Converting Stock Distributor Cap

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Unfortunately, no pieces left on the shaft, bare metal and no cap of any kind. I haven't called Summit yet, but plan on doing so first thing in the morning. It's either a manufacturing error or a rotor that got mixed up in shipping.

Weird and frustrating.

If I learn anything interesting, I'll pass it a long.

Thanks Paul

Edit: I did have my distributor curved and rebushed by someone here on the sight. I can't imagine that a different sized shaft end was used, but I'll check the o.d. against an old distributor and see if their the same size.

 

[jckkys]

Somehow I didn't adequately communicate the fact the large distributor cap isn't an upgrade from the stock cap. They ARE the stock cap, at least on the '77s. By simply going to RockAuto or any parts supplier and ordering a '77 cap, cap base, rotor, and plug wire set, you'll have everything you need. The Duraspark rotor is much bigger than the points type. The upper shaft is 0.625" or 5/8" diameter where it fits into the rotor. I think most all Ford distributors are the same in that dimension, as Paul said.

 

[k13evin]

I always get mine from a 80 to 86 f150 cap,coil. The tfi coil works the best I think with 8mm wires.
Had a wagoneer with the same thing amc 360 and that would start in any weather a purr. But it did have the motorcraft carb tho. ;D

 

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"Somehow I didn't adequately communicate the fact the large distributor cap isn't an upgrade from the stock cap. They ARE the stock cap, at least on the '77s..."


Ah yes, I should have through my own thread. Thanks for your help.

 

[DaveLev]

So if you have a stock distributor with points / condenser / resistor thing and stock coil on stock 289/302 1968 engine, and you want to upgrade to HEI (integrated coil, etc.), which one does the group recommend? Thinking of upgrading the whole works vs. doing the electronic only conversion and huge external coil. I would be upgrading wires at same time.

 

[ntsqd]

Some nomenclature first. "HEI" is specifically a GM ignition system though the term gets used to (erroneously) describe other electronic ignition systems. HEI's are the only system that has the coil reside in the distributor cap (& only the non computer controlled versions at that), all other electronic ignition systems, such as Ford's Dura-Spark & Dura-Spark II systems continue to use an external coil. At least within the US, no idea about abroad.

Some guys like the simplicity of the install with an HEI, but they have two issues that need to be addressed. One is hood clearance. I'm not up on the details since I haven't done such a conversion, but I've read of hood clearance problems w/o a body lift. Second is the bigger deal though it gets less attention, that is that HEI ignition modules are power hogs. GM HEI factory power wiring is 12 gauge and in some instances it really should be 10 gauge wire. This kind of power should NOT be run thru the Bronco's ignition switch. It will work, but it will shorten the switch's life at the same time. Run HEI power direct from the battery thru a relay. Purists of course will hate the idea of a GM ignition on a Ford. I'm not a purist, but I'm also not a fan - it will take a very specific set of reasons for me to use one on any vehicle.

OTOH I've adapted Ford Dura-Spark II's to many Ford engines as well as several I-H 304/345/392 engines. This conversion is a bit more wiring, but it's not bad or hard. The first conversion that I did in ~1987 to my 1966 Econoline's transplanted 300 six (had a 240) was considerably harder w/o the net or anyone local who knew anything about it. Now there are almost too many wiring diagrams out there.
Advantage here is that the distributor can be had from many sources, is a factory part so can be replaced with another factory part and it fits and clears like it should. If the big cap used on the D-S systems does run into something or visually offends the cap (& cap adapter) and rotor can be simply exchanged for the smaller points type cap & rotor.

 

[DaveLev]

Okay - so no such thing as HEI on ford, and none - not even racing or off-road style - have coil in the top, only GM? Had no idea.

Okay, with external mounted coil, and something that bypasses the coil ballast, what do the people here recommend I swap to? Looking for electronic, no points/etc. Have factory distributor now for 68 289/302.

 

[ntsqd]

In the aftermarket there is a Buick (I *think*) HEI modified to fit a Ford engine by D.U.I. That is the unit with possible hood interference problem(s). If you don't want one of them then you have two options, as suggested Ford Dura-Spark II for OEM reliability, or Pertronix which some guys swear by but I've had/seen nothing all that great.

 

[jckkys]

If you want the least expensive, most reliable, system, get the Duraspark that was stock on '76-'77 Broncos. You can find all the parts in any good parts store, but not in speed shops. In fact speed shops are the last place to find good parts. They don't make any money on OE type parts so they don't carry them.

 

[DirtDonk]

What they said Dave.
As ntsqd clarified, while the origin of the new units is the old GM design, several companies do make them for our Fords now.
The good news is they install pretty simply and put out a great spark.
That's the only real good news however. The bad news is that the cheaper ones are a crapshoot, where most work, but so many have complained of failures that it wouldn't be an option for me. Maybe it's the extra current drawn through our old wiring and switches that does them in early? Or maybe not, but updating the wiring is a good idea usually anyway.
The DUI brand mentioned (Davis Unified Ignition) is the originator and still considered top quality. Don't know but maybe one or two that had any issues, but frankly just about any electronic device can have issues these days.

The real deal-breakers for me are that you either have to install a body lift, or cut your hood braces just to get it to fit in our engine compartments. Add a taller 351W and you make that even more critical.
Then there are the air cleaner choices that go way down. Or just do what has been done and modify your standard round air cleaners to fit.

Most of that was discussed already. Just wanted you to hear the negatives right up front. There are MANY members here running them, and most still like them because they either didn't mind the additional modifications necessary, or had already done them for other reasons. Body lifts come to mind. But a cut hood brace is a no-deal for me.

Paul

 

[ntsqd]

Just by using the wrong heat-sink compound or no compound at all, or if it dries out, under the GM HEI module you will (not can, will) fail the HEI module. Ask me how I know this.

 

[DaveLev]

As stated previously, my rig is stock - no body lift, no drop engine mount brackets, no hood scoop. The intake is stock, the carb is factory 2 barrel autolite, and there is an aftermarket 18" or whatever chrome 3" tall air cleaner. The stock dist cap clears it just fine.

So don't use distributor from speed shops, and don't use GM converted style. I have one vote for vintage duraspark if I can find one and wire it up to my OEM 1968 wiring, or the Pertronix device that no one seems to be raving about here.

Any other suggestions? Did not expect this to be so difficult.

 

[ntsqd]

They're not hard to find in the right junk-yard. Yer skrewed in So.CA, but most anywhere else should have a sample or three. Pick the donor whose blue strain relief module looks to have been there the longest. You'll need the distributor, the module, the wiring between the dist./coil and the module, and the plug side of the other two wire connector on the module. I cut those wires as long as possible.

Alternately you can buy the distributor from places like Rock Auto and they seem to be reasonable quality. The modules are a different story. Parts store new ones do not seem to last (chinese). This is why I suggest finding the oldest module in the JY. It should be a Motorcraft branded part. If not, do not buy it, you want a Motorcraft. I've never used anything except JY sourced Motorcraft modules for any of the conversions that I've done and I've never had one go bad. I've read that you can get the wiring from Painless. I've never even looked at it much less used any so no idea how good or bad or if still available.

 

[jckkys]

New real Motorcraft Duraspark modules are available here;http://www.ebay.com/itm/Ignition-Co...ash=item2ca8239fc4:g:FZIAAOSwzhVWs~H3&vxp=mtr these are actual US made Motorcraft parts. The rest can sourced at any junk yard. More trucks are survivors than cars and heavy duty trucks were built with Duraspark II blue strain relief modules until 1999. The Duraspark ignition is far superior to GM HEI. GM was the first transistorized ignition in the US, while Ford worked out some of the bugs first.

 

[Kdub]

Just wanted to bring this back up..seems kinda relevant.

http://classicbroncos.com/forums/showthread.php?t=252202

Have not been there yet so dunno?
KW

 

[jckkys]

If anyone is interested in the stock look for a '77, the big cap, adapter, rotor, and plug wires were blue. The wire boots were orange/red. The big cap has presented no problems for nearly 40 yrs. There's no reason I can see, to go to a small diameter cap.

 

[ntsqd]

The big cap will interfere with some/most enclosed air filter options. To get a decent sized air filter on my '67 Ranchero with the big cap I had to use an Olds air filter can with an off-set carb hole in it. I had to run it backwards from the way Olds designed it, so that meant moving the alignment tabs 180° too. One with a centered hole would not clear the cap. The Ford filter cans from the era of the big cap have a large divot in them to clear the cap, but their filter element size is tiny.

 

[jckkys]

The OE Bronco air filter has no problem. If for some reason you want to run a large diameter air cleaner, the 5.0 and 5.8 HO 4V air cleaner from mid '80s Mustangs and trucks is made for just that distributor cap. Of course the cross brace in the hood isn't cleared by the lid on any of the conventional air cleaners, unless it's barely above the choke horn reducing air flow. The OE air cleaner gives the carb more "head room" because it sits just ahead the brace. The aesthetics of the OE air cleaner seems to bother a lot of people, so they go to great lengths to shoehorn an open element or large can air cleaner into EBs. I don't see any real benifit in this.

 

[ntsqd]

You're assuming a stock hood and no body lift, which is only one of hundreds of possible combinations.

I looked at those filter assemblies when working out an air filtration system for the Ranchero. The physical size of the "can" on those filters is large, but the filter element itself is pretty small and IMHO not worth the trouble. Particularly not on something that will see dirt or is high performance.

I'm with Kdub, I wouldn't mind a small cap with tower terminals on it. The large caps were needed when the OEM's radically opened up the spark plug gaps. GM went well and beyond everyone else in this. Later ignition system designs don't seem to need the large distance between cap terminals that those earlier designs required. For a mild engine running 'normal' plug gaps I'm not so sure that the large cap is an absolute necessity. I do prefer the tower type cap terminal though. It is a much better design.

 

[jckkys]

Until someone articulates a list of changes from stock, there's no reason to assume any of those changes are part of this scenario. I have yet to hear a persuasive argument for need or desirability of any air cleaner, other than the original. You brought up the possible interference issue with some air cleaners. I wouldn't recommend any of them for an EB. I was only suggesting a way for those feel a need for a large diameter air cleaner, to do so with a large distributor cap. Ford used the Duraspark II and small distributor caps in most '76 vehicles. That experience led them to go to the large cap in '77. These were used in all vehicles that had distributors through the 1997 heavy trucks, that were the last use of distributors. I don't know when you think they dropped it.