disconnected and plugged like KK says, right?

 

[MO.RR]

Yep, and pulled vacuum reading straight off the manifold.

 

[69L48Z27]

He means, did you disconnect and plug the vacuum line running to the distributor? This eliminates any added advance from the vacuum canister.

 

[MO.RR]

Yes

 

[Johnpat]

If it's 35-36Degress initial, can't understand
how you get it to turn over &start????

 

[MO.RR]

If it's 35-36Degress initial, can't understand
how you get it to turn over &start????

That’s why I had to ask. If I pull it back down to around 12* initial it sputters around and backfires. I know it’s best to set it to total mechanical timing but once I give it some rpms it wraps way past where I have marked 36*’s.

 

[BB BELLA]

could the cap be arcing across teminals,something strange happening!

 

[mopar 3 B]

Something about that picture just doesn't look right for a 77 engine.

 

[threewood]

Could the mechanical advance be stuck open? What was your vacuum at idle and idle rpm? Any issues with it running or pinging?

 

[Bill Monk]

Are you using a dial back timing light? My understanding is that you can't use them with an MSD ignition because they give a false number. Pretty sure you have to use a standard timing light with MSD

 

[MO.RR]

Something about that picture just doesn't look right for a 77 engine.

Not my picture, I have a cast crank damper.

Could the mechanical advance be stuck open? What was your vacuum at idle and idle rpm? Any issues with it running or pinging?

Took the cap off and it seems to move freely. Vacuum is at 17. It’s a turd but it doesn’t ping.

Are you using a dial back timing light? My understanding is that you can't use them with an MSD ignition because they give a false number. Pretty sure you have to use a standard timing light with MSD

Nope, using and old actron corded.

 

[wagonman]

From what I have heard you cant use a regular lite with the MSD. Has to be one of their lites becase of the multipule sparks. Thanks MSD.

 

[Bill Monk]

Sounds like you have checked all the boxes. I would go with moparedtn advise and check with a piston stop to confirm true TDC. Beyond that, if it aint broke, don't fix it. If it starts well there and runs with no valve knock then leave her there. Something isn't right though. No way she is truly at 35 or 36 at idle, you would almost certainly be looking at detonation at WOT even with a lower compression engine.
I had a 68 cuda with a 340 and an MSD ignition that I never could time with a light. The engine just didn't like it there so I timed it by ear and ran it that way for years without issue.

 

[wagonman]

X 3 on the piston stop. Each engine is different , like the 440 in my R/R runs best at 34 then add Vac Adv. The 470 in the Duster likes 38 with 92 and can go to 40 with race fuel. They used to say pinging is the sound of Economy. LOL