Advice on 3.9l distributor/ignition setup

WildBoar · Mar 20, 2015

The 2.25l in my 109 is getting replaced by a 3.9l that will be carbuerated. The 3.9l currently has no distributor so I need to source a suitable ignition system. Should I stick with LR parts or look at an after market set up?

Firemanshort · Mar 20, 2015

You need to fit the timing cover from an old 3.5 motor that has a dizzy. You will probably need cam gears and such, too. You can retro fit the modern fuel injected motor with the older parts.

d110pickup · Mar 20, 2015

I've used the Mallory Unilite dizzy & coil in the past with very good success. I would certainly still recommend it.
Mike

o2batsea · Mar 20, 2015

What's wrong with the electronic diz? they are pretty darn reliable. They're available for chips.

ezzzzzzz · Mar 20, 2015

I look at a mid seventies Buick V8 HEI (coil in cap) distributor. It runs reliably with only a ground, +12v and tach output. 40kv output and the module in under the cap.

WildBoar · Mar 20, 2015

I am reading what I can online and trying to get smarter on this topic...something of which I have no experience with. I definitely want to keep this simple so I am not sure an electronic ignition is what I am looking for unless I don't understand what the minimum components are for this type of set up. I also didn't think I would need to swap any existing engine components out like cam gears and so forth.

Fleabay has a Pertronix D175520 Rover V8 Distributor 35DLM 8Cyl 3.5L 3.9L 4.2L 2-Pin 1992-1995 - should be the right gearing (according to the accompanying fit chart) and all I would need is a coil right? Unless Pertronix is junk...which I don't even know.

There are also several used 3.9l dizzys for sale...should I steer clear of these?

------ Follow up post added March 20th, 2015 10:37 AM ------

o2batsea said:
What's wrong with the electronic diz? they are pretty darn reliable. They're available for chips.

This is going in to my Series IIa...what would this set up look like in this scenario?

------ Follow up post added March 20th, 2015 10:42 AM ------

ezzzzzzz said:
I look at a mid seventies Buick V8 HEI (coil in cap) distributor. It runs reliably with only a ground, +12v and tach output. 40kv output and the module in under the cap.

Would this drop right in or would gearing be an issue? I like the simplicity...isn't a mid seventies Buick V8 a 215? And the Rover 3.9l is just a bored out version of the Buick 215? I am looking at using the intake manifold for a 215 for the carb conversion.

o2batsea · Mar 20, 2015

The 3.9 diz is electronic. Needs only the wire harness that connects it to the coil and ignition amplifier module. It has nothing to do with the engine ECU. However, if you were to obtain the EFI components, engine wiring harness and an ECU, then you'd be golden...allowing you to just run the whole mess with the stock engine management.
Don't poo pooh that option. Gazillions of trucks running around the planet with that setup. It works, is easy to get parts for and is plug and play. In terms of "keeping it simple" this is the obvious choice as there are way fewer moving parts. I don't want to say that carbs are a bad option, but they are given today's electronic engine control.

WildBoar · Mar 20, 2015

o2batsea said:
The 3.9 diz is electronic. Needs only the wire harness that connects it to the coil and ignition amplifier module. It has nothing to do with the engine ECU. However, if you were to obtain the EFI components, engine wiring harness and an ECU, then you'd be golden...allowing you to just run the whole mess with the stock engine management.
Don't poo pooh that option. Gazillions of trucks running around the planet with that setup. It works, is easy to get parts for and is plug and play. In terms of "keeping it simple" this is the obvious choice as there are way fewer moving parts. I don't want to say that carbs are a bad option, but they are given today's electronic engine control.

Hmmm...well I do have this in the garage. No ecu or harness..or diz.

fishEH · Mar 20, 2015

I'm kinda curious as to what kind of distributor everyone is running as well?

ezzzzzzz · Mar 20, 2015

I had one sitting in a 4.2 here at the house. It's tight but doable. That dizzy is going into the 4.0 I'm building for the 110. The GM module is dead reliable with no extra wires and available at every parts across the country as is the coil. Plus you get 40kv vs about 25k-30k with the stock coil. I think the clearance issue is with the earlier engines that had the water pump sitting higher up or a bolt on the intake manifold but it could still be worked with a bit of grinding.

Uncle Douglas · Mar 20, 2015

o2batsea said:
The 3.9 diz is electronic. Needs only the wire harness that connects it to the coil and ignition amplifier module. It has nothing to do with the engine ECU. However, if you were to obtain the EFI components, engine wiring harness and an ECU, then you'd be golden...allowing you to just run the whole mess with the stock engine management.
Don't poo pooh that option. Gazillions of trucks running around the planet with that setup. It works, is easy to get parts for and is plug and play. In terms of "keeping it simple" this is the obvious choice as there are way fewer moving parts. I don't want to say that carbs are a bad option, but they are given today's electronic engine control.

This is what I have on Trey's 4.2 in the 83 110. It has the Atlantic British module relocation setup and I have that bolted to the same plate the coil mounts to. This on a truck with a 4bbl edelbrock.
I drove it today to return a concrete mixer I had rented. That truck puts a smile on my face every time I drive it.

Advice on 3.9l distributor/ignition setup

WildBoar

Firemanshort

d110pickup

o2batsea

ezzzzzzz

WildBoar

o2batsea

WildBoar

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fishEH

ezzzzzzz

Uncle Douglas

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