Drag race MSD distributor locked or not?

Taking our W9 engine to the dyne next week. We were running 35* total with lightest/silver advance springs for easy starting in the staging lanes. Any advantage to locking out the distributor advance?

Plenty. Nicer idle. Throttle response. Rock steady timing. Next best thing to a crank trigger. Try it. You can always put the springs back in.

Start retard if needed. I never had to use one.

There is zero reason to lock out a distributor, even in a drag car. If you need full timing to get the engine to idle you have other issues.

If you are going to lock it out, you need to get the engine to whatever the highest RPM the engine sees and set the timing there. If you set the timing at idle you won’t have a clue what the timing is at max RPM. Or anywhere else in the power curve.

That’s the ONLY away to set the timing on a locked out distributor.

IMO it’s bad tuning to lock out a distributor.

Unless there is an electronic “box” that’s providing some sort of “curve”, everyone running a crank trigger has the timing locked out.

We've always run our street engines with the super light springs which essentially locks it out at 36* and aids in starting.

It runs like a champ and has almost zero carbon on the pistons when torn town. The 505 will get 11mpg when I keep my foot out of it, too, so call it "bad tuning" but I really haven't seen the evidence of that being the case in our engines.

Try it and see if makes any difference. Locking out the distributor removes a variable from the setup which makes things less complicated but it might make it harder to start.

I'm tuning some EFI cars now that have more timing at idle than at WOT. So they don't have an advance curve, more like a retard curve. But EFI has built in start retard so they always have 15 degrees when cranking.

Just for info, MSD grid does, pretty sure most of the MSD digital ign boxes do too.

So you put "super light" springs in so the timing is all in at 1500. How much time does your drag race engine spend below 1500, or 2500 even?

Big cam, little vacuum, engine idles down, timing comes out and slows the engine, Now more timing comes out. Now it shuts off in gear unless you keep you foot on the gas or crank the idle screw in. Now you've upset the throttle blade to transfer slot relationship.

I know, let's make the total curve real short so the timing doesn't fall back 25 or 30 degrees at idle. Let's make it 10, or less.

Why bother. Lock it out. You can always put springs back in, if you don't like it, But you won't.

I have never seen anyone set the timing at "whatever the highest RPM the engine sees". Usually, unless they have to rev the guts out of it to get the thing totaled out with 3 or 4000 RPM springs in it, it gets set at idle. Pro Stock, fuel cars, Comp, Super Stock, Billy Bracketracer, doesn't matter.

Typically, distributors are locked, just like a crank trigger. Most people who can use a crank trigger, do. Some can't. Timing is set to the max desired. Ignitions, Grids, boxes and gizmos are used to retard the timing from that point, for whatever reason there is to retard it. Start, manage the tire early, nitrous, top end speed, traction control, whatever,

Not that I know of or like I try to recure my standard electronics distributors so the motor has between 14 BTDC to 18 degrees BTDC at idle, under 1500 RPM and all in by 2000 to 2500 at 34 BTDC to 36 BTDC on BB and 426 Hemi motors on gasoline. I like and use the same idle timing for small block and usually find that they like between 30 and 32 degree BTDC at or above 2500 RPM

The dangers of a locked out distributor are on combinations that have tight converters or manual transmissions. A normal engine will need at least some form of timing curve, advancing some with RPM, in order to make MBT torque at all engine speeds. It also needs to reduce timing as a function of load, which helps with part throttle cruise and is much more important in boosted applications.

With a typical street/strip loose converter, at WOT it's going to flash to peak torque or better immediately so you don't have to worry about the engine having too much timing, but if you have a manual trans and try the same maneuver just off idle it's going to have too much timing and you probably won't hear it rattling away. That shows up on the bearings and the main caps.

Been there , done that The only issue I had was an intermittent kick back when starting .
Switched to a crank trigger and grid, no more issues, they are pretty awesome and you can set the curve to wherever you want. We've used launch retard to control wheelstands (it did work), the whole thing is triggered from a footbrake launch (or what ever you want). You can also add on modules for traction control, O2 monitoring and Boost / Timing control.
Below is a typical timing curve on ours. (Auto Box)

On my old 408 small block i ran a crank trigger. No issues with distributor lock out. I tried that on my 511 BB and sometimes when hot would try to break the starter off on startup. So i modified the msd with a large bushing to get about 7* of advance, so i have 29* at idle and all in at about 2200 with 36* total. Works great.

[/quote]
Not that I know of or like I try to recurve my standard electronic distributors so the motor has between 14 BTDC to 18 degrees BTDC at idle, under 1500 RPM and all in by 2000 to 2500 at 34 BTDC to 36 BTDC on BB and 426 Hemi motors on gasoline. I like and use the same idle timing for small block and usually find that they like between 30 and 32 degree BTDC at or above 2500 RPM [/quote]

Interesting Cab, I've never seen a big inch Hemi need more timing than between 28 to 33 deg to make all the power its gonna make on pump swill. At 11:1 CR, I run 30 deg on the street with pump gas 98 octane here in the Summer, and experiment with around 32 deg in the winter. My combo made peak power on the dyno at 33 deg with some 102 race gas splashed in.

Am I missing something here?

I run a MSD Digital 6 box, crank trigger, locked out MSD dist. The box pulls timing when cranking so starter kickback is'nt an issue, works great. I may add some kinda digital timing retard when I hit the track if I need to pull some timing/kill some power on the hit, will see.

So? Does that mean it’s what the engine really wants? I doubt it, as most engines I know want a curve of some sort.

OP has a W9 combo in a drag race application.
Probably will have a converter with close to 6000 stall.

I doubt there will be a need for any type of advance curve from 5500-6000 and up.

^^^ exactly this.

When it comes to tuning and timing not all of our tools are exactly the same or give us the same results. I saw a timing light tests at the races one day were three different timing lights gave two different results
One of the main things I've learn is to use my tools on my cars and engine and look at the time slip and spark plugs to get the best results regardless of wat the readings look like
I had eye opener many years ago when a good division 7 SS racer told me his 415 HP M.W. motor in his 1963 Belvedere like 42 degree total timing revved above 3500 RPM, my stocker with the same combination didn't like any thing above 36 BTDC or less than 34 BTDC. I found out later he didn't build his engines, his sponsor did and they had change the early timing cover to a new later year one, the early ones have the zero mark at the top of the timing tab and the later ones, after maybe 1965 or 1966 have them in the middle of the tab, which reads incorrectly with the wrong balancer. I always verify TDC on the dampener and timing covers compare to TDC off of the #1 or #6 piston at TDC before putting the heads on

Street cars, yes. Different animal.

Drag race. Lock it down. Set it at the max number. Control retard from there.

Digital/programmable ignition, timing controls, Grid, chips, whatever. Sometimes retard is needed or desired. Tire management, starting, high gear - do it electronically so you can control it. That's how most are doing it now.

I'm talking drag race, big cam stuff. Got tired of trying to make stuff idle and respond from idle years ago, because that's how they said you should do it. Never looked back. Big rollers, clean, crisp idle, in gear at 700RPM, with great response, all day long if you want.

Why? Drag race? I've never had a drag race engine run at anywhere below 5000, after the hit, unless it was on the stop for .90 racing for a few seconds. Most of the time, they are well above 3k before the hit.

Unless it's a street driven, foot brake non-two stepped or Heavy Eliminator deal, I don't know anyone else who would spend any amount of time below 3K.

Now I do know people who need to use timing retard for any number of reasons at different places on the race track.

So I are saying an engine doesn’t need a timing curve as long as the RPM is 5000-9000k? I don’t see it that way.

Why would it?

Why not baseline it at max timing and control any desired retard from there electronically according to when and why it is desired? That's what most people are doing.

Pulling power out of it is the only reason to pull timing on a race situation. Taking the ignition trigger out of the distributor and putting it on the crank is always better. If you can't do that, a locked distributor is the next best option. Although, you will still have timing chain slack, cam twist, gear clearance, oil pump load, etc., causing some degree of scatter to deal with.

Ok. I won’t lock one out. The OP is NA, and he didn’t say he’s running 9k. Lock out whatever you want. But the laws of Physics that govern combustion chamber dynamics doesn’t change.

I have heard of the circle track guys running a curve. They say the cars pull harder out of the corners, but i dont think we are talking circle track stuff here.

The only reason for a curve in a race car is to start it. If you can start it with it locked have at it.

I've never had a trans brake and have always foot-breaked and always prefered locked out for the above reasons. But the current combo in the car has a curve in it because at anything over 28 it won't start.And running it at 27 was burning the coating off my headers. Otherwise I would have left it there.

I use a programmed curve as I have a crank trigger - for starting it starts at 25 then it goes all in at 32 at 1200 RPM - I also use a curve at the top end to slow it down for the index - when it hits third gear it pulls the timing back over a prescribed time - works great at scrubbing 2 tenths !

If I wanted to get creative I could use it for traction control off the launch - but I have not yet..........

Mine uses a crank trigger. Fixed timing@35. 15-1, 580". It cranks with no retard, the ignition on, with one single16volt. Ran it with two 12volt in the pastas well. Tough the single 16volt is way better.
Doug

Some ECU won't fire the coil until the starting of the third crankshaft revolution I've been told
Any motor I have had that had 19 BTDC timing or more at idle or start up would kick back against the starter, even broke the nose off of one starter when it kick back against it

Buddy of mine has an engine shop, does a lot of late model dirt stuff, as well as drag and resto. Good stuff. I'm going to have to call him tomorrow and see what he does now.

That would be awesome. I’d love to hear what he does.

William Baldwin at Baldwin carbs is who i'm speaking of. He has a distributor machine for dialing the curve in.

He’s the guy that called me out for locking out distributors on this very forum.

I was so wrong (and he was so right) I went and bought a distributor machine so I can test this stuff and set up a proper curve.

Talked to my engine guy this AM. Legit shop. Do a lot of engines.

Everything he does gets a crank trigger. If the rules don't allow it, distributor is locked. None of "that springs and weights stuff" for many years.

Drag race uses ignition, Grid, whatever for retard, if needed for tire management, nitrous, etc..

Dirt uses crank trigger locked with no gadgets. Some of them will also use a locked distributor with a pickup to run a separate system (box, coil) set up at 4 or 5 degrees retarded they can switch to for when the track slicks up. Or they will slip a restrictor under the carb to take some power out of it before they go out.

That's all I'm saying.

Locked is a safe position: fewer variables.
However: consider coming off the trailer, pit driving, and return road.
If you have a high stall converter, you're (probably) safe.
With tall ratio MT cars, forgetting to slip the clutch that one time, followed by low RPM part-throttle acceleration, will rattle badly.