stroker distributor questions

[Vitamin c]

The machine shop is nearing completion of my small block stroker and the question of what distributor i will be running came up.
My plan was to use a stock Mopar distributor kit with, chrome box, and Accel coil. The machine shop made the comment that this may not be the way to go, and it may need to be locked in full advance to get a good idle quality and best performance. Can someone explain what this means? The motor will consist of Indy/Edelbrock heads, comp solid 254/262@50 .576/.584 109LSA cam, approx 4500 converter, 4.10 gear, super victor intake, 1 3/4 headers, 11.5 CR
The only reason for the mopar dist kit is that i already have it from a previous small block.

 

[Mad Dart]

You will definately need at least a re-curve and I would for sure have it locked out. It will not pull enough vacuum with those @50 numbers to be of use anyway's in my opinion.

You can send your Dist in and have this done. Don at 4secondsflat.com can do this for you and it is inexpensive. He will ask you a few questions about your car and dial it in for you. You should probably have a rev limiter of some sort also cause it is gunna come on the pipe really quick! Miss a shift or if something lets loose, BOOM goes your engine. Dont ask me how I know this......haaaaa, I run the Digital 6 Plus MSD ignition that has the 2 step limiter. It is will handle Line Loc, Launch Rev and NOS Retard is also built into the unit. It is also has Multispark.

http://www.4secondsflat.com/Ignition.html

 

[1wild&crazyguy]

They think the cam is a lil too big for typical street manners and that it won't idle run good down low without having a high initial.

what dynamic compression will you have, as in what * does the intake valve close?
to simply put it..
dynamic- is your cranking psi left after bleed off from the cam 'over lap' or simply..your cranking psi

a cam can have enough over lap to lope and 8 cycle so bad it won't stay running without a lot of initial timing and can foul the plugs.

static- is what it would be 'comp' with no bleed off from the cam.

I say get it running 1st with 30-34* total timing @ 2500rpm then try setting the initial at 25* [after the cams broke-in] and adjust the ditributor so that you have as much initial timing as the motor will start with and not kick the starter back 'fully warmed up' then limit [mp dist is adjustable] the mechanical advance so that you only have the desired 30-34* total-example 25* initial at idle with 32* total/full advance at 2500rpm

 

[pettybludart]

I also had my MSD distributor re-curved,also running the MSD-6al with rev limiter.It,s a must if you want to keep your investment together.:-D

 

[70aarcuda]

http://www.summitracing.com/parts/MSD-8534/

the msd distributor can have the advance locked out...

 

[Vitamin c]

You will definately need at least a re-curve and I would for sure have it locked out. It will not pull enough vacuum with those @50 numbers to be of use anyway's in my opinion.

You can send your Dist in and have this done. Don at 4secondsflat.com can do this for you and it is inexpensive. He will ask you a few questions about your car and dial it in for you. You should probably have a rev limiter of some sort also cause it is gunna come on the pipe really quick! Miss a shift or if something lets loose, BOOM goes your engine. Dont ask me how I know this......haaaaa, I run the Digital 6 Plus MSD ignition that has the 2 step limiter. It is will handle Line Loc, Launch Rev and NOS Retard is also built into the unit. It is also has Multispark.

http://www.4secondsflat.com/Ignition.html

I did start to read an article from 4seconds flat.com on this. What exactly is meant by locked out? does that refer to the vacume advance, or does that mean it is locked at one specific advance, and the car starts, idles and runs at 34 deg? I have purchased the pertronixs rev limiter.

 

[Vitamin c]

They think the cam is a lil too big for typical street manners and that it won't idle run good down low without having a high initial.

what dynamic compression will you have, as in what * does the intake valve close?
to simply put it..
dynamic- is your cranking psi left after bleed off from the cam 'over lap' or simply..your cranking psi

a cam can have enough over lap to lope and 8 cycle so bad it won't stay running without a lot of initial timing and can foul the plugs.

static- is what it would be 'comp' with no bleed off from the cam.

I say get it running 1st with 30-34* total timing @ 2500rpm then try setting the initial at 25* [after the cams broke-in] and adjust the ditributor so that you have as much initial timing as the motor will start with and not kick the starter back 'fully warmed up' then limit [mp dist is adjustable] the mechanical advance so that you only have the desired 30-34* total-example 25* initial at idle with 32* total/full advance at 2500rpm

Youve reached the limits of my cam knowledge with the compression questions, so i cant answer you. the only other info on the cam that i left out is 112 LSA installed at 109. Does that help? Also how do i determine if my MP dist is adjustable to limit the total advance?

 

[Mad Dart]

I did start to read an article from 4seconds flat.com on this. What exactly is meant by locked out? does that refer to the vacume advance, or does that mean it is locked at one specific advance, and the car starts, idles and runs at 34 deg? I have purchased the pertronixs rev limiter.

Locked out means NO Vacuum advance. Only Mechanical. So like Justin aka "1wild&crazyguy" is telling you with your cam you will need alot of initial timing at IDLE or it will want to stall or DIE without say around 24-25* AT IDLE, then when you rev it to 2500 by hand with the timing light on it you will see the timing advance and you dont want that anymore than 34* TOTAL timing, which would be called ALL IN 34* at 2500rpm or so.

With your cam it will probably idle somewhere around 1000-1200 rpm's, for reference only!

 

[Vitamin c]

Locked out means NO Vacuum advance. Only Mechanical. So like Justin aka "1wild&crazyguy" is telling you with your cam you will need alot of initial timing at IDLE or it will want to stall or DIE without say around 24-25* AT IDLE, then when you rev it to 2500 by hand with the timing light on it you will see the timing advance and you dont want that anymore than 34* TOTAL timing, which would be called ALL IN 34* at 2500rpm or so.

With your cam it will probably idle somewhere around 1000-1200 rpm's, for reference only!

I just spoke with the machine shop and asked them a few questions. One of his answers was that they "do" on some race engines run the distributor in a full advance mode. what i understood him to say was that the mopar dist would need to be run this way if its not the adjustable style. (i dont think i have an adjustable style, he explained how to identify.) He did confirm this engine will need the 20+ initial and the mopar wont get me there. Am i spinning my wheels here with the mopar distributor? should i just convert now to an MSD?

 

[Mad Dart]

Comes down to Picking your poison.........A recurve and vacuum canister delete would be the cheapest way to do it. I run the Stock dist with a stage 2 Curve in mine done by Don at 4secondsflat with the canister deleted.

I have a 410 stroker, 256@50 intake 260@50 Exhaust Flat Tappet SOLID cam with .618 lift on the intake and .624 on the exhaust. 10.20:1 Compression.

Initial timing is 24* all in at 2800 rpm is 34* total timing. Mine idles at around 1150 rpm clean..fwiw

 

[Vitamin c]

Comes down to Picking your poison.........A recurve and vacuum canister delete would be the cheapest way to do it. I run the Stock dist with a stage 2 Curve in mine done by Don at 4secondsflat with the canister deleted.

I have a 410 stroker, 256@50 intake 260@50 Exhaust Flat Tappet SOLID cam with .618 lift on the intake and .624 on the exhaust. 10.20:1 Compression.

Initial timing is 24* all in at 2800 rpm is 34* total timing. Mine idles at around 1150 rpm clean..fwiw

well that doesnt sound to bad, maybe ill give them a call. i already have the mopar setup with chrome box and accel coil. i also have the pertronix rev limiter. sounds like our setups are similar.

 

[Mad Dart]

well that doesnt sound to bad, maybe ill give them a call. i already have the mopar setup with chrome box and accel coil. i also have the pertronix rev limiter. sounds like our setups are similar.

Does that Pertronix unit have a MULTI-SPARK feature? If not that would be about the only difference and that I have a coil from Don also. Something you might want to look into.

 

[70aarcuda]

locked out means the distributor mechanical advance is locked .....

the msd distributor allows this...the old mopar mechanical/tach drive distributors will have full advance by 1000 rpm but they are not locked...

went you crank the engine the stater will be fighting the total advance with a locked out distributor...

 

[Vitamin c]

Does that Pertronix unit have a MULTI-SPARK feature? If not that would be about the only difference and that I have a coil from Don also. Something you might want to look into.

not that i am aware of, i believe its a rev limiter only.

 

[Vitamin c]

locked out means the distributor mechanical advance is locked .....

the msd distributor allows this...the old mopar mechanical/tach drive distributors will have full advance by 1000 rpm but they are not locked...

went you crank the engine the stater will be fighting the total advance with a locked out distributor...

thats what the machine shop led me to believe they would do with the mopar dist. to me that sounds like you would struggle with starting the motor hot.
I dont think you can buy the old tach drive distributors any more. sounds like you have to modify the newer style.

 

[dgc333]

Locked out means NO Vacuum advance. Only Mechanical.

Any time I have heard reference to a locked out distributor it is the mechanical advance is what is locked out. Vacuum advance only works at part throttle light load when the manifold vacuum is high, it does not work at idle (when hooked as ma mopar intened) or at WOT.

Locking out all advance and having it set to 35ish is common on race motors and will more than likely make starting some what difficult with out a timing retard. It's easy enough to do by anyone of the following; weld the mechanism, epoxy the mechanism, replace the springs with wire that prevents the weights from swinging out.

If you want to stick with a stock mopar style distributor and have not purchased one yet I would go with the Mopar Perfromance one. It has an adjustable mechanical advance. Just loosen the set screws and you can slide the stops for anything from zero (locked out) to 30ish degrees. If you want to spend a few bucks more MP has a billet distributor that does not have a vacuum advance pod on it.

Here is a picture of the MP billet distributor;

And here is how you adjust it.

If it were me I would figure out what the engine wants to see for initial advance by setting the timing to obtain max manifold vacuum and then adjust the mechanism to limit the advance to 35ish degrees.

 

[1wild&crazyguy]

weld up most of the slots in the mopar distributor and fine tune the amount of advance by filing it out some.=shorten the advance slot, it's easy.


OR buy an MSD pro billet and make your own advance bushing.

either distributor will have fiddling on it still.

 

[1wild&crazyguy]

If it were me I would figure out what the engine wants to see for initial advance by setting the timing to obtain max manifold vacuum and then adjust the mechanism to limit the advance to 35ish degrees.

There is never a 'set in stone' total setting, only a starting point....
and the correct starting point is on the lesser side in which you would then increase from there till you noticed either 'no more power gain/ or detonation'.

 

[brewil]

Get a full ignition kit from ICE Ignitions. An Australian product that has blown MSD etc out of the water at SEMA!
check them here and find a US distributor. They have amazing customer service!
www.iceignition.com

 

[dgc333]

Agreed, There are some rule of thumb numbers for different engines that get you into the ball park and 34 to 36 is in the ball park for a sb mopar.

 

[1wild&crazyguy]

Agreed, There are some rule of thumb numbers for different engines that get you into the ball park and 34 to 36 is in the ball park for a sb mopar.

IMO 30*-35*
more than that and the compression is WAY weak for the combo.
splitting hairs but hey...chrysler designed & tested these engines and determined that if everything was matched between cam/compression then 30* is what makes the better power figures...& it's their chamber design.

 

[Vitamin c]

Any time I have heard reference to a locked out distributor it is the mechanical advance is what is locked out. Vacuum advance only works at part throttle light load when the manifold vacuum is high, it does not work at idle (when hooked as ma mopar intened) or at WOT.

Locking out all advance and having it set to 35ish is common on race motors and will more than likely make starting some what difficult with out a timing retard. It's easy enough to do by anyone of the following; weld the mechanism, epoxy the mechanism, replace the springs with wire that prevents the weights from swinging out.

If you want to stick with a stock mopar style distributor and have not purchased one yet I would go with the Mopar Perfromance one. It has an adjustable mechanical advance. Just loosen the set screws and you can slide the stops for anything from zero (locked out) to 30ish degrees. If you want to spend a few bucks more MP has a billet distributor that does not have a vacuum advance pod on it.

Here is a picture of the MP billet distributor;

And here is how you adjust it.

If it were me I would figure out what the engine wants to see for initial advance by setting the timing to obtain max manifold vacuum and then adjust the mechanism to limit the advance to 35ish degrees.

good info here guys! I do already have a distributor, but non adjustable. if mopar has a billet adjustable unit available ill check into that. Am i understanding correct that even an MSD unit will need to be modified? if thats the case, the only advantage to an MSD would be the multi spark and rev limit

 

[Mad Dart]

Any time I have heard reference to a locked out distributor it is the mechanical advance is what is locked out. Vacuum advance only works at part throttle light load when the manifold vacuum is high, it does not work at idle (when hooked as ma mopar intened) or at WOT.

Locking out all advance and having it set to 35ish is common on race motors and will more than likely make starting some what difficult with out a timing retard. It's easy enough to do by anyone of the following; weld the mechanism, epoxy the mechanism, replace the springs with wire that prevents the weights from swinging out.

If you want to stick with a stock mopar style distributor and have not purchased one yet I would go with the Mopar Perfromance one. It has an adjustable mechanical advance. Just loosen the set screws and you can slide the stops for anything from zero (locked out) to 30ish degrees. If you want to spend a few bucks more MP has a billet distributor that does not have a vacuum advance pod on it.

Here is a picture of the MP billet distributor;

And here is how you adjust it.

If it were me I would figure out what the engine wants to see for initial advance by setting the timing to obtain max manifold vacuum and then adjust the mechanism to limit the advance to 35ish degrees.

Well I may be half wrong on my answer. I have never seen a distributor that is locked out with the vacuum canister still functional. I also have never seen a distributor that has a NO LIMIT on the mechanical advance?
So in a sense all distributors are locked maybe not welded but you will only get so much advance right??

Am I drunk or on crackkkkkkkk??:-D

 

[Mad Dart]

Damn guess I am Drunk..........and on Crackkkkkkkkk both........haaaaaaaaa

Found this on the net........

no matter which term is used...
locked out
or
locked in..

it means that the distributor internal advance mechanism does not change / move the timing...

some electronic ignition systems can have a "internal" electrical or electronic mannor that changes (retards) the timing....usually to help in starting....

it is pretty difficult to start an engine that has 34 degrees in it all the time...
some will barely even crank.

 

[dgc333]

good info here guys! I do already have a distributor, but non adjustable. if mopar has a billet adjustable unit available ill check into that. Am i understanding correct that even an MSD unit will need to be modified? if thats the case, the only advantage to an MSD would be the multi spark and rev limit

No, MSD distributors use different diameter bushings to limit the mechanical advance and they have one that is totally electronic with pots to adjust the advance and rate. You will have to dial it in but I would not call that modifing it. For the most part any aftermarket distributor that is adjustable will be set up for a close to stock motor and require some adjustment to get it right for your set up.

One of the advantages with most of the distributors from MSD, Mallory, Accell, Pertronix, etc is they have a self contained electronic module. You do not need an external box like the orange or chrome mopar modules. This is also a disadvantage in that if they happen to fail parts aren't readily available like an all mopar system.Even the billet unit I posted a picture of uses the same pickup as a stock distributor so it's available at the local parts store.

Also the stock looking MP distributor with the vacuum advance has the same adjustable Mallory mechanism as the billet unit.