Hello, I just putted a MSD ready to run ignition in my stock 1960 Buick nailhead 401. The engine now keeps running after turning the the ignition key to off position. In the book it says 12 degrees for timing the ignition, but with the 12 degrees it did run very bad. So I turned the distributor until it seemed to run well in the idle rpm. The timing light told me then I have the ignition on 5 degrees. The engine runs smooth but how can I find out the correct timing with that MSD ignition / I think the original timing is total wrong.
Hello I am French, sorry for my very bad English. I had the problem with my msd. The problem is that at 12 degrees, when the vaccum is connected, the advance is 30 degrees. It's too at idle. Because the vaccum gives about 20 degree. The solution is to make a stop limit bushing with a screws for blocking the vaccuum to 8 to 10 degrees. In this way, the timing at idle will be 20-22 degrees. Changed the igniter using centrifugal spring with 1 silver heavy spring and 1 silver light spring. Use the black limit bushing. With this configuration, your nailhead will work very well! It is not easy to explain when you do speak good English.
Herby, Your English is great, so I know you can read and understand, so how is it that you install a part without reading the directions. The MSD distributors are fully adjustable. The instructions tell you how to adjust the mechanical advance, both for amount, and rate. I don't know how many times I have to repeat this, but once you remove the original distributor from an engine, the original timing specifications no longer apply, specifically, the initial timing. The only time your engine runs at the initial timing is at idle. Total timing is what you need to adjust. The distributor comes with 4 different advance stop bushings. The bushings let you adjust the amount of mechanical advance in the distributor. 30-34* is the total timing that the Nailheads like, just like the later engines. The largest (black) bushing limits mechanical advance to 18*. If you run 12* initial, the total should be 30*. The next smaller bushing (blue) gives you 21*. Again, with 12* of initial, you will have 12 + 21 = 33* total. The best way is to set the total advance with a light. If the springs in the distributor are light, there is a possibility that some of the mechanical advance will be in at idle speeds. That will hide your true initial timing, therefore, if you want to set the initial, you need the heaviest springs (2 heavy silver), and the lowest idle speed in order to set the initial accurately. I just set the total as described in the Power Timing thread as I find that easiest and most accurate. You should have an original Buick chassis manual for your car. If so, read the ignition system chapter until you understand the basics of advance. It really isn't that complicated, yet so many seem to have a problem with timing.
What I said is that the vacuum advance gives 20 degree at idle, So 12 +20 = 32 at idle. Too much. The vacuum is not adjustable. The solution is to either remove the vaccum or make a stop limit bushing with a screws for blocking the vaccuum to 8 to 10 degrees. 12+10=22 at idle. At full load, the vacuum does not work so 12 initial + 18 mecanical = 30 total His problem is not the total advance, but the vacuum advance gives too much advance at idle and low acceleration.
http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Support/WDTN_pn9615.pdf Almost sounds like you have a wiring issue. Are you sure you have a good switched +12VDC?
In your opinion, the 18 degree of vacuum, I invented?? Ready to run gives 10 degrees with 15 lbs of vaccum. On the naillhead 401 with carter carburator, it therefore elevated and the vaccum gives about 18 degree vaccum! Herby than done to the test, to 12 degree initial vaccum disconnected, reconnect the vaccum and see how much of degree, 10 or more .....
Invented? Maybe we are having a language problem here. Here is the Nailhead ready to run distributor, http://www.msdignition.com/Products..._Buick_Nailhead_Ready_to_Run_Distributor.aspx In the instructions, which neither of you have read apparently, it says that the vacuum advance will provide up to 10* of advance. You can download the pdf and read it yourself. I didn't invent anything. I just looked at the instructions.
You said it keeps running???? is it running like the key is on or 'Desiling' If it is running as normal you might need a resistor on the alternator. I have a MSD box on one that would keep running and found it was running off the power from the gen light. Found that by going back and reading the instructionsou:. If it is 'desiling' move your vaccumn sorce to a ported source where there is light to no vaccumn at idle.
I had that problem with the MSD-6A I installed.... turning the key off did nothing, the engine kept running. Had to install a DIODE. The installation was described in the instructions for the 6A. I do not see the issue mentioned in the 8524 distributor instructions. I noticed the full-line MSD instructions that Larry linked to has the firing order for the Buick Nailhead wrong.... the pic shows the cylinders numbered with #1 on the drivers side. The Nailhead has the #1 cylinder on the passenger side!
Hope everyone is remembering that Distributor degrees are crank/timming light degrees divided by 2. OR, 10 Distributor degrees X 2 = 20 degrees at the crank/timing light. ...Just making sure nothing is lost in the translation here.
The MSD ready to run distributors use a module and are not like the CD type boxes MSD is known for, so the run on is probably the result of the more common reasons, idle speed too high and lean mixtures. The CD boxes can experience run on when voltage back feeds and keeps the box on. The diode in line takes care of that, but again, this is a ready to run distributor. I hope Herby knows his engine well enough to know where #1 is, but if he hooked the timing light up wrong, that might explain some things. ---------- Post added at 01:56 PM ---------- Previous post was at 01:51 PM ---------- The instructions don't specify distributor degrees. It makes sense that MSD would supply a canister with 10 crankshaft degrees as the springs they supply bring the mechanical advance in quicker, so you need less vacuum degrees. There is always the possibility that MSD has the wrong info in their instructions. To verify, you would have to use very stiff springs and a very low idle speed, and then hook and unhook manifold vacuum to the canister while watching the timing with a light. With light springs, some of what you see can be mechanical advance.
