V8 Ignition

[stevehuckss396]

I have been considering what to use for an ignition system for the small V8. Roy's module will only yield 12,000 sparks per minute.

(12,000 X 2) / 8 = 3000RPM

Unless my math is wrong, it will only support 3000 RPM on a V8 engine. Using the same math I think I need.

(8000 X eight) / 2 = 32,000 Sparks per minute.

Is there another module out there that will supply spark at that rate, or am I going to have to build my own. I have a drawing of a TIM type ignition that my pal Louis designed that might work. I won't need alot of energy (CDI) because the plugs will be so small.

This circuit will drive an automotive coil.

 

[Lakc]

Yes, there is, but I have not finished designing it yet.

Frankly, I am not sure where your limitations come from, even the most basic of ignition circuits like you pictured should be capable of greater then 3k rpm on an 8 cyl. Perhaps your math is half off because there are only 4 sparks per rev of a 4 stroke 8 cyl.

 

[Blogwitch]

Steve,

I don't know if this will help

http://www.5bears.com/tim4.htm

Maybe the TIM7 unit. I used to use the TIM6, and it performed faultlessly once I started to pot the hall sensor up to keep it away from any stray whatsits that could short it out. I was not quite up to your RPM, but I do know the model V8 lads were using the same sort of system a few years back by using a distributor and a steel interrupter plate. I used to make my own TIM boards up, but the last one I used was the generally available kit ones, and that seemed to work just as good as the others.

It is also worth rooting through the 5 bears site, as a few interesting things are going on there in the oldish stuff.


Bogs

 

[stevehuckss396]

Yes, there is, but I have not finished designing it yet.

Perhaps your math is half off because there are only 4 sparks per rev of a 4 stroke 8 cyl.

4 X 8000rpm = 32,000

 

[stevehuckss396]

Frankly, I am not sure where your limitations come from

Not my limitations, Roy posted on his site that his CDI will only deliver 12,000 per minute. Being too lazy to build my own, I was hoping someone makes a module that delivers what i need. If I have to, I'll build the circuit that was posted.

 

[gbritnell]

Hi Steve,

When I sorted out the problems with my 302 ignition I pondered the same questions as you regarding Roy's ignition versus Jerry Howell's ignition. I have several of each type.

My 302 will rev to 7200 rpm so that's 28,800 sparks per minute. Not that I have held it there for any amount of time. I am currently running it on the Howell style ignition (TIM-6). I have switched over to Roy's and it seems to run fine but I have never taken it up to maximum rpm as I did with the other ignition installed. Once I found out how high it would rev I was satisfied and don't press the limits anymore. I don't need a box full of bent and broken pieces.

I had gone to the 5 Bears site quite awhile ago when I got into the electronic ignitions. I bookmarked it for reference. When I was having trouble with burning up or shorting out Hall sensors I thought that maybe it was the sensors themselves as the ones being supplied by Alan Howell now are different from the ones his Dad was providing. I did a search for the HAL 506-UA and found one place in California that sold them. Other places like DigiKey have replacement types but being as 5 Bears picked that one I ordered 6 from out west. I wired up a couple as replacements and have tested them for a long duration and have had no trouble.

I guess to answer your question, I would think that Roy's ignition or the TIM-6 would work fine for your engine.

I am planning on being at Zanesville in October so we can swap notes there.
George

 

[fltenwheeler]

Here's a link to a data sheet for HAL5** Hall Effect Sensor Family.

http://www.dsymcu.com/templates/200612199453300.pdf

Current information: http://www.micronas.com/en/automoti...xy/product_information/index.html?doc=1355238

Tim

 

[tonyengines]

FANTASTIC ............. See this ;D

http://www.cncengines.com/orderpage.html

 

[Lakc]

4 X 8000rpm = 32,000

I try to make it a habit not to do math before 8am, shame on me.

Ignition primary systems are mostly about current flow, as that is the factor that creates the magnetic field. Any installation that cannot provide large inrush current to the coil primary will limit spark energy to the point it could diminish at higher rpms. Same could be said for any coil with too high primary resistance. So, there are a lot of factors outside of the module itself to consider.

 

[stevehuckss396]

FANTASTIC ............. See this ;D

http://www.cncengines.com/orderpage.html

Hi Tony!

This site is Roy's site for the CDI module.

 

[stevehuckss396]

I try to make it a habit not to do math before 8am, shame on me.

Ignition primary systems are mostly about current flow, as that is the factor that creates the magnetic field. Any installation that cannot provide large inrush current to the coil primary will limit spark energy to the point it could diminish at higher rpms. Same could be said for any coil with too high primary resistance. So, there are a lot of factors outside of the module itself to consider.

I have some time to figure it out but it would like to have all this stuff worked out in advance.

 

[d-m]

Hi guys
I may be missing something here but Ill throw this out. I have read several post on this topic and still am confused as to why your buying these modules to run your IC engines. It cant be size because your running a full size auto coil and oil filled at that! Has any one gone and bought a 35.00 delco 4 pin module and tried one, it wont do much over 5000 rpm but for most apps it will be fine. it is my first choice when refitting a burnt up module on any vehicle from Toyota to Ford some of the modules are vary spendy, take the Toyota igniter years ago they were well over 250$ the customer was vary happy when the bill was less than half.I have a friend that I put delco module on his Toyota and it has been on there for years trouble free. Here is how i see it it is just an electrical switch give it a signal and it will fire the coil.The 4 pin module is even marked as to how it is wired and has a tac connection. Be sure to put it on a heat sink and use dielectric on the surfaces.And if you need more rpm google used motorcycle parts and buy a moudle from a bigger rice rocket some of them are up 12+ rpm! and find yourself an E coil you wont regret it.
Dave

 

[Rustkolector]

Steve,
I was talking to Roy Sholl today on a CDI module for one of my engines. I mentioned this thread to him, and his comment to me was that he can provide CDI systems up to 30,000/min. He doesn't have much calll for them, but he can provide them. You might want to give him a call.
Jeff

 

[fltenwheeler]

Hi guys
I may be missing something here but Ill throw this out. I have read several post on this topic and still am confused as to why your buying these modules to run your IC engines. It cant be size because your running a full size auto coil and oil filled at that! Has any one gone and bought a 35.00 delco 4 pin module and tried one, it wont do much over 5000 rpm but for most apps it will be fine. it is my first choice when refitting a burnt up module on any vehicle from Toyota to Ford some of the modules are vary spendy, take the Toyota igniter years ago they were well over 250$ the customer was vary happy when the bill was less than half.I have a friend that I put delco module on his Toyota and it has been on there for years trouble free. Here is how i see it it is just an electrical switch give it a signal and it will fire the coil.The 4 pin module is even marked as to how it is wired and has a tac connection. Be sure to put it on a heat sink and use dielectric on the surfaces.And if you need more rpm google used motorcycle parts and buy a moudle from a bigger rice rocket some of them are up 12+ rpm! and find yourself an E coil you wont regret it.
Dave

Hi Dave

Do you have a model/year or part number?

Thanks

Tim

 

[gbritnell]

Hi Dave,
The thing is were not running full sized automotive coils on these engines. The CDI unit the Roy Scholl sells is self contained with a coil. The whole unit is no larger than 3x2x1 inches. If one chooses to use the TIM-6 style ignition, it's about the same size as the S&S unit except that you need a separate coil.
The problem with using automotive electronics for small engine work is the compatibility of triggering devices. I'm sure in this wonderful world of electronics there are components out there that could be made to work but in all my years of playing with these things no one has stepped up to give a list of parts (automotive) that can be put together to work any better than the two systems being discussed.
I and many others started out with a 12 volt system with an automotive coil, ballast resistor, points and condenser to run our engines. The problem was that you needed to design miniature points and then you had high currents running through them that would make them erode in a very short time. If you look at some of the earlier multi-cylinder engines the distributors were made way out of scale to the engine. The reason being mainly to get a large set of points inside them.
With the Hall trigger ignitions a remote timer can be set up, it doesn't even need to be inside the distributor. The spark can then be sent from the CDI back to a scale distributor and then out to the appropriate cylinder.
The problems I had with my 302 over the years were 90% ignition because I was trying to use miniature points inside of a scale distributor.
As miniature engine builders we are all open to any better way to 'fire' these things but most of us have no background in electronics. We are just machinists.
gbritnell

 

[Lakc]

I have a hunch that most of Roy's customers are from the model airplane fraternity, size and weight matter a whole lot to them.

The early solid state ignition systems were simple enough, and can be pressed into service easily if so desired. The 5 pin family, as I call them, consists of the 1971-90's? Chrysler 5 pin ECU, the 1973-90's? GM HEI system, and the Motocraft 1971-??? in the Fords. These are all basic ignition control systems, ground side switching like points. All need 5 wires to work, power, ground, coil negative, and both sides of the pulse generator. They use a reluctor setup similar to a lawnmower magneto where a rising voltage from the pickup in the distributor triggers the coil firing. They are simple, but they are made to trigger from an AC generator signal, require a ballast resistor or some form of current limitation, and may be difficult to trigger with a hall effect or optical pickup. They are all current hogs, and will suck batteries dry rather quickly. Except for the HEI, the domestic choices are not very small, but the HEI will soon fail without a full contact heat sink.

Around the 1980's the ignition modules began to acquire a few extra pins, and abilities like timing adjustment. Some modules disappeared into large multi wire engine control units, others lived in the distributor still. The imports into the US would sometimes use optical pickups, but would still need the same 5 things to operate. Towards the end of the 80's distributors were disappearing, coil packs were appearing, but some of the truck lines still used the older systems.

Coils, as you probably have noticed, have changed quite a bit along the way as well. The old round oil-filled coils gradually got phased out by a more efficient, PCB oil free, E-core. Those coils require an entirely different driving strategy, as they lack their own cooling.

Fitting automotive modules, especially if you get them and the associated harness pigtail connectors from a junkyard, is entirely feasible. Building them into a reliable ignition system takes a little bit more work.

Edit: Old age must be setting in, the HEI does not require any current limitation.

 

[stevehuckss396]

I have read several post on this topic and still am confused as to why your buying these modules to run your IC engines.

Roy's module is $58 complete. That includes the module, coil, and sensor.

You could buy the delco module and a coil and then order a hall sensor and see if you can get the ignition to work. You also then need to get some wire and make a heat sink. The only way I wouldn't use his board is if it didn't do what i need as in the case of the V8.

Why do all that when Roy's is the same price and there is no guess work. It will also be 1/4 the size.

 

[d-m]

Hi guys
This is why I and so many like me read and ask questions on this board the knowledge base here is vast. Answers are to the point and relevant thanks for the info.
Dave

 

[stevehuckss396]

Hi guys
This is why I and so many like me read and ask questions on this board the knowledge base here is vast. Answers are to the point and relevant thanks for the info.
Dave

All part of the service!

 

[kcmillin]

Steve, I cannot find the $58 kit on Roys website.

Cheapest I can find for a kit is $80.

Can you post a link to the page?

Kel