[DeTomaso] vacuum advance

[Dennis Sanford]

Thanks Andy,

 

Are you talking about total advance of 20 degrees or just the vacuum portion
(which would give me a total of 36 degrees at the crank).  I have a mostly
stock engine with an Edlebrock Performer manifold and a new Holley Ultra 650
double pumper carburetor.

 

From: Andy May [mailto:andymay24 at gmail.com] 
Sent: Friday, August 31, 2012 8:31 AM
To: dennis617 at aol.com
Cc: detomaso at realbig.com
Subject: Re: [DeTomaso] vacuum advance

 

In my experience a good place to start with vacuum advance is about 20 deg
at the crank. However, you need to get the initial and total mechanical
right without vacuum first or you'll just end up chasing your tail. 

I go to a traffic free place and do some full power runs on a reasonably
level road to set the mechanical, finding the maximum advance I can get away
with before detonation then back it out a couple of degrees. Once this is
done I go and find a good hill and connect the vacuum. Climbing the hill
with only moderate throttle, adjust the vacuum canister so it just stops
detonating - then back it off another 2 full turns. Nobody can give you
precise settings for your engine as there are too many variables involved,
especially if its been modified from stock. The above process will get you
very close to where you need to be.

I always connect vacuum advance to ported, not manifold. Others will
disagree I'm sure, but you'll probably see way too much advance at idle for
most applications with manifold vacuum.

Kind regards

Andy

On Aug 31, 2012 12:39 PM, <dennis617 at aol.com> wrote:

So I just got my new replacement vacuum advance for my Mallory Unilite
distributor and it appears that the advance I'm getting at full manifold
vacuum is way too high, around 24-25 degrees (plus the initial 16 degrees
for a total of 40-41 degrees at full vacuum).  Does anyone know what the
total vacuum advance is supposed to give so I can adjust it, at least for a
starting point.  Right now she is backfiring all over the place.
_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso