123 Tune (Pre-serp & Sepentine Dizzy Differences)

[Chimpafrolic]

Hi all,

I've been looking again at the 123 Tune distributor as a nice easy way of moving away from the old mechanical advance distributor on my serpentine V8.

An advance curve that can be influenced not only by RPM (as with the standard dizzy) but by a MAP sensor and engine temperature too does seem like a good idea to me.

With no requirement to fit a crank position sensor or coil packs the 123 Tune appears to be a very neat & easy to fit package that keeps the under bonnet look more or less standard while delivering all the benefits of a fully mapped spark.

The only issue is that 123 currently only offer their Tune model in early SD1 pre-serp flavour.

Obviously the drives are different, so another good idea out the window.

Then I got to thinking

Is it possible to take a pre-serp Lucas 35DE8 distributor body and fit the drive from the later Lucas 35DM8 serpentine distributor?

Is it just a case of knocking out a roll pin & swapping the drives over?

If so the idea could still be a goer.

Your thoughts please.

Dave.


PRE SEPENTINE DE8 (ERC3047)





SEPENTINE DM8 (ERC9122)

Edited by Chimpafrolic on Friday 4th November 11:10

[Chimpafrolic]

Right, it seems there are loads of different drives on the RV8 distributors & it's all starting to confuse me

There are no images of the RV8 123 Tune that I can find but I am sure they just use the same body as with the standard 123 model for the RV8.

So here it is:





They seem to offer two types of drive, neither of which has a helical gear.



DRIVE TYPE 1


DRIVE TYPE 2

So I guess my my first two helical drive images above may be misleading?

Am I right to say the pre-serp used a slot or peg drive while only the serpentine engine uses the helical gear?

For those of you who know the RV8 dizzy inside out, the question is does it look like I could fit a serpentine type drive to this distributor body?

Dave.

Edited by Chimpafrolic on Friday 4th November 11:40

[spend]

Chimpafrolic said:

Right, it seems there are loads of different drives on the RV8 distributors & it's all starting to confuse me

Utter twaddle!

VERY early Rv8s had a groove in the oil shaft so a spade on the dizzy. Later pre-serps had spade on the oil pump drive shaft so a slot in the dizzy drive.

You have a serp so it doesn't matter a toss which one you use (you can remove either completely as long as the cam gear is retained) - the gear to the cam drive is exactly the same and you don't even have an oil pump drive shaft to mate up to!

[Chimpafrolic]

spend said:

Utter twaddle!

VERY early Rv8s had a groove in the oil shaft so a spade on the dizzy. Later pre-serps had spade on the oil pump drive shaft so a slot in the dizzy drive.

You have a serp so it doesn't matter a toss which one you use (you can remove either completely as long as the cam gear is retained) - the gear to the cam drive is exactly the same and you don't even have an oil pump drive shaft to mate up to!

Oh how I do enjoy your condescending answers Spend.

The truth is I have never had any dealings with the different types of RV8 distributor and TBH I am not ashamed of my lack of knowledge, that's why I am asking the question.

I'm not sure why you feel the need to start your answer to my honest question with a statement like.

"Utter twaddle!"

Quite unnecessary and rather offensive if you want my opinion but I will let others be the judge of that.

What I was looking for was a simple answer to a simple question.

Can the pre-serp 123 RV8 type distributor be converted to fit my serpentine engine?

A simple YES or NO will do.

Dave.

Edited by Chimpafrolic on Friday 4th November 12:01

[spend]

I'm sorry I post such rubbish, obviously the world according to Chimpabollics is beyond my simple comprehension.

[blitzracing]

Something I think you cant do with the 123 tune is advance the timing to its optimum advance point for light throttle use,(ie cruse MPG) as mechanically you only have a certain timing period the rotor tip will be in line with the distributor pick up point, and this limits the maximum advance you can use. I would consider this a bit of something of nothing for the money, as all you are doing is getting rid of the bob wieghts. The demo on the web site looks really neat with the loss of timing scatter, but you already dont use points so theres nothing to be gained over the standard trigger system in terms of timing accuracy. Any distributor based system will never be as accurate as a timing wheel system fired driectly off the end of the crank, not via some worn (or otherwise) distributor gears.

[Chimpabollics]

spend said:

I'm sorry I post such rubbish, obviously the world according to Chimpabollics is beyond my simple comprehension.

I'm not really feeling the love from you today Spend.

Time of the month again?

[Colin RedGriff]

According to the website there are two rover versions a Pre sd1 and the other for later cars. Not sure if that includes serpentines though. Looks like an interesting product.

[SILICONEKID340HP]

spend said:

I'm sorry I post such rubbish, obviously the world according to Chimpabollics is beyond my simple comprehension.

Your such a nice man in real life

FORGET IT AND GO MEGASQUIRT.. 340HP and 31.5MPG CRUISING..

Edited by SILICONEKID340HP on Friday 4th November 14:07

[plushuit]

Colin RedGriff said:

According to the website there are two rover versions a Pre sd1 and the other for later cars. Not sure if that includes serpentines though. Looks like an interesting product.

You are right..pretty much. The pre-Sd1 dizzy is similar to the Buick 215. It has a male shaft that turns the oil pump gears. The post-Sd1 dizzies has a female adapter that turns the later oil pump gears (the oil pump was upgraded in 1976). The reason why the distributor images (posted above) look different is because the lower one is missing its female adapter.

From 1976, the dizzie models (from a bad memory) were 35DE8, 35DM8, 35DLM8. They are all really bad..and represent the biggest weak point the engine has.