Modifying the Holley HyperSpark distributor 565-315 (made for the "small block") to work with a "big block" Ford 240 six or 300 six (with Holley ECMs)

[Frank]

I see some good theory in-application here for rotor phasing, but you can calculate the crank angle where the rotor should be exactly aligned at the cap terminal. This ensures the rotor is as close to centered on the terminal at any advance, reducing spark gap and potential cross-fire. I created this 'formula' to find optimal alignment angle, using base timing and max advance. It makes the job clear and quick. An excerpt from an article I wrote a few years ago:

I'll note here that max advance can approach or exceed 50°BTC for many engines, so verify your actual rather than assumed max. Also, that different systems may use different terms for Trigger Angle above.

Nice stuff- thanks. Easier to phase with the TFI with the wide contact blade. It needs to be phased where base timing is at the trailing edge so that the computer initiated advance can "travel forward" on the blade and it's still in contact with the cap contact lug. The wide contact blade is a plus IMO. Superior to Holley distributor with it's narrow blade.

 

[PSIG]

It needs to be phased where base timing is at the trailing edge so that the computer initiated advance can "travel forward" on the blade and it's still in contact with the cap contact lug.

Mmmkay, but that hangs the wide tip much closer to the next terminal when it may not need to be, and why I do a simple calculation to find true center of travel for max clearance on both sides and minimum cross-fire opportunity. The concept works with skinny rotor tips and small caps also, without measuring, cutting holes in caps, for any max advance or base timing, etc. Do your thing.

 

[bangstk]

My timing range is currently from 6 at cranking to 45 at maximum advance so centering the rotor at 25 is a good spot.

Just to share more info, I measured my TFI rotor blade with a protractor and it is about 25 degrees wide (so 50 in crank degrees).
The Holley Hyperspark one appears to be about 15 degrees (30 in crank degrees). It may have wider cap posts to make up some of the difference.

The truck is running very nicely with the advanced-clocked hall effect sensor. I think anyone using the TFI dizzy with Sniper or Terminator should definitely do that. I don't see how it could possibly work without that unless you only want 25 or 30 degrees of max advance.

 

[PSIG]

The truck is running very nicely with the advanced-clocked hall effect sensor. I think anyone using the TFI dizzy with Sniper or Terminator should definitely do that. I don't see how it could possibly work without that unless you only want 25 or 30 degrees of max advance.

Let me see if I can repeat back in different terms, to confirm what you are saying, from a different direction.

Problem definition: When (Holley) static timing is adjusted, moving the distributor body moves the sensor. Unfortunately, this also moves the cap terminals from that nicely centered position and rotor phasing may be lost outside an acceptable range from centered. This limits total advance available. Is this accurate to your point?

As the trigger occurs when the sensor signal goes high (end of tooth), and the sensor is attached to the distributor housing (along with cap terminals), when you move the body to set Static Timing to x° BTC for rotor centering with the distributor housing, the rotor phasing position is not held. Without moving the rotor position on the shaft - the sensor position must be adjusted in order to set Trigger Angle ('offset', 'Static Timing' in Holley), without losing rotor alignment phasing. Is this accurate?

I don't have a running Holley setup here to try this, and this is knee-jerk (I'm time-limited right now); but the solution could be setting static timing at the rotor phasing angle. I do not recall offhand if the Holly versions each use the static timing setting as trigger angle offset; but if your rotor phase crank angle is [45-6/2+6=] 25.5°, then set Static Timing to ±25° and adjust the distributor housing to match with a timing light (which should be very close).

I have not thought this through, and am thinking out-loud for others to review for where I missed anything, or Holley treats things differently in certain versions. The trick in all of this is holding in-mind the relationships between the crank position, versus the shaft, rotor, cap, trigger/shutter wheel, and sensor positions, and how relationships change as any one of them changes. Note this is specific to Holly, as other systems use an offset value to set the relative positions, so trigger point and rotor phasing are independent.

 

[bangstk]

Problem definition: When (Holley) static timing is adjusted, moving the distributor body moves the sensor. Unfortunately, this also moves the cap terminals from that nicely centered position and rotor phasing may be lost outside an acceptable range from centered. This limits total advance available. Is this accurate to your point?

I'd say:
Problem definition: The Ford TFI distributor as it comes has a physical trigger angle of about 30 (when everything is timed to fire with the rotor pointing at a cap post at 25 BTDC). However, in Holley EFI this limits the maximum advance to 30 because the advance cannot be greater than the reference angle.

If you lie to the Holley EFI software to say the trigger angle is 55, this will cause the rotor to fire between cap posts., because:

• The system works by subtracting the desired timing from the trigger angle setting (what holley calls reference angle) in the software. So say your timing table is currently calling for a timing of 15, and your trigger angle setting is set to 55, the system subtracts 15 from 55 to get 40 degrees. When the hall effect sensor is triggered, it will wait 40 degrees and then fire. This is why the trigger angle setting must be greater than the maximum advance you want, because it can't wait a negative amount of time, nor long enough to do nearly a full 360.
• Turning the distributor body alone does NOT affect rotor phasing relative to a cap post, it only affects the global offset of all timing no matter what the EFI computer is calling for. This is because the system will still wait the same amount of time past when the sensor gets triggered no matter how far you turn the distributor housing. You advanced the sensor, but the cap post also advanced with it. So the relationship between the sensor and the cap post does not change from turning the distributor body.
• Changing the trigger angle setting DOES affect rotor phasing, because it reduces how long it will wait before firing in the above calculation. You will need to turn the distributor housing after reducing the trigger angle setting to put the firing back into time, because now it will be firing sooner than before.
• So, changing the trigger angle setting suffices to phase the rotor, but because you must reduce the setting by 2 degrees to advance the rotor by 2 degrees, you can quickly run out of max advance because you will have reduced the trigger angle setting too far. Advancing the rotor by 20 degrees this way would mean having to drop the trigger angle setting by 20 degrees, which can easily make it too low to allow for reasonable max advances of say 40 or 45.

So the fix is to actually physically alter the trigger angle by moving either the sensor, trigger wheel, rotor, or cap posts relative to the rest. I chose to move the sensor because it does not require drilling any new holes, moving the securing link to the sensor body to the other post on the sensor body sufficed to advance the sensor by 20 degrees.


I'm a bit confused by what you mean by "Set static timing to 25". Do you mean the trigger angle setting?
In Holley, what it calls "static timing" is a feature that makes the Holley EFI ignore your timing table and stay at a certain timing no matter what your RPM is. It is not a setting, but a temporary test mode.

 

[PSIG]

Well said, and yes, agreed with all the above. My bad, I had said trigger angle and then said static timing. Yes, trigger angle, or the offset of trigger to TDC. This is an issue specific to Holley as it is limited to timing between cylinders, whereas other systems (e.g., MS) can use 'next cylinder' mode for any trigger angle from 0 to 120 (6-cyl), and simply apply it to the next cylinder/firing. @Baxsie - from this, I would suggest re-titling the thread to add "with Holley ECMs" as this Forum section is Fuel Injection - Mega Squirt. Just for clarity and applicability if using a HyperSpark with others.

 

[Frank]

I'd say:
Problem definition: The Ford TFI distributor as it comes has a physical trigger angle of about 30 (when everything is timed to fire with the rotor pointing at a cap post at 25 BTDC). However, in Holley EFI this limits the maximum advance to 30 because the advance cannot be greater than the reference angle.

If you lie to the Holley EFI software to say the trigger angle is 55, this will cause the rotor to fire between cap posts., because:

• The system works by subtracting the desired timing from the trigger angle setting (what holley calls reference angle) in the software. So say your timing table is currently calling for a timing of 15, and your trigger angle setting is set to 55, the system subtracts 15 from 55 to get 40 degrees. When the hall effect sensor is triggered, it will wait 40 degrees and then fire. This is why the trigger angle setting must be greater than the maximum advance you want, because it can't wait a negative amount of time, nor long enough to do nearly a full 360.
• Turning the distributor body alone does NOT affect rotor phasing relative to a cap post, it only affects the global offset of all timing no matter what the EFI computer is calling for. This is because the system will still wait the same amount of time past when the sensor gets triggered no matter how far you turn the distributor housing. You advanced the sensor, but the cap post also advanced with it. So the relationship between the sensor and the cap post does not change from turning the distributor body.
• Changing the trigger angle setting DOES affect rotor phasing, because it reduces how long it will wait before firing in the above calculation. You will need to turn the distributor housing after reducing the trigger angle setting to put the firing back into time, because now it will be firing sooner than before.
• So, changing the trigger angle setting suffices to phase the rotor, but because you must reduce the setting by 2 degrees to advance the rotor by 2 degrees, you can quickly run out of max advance because you will have reduced the trigger angle setting too far. Advancing the rotor by 20 degrees this way would mean having to drop the trigger angle setting by 20 degrees, which can easily make it too low to allow for reasonable max advances of say 40 or 45.

So the fix is to actually physically alter the trigger angle by moving either the sensor, trigger wheel, rotor, or cap posts relative to the rest. I chose to move the sensor because it does not require drilling any new holes, moving the securing link to the sensor body to the other post on the sensor body sufficed to advance the sensor by 20 degrees.


I'm a bit confused by what you mean by "Set static timing to 25". Do you mean the trigger angle setting?
In Holley, what it calls "static timing" is a feature that makes the Holley EFI ignore your timing table and stay at a certain timing no matter what your RPM is. It is not a setting, but a temporary test mode.

You keep referencing 30 or so degrees max timing. That is within the range of the original EFI 300 ECM with the EFI head. It's not relative to the changes needed for the Holley, just a comment.

 

[bangstk]

Well that makes sense. Sounds like my measurement of 30ish reference angle is pretty spot on then.
I think the older carb 300s would go quite a bit higher than 30 when mechanical and vacuum advance are both in, and that's what I want since ours is a 65 motor without the faster burning EFI head.
I figure it's better to have a little more range than I'd use than not enough.
But that's good info for anybody trying this setup, it didn't occur to me that someone might have an EFI motor and not need as much advance.

 

[PSIG]

You keep referencing 30 or so degrees max timing. That is within the range of the original EFI 300 ECM with the EFI head.

Are you sure that's max advance (base + advance) at part-throttle?

 

[Frank]

Are you sure that's max advance (base + advance) at part-throttle?

My friend, I'm not sure of anything electronic. I do know that the max advance at any time in the factory table is 28*, and it's being pulled back from that as much as 8* at high engine/intake temps. Hot, my EFI engine with mechanical distributor pings with any more than 26* total timing . Base + centrifugal.
See post #83 below

https://fordsix.com/threads/trying-to-get-basic-mods-wrapped-up-help-appreciated.86419/page-5#post-708667

 

[PSIG]

Ah, I thought you might be referring to the MBT base timing table in the EEC. Just remember, that table is incomplete, and does not include function modifiers that can and will change actual timing substantially. You can see this if you connect an OBD reader to watch real-time timing change. For example, it has no part-throttle "economy" timing added, etc. Anyway, not saying you're wrong for total timing at 100% TPS (which the table doesn't even reach), but I certainly wouldn't go by that one table alone to try for total timing using mechanical or convert to typical aftermarket digital table. I'm sure @efloth can guide more specific function data for a complete picture, as he has the bin files for reference, and appears to have a good handle on it.

 

[Frank]

Ah, I thought you might be referring to the MBT base timing table in the EEC. Just remember, that table is incomplete, and does not include function modifiers that can and will change actual timing substantially. You can see this if you connect an OBD reader to watch real-time timing change. For example, it has no part-throttle "economy" timing added, etc. Anyway, not saying you're wrong for total timing at 100% TPS (which the table doesn't even reach), but I certainly wouldn't go by that one table alone to try for total timing using mechanical or convert to typical aftermarket digital table. I'm sure @efloth can guide more specific function data for a complete picture, as he has the bin files for reference, and appears to have a good handle on it.

I only know an EFI-head 300 uses the least total timing at any vacuum or load than any other engine I've encountered. Thus that may be a factor in the OP's surprise at the factory phasing.

 

[Baxsie]

So, to verify the rotor phasing, could I get a spare distributor cap, dremel a semi-circular opening where I could see the spark jumping from the rotor to the contact in the cap? Or would that all be a visually useless blur. Maybe hook a timing light to the plug wire that I'm looking at - that should flash and capture the rotor's position at the time of the spark . . . right? right ?

 

[PSIG]

Yes, you could, but is unnecessary — unless you're just curious (which is cool). Not only is calculating and static visual alignment simpler, but you can look at all the parts and how they relate, to see other options of how to achieve rotor phasing. We're not trying to split hairs here, just have a reasonable alignment at extremes in order to avoid problems. MSD example:

Unfortunately, while you can see if it's reasonable or not, it tells you noting about how to correct it if it's not right.

Also consider the options change depending on the system (EEC, MS, Holley, etc). Most aftermarket DIY systems can use any trigger point and any rotor position to set rotor phase, while others like factory EEC expect a specific position, timing, etc, and are set for that expectation. While total timing for an EFI 300 (and other Ford engines of the early EFI era) could be 28-32°, part-throttle will add another 8-14° to that figure. That's why we can't use the table linked earlier for our final estimates, as it is incomplete.

A very similar situation is found with the Ford 302/5.0 using E7 heads, which like 30° max at 100% throttle, but pushes timing at part-throttle to 41° total. This means the rotor position is now 10° (base/cranking) to 41° for calculations (31° change). Twist the distributor timing 3° for a bit better factory performance and it's now 13-44°. The EFI 300 is likely very similar with factory phasing set appropriately. Most DIY systems don't care and have no restrictions.

If tuning to other spec than factory, the advance range will also likely change, which affects the rotor range extremes and center position. Again, avoid splitting hairs. Just verify it's reasonably close. Rather than complicating the issue, I'm hoping to let others see that it's actually easier depending on what system you're using, and sticking to the basics of movement and timing relationships for a quick and easy solution using pencil and paper.

 

[Frank]

While total timing for an EFI 300 (and other Ford engines of the early EFI era) could be 28-32°, part-throttle will add another 8-14° to that figure. That's why we can't use the table linked earlier for our final estimates, as it is incomplete.

I'm going to say again that at no time does a 300 EFI ever see 40* timing advance. The table may be "incomplete", but my 13 years of daily EFI300 experience is not.

 

[Baxsie]

Thanks for your replies.

I just want to eliminate any possible stupidity. I think my max timing is ~36°. Which I think I just pulled out of the air - or maybe some random forum post? Certainly not scientific or authoritative. At full throttle I have to bring it down (maybe 26° ?) so it does not ping.

I am thinking I would like to eliminate the very real possibility that I did something dumb with the rotor phasing and it is "just barely" working. The slot test should make that visible. Maybe I'll get a new cap for daily use and make a cut-out in the current cap -- which is whatever was on the 1988 junk yard disty.

If there is some trouble I should be able to get some idea which way to move the sensor to correct it by seeing which end of the rotor the spark is having to jump from.

 

[PSIG]

I'm going to say again that at no time does a 300 EFI ever see 40* timing advance.

That's fine, if it is best timing. How did you determine actual total timing applied under various conditions? With an OBDII data logger?

 

[Frank]

26* total is all my EFI head 300 can take hot at hard load.

 

[Frank]

That's fine, if it is best timing. How did you determine actual total timing applied under various conditions? With an OBDII data logger?

This engine is carbed and has a DS2 that has 21* total cent advance. Base timing is *5*. Vacuum advance is 10*. Worst mistake I've made, removing the factory EFI. It's been said but bears repeating here- this engine is the most sensitive to heat, ambient or engine, of any engine in my experience. The knock sensor is the best feature of the stock configuration. The factory table begins pulling timing @ 185* coolant temp, and has reduced total timing across the load range a whopping 8* by 200* coolant temp. At this season of the year (summer) my engine pings from light load thru WOT beginning @ 185* coolant temp. If the engine reaches 200*, which happens occasionally pulling the trailer, I pull over and remove the vacuum advance hose. Otherwise the pinging is severe enough to be damaging. With no vacuum advance the cruise-load vacuum is better, and so is power, when the engine or ambient air is hot.

 

[pmuller9]

This engine is carbed and has a DS2 that has 21* total cent advance. Base timing is *5*. Vacuum advance is 10*. Worst mistake I've made, removing the factory EFI. It's been said but bears repeating here- this engine is the most sensitive to heat, ambient or engine, of any engine in my experience. The knock sensor is the best feature of the stock configuration. The factory table begins pulling timing @ 185* coolant temp, and has reduced total timing across the load range a whopping 8* by 200* coolant temp. At this season of the year (summer) my engine pings from light load thru WOT beginning @ 185* coolant temp. If the engine reaches 200*, which happens occasionally pulling the trailer, I pull over and remove the vacuum advance hose. Otherwise the pinging is severe enough to be damaging. With no vacuum advance the cruise-load vacuum is better, and so is power, when the engine or ambient air is hot.

So why isn’t 63 Sprint with a 192 thermostat having the same problems?

Stock EFI long block with stock cam.
EFI head, DS2 distributor, Holley 390, Offenhauser C and EFI exhaust.
2.42 overall gear ratio in OD.