Read my lips:

I prefer Microsoft's mate to Powerpoint, which is Excel, when I do bar graphs and financial charts.

So, what did I do to my truck? Started it.

 

It's a new type of pointing implement. You strap it to your index finger, and a little tiny super power laser points in the same direction as your index finger.

 

I didn't do anything to my truck except drive it today. (about 60 miles round trip)

The cruise control wouldn't set on the way home.
I'll check it out tomorrow...?...It WAS working..Trav.

 

I didn't know you could use the vacuum advance with the mechanical advance. But the good news is that I fixed the timing issue some dumb@$$ namely myself had the timing off by about 180 but once I got that figured out I was able to crank it up no problem and man it sounds good with that new 4Barrel 570 holley street avenger carb and that edelbrock performer air gap manifold it is now running like a champ thanks to everybody that was giving advice cause I felt lost till I read some of the posts that led me to be able to find the problem.

 

Not a bad idea maybe you should try and patent that.

 

I would like to know how you use both the vacuum and mechanical advance together. When I read the manual that came with my MSD distributor it said use the vacuum or the mechanical because you have to remove the vacuum advance to install the mechanical advance?

 

Almost all distributors used in our trucks, except the new computer controlled ones, have mechanical advance(and some of the computer controlled ones have it too). You cannot have vacuum advance without mechanical advance. Both advances are in the DSII distributors.

Mechanical advance uses weights and springs attached to a plate that moves the rotor forward as rpm increases. This increases advance. Vacuum advance is also attached to this plate. Depending on the amount of vacuum, it may advance more at high vacuum, or it may be controlled by the mechanical side, such as WOT(low vacuum).

Total advance for both is limited by a pin that goes through the moving plate.

Both advances work together and separately depending on engine operating conditions.

On edit: I was just thinking, someone could come up with a vacuum only advance distributor. The biggest fault there is timing would jump around badly as vacuum changes. I can see some severe pinging as a result.

 

Glad you got that sorted. It is a good feeling when it all falls into place, even when you've been the reason it wasn't. At least it is for me and I have lot of practice.

 

If that is what you have to do, it reinforces my opinion of MSD stuff. Every engine built since some time in the 30s until computer controls came along, with the exception of high performance engines had what is referred to as "dual advance" distributors.

The mechanical advance curve is tailored to the maximum advance the engine can use under load, the vacuum advance curve is tailored to the maximum advance the engine can use under light load. The purpose of the vacuum advance is fuel economy.

I just looked at the instructions, I don't see that one requires removal for the other. It is a GM style design with easy to adjust mechanical advance. The instructions state that the vacuum advance adds 10 degrees to the curve when the vacuum signal is applied.

 

It may be a dual advance distributor. I have very limited knowledge on the ignition side of mechanic work. I normally just have to change bolt in non-adjustable parts but I'm mechanically inclined so I always try and learn knew things that can help me out now and/or later. As far as my distributor having a dual advance I guess it might because it does have the springs on it along with what I am guessing are little circular weights.

 

I drove it!

 

It was awesome hearing the engine fire up and start purring. It is acting so much better than I thought it ever would. It'll run like a scalded dog and still beg for more!!

 

The springs and circular weights up top are the mechanical or centrifugal advance, the vacuum can is the other. Dual advance means both centrifugal and vacuum. Pur centrifugal is used on performance engines and industrial engines. Ford used a purely vacuum system built by Holley caled a load-a-matic system. It used venturii and ported vacuum to control spark advance.

 

I think I might have done that too once. I troubleshot another members issue that was 180° out. Some people dont know enough about the way motors work to know the cam turns once to every two rotations of the crank. I used to think anytime the #1 piston was all the way up it was TDC and time it from there. However, there is compression and exhaust strokes for TDC. After I figured that out my problem was obvious.

 

Cool!






Extra letterz to make the software happy.........................