Delco est conversion issues

[Dogdave]

I. Just installed a Delco EST I place of my TB4. The issue I have is I'm only getting 9 degrees advance out if the distributor. Base is set at 10 total timing is 19 degrees @ 2400 rpm. Any suggestions ? I have checked the voltage and it's @ 12 to the distributor.

 

[bruceb58]

Base is set at 10 using the timing shunt?
What engine?

 

[Dogdave]

The engine is a 260. Yes the base set at 10 with the timing shunt installed.

 

[bruceb58]

What is the timing at higher than 2400RPM? Timing should still be advancing past that RPM.

 

[alldodge]

I. Just installed a Delco EST I place of my TB4. The issue I have is I'm only getting 9 degrees advance out if the distributor. Base is set at 10 total timing is 19 degrees @ 2400 rpm. Any suggestions ? I have checked the voltage and it's @ 12 to the distributor.

Your stating your only getting 19 degrees at 2400 rpm, agree should be more.

Question; are you having running problems, stalling, missing, pinging or something else other then your only getting 19 degrees advance?

 

[Dogdave]

I pulled the boat out of the water to change out the failed TB4 . With a Delco EST. All went well except the timing . ( a little info, the engine has ported , polished and chambered heads. 9:1 compression. Balanced and blueprinted small marine cam. ) the engine made 311 hp 385 tq on 87 octane on the dyno with total timing @ 31 degrees. That said my tb4 amplifier failed so I went to the EST. Reading that it has 20-22 in the module, all in @ 3k or so. I did rev to 3800 with no change. 19 total. 10 initial 9 in the dist.

 

[alldodge]

I pulled the boat out of the water to change out the failed TB4 . With a Delco EST. All went well except the timing . ( a little info, the engine has ported , polished and chambered heads. 9:1 compression. Balanced and blueprinted small marine cam. ) the engine made 311 hp 385 tq on 87 octane on the dyno with total timing @ 31 degrees. That said my tb4 amplifier failed so I went to the EST. Reading that it has 20-22 in the module, all in @ 3k or so. I did rev to 3800 with no change. 19 total. 10 initial 9 in the dist.

My first thought is your module is bad, wouldn't be the first time. The EST system is very good but many have had bad modules before. In most cases if you call the place where you purchased it they will take it back and have it checked and if bad will replace. I'm sure you know this but the base timing connection is made and removed while the engine is running. Here is a link which shows the testing procedure, and the timing curve it should have

http://www.boatfix.com/merc/bullet/90/90_15.pdf



Another thread discussing same issue
http://forums.iboats.com/forum/engi...93-delco-est-distributor-timing-not-advancing

 

[fishrdan]

The engine is a 260. Yes the base set at 10 with the timing shunt installed.

Then what happens when you short the +12V shift interrupt wires, what does the timing go to? (You need to short the shift interrupt wires, after the white wires are jumpered, to get into base timing mode.) Verify the engine is at 1* BTDC while in base timing, then it goes to 10-12* at idle when out of base timing, then approximately 28* at 3000RPM.

If you don't hear the engine bog and dog down, it's not going into base timing mode...

 

[Dogdave]

Thank you all. The seller is sending me a new module. This makes me question the EST.... I did test the shift interupt and it worked as it did with the tb4. I did not know that you take the dist out of timing mode while the engine is running. That was not in the directions and it's the first time I have read it. I will try that tomorrow ...

 

[alldodge]

The in/out of timing while running is from the Late DonS listed in previous thread, and if there is one thing we here can all agree on is Don knew his stuff

 

[bruceb58]

I did not know that you take the dist out of timing mode while the engine is running.

That doesn't matter. By the time you do that, you have already set the timing.

 

[fishrdan]

I did test the shift interupt and it worked as it did with the tb4.

Check the shift interrupt switch and see if it is connected to ground or +12V, it needs to be connected to +12V for the EST ignition. The TB4 diagram I found shows that the shift interrupt switch is connected to ground, which could be bad for the EST.

OK that link didn't work, let's try this again....

 

[Dogdave]

The interrupt is not grounded anymore. The company sent me a new module that I'll install this weekend. I'm a bit concerned that a new module is bad. I'm wondering if it's a true delco module or aftermarket . The new module they sent is not stamped Delco, like all the stock chevrolet parts I have purchased over the years. I think a phone call is in order. I'll report back

 

[Fun Times]

Unfortunately It's the luck of the draw.. 97% of the time you get a good one that works and when they do it lasts awhile.. That mentioned, they do go out. It's best to have one in your onboard tool box. If you do your home work comparing part numbers online and using AC-Delco part numbers you can find them in the $40.00 range. EBay helps when looking for the correct ones. If you by from a marine dealer, they're more around the $165.00 range. Good luck.

 

[I Can Fix That]

I've had bad luck with dozens and dozens of aftermarket modules, stick with the delco or it's just a crap shoot. Also be sure to check your play on the distributor gear. Have done tons of distributors on trucks for worn gears.

 

[Dogdave]

I installed the new module and the timing is spot on. I will buy a new on to keep on the boat though.

 

[alldodge]

Glad you figured it out and thanks for let us know and closing out the thread for others

 

[Fun Times]

Glad you figured it out and thanks for let us know and closing out the thread for others

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