Magnetic & Hall-Effect Crank/Cam Sensor Setup

[Danny Cabral]

So in current position, the reluctor edge will be rotating counter-clockwise passing the sensor "beam", and thus digital falling. Thanks!

Then you have it right. Ensure it's programmed as such in the Custom Ignition Parameters (Cam Sensor Type - Digital Falling).

[kingtramp]

I'm looking for some technical input on how to properly setup a 24-1 crank trigger.
Question (1): For 24-1 trigger wheel, will the “TDC TOOTH NUMBER” be the tooth after the missing tooth, that aligns
to the crank sensor when at TDC for cylinder #1, even if it is not the 10th tooth as noted for 60-2 trigger wheel?
Question (2): When using a 24-1 crank sensor wheel, the cam sync signal trigger MUST occur when?
For the 60-2 trigger wheel it advise “If the crank sensor is setup such that the 10th tooth after the missing teeth is at TDC,
position the cam sensor such that it is between 110 -250 degrees before TDC on cylinder #1.”
I have carefully search various forums on how to setup 24-1 crank trigger, but nothing very clear. Any input will be greatly appreciated.

[S2H]

With the 24-1 wheel, you can put it anywhere you want, but its default setting is designed to be placed so that the 10th tooth after the missing tooth is TDC. You can put it earlier if you want to, make it the 5th tooth, and just change the value in the Ignition Parameters to match. If for some reason you can't (or don't want to) put it on the 10th tooth, you can adjust it in the Ignition settings to match where you had to put it. If it's not exactly perfect, don't worry too much, you can always move the "Timing Offset" so that your actual ignition timing is correct and matches your commanded timing.

In simple terms, the cam sensor just needs to be before TDC. Exact position is not important as it's just a reference for which stroke it's on (exhaust/intake or compression/power). So as long as it falls within that window of 110-250, it's just fine. I usually just try to put it at 180° because it's easy to find on the engine/balancer, and it's OK if you aren't exact.

[kingtramp]

I should have mentioned the 24-1 trigger will be used on an inline 4 cylinder motorcycle engine. My question is, will the same cam sync signal window of 110°-250° apply to inline 4 & V8 engines?

[Danny Cabral]

My question is, will the same cam sync signal window of 110°-250° apply to inline 4 & V8 engines?

Yes, it's the same for missing tooth type crank trigger kits. It only changes if using a 2x (4 cyl), 3x (6 cyl) & 4x (8 cyl) type crank trigger kits ("1 Pulse per Fire").

[kingtramp]

Thank you very much Danny for the feedback. I think I will stick with "1 Pulse per Fire", because I can still use sequential injection, cam signal at 330° BTDC, which is perfect for 2x "1 Pulse per Fire". There is no way to adjust cam signal to 110-250° using 24-1, with sequential injection.

[beck]

I also have some concern setting up my crank trigger wheel & sensor. I'm using a 36-1 wheel. The instruction manuals for the Holley 36-1 trigger wheels (556-116, 556-125 & 556-126) all say to use the 7th tooth after the missing tooth. Another Holley “expert” recommended the 8th tooth after the missing tooth. Now you guys are saying the 10th tooth. I'm expecting that the tooth number isn’t critical, as long as you program your main file to match your actual installation.

On the 60-2 wheels the 10th tooth is used, or 36 degrees. On the 36-1 the 10th tooth would be 100 degrees. On the 24-1 the 10th tooth would be 150 degrees. If the 7th tooth was used on the 36-1 it is 70 degrees. I don’t know if it matters since the EFI is counting the teeth? Input here would be appreciated.

I may have created a problem during my 36-1 installation. I put my 36-1 wheel between the balancer and the timing cover. My wheel (5” O.D.) is smaller than the balancer (6.4” O.D.). Now I read somewhere that the wheel should be larger than the balancer to eliminate missed pulses. My Hall-Effect pickup fits between the balancer and timing cover, and it is centered on the timing wheel. Think I will have a problem?

[Danny Cabral]

The instruction manuals for the Holley 36-1 trigger wheels (556-116, 556-125 & 556-126) all say to use the 7th tooth after the missing tooth.

Yes, follow the Holley EFI 36-1 crank trigger instruction manual.
http://documents.holley.com/199r10898.pdf (Holley EFI 36-1 Crank Trigger Kit Instructions)

Now you guys are saying the 10th tooth. I'm expecting that the tooth number isn’t critical, as long as you program your main file to match your actual installation.

Who said 10th tooth for a 36-1 crank trigger kit?

Now I read somewhere that the wheel should be larger than the balancer to eliminate missed pulses. My Hall-Effect pickup fits between the balancer and timing cover, and it is centered on the timing wheel. Think I will have a problem?

No, my 60-2 trigger wheel is smaller than my vibration damper; it's not a problem (LINK).

[beck]

Who said 10th tooth for a 36-1 crank trigger kit?

S2H was talking about the 24-1 timing wheel above, in post #33.

No, my 60-2 trigger wheel is smaller than my vibration damper; it's not a problem.

From the photos, it looks like you have a little more clearance. I have about .9" between my timing cover and the balancer. It should work if yours does.

I set mine up on the 10th tooth a couple days ago. I'm going to change it to the 7th tooth.
Another interesting thing is that Holley recommends triggering on the rising edge in the 36-1 instruction manuals. I think the falling edge would work better. Thanks for the help.

[Danny Cabral]

From the photos, it looks like you have a little more clearance. I have about .9" between my timing cover and the balancer. It should work if yours does.

Yes, my six inch 60-2 crank trigger kit works flawlessly.

Another interesting thing is that Holley recommends triggering on the rising edge in the 36-1 instruction manuals. I think the falling edge would work better.

That's only because their crank sensor manufacturer suggested Digital Rising. I contacted Doug F. about this, and he agreed that Digital Falling should work just as well.

A few years back, I did some System Log testing with a few Cherry Hall-Effect sensors, and Digital Falling was definitely better. I've also Datalogged the difference on the same Hall-Effect sensor, and Digital Rising had random RPM errors at cranking speeds. Now I can't bring myself to ever use Digital Rising. Digital Falling is a cleaner, more consistent signal.

http://forums.holley.com/showthread....7990#post47990 (Wiring Modification To Pin B20, "EST +12V Output")

[S2H]

It's always better at Digital Falling because the electronics can see the voltage, and determine a drop in voltage easier than a rise in voltage.
It doesn't know a rise in voltage until it's leveled off at the top, and it's largely dependent on battery voltage. (Especially on a 12V sensor.)

[AdvAutoBob]

After reading & re-reading this, I have a question about cam sync with the 36-1. I currently have the trigger wheel set at the 7th tooth with the damper at TDC, per the instructions. My question is now at what position do I put the damper to set the cam sync shutter? In other words, how far back BTDC do I roll the engine to set the falling edge?

[Danny Cabral]

My question is now at what position do I put the damper to set the cam sync shutter? In other words, how far back BTDC do I roll the engine to set the falling edge?

That's what post #1 of this thread is all about:
http://forums.holley.com/showthread....m-Sensor-Setup (Crank & Cam Sensor Setup)

[AdvAutoBob]

I read that link already. There's no mention of 36-1 trigger wheel, only 60-2 or the 1x Flying Magnet. So using the example for the 60-2 trigger, I place the falling edge of the cam sync wheel at 50° before the "missing" tooth is read by the sensor (120° BTDC)?

[Danny Cabral]

So using the example for the 60-2 trigger, I place the falling edge of the cam sync wheel at 50° before the "missing" tooth is read by the sensor (120° BTDC)?

Cam Sync Setup: 180° BTDC, #1 cylinder, compression stroke.