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Delco Voyager distributor on Vortec 4.3L timing

M

mtrigger

Member
Anyone care to suggest a shunted timing figure for a Delco Voyager EST distributor on a 4.3L Vortec? The original engine (AQ205A) with a standard VP distributor was 8 deg BTDC. The paperwork that came with the Delco was not at all clear.
 
Read the instructions again. I'd be surprised if this wasn't spelled out.
The pig-tail or little harness should be included.
Also, you'll know when it's in BASE mode because it will not offer any further EST Advance.



Be sure that you understand the importance of TA (total advance) and that BASE is just that...... BASE!
I'd strongly suggest that you mark off the balancer, and watch/see your progressive ignition advance in Real Time/Real Degrees!

See your OEM ignition advance specs.

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Rick

Many thanks Rick. My local engineer colleague recommends sticking to 8 deg BTDC and when adjusting blind initially without the timing light and going on engine sound and experience that is about right. I then have used the timing gun to take it to 8 degrees. The instructions recommended 16 degrees but no way was that correct! What do you think? Mike
 
Mike, the book will usually give us two timing specs.
One will be BASE...... or Initial!
BASE/Initial is that only.
The engine fires on BASE, and it idles on BASE advance.

The other and more important number will be the TA number..... (total advance)
Occasionally this number will not reflect BASE in with it.
So BASE must be added to this.

Example ONLY:
If the book calls for 16* advance, it will assume that a BASE advance has been established.
So, we'd add a BASE of 10* to the 16*.... which equals a TA of 26* @ X,XXX rpm.
NOTE: TA numbers are worthless without an associated RPM.

DO NOT...... repeat.... DO NOT allow anyone to set your timing by ear or feel or sound on your MARINE ENGINE.... PERIOD!
Guys with this attitude have ZERO business working on a gasoline Marine Engine..... unless they are willing to be completely responsible for the resulting potential Detonation Damage.

.
 
Thanks Rick. The instructions I received from Michigan Motorz for the Delco EST shows an Initial of 2 degrees for a 4bbl 262 Vortec 4.3 with a max of 26 degrees at 4800rpm but it wont swing the props on my DP290A to those revs - probably around 4200. I have another set of instructions which did not come with the Delco but came from the guy from whom i bought the engine which shows Base as 1 degrees but 18 degrees at 600rpm. Any guidance on which is correct would be welcome. Mike
 
Mike, you'll need to see your OEM ignition timing specs.
These specs should give you BASE/Initial and TA @ a given RPM.

Like said, the more important spec is the TA (total advance) at the recommended RPM.
The correct or incorrect TA will make the difference between good performance and poor performance, given that all else is OK.

You'll want to have your balancer marked off, and you'll need to strobe this from idle RPM to the Full-In RPM to see what it's doing.
While I'm not a big fan of using the digitally advancing timing lights for a Marine Engine TA check, it will work as long as the equipment is good, and as long as no user error.
If the BASE is off by several degress, yet the TA is correct, you'll be OK.

NOTE: minus knock sensor data, and ECU/ECM data influence, any change to BASE/Initial will be an equal change to TA.

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