distributor maximum advance adjustment?

[Lugnut]

I'm wondering how to set the maximum advance on my Motorcraft distributor. I'm told there is an adjustment inside but I'm not sure where. I'm having spark ping, and hooking up the EGR valve thru the two-port CTO and to the passenger side ported vacuum, and routing the dist. thru the three-port CTO and then to manifold and driver's side port have not helped. I have tried several variations of these hookups and none have helped. I have an '83 J-truck with a fairly new long-block assy. and a '78 4bbl intake with the 4350 Motorcraft carb. Most all of the emissions stuff was removed or disabled by PO. I've only rehooked the stuff I've mentioned above and I didn't use all the paraphenalia that the underhood diagram shows the engine having when new.
Am I aiming in the right direction by setting the maximum dist. advance? If so, how can I do it accurately?

[Langdon]

You would want to decrease advance to lessen spark knock, AKA ping. The vacum advance adjustment is a small Allen-head screw inside the nipple. IIRC, turning clockwise increases advance but this will be easy to check :cool:

[Michael]

Lugnut.

I believe it is a 1/8 allen wrench. I am going to try mine this weekend. I would hook up a timing light and measure what you advance is now. If at around 3,000 rpms it is more that say 28-32 than you are advancing way too much. I know mine is, I check it a couple of weeks ago. Just have not adjusted it yet. I very interested in what you find out.

[coolram]

Michael and Lugnut I'm having the same problem(timing at 10BTDC idle 700rpm).Part throttle ping but I don't think my EGR valve is opening.I'm going to try hooking it to a good port vac source and see if it cures the problem.Then I know I have a bad CTO.If it doesn't then I'll try adjusting my vac advance then.But please post your results as I will mine.

I hooked the EGR valve directly to a ported vac source and it helped a lot with reducing pinging.But it didn't solve it so i tried adjusting the vac advance.Micheal your right it is an 1/8" allen.Turned counterclockwise 1/4 turn at a time till I can't hear pinging(may not be the best way but works).I do know now that 1 or maybe all 3 of my CTOs are bad.Good luck with your's smile.gif

[ March 01, 2002: Message edited by: coolram ]

[ March 01, 2002: Message edited by: coolram ]</p>

[Lugnut]

Langdon, you say the adjustment is inside the nipple. Are you referring to where the vac. hose plugs into the vacuum advance -- inside that?

[coolram]

Yes,it's inside the nipple of the vacuum can.Use an 1/8" allen wrench.clockwise to add advance,counterclockwise to lessen advance.

[Millerluck]

Lugnut

I have a 4350 on my 360

I finaly am burning 87 oct. with no ping.

I read a thread over on the Genral des. the other day on the same thing. This led me to start playing around and try and get rid of my ping.

First of all my base timming was off.

I skipped all the CTO crap on both the EGR and the vacuum advance. And am running ported to both. I still have the delay valve in line to the EGR.

My base timming is now set at 10 BTDC.
I played around alot with the adjustmants on the vac. Seems like 1 full turn = 5 deg. CW = advance CCW = retard. Like others have said.

Now this is just my .02 here.

Becase I no longer use all the CTO's and that non liner vacuum regulater thingy I no longer have any vacuum at idle getting to the vac advance.

I have way way more grunt down low off the line. With no ping at all.

Mid feels solid.

Top end still needs a little work. I need more advance still. It kind of has some very slight jerk to it when mashed all the way to the floor. So I'm going to turn the screw CW a little more each day till I start to get some ping up in the higher RPMs (ported vac comes alive with RPMs) when I start to get some ping...I'l turn it back the other way and leave it. Its not to far off now. But it could be a little better.

Another thing I have noticed is the Jeep seems to coast farther when I let of the gas. I think it's because it is fireing late enofe to take away the Jake brake efect of it preignighting.

Later

Larry Miller

[ March 01, 2002: Message edited by: Millerluck ]

[ March 01, 2002: Message edited by: Millerluck ]</p>