[73LeMans]

Street? Race? Not sure where the line is any more..... Maybe wrong section, but here goes -

Looking to run a crank trigger on my 463 and wondering if the risk outweighs the reward. Curious your thoughts.

The reason this is raised here is this this combination will see mostly street miles - track maybe 2x year.

12.5:1 C.R.
KRE Dports by Dave @ SD - 335int/230exh
Solid Roller - Duration @.050 is 272/280 degrees
TH400 - 4.10 gears
3800 stall converter


Here are the drawbacks I can see
- Hard start
- MPG
- Detonation potential

Starting -Since I'm cranking the engine first and adding power to the ignition after, I no longer consider starting to be a concern.

MPG - The mileage may suffer because I'm not optimizing my timing curve below 3000 rpm, but I don't think I'll see any measurable difference. With 4.10s, 3800 stall converter and an advance curve, I barely saw 8 mpg running 20 degrees initial and 29 total all in by 3000rpm. Can it get much worse being only a 9 degree difference?

Detonation - This is the big question and I'm wondering how concerned I should be. I have no timing control devices. I'll have 29 degrees of advance all the time. My cooling system is up to the task, but I'm afraid I wont be able to detect detonation because I can barely hear conversations, much less pinging over the exhaust of that car.

Thoughts?

[Jack Gifford]

I'm not sure what "risk" you're concerned about. For six years now I've been running crank trigger ignition on the Pontiac in my GMC. It uses a Crane TCU (timing control unit) to allow dialing-in an advance curve. The TCU also uses a MAP sensor to emulate vacuum-advance function. I'm quite satisfied with it.

[steve25]

With a steel roller Cam that's the way to go since with roller spring pressure the steel Cam twist so much front to rear which changes the timing that atleast with trigger up front you have number 1 and 2 cylinder timed up right and then with the computer and coil packs you can then make up for the Cam twist and fire the cylinders when they should be fired.

[takid455]

I designed a front mounted crank trigger for the Pontiac 24x EFI system . Been working solid after several thousand miles & 6k+ rpm speeds.

[taff2]

Depends on what fuel you use, I ran a mild race 406 with 13-1 compression combo with iron heads and a smaller 250 degree @.050" cam at 32 degrees of fixed timing, it didn't show any signs of detonation . I used our 95 octane pump fuel with octane booster added. At least 3 years of use without a problem, car only weighed around 2600-2700lb though

[73LeMans]

Risk is a strong word. Drawback is probably better. My concern is I'm not running any sort of timing controller. Just 29 degrees, all the time. Although a controller solves any concern I may have, its not in the cards right now. I'm glad folks are getting it done, and had no idea steel rollers would twist (yikes!).

Fuel is excellent point - forgot to mention it. I've been running C12 in this car long before it needed it, and am sticking with it. That has a motor octane of 108. Still overkill, probably costs some power, but lessens my detonation risk.

[Scott65]

I ran a distributor locked at between 35 and 37 degrees for years. I did have an MSD that had a 20 degree start retard. Last year and half have been on a trigger wheel (with full timing control with an ecu) no issues with it either. Except outstanding timing control....

[Tom Vaught]

I run a old school ignition system on my 64 GTO but would have no issues with running a crank trigger timing system like the Ford and GM vehicles have been running the last 10 years. Their systems have a full spark map which most might have difficulty with but the SENSING of the Crank Position Sensor and the Cam Sensor tell the Control system exactly where the mechanical parts are and then the ignition strategy takes over from that point.

Ignition systems like fuel systems can be made better over more modes of driving with Electronic Engine Controls, EEC.

I personally am not after absolute best power/ F.E., or Emissions. My simple Points triggered MSD Ignition system with RPM Control is all I need for MY APPLICATION.

That being said, if I go EFI it will have Fuel and Spark Control with CNP (Coil Near Plug) and Crank Trigger/ Cam Sensor capability.

Tom V.

[STEELCITYFIREBIRD]

Run both.
A DPDT switch can be used to select one or the other.

[krisr]

36-1 tooth crank trigger here handles my EFI system. As long as you're using an OE sensor off an OE car, you should be fine. I'm running a Ford magnetic VR sensor and always carry a spare in the glovebox. I've had that same first sensor on the engine for around 10 years now!

[chuckies76ta]

You can get yourself an MSD 6AL2 digital box which works with the crank trigger. It has lots of features. It has a programmable retard timing feature that allows you to set timing for starting. plot whatever curve you want. Lock your distributor out and plot your timing curve in the software. Up load to controller done. You can check your curve after with timing light.

Charles

[Schurkey]

The issue--and the resulting problems--have nothing to do with "crank trigger"; and everything to do with lack of additional advance tailored to engine speed and engine load.

Every 1996-newer Vortec engine, for example, was crank-triggered; but real engineers know to add some timing control instead of crippling the engine with no ignition advance. Make no mistake, that's EXACTLY what you're doing--crippling the engine. You're deliberately destroying power AND economy, sacrificing efficiency in the name of keeping spark timing "simple".

[HWYSTR455]

Yes, programmable MSD box, with a MAP or EFi ECU.

With today's electronics, if you're not running EFi, it's kind of pointless to run a crank trigger. I don't think you will gain any noticeable performance, and as stated, you are crippling the engine without some type of advance.

Are you sure of your SCR? Calculate your SCR, check your cranking psi, or test with pump gas, to be certain where you're at. Or do all 3. It's a waste to just dump expensive fuel in there if you don't need it.

What heads? If iron, you could do aluminum and make it pump friendly without pistons, and pick up some power.


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[chuckies76ta]

So just to understand Schurkey and HWYSTR455 The 6AL2 is programmable and you can tailored an advance curve which follows RPM. Are you saying this is not a good setup? The rpm is load sensitive, no?

Thanks
Charles

[HWYSTR455]

I'm saying there's no need to run a fixed timing setting with today's electronics, and depending on the use, crank trigger either.

But yes, the MSD 6AL-2 programmable is controlled by a curve you dial in on a laptop.

https://www.holley.com/products/igni...rip/parts/6530

You can add a MAP sensor and it mimics a vacuum advance, which it too is adjustable via the laptop.

Flip through the instructions, or watch a youtube vid on the MSD 6AL-2, tons of info out there.


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[Scott65]

RPM is the engine speed component, MAP is representative of load. With a distributor, the vacuum advance covers that. To the OP, if you haven't already purchased the crank trigger, maybe investigate the other options available that will offer greater control. Some of the available options would serve as rev limiter, launch control, traction control etc, all in one.

[HWYSTR455]

If you already have a pro billet distributor, the programmable MSD with a MAP sensor is probably your best bet.


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[HWYSTR455]

Or just do a whole Xflow Sniper setup with a Hyperspark.

https://www.holley.com/products/fuel.../parts/550-540


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[Schurkey]

Originally Posted by chuckies76ta

So just to understand Schurkey and HWYSTR455 The 6AL2 is programmable and you can tailored an advance curve which follows RPM. Are you saying this is not a good setup? The rpm is load sensitive, no?

RPM and load are totally separate. 4000 rpm going up a mountain pulling a trailer may require WFO throttle. 4000 rpm coming down that mountain may happen with the throttle at idle.

Sensing manifold vacuum and/or throttle position are ways to sense load. If the 6AL2 has provision for either or both, you should be able to map timing based on load.

[chuckies76ta]

Awesome guys. Make sense. Thanks

Charles