How to pick ignition coils (for use w/ MS3 etc.)

[Moderator]

MS3-Pro will support pretty much any ignition coil I want to use, but what are the trade-offs?

Some specific questions:
If I can neatly package eight individual Chevy LS2/Truck coils, is there a reason not to use them?
Is it possible to have too-hot a coil, on a programmable, crank-fired electronic ignition system?
Are some coils audibly louder?
Do some coils produce more electronic noise which might disturb other electronics?
Apparently external capacitors are suggested for some coils, and some require an extra lead or two.
Is it harder or easier to keep some coils cool... or does that really matter much?

Note: I started researching here...  http://www.megamanual.com/seq/coils.htm

[BlownMGB-V8]

Curtis, I think it comes down to the choice of logic-level coils with a built in driver, or the use of an external driver circuit to power the coils. I do believe that MS3 has logic level outputs. (Please correct me if I am in error.)

What this means is that if you don't want to buy or build a separate 8 channel amp to drive the coils (I don't) then you cannot use direct fire coils such as Ford commonly used on their COP applications, which is a shame because they were a nice looking and compact coil. Small, cylindrical and with the lead coming right off the end.

I believe the coils GM used on the LS series motors are logic level coils and have a built in driver. But pretty is one thing they are not. I'm waiting for an attractive logic level coil to show up before I proceed with the MS3 (well among other things).

Jim

[lars49]

For a selection of what coil designs are available, check this out.  I came across it today while trying to determine if my ICM had a tach output.

http://www.regitar.com/FlyerPDF/IGNITION%20SYSTEM%202013_2014%20re1.pdf

[mgb260]

Curtis, The LS coils don't look bad if you make a bracket to mount them on the head. Or fenderwell.

[MGBV8]

If I ever go that route, they won't be on the valve covers. A lot of rodders hide them. Put them behind the dash, the cowl, down on the subframe, anywhere out of sight.

[BlownMGB-V8]

Yes but then you have all those plug wires. That was the beauty of using the Ford coils, they could plug right onto the spark plugs and you could mount them above on a slim rail attached to the valve cover bolts.

Jim

[MGBV8]

I thought we were pretty much used to having plugs wires coming out of the engine. Kinda like headers, radiators, carburetors.....all that good stuff.  

[Moderator]

Good insights - Keep 'em coming!

I expect to change from block-hugger to RV8-style headers after the ignition upgrade... That may add extra complexity to the problem.  I don't want to design two different coil & cable installations.  

Larry's link is enlightening. The OEMs have developed a mind-numbing variety of coils, very few of which look promising.

I like the photo Jim N. posted above... it certainly demonstrates that the coils will group tighter than GM puts them.

Perhaps I could put all the coils on my firewall, in two decks, stacked directly behind the respective valve covers.  Art's suggestion (in another thread) that I should consider Buick 340 valve covers is timely. I have a pair of those laying around. One thing that differentiates them is they have welded-on clips for routing spark plug wires in four neat rows right down their length.  

I may be "pretty much used to" the ugly spider of cables coming off my distributor, but that doesn't mean I've grown to like it. Bill Jacobson's solution of bringing cables up from underneath is the cleanest I've seen, but I don't have a lift and so I try to keep things serviceable from topside wherever possible.

(Gorgeous!)

[mgb260]

Curtis, Here is a good picture showing the bracket design. All thread,locknuts and tubing for spacers. I think there is enough room on either side of your fresh air intake on the firewall or directly above the RV8 style headers.

[MGBV8]

Coil relocation brackets

http://www.ironworksspeedandkustom.com/index.cfm/page/ptype=results/Category_ID=145/home_id=-1/mode=cat/cat145.htm



Or hide them under the subframe.

[BlownMGB-V8]

On top of the subframe. There is plenty of room between the rail and the headers. Block huggers would be different of course. I ran the wires underneath on my last engine similar to Bill's but had one coil pack up where it was visible. That would be my second choice but I would prefer that the wiring be more accessible, hence the idea of hanging the coils off the lip of the valve cover.

Several MFGs make coils that look pretty good, Honda, Hyundai, Kia, Audi/VW, Suzuki, Toyota, Landrover even. But there is no information about whether or not they use logic level inputs. For that they have to have at least 3 and probably four terminals plus the high tension lead.

May be time to browse the shelves of the local Advance store again.

Jim

[WernerVC]

Curtis,
I bought a coil bracket from Nigel Barker in the UK.
Here his e-mail : megasquirt.v8@gmail.com
Hope this helps you searching for coils and brackets

[NCtim]

Hey Guys,

What about the stock Lucas/Bosch coils that are are already installed on the newer Rover engines? Or, what's wrong with a magneto ignition? All those race Ferraris, Alfas, Masers and all the motorcycles in the world were/are using them. Such a simple design if your engine has accommodation for a distributor.

Mine does not accommodate a distributor so I'll try to use the stock coil packs like Evan Amaya did. His web site is no longer online but he stuffed the coils back next to the firewall like stock Rover. I'll try to ressurect his site because I want to reference his photos.

Tim

[Moderator]

Well... magnetos have been obsolete since ~1964 when Lucas (of all companies!) introduced their crank-fired electronic ignition systems on Coventry Climax and BRM Formula One engines.  (<a href="http://www.britishracecar.com/KurtDelBene-BRP.htm">Detailed photos and explanation here!</a>) Back in the day, the best magneto installations featured gears off the crankshaft. So, gear lash was relatively manageable compared to the bouncing timing chain set-up on my humble little Buick engine. Magnetos were for race engines... so no vacuum or mechanical advance features. By timing my ignition with a crank position sensor, I'll eliminate spark scatter!  The MS3-Pro computer will make it really easy to tune vacuum and mechanical advance. I can have multiple tunes: one for road and one for track. MS3-Pro can even be programmed to provide slightly different timing/advance characteristics for specific cylinders!

I'm not sure that the Rover coils would be any cheaper than Chevy coils. I don't have any laying around, so I'd still have to buy them. I'm not sure about how they're wired/triggered either (e.g. "logic level" inputs or not.)

[WernerVC]

Curtis,
Here a picture of the bracket that will hold two 4 cyl coils from a Ford EDIS ignition system.
The distributor might be in the way of the bracket.

[lars49]

Magnetos obsolete?? Depends on the application.

[BlownMGB-V8]

I know for a fact the EDIS coils are not logic level. However there is an argument to be made for the simple non-logic level coils. Fewer wires to each coil may make for a cleaner wiring job, the 8 channel coil amp could be hidden somewhere and I'm pretty sure there are coil amps available as modules. But personally, I like my wiring to be accessible.

Jim

[MGB-FV8]

Bill Jacobson, to put it simply, is an engine bay artist; who knows, he may be related to "Chip Foose"........ (LOL)

Here's what I've learned about the Ford, coil on plug, versus the GM coils; in our large fleet, we probably replace 15-20 (if not more) Ford, coil on plugs, for every GM coil.  We've always figured that the extreme heat was killing the ford coils, and also, it turns out that we had to replace the boots on a regular basis as corrosion formed between the plug tip and the coil insert.  Ford later on got wise and replaced them with silicone rubber boots.

Coil on plug have the cool show factor but if I had to chose, I would go with the GM coils and hide them just like Bill did.  Ford hardly ever had any problems when they were using the DIS system on the early Crown Victoria.

My 2 cents

[BlownMGB-V8]

Hmmm... wonder if the MS-3 can be set up to run the Ford EDIS-8 with the two double coil packs and still independently time the cylinders using the wasted spark? Since I already have the EDIS system on the car it may be something to consider.

However as you say Jacques, COP has the coolness factor. I'm thinking one of the imports might be the place to look. Anybody have experience with those? A good reliable logic level coil with a clean appearance and a simple one or two lug mount would be just the thing. A longer boot would get it away from the headers, and the boot would need to be able to handle about a 45 degree bend.

I don't think anybody could fault Bill's engine bay treatment. Mine looks like a spaghetti factory by comparison. I would like to do something about that. Lately I've been looking at Summit's woven split wire looms. Kinda expensive and I'm not sure how it will look or perform. My aircraft lacing may look sort of trick but it doesn't really give that clean appearance and despite being able to see all the wires it still isn't that user friendly when you have to cut the lacing to get to anything. I've actually been thinking about installing a bulkhead plug for a separate engine wiring harness but that's way, way down on the priority list and may never happen.

Jim

[MGB-FV8]

Jim, Toyota's V6 also uses the COP, it's a little different mounting but it also experiences occasional coil failures.  The EDIS uses its own independent module to take care of the ignition and timing, but I don't know how you could tie it to the MS-3 for fuel injection management???  The EDIS is the perfect ignition system for carburated engines........

[BlownMGB-V8]

Jacques, you would drive the EDIS coils from the MS3 but you would have to have a driver module, the idea being to drive the four windings separately. EDIS is good, it only needs a trigger sent to the MS and a SAW wave returned for advance. But it is not capable of timing the cylinders independently so far as I know so "ideal" is currently a bit dated.

I just hooked my spark plug wires back up and will use the EDIS initially on this new engine, but the coils are big, clunky and not attractive so they will probably go, in the MS3 upgrade. Provided I find some coils I like.

Jim

[NCtim]

Has anyone looked at the Honda 3.5 V6 coils? They're 3-wire but have a 90° angle. I don't know if that helps.

[Moderator]

My ignition coils arrived this morning!  I bought a full set of eight used "LS2 Truck" coils, on their original brackets and with harnesses. These are the coils GM used from about 2002 through 2006 on LS2 V8 powered Trail Blazers, Yukons, Escalades, etc. (They're type D585, coil part number 19005218.) Here's what they look like...

on their original bracket:


removed from bracket:


It's hard to see in that first photo, but each GM bracket assembly actually consists of five stampings. There are steel sub-brackets which wrap 270+ degrees around each individual coil. I don't think those brackets are particularly attractive or clever, so I'll probably discard them and cobble up something new. Doing so will allow me to pack the coils closer together. I think the absolute minimum footprint for four of these coils in a single row is about 6.5" by 2.25". From tip to tip, the coils measure ~3.75" long and then of course you need to allow room for the mating 4-terminal connector (at least 3/4") and the spark plug wire.

One unusual feature of these coils is that they have finned aluminum heat sinks. Even more interesting, GM installed little clips to ground the heat sinks of each respective coil to the steel brackets.

I'm still not certain where in the engine bay they'll fit best. You know that bracket MG mounted their fuse block on? I'm thinking about making a mirror image version of that for the driver side... I'm not really in love with that mounting location, but (a) it keeps the spark plug wires short and nearly equal length, (b) it puts the coils and their connections in a particularly serviceable location, and (c) the installation would be nicely symmetrical. The main downside is relatively close proximity to the exhaust headers - so I'm pondering covers and heat shields.

[BlownMGB-V8]

Those look really good Curtis! I might have to buy a set myself. I'm thinking about a bracket of some sort that attaches to the two outside valve cover bolts and positions the coils directly above the spark plugs. Then just a short conductor and a long boot should make the connection.

With four contacts I take it these *are* logic level coils? How about an end view showing the connector and heat sink?

Jim

[Moderator]

Definitely logic level... so MS3-Pro will drive them directly. (No additional electronics req'd.)

Here's another snapshot: