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Confused over setting up my MSD distributor

30K views 23 replies 5 participants last post by  Frisco 
#1 ·
I'm trying to find the "sweet spot" with my SB Ford 8479 MSD Pro Billet distributor. I set it up a year or so ago using the one heavy silver/one light blue spring and the blue bushing, if I recall correctly, and gave it 9-10 degrees of initial timing for what looks like 30* - 31* total. Since most of my driving is at 65mph or less and at less then 3000rpm, this doesn't look like it will give me much advance, i.e.~15* @ 3000 for my mid range acceleration and, in today's world, economy.

This brings me to my question - would it be better to speed up the advance, for instance, use the "E" or "F" settings**, based on the instruction graphs supplied with the distributor or am I going to be getting into the detonation (ping) world at low RPM with too much mid range advance - which I try to avoid. I don't race but do kick it in the butt occasionally, so am not looking for continuous top end performance (yeah, I know, I'm not normal :nono: )

Engine/car specifics:
2400# '31 Ford roadster w/SB Ford 5.0, SVT 'E' camshaft w/1.7 rockers, GT40P heads, Edelbrock Performer RPM intake and 1405 Performer carb. all going out through a 3.25 rear gear and 29" tall tires and trying to run 87 or 89 gasoline (cheep)

**Here's a link to the IB information.

Yes, it does run fine now, but could the engine be just a bit better. I'm doing the carb too as it is a bit rich. It was set identically to the one on a long gone but significantly warmer 351W

Dave W
 
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#2 ·
The situation you describe- too low RPM for the total mechanical advance, etc.- is why a vacuum advance can be so helpful for adding timing under light throttle cruise conditions.

If you don't have and cannot add a vacuum advance, your options are limited, but whatever you do, avoid detonation at all costs- as I'm sure you already know.
 
#3 ·
cobalt327 said:
The situation you describe- too low RPM for the total mechanical advance, etc.- is why a vacuum advance can be so helpful for adding timing under light throttle cruise conditions.

If you don't have and cannot add a vacuum advance, your options are limited, but whatever you do, avoid detonation at all costs- as I'm sure you already know.
I'm surprised that you were the only responder, Cobalt - maybe everyone else forgot what a distributor does with their new computer cars and COP's run from that gadget:D

OK - this particular distributor does have a vacuum advance. I tried it without and that was not a good scene!!

I've looked for my alternate spring and stop set and it's gone, so have to call on my buddies at Summit along with $13 for another. Probably find it 20 minutes after committing my money. Also need some Edelbrock carb parts so...... Now that the hood is in place, even doing it trial and error is a PITA :rolleyes: . Heck, I made a post on the MSD forum yesterday, and their techs didn't even respond, so it must be a lost 'black art'.

Dave W
 
#4 ·
Irelands child said:
I'm surprised that you were the only responder, Cobalt - maybe everyone else forgot what a distributor does with their new computer cars and COP's run from that gadget:D

OK - this particular distributor does have a vacuum advance. I tried it without and that was not a good scene!!
I figure it's worth a few minutes of my time to respond- it's rare that something has you puzzled enough to post and that's reason enough to take a look, for me!

Anyway, if you can get upwards of 45º of combined timing at cruise, you should be very close to optimum for performance and economy. A little more won't hurt- just 'feel' for a surge at cruise that will indicate too much advance. Excessive timing coming from what the vacuum advance adds in won't cause damage because the engine isn't under a load when the vacuum advance is adding timing, plus the vacuum advance will drop that timing right back out as soon as the vacuum of the engine drops- like when encountering a load- so no worries of detonation.

If you find that the mechanical will only bring in "X"º timing at cruise RPM, but the rest of te curve is right on, it might take more than the "usual" 10º-12º additional timing from the vacuum advance. You'll want to be sure the vacuum advance is all in at the vacuum the engine is cruising at, as well as all in at idle if you use manifold vacuum.

Good luck, and let us know how it turns out. :cool:
 
#5 · (Edited)
I'm not familiar with the recommended timing for your Ford engine.

Based on what I do know about the timing for small block Chevy's, I would suggest that you bump up both the initial and the Total mechanical specs.

Start with the Total mechanical "all in" about 2500-3000 RPM and a reading of 34-38 degrees with the vacuum advance disconnected from the vacuum canister and the line plugged off. Let the initial fall where it may with this setting. According to your link, your distributor adds 21 degrees mechanical advance with the blue bushing. My guess is that it will be around 13-17 with the idle RPM below 800 RPM. I'm sure you know this but "all in" is when the timing no longer advances as the engine RPM increases.

As you are very knowledgeable, some of the info I post you are aware of. I post in a little more detail to hopefully be helpful for others with a similar problem that do not have your experience.

After that setting, re-connect the vacuum advance. I always use and suggest connecting the vacuum advance to a full manifold source. The idle RPM should increase when you hook up the vacuum advance. Adjust the idle back down to about 650 RPM when the trans is in Drive. In Park the idle will be around 900 RPM.

If your vacuum advance is an adjustable one, set it so that the total amount added is about 10 degrees.

Test drive. When going up a slight grade about 35 MPH in high gear there should be no pinging. If there is, drop the timing 2 degrees and re-test. You may have to re-adjust several times. You may even find that you can increase the timing a couple of degrees.

The goal is to get the maximum timing your combination can utilize without any pinging. This will yield the best overall performance for your combo.

Another "clue" to the advance being too high would be a slow turning engine when starting a cold engine. Slow turning when the engine is Hot (Normal operating temperature) is usually caused by the starter solenoid getting overheated from the exhaust heat. This usually is not a problem with the Ford due to the remote starter solenoid.

Your link was posted incorrectly. Here is the link
 
#6 ·
Irelands child said:
Engine/car specifics:
2400# '31 Ford roadster w/SB Ford 5.0, SVT 'E' camshaft w/1.7 rockers, GT40P heads, Edelbrock Performer RPM intake and 1405 Performer carb. all going out through a 3.25 rear gear and 29" tall tires and trying to run 87 or 89 gasoline (cheep)
Depending on the compression, you may or may not be able to run the lower octane gas. Below 10:1 with aluminum heads you could be OK with 87. Cast iron heads below 8.5:1 should get you there.
 
#7 ·
Irelands child said:
This brings me to my question - would it be better to speed up the advance, for instance, use the "E" or "F" settings**, based on the instruction graphs supplied with the distributor or am I going to be getting into the detonation (ping) world at low RPM with too much mid range advance - which I try to avoid. I don't race but do kick it in the butt occasionally, so am not looking for continuous top end performance (yeah, I know, I'm not normal :nono: )
According to the graph, I'd try the "E" settings. This seems to get the "all in" around 2500 RPM when using that spring combo and the blue bushing.
 
#8 ·
Thanks, Frisco. You as well as Cobalt made me get out my thinking cap, then do some basic engine timing reviews for what I had really lost track of in the past few years.

The only part that concerns me is using full manifold vacuum. Ford has historically used ported vacuum and the MSD instruction sheets call for it as well. Even the Chevy versions (their 8361 dist) say to use a ported vacuum source. I don't have a problem trying it, and will, but am not sure what it brings to the situation. At full manifold vacuum (~14 degrees with the cam I'm using) it will give me an as yet unknown number of degrees at idle and possibly into the detonation (ping) region when I'm accelerating from a standstill.

The vacuum advance does not appear to be adjustable - it doesn't have the big hex at the vacuum inlet - might not be a 100% indicator, but that has always been my rule of thumb. I am going to try the 'E' setting. My replacement MSD 'advance kit' arrives from Summit tomorrow.

Trying to use 87 octane gas is probably wishful thinking with this kind of cam, carb and distributor along with the iron GT40P 9.5 CR heads :eek:

I'll get this dist. figured out, then on to fun with the carb. I do have the Edelbrock tuning kit for it, but may need a replacement as it has been well used with earlier and now long gone carbs. It seems to run fine with no dead spots, but, again and as always, probably could be better. I also want to replace the aluminum 1" spacer with my phenolic version to try to keep some heat off of it.

Dave W
 
#9 ·
Irelands child said:
The only part that concerns me is using full manifold vacuum. Ford has historically used ported vacuum and the MSD instruction sheets call for it as well. Even the Chevy versions (their 8361 dist) say to use a ported vacuum source.
WAY back in time there was no vacuum advance on the automotive distributor. Somewhere along the way (about the early 1950's) someone discovered that the addition of vacuum advance would greatly improve the timing curve needed for varying engine load conditions. This improved the drive-ability of the vehicle as well as the overall performance. At that time the vacuum source was full manifold vacuum. Ford included. Look at the distributor on a 1950 Ford V-8 flathead.

The manufacturers went to ported source for the vacuum advance in an attempt to meet Federal Emissions guidelines back in the '60's. At the same time they reduced the initial timing to very low numbers (2-4 degrees) and in some cases negative-0 degrees. This caused the engine temps to increase dramatically and at idle burn off the carbon emissions to meet the guidelines at the time. Performance and fuel consumption dropped off considerably.

Since that time with the advent of computer controlled ignition and fuel the emissions are better controlled as well as the timing and fuel delivery.

Basically the difference between full and ported vacuum source are that with the full source, the advance is added as soon as the engine starts. As the load on the engine is increased the vacuum is slowly reduced and the amount of advance added is reduced. At WOT the vacuum drops to '0' and no advance other than centrifugal is utilized. At cruise speed, there is very little load on the engine and the vacuum advance increases the total timing and better utilizes the fuel.

With ported source there is only the centrifugal advance at idle. As the engine RPM's increase the vacuum increases and the vacuum advance adds timing to the distributor. At WOT the vacuum drops to '0' and all the vacuum advance is dropped. The same conditions as full vacuum source are present at cruise speed.

In both cases the amount of vacuum and the amount of timing added are constantly changing depending on the load on the engine.

Which source you use is your choice. Try them both and see what you prefer.



Irelands child said:
The vacuum advance does not appear to be adjustable
According to the MSD website link, the vacuum advance for your unit is a fixed 10 degrees total.


Irelands child said:
Trying to use 87 octane gas is probably wishful thinking with this kind of cam, carb and distributor along with the iron GT40P 9.5 CR heads :eek:

I'll get this dist. figured out, then on to fun with the carb. I do have the Edelbrock tuning kit for it, but may need a replacement as it has been well used with earlier and now long gone carbs. It seems to run fine with no dead spots, but, again and as always, probably could be better. I also want to replace the aluminum 1" spacer with my phenolic version to try to keep some heat off of it.

Dave W
The only concern I have with the phenolic spacer is that they are usually manufactured with linen and resin. Some are manufactured with paper and resin. Both can soak up fluid and this will cause them to eventually de-laminate.

Wood is often used as a heat barrier for carb spacers. They also can soak up fluids and crack over time.

Unless you are getting so much heat from the intake and/or the engine to cause vapor lock, I don't think the aluminum spacer should give you any problems. I do suggest using a four hole spacer for the street rather than a single opening spacer.

There is a heat deflector shield that is sometimes used between the carb and the intake to deflect some of the radiant heat away from the carb. I've never used one, so I can't comment on the effectiveness.
 
#10 ·
I got the mod physically done tho haven't run the engine yet - tomorrow sometime. Changing the springs - simple. That stop bushing .... gotta pull the distributor unless you have teeny tiny fingers. Mine aren't huge, but a lot bigger then would fit between the advance plate and the dist. body.. Then, of course, there is no gravity help and the magnetic pull of the electronic module fights you as well. To get to mine - the @#$% hood needed to come off as well which is a royal PITA But hot rodding - it is fun :sweat: :pain:

The setup is "E" on the MSD chart but am using the silver stop for a bit more advance at 3000 - 3200 RPM and 8-10 initial. Still not sure about the vacuum advance, but will experiment with that as well

More later :D

Dave W
 
#11 ·
I wonder if a cushioned pair of 'stats (jaws wrapped w/a turn of masking tape or my favorite- push a short piece of gas trimmer silicone fuel line over each jaw) would help R & R the bushing?

In my experience, the closer the cam is to stock, the less advantage there is in using manifold vacuum for the advance can. I agree about the hex can- all of the adjustable advance cans I've had were that same hex style- but sure as I say that, there will be 10 guys who have adjustable cans that aren't hex! lol

If you've never set your engine up using manifold vacuum, you might find it to your liking- it's definitely worth a try IMHO. You need about 10º-12º from the can, and have the can set to give full advance an inch or two LESS than the idle vacuum in gear so there won't be any chance of the advance "hunting" at idle. For the mechanical advance springs/weights- you want NO mechanical advance at idle for the same reason.

I'm sure you know this, but it may help someone else who finds this thread.
 
#12 ·
sbford dist

discard the msd,use the ford dist.and ign box with a older vacume advanc unit,that is adjustable,use only ported vacume.but first get the distributor set upon on a machine by a shop that is familure with ford sbs.iwent back to that setup with mid grade. gas works great.useing later vacume unit gives to much advance at part throtle. my bud has a msd on his 347 ,nothig but trouble,dificult to work on,lots of pickup coil isues,small caps dont last long.i use the early vac unit with spacers and stop,the type with removable fiting so easly adjusted. ford used vacume and cent units frome 32 to 48,then got dumb,frome 48 to end of 56,when they went back to cent and vacume,which cant be beat for street use,just my take. have a 302 in my 32 and a 5ltr in 53 f100 both with stock point less ford set up large caps good spark trouble free and cheap cliff
 
#13 ·
Cliff, just curious, why do you recommend he "use only ported vacuum"?

Also, what would you say to run for the initial timing, what RPM should the total be all in by and what should the total be and how many degrees added by the vacuum advance, and what vacuum should the vacuum advance begin to add advance and at what vacuum should it end? That way, the machine isn't needed and he can just set it up "manually". thanks.
 
#14 ·
cobalt327 said:
Cliff, just curious, why do you recommend he "use only ported vacuum"?

Also, what would you say to run for the initial timing, what RPM should the total be all in by and what should the total be and how many degrees added by the vacuum advance, and what vacuum should the vacuum advance begin to add advance and at what vacuum should it end? That way, the machine isn't needed and he can just set it up "manually". thanks.
My comment's are from tryl and error,and the vacuum signal info from ford.i had part throttle miss under light load and corrected by adding spring pressure on vacuum advance unit,with out a dyno only way was multiple road tests.try ed manifold vacume to no avail.the guy i sent the dist. to to set up cent advance was experienced in sb fords and did not give me the numbers on the curve,tho he coached me on the vacume side, i found it dificult trying to get good responce at idel and higher rpm with no load,like other hot roders on limited budgets and more time than $ my efforts eventually worked. one day i will plot the curve,i use holley carbs on both my toys
 
#15 ·
Cliff - thanks for the response. I have often and sucessfully run Dura Spark distributors in the past and with either the failure prone OEM module or the MSD box. I chose to go the all MSD way this time along with the small diameter version. As far as the pick up failures - these are the same pieces as the Dura Spark so quality parts from any NAPA will work. The cap and rotors are some vintage GM, I believe, which I haven't determined yet. I have MSD spares of all maintenance parts anyhow.

The MSD vacuum advance is limited to 10* so everything is centrifugal during acceleration, with that advance maintaining and following the vacuum signal during cruise mode. Both Frisco and Cobalt have suggested that I try full manifold vacuum, and since they are a couple of the more knowledgeable 'tuning' folks here, I'll give it a whirl - but final analysis will be which I feel is better for my use. As I said above, it isn't a race car, but I will give it a boot in the butt if tempted.

Sun distributor machines are collecting dust in hidden old timey garages. The last time I had personal access for one, I was wearing a soldier's uniform - 1965. This brings up the point of Ford distributors. They are fairly easy to set up on a Sun machine but first of all, there are a limited number of known spring rates plus there are no interchangeable advance stops. To modify the OEM dist. spring rates, you have to bend a couple of posts. If you need to expand or limit total advance, you have to either enlarge (easy) of decrease (no so easy) a limiting slot in the advance plate - more reasons to go with an after market distributor. Then - there is the drive gear. The OEM cast iron gear will not work with my steel roller camshaft - it needs to be either a steel (Ford for sure) or a bronze gear for other makes.

Kinda snug in there for a full size cap and adapter:


Thanks again,
Dave W
 
#16 ·
Irelands child said:
Cliff - thanks for the response. I have often and sucessfully run Dura Spark distributors in the past and with either the failure prone OEM module or the MSD box. I chose to go the all MSD way this time along with the small diameter version. As far as the pick up failures - these are the same pieces as the Dura Spark so quality parts from any NAPA will work. The cap and rotors are some vintage GM, I believe, which I haven't determined yet. I have MSD spares of all maintenance parts anyhow.

The MSD vacuum advance is limited to 10* so everything is centrifugal during acceleration, with that advance maintaining and following the vacuum signal during cruise mode. Both Frisco and Cobalt have suggested that I try full manifold vacuum, and since they are a couple of the more knowledgeable 'tuning' folks here, I'll give it a whirl - but final analysis will be which I feel is better for my use. As I said above, it isn't a race car, but I will give it a boot in the butt if tempted.

Sun distributor machines are collecting dust in hidden old timey garages. The last time I had personal access for one, I was wearing a soldier's uniform - 1965. This brings up the point of Ford distributors. They are fairly easy to set up on a Sun machine but first of all, there are a limited number of known spring rates plus there are no interchangeable advance stops. To modify the OEM dist. spring rates, you have to bend a couple of posts. If you need to expand or limit total advance, you have to either enlarge (easy) of decrease (no so easy) a limiting slot in the advance plate - more reasons to go with an after market distributor. Then - there is the drive gear. The OEM cast iron gear will not work with my steel roller camshaft - it needs to be either a steel (Ford for sure) or a bronze gear for other makes.

Kinda snug in there for a full size cap and adapter:


Thanks again, the later gear of5ltr dist is steal and will fit older dist.the pickup coil is different,just changed buds msd not easey.nice looking engine.good luck cliff
 
#17 ·
OKaaay - took her for a ride - must be 50 horsepower at the lower rpm that magically appeared.

Have the light silver and blue springs in there as well as the silver stop. Initial at 12-13 now, OMG - what a low end difference.

I really did a dummy though - I 'lost' my timing mark, something I haven't done in years :nono: . 180* out. I looked at that @#$% round GM looking rotor then when I put it back - dammit, these old eyes saw something different. Gotta say - when it backfires, rattles the neighborhood :pain: . I was going to play with the carb, but it seems to be 'right'. Starts well and no stumble or dead spots.

Thanks to those that lent their advice and restoked my banked memory pit. I hope that others will see what can be done with that package of springs and stops that comes with an MSD distributor. If it's missing from yours, the part number is MSD 8464 and it's ~$13 from Summit

Dave W
 
#18 ·
Irelands child said:
OKaaay - took her for a ride - must be 50 horsepower at the lower rpm that magically appeared.

Have the light silver and blue springs in there as well as the silver stop. Initial at 12-13 now, OMG - what a low end difference.

Dave W
That sounds great!!!

Just curious what you have ended up with as to the vacuum source?
 
#19 ·
Frisco said:
That sounds great!!!

Just curious what you have ended up with as to the vacuum source?
I'm still hooked at the ported source but will try manifold vacuum, probably this coming week, pending the weather. I ran out of 'experiment' time yesterday with my installation dumb trick and went to a car show today. I'll post what I find soon.

Dave W
 
#20 ·
Well it's still raining so no change in the vacuum source.

I have some concern over my harmonic balancer now and always have. Being originally a crate motor, it had the wrong timing arrangement (EFI/mag pick up, no timing pointer) so I replaced the damper. It's keyed to only go on one way and with the #1 piston at the top of its stroke and found by dial indicator, determined what set of marks were correct for my engine. Timing it the other day (see the posts above) started the engine at 25-30* BTDC based on the timing tape and the marks. It ran very smoothly - until I moved it to the 12-13* I've left it at and it is quite rough. This makes me suspect the balancer (and maybe the tape) regardless of how I originally did my installation. Supposedly this is a new, not a rebuilt 50 in.oz. damper for my late model 5.0 and from a decent vendor. Makes me wonder if the elastomer may have failed or assembled wrong. I don't have a problem buying a new damper as this one is not SFI approved, not that I'll turn huge rpm's for any length of time (couldn't find a damper reasonably priced when I built the engine up for non EFI use).

Comments appreciated.

Dave W
 
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