igniton timing / tune up

[CFMopar]

Hey guys,

Now that I'm settled in my new house I'm getting close to starting my project.

I was giving it a bit of a tune up after getting it running after sitting for over 10+ years and limping it to the new place. It was really difficult to start and sputtered and died when getting on the gas. Pulled several plugs and they were heavily fouled and looked like crap.

Replaced most the plugs (cant reach two due to headers without jacking up the motor a bit I'll get around to them in a bit) and adjusted the timing. Got it to about 20 degs at idle (900 rpms) and the idle improved significantly. When I revved  it up to 2800 or so the total timing was about 40 deg which seems a bit high. I'm guessing 36-38 would be more ideal?

Its a 440 with 8:1 compression, eddelbrock heads, proform 750 carb, comp 292/501 cam.

So question is should I change the springs in the distributor to reduce the total advance? Even though it starts easier now and idle is improved, it will idle for a sec or so and you can hear a significant drop in rpm every few seconds or so, so likely a miss I'm guessing? I'll probably get it fired up and start pulling plug wires 1 by 1 to see which cylinder it is and inspect the cap and rotor also to see if it could be that.

Anything else?

[jlatessa]

Changing the springs will slow the advance if that's what you want, but not change the range available.
You need to shorten the weight slot for that solution.
Depending on what dist. you have there are kits for that end.

You need to be aware of the real possibility of detonation with that amount of advance.
I would at least temporarily reduce the initial to about 15* and tune your idle best you can until you
figure out what your combo needs.

Joe

[b5blue]

If ya can pull the bowls and check the carb. for crud. Modern fuels suck. I replaced the carb. on my little TW200 18 months ago and last week it stated flooding. The bowl had crud/corrosion and the float had stuck open!

[XH29N0G]

I am not the one who will know the exact answer but I can tell you how I approached it with my car. 

I figured out how advanced the engine could run at WOT without knock and I figured out what the engine liked at idle.  I am running about 18 to 19 at idle and 32 to 33 at WOT. 
I used the springs to set the curve because that also seemed to have an impact on knock. 

I may have missed what type of distributor you have.  I think that might determine what would need to be done to set total advance.

I have heard 36 to 38 total for many stock set ups.  If yours does not knock when set to 40, then I think you are OK.  The question is whether 40 is actually 40 and also if the dynamic compression lets you get away with it.

   

[c00nhunterjoe]

An 8:1 bottom end with aluminum heads acts like a 7:1 mill. Add a large overlap cam to that mix.... 40 degrees is not scary to me. I ran well over 40 on my 383 with iron heads and compression. If its been sitting 10 yrs, a good carb overhaul will most likely be all it needs.

[Challenger340]

It would be nice to know more information on the car/drivetrain combo before giving Tune up/Timing Curve advice ?

Just say'in....
Auto or 4 Spd ?
Rear Gearing ?

I mean typically the compromised psi low-pop aluminum Head engines may require TONS of ignition advance to generate enough incipient heat of combustion for a good burn and push ?
But that optimal TOTAL advance can compromise other aspects like cranking/starting and mid-ranges where 'flutter' can occur at cruising speeds away from WOT conditions ?

More info please ?

[CFMopar]

So it's a 3 speed auto with 3.91s


My main concern is getting to start easier so I can just move it around the drive way. I'm going to start stripping the car soon and do a complete tear down.

Lot of things I've done to the car as a kid that just doesn't work with middle age adult life  .

[c00nhunterjoe]

Based on the relatively small details, dependijg on the distributor capabilities, i would shoot for 26/42 and see how she reacts.