[Healeys] Lucas Distributor questions.

Chris Dimmock austin.healey at gmail.com
Tue Jul 27 11:24:43 MDT 2010


Hi Ron. The distributor runs off the camshaft, not the crankshaft.
In a 4 stroke engine, the relationship is that the cam only turns one  
full revolution, for each two full revolutions of the crankshaft.
You are adding cam degrees to crank degrees without allowing for the  
fact the crank turns twice for one revolution of the cam.
If you have a 15 degree cam in your distributor, which is driven by  
the camshaft,  then I'd be starting at a static advance of 5 or 6  
degrees BTDC
Your 100/6 numbers add up (2x 15 cam = 30 for one crank rev, plus 6  
btdc crank degrees) but your MK 2 numbers are 45 ( 2x 15= 30 + 15  
static)
Around 34- 36 degrees when all advance is in, around 2,800 - 3,000 rpm  
is the guidline.
Just out of curiosity, which cyl head casting do you have????

Chris

Sent from my iPhone

On 27/07/2010, at 10:39 PM, Ron Mitchell <healeyron at yahoo.com> wrote:

> I rebuilt the
> Distrutor on my MkII 3000 last night and found that everything
> was working
> properly
> One
> question I don't have the answer to is, the mounting plate for the
> mechanical
> advance is marked 15 degrees.  The advance setting spec for my
> distrubutor is
> 15 degrees BTDC.  So at 2500 RPM the specs call for 35
> degrees mechanical
> advance.   The 15 degree plate and the 15 degree BTDC setting
> at 600 RPM adds
> up to 30 degrees available advance.  Where does the extra 5 five
> degrees come
> from?  What am I missing?  The specs on my 100-6 BN6 distributor is
> 6 degrees
> BTDC with a max Mechanical advance of 36 degrees.  It also has a 15
> degree
> plate that the weights are attached to.  That only adds up to 21
> degrees.  I
> know some one out there has the answer.
>
> In answer to the closed system.  I
> do have a fluid recovery bottle installed so
> there isn't a problem with low
> fluid level.
>
> Ron Mitchell
> ____________________________


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