BA-4 Ignition Coil

Bowman74 · Post by **Bowman74** » Mon Dec 06, 2004 6:20 am

The ignition coil on my BA-4 heater is shot. Of course it is a very specialized part to be shoehorned in that small space. Does anyone know of a good source of a replacement?

Thanks,

Kevin

albert · Post by **albert** » Mon Dec 06, 2004 2:21 pm

i see at the samba.com (1or 2 )complet heather for appx. 40$ and 100$ you have bunch spare parts.

MGVWfan · Post by **MGVWfan** » Mon Dec 06, 2004 8:16 pm

Apologies for the long dissertation

Funny you should mention BA4 ignition coils. While I was waiting for the rain to end so I could pull the drivetrain from my 412, I pulled the stuff off the BA4 to work on it. The BA4 coil on my 412 is inop, open primary. I pulled one from the 411 in my local yard a month or two ago, also inop, open secondary. I checked with some sources of Bosch supply, $120 new. Hmmm. I went back to the junkyard, and found one from an 80's Mazda that is bigger, but appears to fit mechanically...$10. The only problem is that it's made for transistorized ignition, so it's got a low impedance primary, measures around 1.2 Ohms vice the 4 Ohms of the original Bosch coil. If you connected it up to the BA4's blower motor points, it'd fry them in short order. The only mod needed to make it work is to extend the wire from the points to the other side of the coil from the OE coil (the "-" side of the coil), and add a ballast resistor in the green wire going back to the heater relay (the "+" side of the coil). The resistor should be 3-8 Ohms, minimum of 25 Watts. This is a larger resistance than most standard ignition ballast resistors, but Dale, Ohmite, and others make aluminum-cased resistors in this power rating that should fill the bill nicely. I'm checking the Mouser catalog next. It looks like a slightly bigger brother of the Bosch coil, with the low voltage terminals on the other end from the HT nipple. It's also on Mercury Tracers (Mazda by any other name), it's a Hanshin F280 18 100. I tested this setup with a paralleled set of 6 - 5 Watt resistors, and the spark plug showed a nice, fat spark...and the current draw (with a 7 Ohm resistance) was less than 2 Amps, which should help point life considerably.

EDIT - Not that I have any Mouser stock or anything, but here's a link to an appropriate resistor (Mouser P/N 71-RH25-7.0, Dale P/N RH0257R000FC02)...

http://www.mouser.com/index.cfm?handler ... deid=71014

...and a link to the online catalog page describing the part...

http://www.mouser.com/catalog/620/422.pdf

Scroll to the bottom of the page. Requires soldering two wires, and finding a place to mount it (NOT on the BA4's body, maybe a bracket using the two ignition coil mount screws, or somewhere on the car's body?). $10 for the coil plus $3.28 for the resistor, plus shipping...beats $120 in my book.

Bowman74 · Post by **Bowman74** » Tue Dec 07, 2004 9:59 am

Thanks for the great replies. If I can get a new coil (even if for $120) then that's what I'll do. You never know if the one on either of those heaters work and I don't want to modify the car if I don't have to. I'll just have to see if I can find a Bosch reseller that will be able to get one for me. I have the VW part number but not the Bosch one off hand and my car is at the shop getting repainted. Hopefully they will be able to look it up by the VW part number.

So, MGVWFan, do you know of a Bosch reseller I could get it from?

Thanks,

Kevin

MGVWfan · Post by **MGVWfan** » Wed Dec 08, 2004 7:06 pm

Well, if you live around Webster, TX, yeah. It's the Webster Import Auto place on NASA Road 1, and last time I asked, they could still cross reference that Bosch number to a listing. Whether that means one's still left on this continent, I have no idea, since I heard the price and lost all feeling in my billfold after that

and decided to "roll my own" solution.

BTW, there are really no mechanical mods required, and the electrical mods can be made to be reversible. If you (or anyone else for that matter) wants more details, I can provide some more info...

Good luck however you get there!

raygreenwood · Post by **raygreenwood** » Wed Dec 08, 2004 9:57 pm

Great info. Also..are you sure your coil is shot? Thats actually pretty rare. Check the points, screw cam and ballasts in the blower motor ends. Also check your high temp limit switch, and the thermo probe switch. All of those can stop ignition.Ray

albert · Post by **albert** » Thu Dec 09, 2004 5:12 am

the name of your heather is eaberpasher , go on the web and the cie have adress. for to by new or repair in your région salutation

Guest · Post by **Guest** » Thu Dec 09, 2004 8:29 pm

Ray Quote: "Also..are you sure your coil is shot? Thats actually pretty rare. "

Yeah, agreed, I've never had a real-live ignition coil die on me either (the kind that causes the go-juice to burn and push the pistons down...Autolite, Prestolite, Lucas, Bosch, Mitsubishi, Hitachi, Hanshin, you name it, I've had it in a car, except Marelli

), but I've run across two OE Bosch Eber coils now that're shot, the one that came with the 412 and one from a junk 411. Two different failures, one with an open primary, one with an open secondary (both read greater than 100 megohms with a Heathkit digital bench DVM, and greater than 10 megohms with a Triplett 630 VOM). It kinda shocked me, too, but there it is.

Moral is, no spark, measure the resistance across the flat blade terminals (primary), it should read something less than 10 Ohms (actual value is around 4 Ohms), and from either of the flat terminals to the metal contact inside the high voltage nipple (secondary) should read something like 10 K Ohms (more or less OK, but not infinity like one of my Eber coils).

Bowman74 · Post by **Bowman74** » Fri Dec 10, 2004 9:05 am

raygreenwood wrote:Great info. Also..are you sure your coil is shot? Thats actually pretty rare. Check the points, screw cam and ballasts in the blower motor ends. Also check your high temp limit switch, and the thermo probe switch. All of those can stop ignition.Ray

No, I'm pretty sure it is dead. I hook it up the the external coil that I use with my BN-2 on another car and it works like a champ. I look it up the the coil on the heater, no dice.

Thanks,

Kevin

raygreenwood · Post by **raygreenwood** » Fri Dec 10, 2004 12:49 pm

Dang...thats too bad. But..it should not be too much different in operation than a regular ignition coil. It may take a variation on the condensor set up though...its worth a try. Also...just for the heck of it...check lawnmower shops. Some ofthe newer 4 stroke models use coils instead of magnetos...I think. Ray

MGVWfan · Post by **MGVWfan** » Fri Dec 10, 2004 4:22 pm

Darn login monster!

MGVWfan · Post by **MGVWfan** » Sat Dec 11, 2004 9:29 am

Hey Ray, good point (what a pun) on the condenser. With a lower impedance primary, my Hanshin coil may require more capacitance to supress point sparking. When I get the Eber out and install the Hanshin coil, I'll take pictures to post, and put it on the scope and see if it needs some external capacitance, in addition to the ballast resistor. Even if it does, no big deal, just another small thingy to mount with the resistor...and metal cased waterproof condensers (capacitor in electrical speak) of various values are readily available, they're used on small engines like Briggs or Tecumseh, as well as for use on old Bosch distributors (like ACVW's).

albert · Post by **albert** » Fri Jan 14, 2005 8:04 pm

allo bowman go to ,,,,www.vw nos .com ,,,,, if you need nos parts for gaz heather, it is cdn adress , go at the end of the page , gaz heather section good luck

Shoptalkforums.com

BA-4 Ignition Coil

BA-4 Ignition Coil

ba4

Found a coil for the BA4, fits but needs electrical mods

ba4

Guest was me...

ignition coil