Delco est conversion

[888]

Got a 1979 omc 3.0 and swapped out to the delco est dizzy. I found 2 different base timing settings. Which one should I use,the 1 btdc or 2 atdc?

 

[888]

Re: Delco est conversion

wow 76 views and not one response,guess your all just as confused as I.

 

[navycowboy44]

Re: Delco est conversion

im thinkin the 2 atdc

 

[888]

Re: Delco est conversion

im thinkin the 2 atdc

That's where my timing is at now ,waiting for the weekend to test it out on the lake.
Seems little bit more sluggish then 1 btdc when the throttle is cracked open.

 

[sam60]

Re: Delco est conversion

That's where my timing is at now ,waiting for the weekend to test it out on the lake.
Seems little bit more sluggish then 1 btdc when the throttle is cracked open.

I did mine a few months ago. It came with specific instructions and different leads with a timing shunt for the initial timing. Where did you buy yours and did it come with any instructions? From what I read, if your not powering the timing shunt at the correct time, it will harm the distributor.

 

[888]

Re: Delco est conversion

I did mine a few months ago. It came with specific instructions and different leads with a timing shunt for the initial timing. Where did you buy yours and did it come with any instructions? From what I read, if your not powering the timing shunt at the correct time, it will harm the distributor.

Marinepower and didn't come with any paperwork at all. Kit Did come with wires,cap,rotor and timing shunt which I used it to set base timing then cut the white wires and taped off. Im not sure what you mean by powering timing shunt at correct time. My interrupt switches are not hooked up yet so the black wire isn't used.

 

[sam60]

Re: Delco est conversion

Marinepower and didn't come with any paperwork at all. Kit Did come with wires,cap,rotor and timing shunt which I used it to set base timing then cut the white wires and taped off. Im not sure what you mean by powering timing shunt at correct time. My interrupt switches are not hooked up yet so the black wire isn't used.

I'll look for the instructions this weekend, (and don't do this until you are sure) but mine said to warm the engine, connect the timing shunt, supply 12V to the timing shunt lead only with running warmed engine and set timing with power applied. Disconnect timing shunt and plug in permanent plug. My instructions were from the supplier that I purchased from so I can't scan them here for your use.

I would get on the phone to MarinePower in the AM and request the procedure.

 

[888]

Re: Delco est conversion

I'll look for the instructions this weekend, (and don't do this until you are sure) but mine said to warm the engine, connect the timing shunt, supply 12V to the timing shunt lead only with running warmed engine and set timing with power applied. Disconnect timing shunt and plug in permanent plug. My instructions were from the supplier that I purchased from so I can't scan them here for your use.

I would get on the phone to MarinePower in the AM and request the procedure.

I understand that black wire needs 12+ v when timing shunt is installed and it must be installed and removed when ignition is off
There is plenty of info on net for wiring and how to. The only thing I'm getting is conflicting info on where to set base timing. I've seen two mods on here and one says 1btdc and other says 2atdc. I thought maybe one of them would chime in by now.

 

[fishrdan]

Re: Delco est conversion

Did OMC ever use the EST, and have a timing spec?

Mercruiser's timing spec for the EST in a 3.0L is with timing light connected, check timing. Timing should be 1 degree BTDC (Service Bulletin 90-15), then with timing light still connected, and engine at IDLE, verify that timing did advance to 12 degrees BTDC, plus or minus 2 degrees. At 2400-2800 RPM maximum (total) advance is obtained and should be 27 degrees BTDC, plus or minus 2 degrees. (copy-n-pasted a portion of that)

There was another "Mercruiser" service bulletin for specific engines (serial number range) that had the initial timing retarded IF the engine blew a head gasket. I think that's were you are getting the 2 ATDC from. I'd have to scour my service bulletins as I don't remember which one refereed to the head gasket problem and retarded timing.

 

[888]

Re: Delco est conversion

Did OMC ever use the EST, and have a timing spec?

Mercruiser's timing spec for the EST in a 3.0L is with timing light connected, check timing. Timing should be 1 degree BTDC (Service Bulletin 90-15), then with timing light still connected, and engine at IDLE, verify that timing did advance to 12 degrees BTDC, plus or minus 2 degrees. At 2400-2800 RPM maximum (total) advance is obtained and should be 27 degrees BTDC, plus or minus 2 degrees. (copy-n-pasted a portion of that)

There was another "Mercruiser" service bulletin for specific engines (serial number range) that had the initial timing retarded IF the engine blew a head gasket. I think that's were you are getting the 2 ATDC from. I'd have to scour my service bulletins as I don't remember which one refereed to the head gasket problem and retarded timing.

I dont think omc lasted long enough to see the est come out. Thanks for the bulletin. This engine is rebuilt and has the latest and greatest felpro marine head gasket if that matters. If I set to 1btdc and remove stunt the timing does go to 12btdc. Im gonna try 1btdc first. Sure does feel and sound alot more snappier then 2atdc. Im running 93 octane.

 

[fishrdan]

Re: Delco est conversion

Here's some more info from MercMan 26: (GM 4cyl, 3.0 1998 and up_

? If initial timing is 1? BTDC: 12? BTDC, plus or minus 2?. At 2400-2800 rpm maximum
(total) advance is obtained and should be 23? BTDC (plus or minus 2?).
? If initial timing is 1? ATDC: 14? BTDC, plus or minus 2?. At 2400-2800 rpm maximum
(total) advance is obtained and should be 25? BTDC (plus or minus 2?).
? If initial timing is 2? ATDC: 15? BTDC, plus or minus 2?. At 2400-2800 rpm maximum
(total) advance is obtained and should be 26? BTDC (plus or minus 2?).

Further on...

Initial Timing: 1? BTDC{1} / 1? ATDC{2} / 2? ATDC{3}
Total Advance: 23?
{1} Serial number break: 0L340999 and below unless specified differently below
{2}Serial number break: 0K001529 - 0L097000 Timing changes to 1? ATDC only if engine experiences a cylinder
head gasket failure that has blown out toward the intake exhaust manifold on the port side of the engine.
{3} Serial number break: 0L341000 and above.


MercMan with the points dizzy says: (GM 4cyl 3.0L 90-97)

MCM 3.0L with Prestolite Distributor
Distributor Advance: 16?
Initial Timing: 8? BTDC
Total Advance: 24? @ 4100 RPM
Point Gap: .016 in. (0.41 mm)
Point Dwell: 39? - 45?
Point Spring Tension: 20 -27 oz.
(567 - 765 g)

I'm running an EST on my 73' 140HP (3.0L) Mercruiser with the timing set at 1 BTDC and it works fine. My engine was rebuilt 2-3 years ago and I haven't had any problems running it at 1 BTDC. I bought an advance timing light to see what I'm getting for total advance, but haven't done so yet. I want to verify I'm getting the 24* of total advance the points dizzy does.

I'm not sure how this is going to match up to OMC, but since you are using an EST, it's probably better than nothing.

 

[888]

Re: Delco est conversion

Thats exactly what I've been looking for. I just picked up light with advance as well. Im gonna set total timing at 4100 rpm to 24? without shunt and let base be where it whats to be. Wat ya think?
Thanks for the very informative post.

 

[fishrdan]

Re: Delco est conversion

I don't think you can time an EST like that as it's not locked in to base timing mode and it might try to compensate as you turn the distributor. I'd time it at 1 BTDC and see where it goes at full advance, then adjust base timing if needed from there.

I wouldn't be turning the engine at 4100RPM on the muffs, bad things could happen... The EST advance curve charts show it has everything in at 2400-2800RPM, so there is no reason to take it up to 4100RPM. (The point's dizzy curve chart keeps advancing all the way to 4100 though.)

 

[bruceb58]

Re: Delco est conversion

Fishrdan, the total advance numbers don't make sense. The total advance of the distributor should be a fixed offset from the initial setting. You have more total advance with base settings at 2? ATDC than you do with 1? BTDC even though the 1? BTDC is 3 ? more advanced from the start.

From the Volvo manual with the 3.0 and EST distributor, a 1? BTDC base timing would yield 10? @ 600RPM and 23? @ 4600RPM.

The advance curve listed in the Volvo manual lists advance all the way up to 4600RPM. I have seen other charts where the advance does stop at 2800 so not sure which one is correct.

 

[888]

Re: Delco est conversion

With idle at 750 rpm,Doesnt seem to matter where i set base,soon as i remove shunt it goes to 14-16 btdc.Then maxes out at 2400-2600 rpm at about 22-24 btdc.

 

[bruceb58]

Re: Delco est conversion

You have an advance timing light?

 

[888]

Re: Delco est conversion

You have an advance timing light?

yuup

 

[sam60]

Re: Delco est conversion

Why weren't you willing to call your vendor and get the instructions that should have came with it? Mine must be in my boat 'cause I kind find them in my garage boat files. The boat is covered and the wind is almost at 2 flags or I'd go looking tonight.

Mine had 2 pages specific to several different OMC years and sizes.

 

[888]

Re: Delco est conversion

Why weren't you willing to call your vendor and get the instructions that should have came with it? Mine must be in my boat 'cause I kind find them in my garage boat files. The boat is covered and the wind is almost at 2 flags or I'd go looking tonight.

Mine had 2 pages specific to several different OMC years and sizes.

They were called and I was told that all of the 2.5/3.0 gm blocks from 1967 - 2011 run 1btdc with delco est. They did offer to send wiring diagram.I declined. I need to get on water and check total advance before I go any further. My base timing is set to 1btdc . 2 more days and I'll have a better feel on things

 

[sam60]

Re: Delco est conversion

They were called and I was told that all of the 2.5/3.0 gm blocks from 1967 - 2011 run 1btdc with delco est. They did offer to send wiring diagram.I declined. I need to get on water and check total advance before I go any further. My base timing is set to 1btdc . 2 more days and I'll have a better feel on things

OK. Let us know how it does.