Tuning VS V8 Ignition timing

[Untamed_VS355]

Hi All,

Could anyone plz help with these two queries. I'm trying to tune the ignition timing on my VS Executive V8, 355 Stroker; but I ran into two problems:

1) The beast has a Haltech E6GMX computer (with MSD 6A ignition) - but according to the repair manual I need to set the computer to diagnostic mode by earthing certain wires. I've checked the Haltech website but can't find how to do this with this computer.

I don't have a laptop so I can't do this the easy way via the software.

Is there any generic way or something of doing this (setting to diagnostic mode), or does anyone know how to do it for particular computer?

2) The distributor seems very hard to get to. Any idea on how to get to it to loosen bolt, etc for rotating?

Thanks guys. I can provide pics if needed.

Cheers,
Mars

 

[dirt drifter]

that diagnostic mode the manual refers to is for the standard computer, as far as i know haltech's dont have diagnostic mode.
those distributors are fun to get at aren't they? taking off the engine covers helps, if a short spanner hasn't got enough leverage/room to move maybe a crows-foot spanner might work (they look like the head of open ended spanner with a square cutout for the ratchet/extension bar) one of those should fit down there easy enough.
it might pay to be careful with advancing it because god knows what the advance curve is like, if u do bump up the base timing it wouldn't hurt to check it on a dyno before giving it a hiding

 

[Untamed_VS355]

Thanks dirt drifter.

So how would I go about doing this with a Haltech, but no laptop? Are there any ways which you see I could do this without taking it into the shop?

Thanks again.

 

[delcowizzid]

if you find out what wire at the ignition module is the EST wire you can cut that to lock timing at 10 degrees then join it back together

 

[dirt drifter]

turning the dizzy will shift the whole timing curve, regardless of load/revs etc the whole show will advance/retard the same from idle to redline and everywhere in between. no laptop needed for that just a timing light and spanner that can get to that bastard dizzy bolt.
from memory the base timing is 10 degrees, with a standard ecu/memcal u know that when set on that it wont be too advanced up top and pinging etc.
where it gets interesting with aftermarket computers (and standard ones with re-burnt memcals) is u have no idea what the timing curve is like, only the guy who tuned it does. when the base timing is set at say, 8 degrees but is wound up almost to the point of pinging up higher in the revs. u bump up the timing so its 10 deg base but up top its got too much and might hurt itself.
if it was my car, that i had bought with the haltech already in it, for my own peace of mind i would dyno it at a reputable shop just to check that the timing and mixtures were ok

 

[Untamed_VS355]

Thanks guys! I really appreciate your help!!

dirt drifter, believe me I would put it on a dyno, but I have had no cash lately - things are a bit screwed cash-wise.

So in general your saying I don't need to touch anything on the ecu to adjust the base (idle) timing? I will be reading into this further, but basically I'm planning on:


1) Loosening bolt at bottom of distributor
2) Hooking up timing light
3) Setting / playing with 10 degrees BTDC (it's currently close to 0 degrees BTDC!!)

For base timing, should any vacuum hoses be removed, or is it simply a matter of hooking up timing light and adjusting dizzy (as described above)?


Lastly, the degree markings / scale on the engine look something like this:
___A_R_
'''|''''|'''

How much is each little dash worth? (1 degrees, 2 degrees, etc). My base reading (with vacuum hoses attached and no computer alterations) is right under the "A" towards the second long line! Not good I think.


If you (or anyone) could confirm all the above, I would be sooo grateful. I really admire everyone's work here.

Cheers,
Mars

 

[delcowizzid]

each mark is 2 degrees but without commanding base timing mode its not really going to give you the correct base timing to set the dizzy it will be at whatever idle timing is set in the tune.also depends where it was set when they tuned the haltech they may have had it set at 0 and tuned it making 10* base timing none existent

 

[Untamed_VS355]

Thanks delcowizzid.

Hmmm. So in a nutshell, either a laptop needs to be plugged in to do it properly, or wack it on the dyno?

Thats a bummer! I was really looking forward to playing around with the dizzy to see what I could gain (at least to regulate the idle timing which seems to sound a bit rough when idling).

 

[delcowizzid]

disconnect the white wire at the ignition module will make it run on base timing so you can check its at 10 degrees

 

[Untamed_VS355]

Thanks again delcowizzid. I appreciate your help.