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MSD ready to run - which springs/tuning on stock 350?
Hello, i have a close to stock 71 2bbl olds 350 which already has a 4bbl qjet and headers. I just wanted you to ask which springs in an MSD ready to run distributor will be a good choice?
At the moment i have the factory 2 heavy springs and the blue advance stop bushing in it.
I’m not familiar with the MSD distributor, so I can’t provide specific spring recommendations. It’s going to take some experimenting to find out exactly what your engine wants.
However, I’d suggest trying to find distributor specs for your engine with a 4barrel, and then installing whatever springs MSD suggests to duplicate the calibration. That should get you close to ideal. To do that , your going to need to ensure the base timing is also set to factory. Then you can change springs and limiters without wasting a bunch of effort and time getting in the ballpark.
If it were me I'd use 1 heavy silver spring, 1 light silver spring, and the black stop bushing. This would provide you with around 18* mechanical advance all in at 3000 rpm. Then I'd set my initial advance to 16 which would give you a total of 34*. Limit the vacuum advance to 10* and see how it runs from there.
If it were me I'd use 1 heavy silver spring, 1 light silver spring, and the black stop bushing. This would provide you with around 18* mechanical advance all in at 3000 rpm. Then I'd set my initial advance to 16 which would give you a total of 34*. Limit the vacuum advance to 10* and see how it runs from there.
On your 8 to 1 Olds 350, add about 4 degrees advance for a total of 38. This gives 20 base timing with 18 mechanical. I also would leave the probably 20 degrees of vacuum advance the can puts out. The above numbers are fine if you have a 9 to 1 or better motor, you do not. Your part throttle will be much improved with more part throttle timing. I have ran many 8 to 1 Olds V8's, they love a lot of timing.
On your 8 to 1 Olds 350, add about 4 degrees advance for a total of 38. This gives 20 base timing with 18 mechanical. I also would leave the probably 20 degrees of vacuum advance the can puts out. The above numbers are fine if you have a 9 to 1 or better motor, you do not. Your part throttle will be much improved with more part throttle timing. I have ran many 8 to 1 Olds V8's, they love a lot of timing.
thanks a lot!
So, i set 20 degrees at idle (base) and adjust the distributor for max 18 degrees advance?
sorry if this is a dumb question.. I do this the first time
Set it up as I stated in post #3. From there you can advance the initial timing higher if you wish. Running 20* of vacuum advance will probably lead to surging and pinging under light load.
No, dont connect the vacuum at all until you get your initial and mechanical set up and verified. After that, connect the vacuum.
Your ready-to-run should come with a chart which shows what which springs and bushings should do you for timing.
Edit: If you happend to buy it used in Austria, which i quess is a slim chance, i have a chart at my posession. I quess that that the chart ( and springs, bushings and weights) is same for ready to run and billet distributor. If you need one, i can take a pictures for you.
Last edited by Inline; October 13th, 2020 at 10:26 AM.
No, dont connect the vacuum at all until you get your initial and mechanical set up and verified. After that, connect the vacuum.
Your ready-to-run should come with a chart which shows what which springs and bushings should do you for timing.
Edit: If you happend to buy it used in Austria, which i quess is a slim chance, i have a chart at my posession. I quess that that the chart ( and springs, bushings and weights) is same for ready to run and billet distributor. If you need one, i can take a pictures for you.
yes, for sure vacuum advance disconnected for the adjustment.
thank you very much, haha i bought it used but never installed and with all instructions and small parts
Set it up as I stated in post #3. From there you can advance the initial timing higher if you wish. Running 20* of vacuum advance will probably lead to surging and pinging under light load.
On a 8 to 1 Olds 350, I highly doubt it. I ran 87 with 10 percent ethanol on a 9 to 1 Olds 350 22 base, 16 mechanical with a 30 degree vacuum advance. It had some bucking at low speeds. I went to a 20 degree can, surging gone along with some part throttle response. He wants a lot of part throttle timing. If he goes much more than the 38 or 40 will affect full throttle performance, otherwise as much as it will take
Sorry to resurrect a year old thread, but I am about to install this same distributor in my '68 Cutlass with the 9 to 1 2bbl 350 that I have upgraded to a Performer 2711 and 4bbl.
According to this other thread, I need to account for the small amount of advance that is already present at idle speed when selecting the bushing that limits the total timing: https://classicoldsmobile.com/forums...estion-146631/
Based upon your recommendations above, I was thinking I would target about 12 or 13 degrees of initial timing at idle (which is working well right now with the factory distributor) and aim for 34 to 35 degrees total to be all in by 3000 RPM.
Based upon this chart, it appears that the mechanical advance will have consumed 2 to 3 degrees of the total advance at idle, so if I use the Silver bushing, it should have about 22 or 23 degrees of advance remaining. Doing the math, at 12 degrees initial, I should hit 35 total with the 23 degrees of remaining advance.
Am I understanding this correctly, and do you think this is a reasonable place to start for a 9 to 1 compression 350?
You can start there. Your goal is to have around 34-36* of total advance, initial + mechanical. The silver bushing limits your mechanical advance to 25* @ 2800 rpm. When you subtract the mechanical of 25 from your goal of 34-36, that leaves 9-11 initial. How I do it is I run the rpms up until the distributor stops advancing, then set my total of 34-36. Then I note what the initial winds up at idle speed for future reference. You will still need to work on your vacuum advance after you get this set up.
For 9 to 1, I would go with what Oldcutlass suggested originally in this thread. You can go to 38 total plus at least 10 degrees of vacuum advance, the full 20 should work without issue. More advance at idle will smooth it out somewhat. You don't need to copy your points ignition curve, the HEI curve brought in a bit faster is a nice curve.
I just put a MAXX MSD knockoff (the samaller body - not HEI shape) with that NAPA 12V non resistor coil in my 73 Cutlass 350 all stock 8:1? 4 barrel with dual exhaust. I put the lightest springs that were in the kit (gold in my kit for curve "F" in attached pic) and left the medium stop bushing. I am also using manifold vaccuum to the distributor instead of the stock ported setup.
I set my inital timing at 1100rpm (with distr vac disconnected) at 10 degrees BTDC
Then I went for a drive and listened for any knock or ping and nothing.
I had a bit of a hesitation when flooring the accelerator from a stand still, so I gave it two more degrees initial, to 12 deg. BTDC and that is now gone.It does a pretty good one wheel peel now.
All new to me, but I keep reading that the faster you can get your advance "all in" without ping or knock is best. I put the mid grade fuel - 5% ethanol this tank just to see how it acted with less than premium fuel. No ping.
Runs so smooth now, I think I went too quiet on my mufflers. Car sounded meaner when it had it's worn out 1973 points distributor .. lol
If I get a fancier timing light some day I will check my total advance and might end up changing the stop bushing or taking it out.
Next year I'm putting the 7 heads I have and a mild cam so we'll see how that goes.then.
Last edited by hystat; August 16th, 2021 at 09:41 PM.
I just put a MAXX MSD knockoff (the samaller body - not HEI shape) with that NAPA 12V non resistor coil in my 73 Cutlass 350 all stock 8:1? 4 barrel with dual exhaust. I put the lightest springs that were in the kit (gold in my kit for curve "F" in attached pic) and left the medium stop bushing. I am also using manifold vaccuum to the distributor instead of the stock ported setup.
I set my inital timing at 1100rpm (with distr vac disconnected) at 10 degrees BTDC
Then I went for a drive and listened for any knock or ping and nothing.
I had a bit of a hesitation when flooring the accelerator from a stand still, so I gave it two more degrees initial, to 12 deg. BTDC and that is now gone.It does a pretty good one wheel peel now.
All new to me, but I keep reading that the faster you can get your advance "all in" without ping or knock is best. I put the mid grade fuel - 5% ethanol this tank just to see how it acted with less than premium fuel. No ping.
Runs so smooth now, I think I went too quiet on my mufflers. Car sounded meaner when it had it's worn out 1973 points distributor .. lol
If I get a fancier timing light some day I will check my total advance and might end up changing the stop bushing or taking it out.
Next year I'm putting the 7 heads I have and a mild cam so we'll see how that goes.then.
You need more timing advance, take out the stop bushing and start there. You need way more than 28 degrees of timing. You will want your base at 16 to 22 degrees. I assume you didn't adjust the vacuum advance, that will be allowing it run half decent now.
Last edited by olds 307 and 403; August 17th, 2021 at 06:03 AM.
You need more timing advance, take out the stop bushing and start there. You need way more than 28 degrees of timing. You will want your base at 16 to 22 degrees. I assume you didn't adjust the vacuum advance, that will be allowing it run half decent now.
ok, I took out the stop bushing and set 16 initial (approximately... my tab only goes to 12).
Many thanks to all of you for the great advice. I finally wrapped up the distributer change, converting from the stock distributor to an MSD Ready to Run distributor with an MSD Blaster 3 coil, and WOW what a difference. Even though I had previously replaced the cap, rotor, points, condenser, spark plug wires, coil and spark plug wires on the stock distributor and ignition system, the ignition seemed to have issues. Using a timing light, you could see the ignition jumping around +/- 5 degrees at idle. I was worried that the timing chain or the cam gears were worn, but switching to the MSD fixed this. The timing mark stays rock solid where you set it.
I ended up using two Blue springs along with the Blue stop which gives up to 22 degrees of mechanical advance. I set the initial timing to 18 degrees before TDC at 850 RPM idle with the vacuum advance disconnected. Since this includes about 2 degrees of mechanical advance at this RPM based upon the chart below, I achieved 38 degrees of total mechanical advance at 3000 RPM. Even with the weather around 100F and the engine fully warmed up, I could not sense or hear any pinging under load at WOT, and the engine pulls really well now.
I ended up at 16 initial and went back to ported vacuum for better hot starts. 18 to 20 and mani vacuum made for difficult hot starts and a touch of pinging in a hard pull up a hill. so I backed up 2 or 3 deg.and I don't hear any ping now. starts good hot and cold
I had a lean condition (a stumble) under hard acceleration from a stop. Nothing seemed to make that go away until I tightened up the secondary air door spring on my quadrajet a half turn. It's the tiniest bit there still. - I may go another 1/4 turn or just leave it for now.- it's as if I need a slightly bigger shot from my accel pump. Is there something to remedy that?
Main thing for me is driveability and I'm in good shape there. No one would notice this slight stumble but me and I really don't do a lot of driving where it would be an issue (you'd have to be drag racing or something)
Cliff Ruggles offers a faster release choke pull off. The pull off also affects how the secondary air door opens. With a stock converter and factory mid 2 series rear gears, the air door needs to be quite tight. Nearly every Qjet I have touched had the air door super loose. Maybe the springs weakened over time?
Thanks for all the great information in this thread. I'm leaving everything as it is until I do the heads and cam/timing gears this winter. I wish I knew all this tuning stuff back in the 80s when I first started messing with cars. This is more fun to drive when I'm understanding this stuff.
Thanks for all the great information in this thread. I'm leaving everything as it is until I do the heads and cam/timing gears this winter. I wish I knew all this tuning stuff back in the 80s when I first started messing with cars. This is more fun to drive when I'm understanding this stuff.
You should start a thread of your own, and have the moderators move your posts and replies to it.
You should start a thread of your own, and have the moderators move your posts and replies to it.
I considered starting a thread but this thread was active and totally on topic with what I'm working on. I can't imagine my info needing to be separated. Low compression engine, msd style ignition, tuning and advance curve discussions etc. Mods can move it but I don't think that would best serve anyone searching this topic up as I did.
I considered starting a thread but this thread was active and totally on topic with what I'm working on. I can't imagine my info needing to be separated. Low compression engine, msd style ignition, tuning and advance curve discussions etc. Mods can move it but I don't think that would best serve anyone searching this topic up as I did.
Yes it was a similar issue, but you guys were using 2 different distributors with intentions of 2 different timing curves. It can get confusing on which reply applies to which application. I thought of moving you to your own thread.
Cliff Ruggles offers a faster release choke pull off. The pull off also affects how the secondary air door opens. With a stock converter and factory mid 2 series rear gears, the air door needs to be quite tight. Nearly every Qjet I have touched had the air door super loose. Maybe the springs weakened over time?
If you want you could also pull the top off the carb drill and tap for a 1/8npt plug right above the apt adjustment so you can tune it without pulling the carb apart every time.
If you want you could also pull the top off the carb drill and tap for a 1/8npt plug right above the apt adjustment so you can tune it without pulling the carb apart every time.
Both my 78 403 carb and 83 Canadian non CCC carb have a thread in plug and I notched the APT adjuster so a small screwdriver.
October 12th, 2020, 03:58 AM
