Locked Distributor for Strteet Use

[63qcar]

Car is fairly light weight .... under 2700 lbs with me in it and half tank of fuel , and a 5speed manual . Engine is a 482 FE with a BLP Billet 4150 mini annular carb on an Ebrock dual plane intake .
Been playing with springs on the MSD distributor ( no vacuum advance ) and beginning to wonder if I wouldn`t just be better off with the distributor locked out at 36 degrees .
What downsides for a street car/play toy would there be if I did that ? I`m thinking ( while having a brew or two ) if I take the two lightest MSD springs and stretch them slightly so at cranking speeds , I have zero centrifugal advance , but when the engine fires , it goes to full advance , 36 degrees , that should tell me how the car runs without pulling the dizzy to lock it .

Thoughts ?
BTW ... It runs on premium 91 pump gas .

[F-BIRD'88]

If you stretch oit the advance springs like that the advance system will bounce around.
You don't need to remove the diz to lock out the advance.
Temove the weights and springs. Now move the advance mechanism fully advanced. Wrap the fully advanced mechsnusn with 2 HD cable tie wraps. Orient the buckle of each down under so the rotor csn go back on.
Reinstsll the rotor and cap and fireit up. Reset timing say 36 deg at idle... When locked as this the electronics may slightly retard the spark when running at very high rpm....
Can be A +...... Or....- effect.
If the cam is tame you don't need this.
If the cam is radical it csn help a ton..

To aid hot re-start you can add a ignition piwer interupt
Toggle switch on the dash to allow hot starter cranking
Get it cranking then throw the switch and it will fire right up. If its a GM usibg a GM starter motor. Be sure the OEM starter motor mounting bracket/brace is installed.
If yours is missing, get it FIRST and install it.

[rebelrouser]

In drag racing I lock the distributor, because I want to make sure my timing is correct at WOT, because that is where the engine runs most of the time. I run a MSD box with start retard, so its easy to start, been doing it that way for years. On a street car you need a working advance for best part throttle driveability and fuel economy, if it is a hot street car and you just bring it out to have some fun, lock the distributor. If you want to drive it a lot, then find somebody who has a distributor machine and set up the advance curve. You can take a timing light and check at 250 rmp increments and plot on a piece of paper if you don't have a distributor machine. Most distributors the advance will be all in by 3,000 rpm. I use performance trends engine program as a starting point, as it plots a timing curve for the engine, I have found it to be very close.

[F-BIRD'88]

If the cam is radical racey with lots of overlap the locked out timing is fine on the street.
Say 245@.050" or more. especially w tight LSA 106 ish.
Can combine the locked mechanical with functional vacuum advance (10-12-15) for part throttle cruise.
The rate of vacuum advance is found by drive testing.
This works very nicely overall on racey cammed up street strip cars.... Especially w/auto trans.

[F-BIRD'88]

You cannot get the required street strip mechsnical advance curve with correct idle base timing using the supplied MSD advance limit bushings, no matter which springs. But you can buy the right 10 degree advance limit bushing from 4 seconds flat.
Now you can set up a street strip friendly 10 degree mech advance curve 24-26 idle base initial + 10 = 34-36 total at max advance. Use medium tension Dvanve springs to get a smooth stable advance curve and stabe idle timing.
The MSD instructions show how to install the bushings and or lock out the advance mechanism.
But they do not give you the correct advance limit bushings..

[ClassAct]

Tuner...calling Tuner.

To the OP...id do some serious research before I locked out your distributor. I used to do it all the time, but now, not so much. I'm in the process of being able to check my own stuff.

[mag2555]

The down sides are higher engine temps a cruse and maybe idle , greater fuel usage which tie's in with faster engine ware!
Here's what the tipical mid 1960's GM V8 Dizzy came set up for.

[F-BIRD'88]

The diz advance curved used on oem stock engines of that era. Even the high perf ones will not match the diz curve needed for most all but the mildest engine combos of street strip perf engines today.
Again on many radical cammed engines the locked out advance( + vaccum advance) works great overall.
The more cam overlap the more likely that simple locked out timing is just right.

[F-BIRD'88]

Either way you'd be much better off getting a diz that has vacuum advance. Those msd diz are 1/4 mi race only.
On the street you want a vacuum advance diz..
Now you can do it right. Ya it makes a difference.

[GARY C]

The down sides are higher engine temps a cruse and maybe idle , greater fuel usage which tie's in with faster engine ware!
Here's what the tipical mid 1960's GM V8 Dizzy came set up for.

Looks a lot like my 2009 LS timing curve and similar to what I try to achieve running an adjustable vac advance to full vacuum.

[cv67]

Often wondered this myself, sbc wih 82 deg overlap. Oughta be slightly snappier and the slightest hesitation right off idel when you blip it.
Would this cure it? what are the downsides, how much more at risk for pinging even if you keep it say below 185 with good gas?
(could care less about mpg) driveability is great, will it take a nose dive
Dont mean to hijack-

[F-BIRD'88]

Often wondered this myself, sbc wih 82 deg overlap. Oughta be slightly snappier and the slightest hesitation right off idel when you blip it.
Would this cure it? what are the downsides, how much more at risk for pinging even if you keep it say below 185 with good gas?
(could care less about mpg) driveability is great, will it take a nose dive
Dont mean to hijack-

Not enough info that matters
How can the drivability be great, yet has tip in blip it hesitation? Which is it?

[63qcar]

F-Bird , already have the 4 sec flat bushings and am set at 26 degrees at idle ( 1000 to 1200 rpm ) and max out at 36 degrees at 3700 rpm . Cam is 250 at .050 and LC are 110 or 112 , can`t remember .
" Use medium tension Dvanve springs" .... not familiar with Dvanve springs ????

I`ll lock the distributor out this evening with the tie wrap method .... thanks , hadn`t thought about doing it that way. As far as the vacuum advance dizzy , I`ll have to do some measuring as there isn`t much clearance between the expansion tank and the current mech. adv. dist , hence that`s why I playing with locking the current unit out . Had any experience with the Ford Duraspark unit ? Lots of guys on the FE Forum site swear by them and swear at the MSD units .

After I finish playing with this , I have a M/E Wagner adj. PCV unit I borrowed to play with . Current PCV is a fixed orifice that was used on the old Vettes back in the `60`s . Also have an oil separator in the system . This unit ( hopefully ) will allow me to match the PCV system to this particular engine.

Just trying to clean up and smooth out the bottom end some .

[F-BIRD'88]

It should idle e better. Improve throotle responce..if the cr is low the 250° 112 lsa cam often get much better by advancing the cam more..
If you want more grunt this can be effective.
102 to 105 ish intake c/l. Checked.
If you do get momentary off idle tip in driving
Knock go back to your agressive mech advance curve.
Friendly for manual trans....
Slight momentary ping on throttle is ok
With manual trans as long as it is momentary low rpm.
If anoying you knowvehat to do.The Ford Dura spark Ii
Ignition with correct coilbis sll the sparkbpiwer you need for this. They have a start crankibg retard built in.
I believe it is the white wire on that oem box.
Auto Triggered by the Ford start solenoid during cranking. This oem spark box is fine with .035" spark
plug gap..
The locked diz scheme is more intended for racey cammed auto trans with high stall, than for manual trans cars..... It wants what it wants...
Cammed up cars like generous idle timing....so...

[ClassAct]

F-Bird , already have the 4 sec flat bushings and am set at 26 degrees at idle ( 1000 to 1200 rpm ) and max out at 36 degrees at 3700 rpm . Cam is 250 at .050 and LC are 110 or 112 , can`t remember .
" Use medium tension Dvanve springs" .... not familiar with Dvanve springs ????

I`ll lock the distributor out this evening with the tie wrap method .... thanks , hadn`t thought about doing it that way. As far as the vacuum advance dizzy , I`ll have to do some measuring as there isn`t much clearance between the expansion tank and the current mech. adv. dist , hence that`s why I playing with locking the current unit out . Had any experience with the Ford Duraspark unit ? Lots of guys on the FE Forum site swear by them and swear at the MSD units .

After I finish playing with this , I have a M/E Wagner adj. PCV unit I borrowed to play with . Current PCV is a fixed orifice that was used on the old Vettes back in the `60`s . Also have an oil separator in the system . This unit ( hopefully ) will allow me to match the PCV system to this particular engine.

Just trying to clean up and smooth out the bottom end some .

Not to derail the thread but I love those ME Wagner PCV's. They are the BOMB.