Converting to Delco EST ignition

[Last Nerve]

Boat is a 1976 Glastron that I was told has been re-powered. Mercruiser 260 ser.# OL364398 with pre-Alpha outdrive. Previous owner had installed a GM HEI distributor (main reason for changing).
When I install the new distributor I know that I have to use the shunt plug to set base timing. When setting base timing do I set to 8 degrees BTDC as called for in engine specs @ 650-700RPMs or is there a degree of advance in the module that I have to compensate for?

Does the spark plug gap have to be changed?

 

[Bondo]

Re: Converting to Delco EST ignition

It's the Shunt that takes the built-in Advance Out of it..........

Set it to 8*........

Does the spark plug gap have to be changed?

I would think Not......

 

[Last Nerve]

Re: Converting to Delco EST ignition

Thanks for the reply Bond-o. Plugs are currently gapped at .045 for HEI. So I should leave them?

 

[Bondo]

Re: Converting to Delco EST ignition

Don't Know,......... You mention twice that you're removing a HEI,.....
I Still don't see What you're installing........

Whatever it is,...... I Know it'll run Just Fine with the plugs at .035".........





Oh,.... I see it in the Heading,......... Duh,.... Delco EST.............

I Still don't know for Sure.... But, it'll run at .035.......

 

[Last Nerve]

Re: Converting to Delco EST ignition

Sorry I wasn't clear on that. Boat actually belongs to my brother. When He got it I noticed that some-one had installed an automotive HEI distributor with coil in cap and vacuum advance module. Distributor was not advancing at higher RPM's due to rusted mechanical advance mechanism. Installing a marine distributor
with remote coil and EST module in distributor.

 

[rodbolt]

Re: Converting to Delco EST ignition

shunt it and set the engine speed at about 100 RPM then set the timing, I would use the 8*BTDC setting. then unshunt it and rest the idle speed to about 650-700 RPM. gap the plugs at .045-.055 to get the best firing voltage.
when your done its mandatory to check for ign advance at about 3300 RPM. you should get a total somewhere close to 33* or so.
I have seen new modules that either fail to advance and one actually retarded with increased RPM's.
if it wont shift then you will have to rewire the shift interupt circuit.

 

[rodbolt]

Re: Converting to Delco EST ignition

cant remember how to edit, make the 100 RPM a 1000.

 

[Don S]

Re: Converting to Delco EST ignition

Just to make sure eveyone is on the same page and is talking about the same distributor and coil, here is the Delco EST distributor and coil parts breakdown picture.

PS: For Rodbolt
under the Reply+Quote button where it says -interact- just click the arrow and choose the Edit Post option.

 

[Last Nerve]

Re: Converting to Delco EST ignition

The distributor I am installing is the Delco EST that Don has posted the diagram of.

Rodbolt, how often do you see defective modules on these distributors?

 

[bjcsc]

Re: Converting to Delco EST ignition

re:defective modules, I replaced mine last season, but it took two trys as the first one failed to advance right out of the box...

 

[180shabah]

Re: Converting to Delco EST ignition

defective modules are not that common(out of the box) but it is a posibility, so it is a good idea to always verify operation of any new part.

 

[Last Nerve]

Re: Converting to Delco EST ignition

Well I installed the distributor, connected lead from shunt to 12V source and set base timing.When I removed the shunt and increased RPM's to check advance -NO ADVANCE!

I installed an aftermarket ignition module (Sorensen) and had the same results.

Any suggestions as to what may be the problem?

 

[Don S]

Re: Converting to Delco EST ignition

After you set the timing, shut the engine off THEN remove the shunt.