Delco EST Initial/Advance Timing Concerns

[propuckstopper]

Hi folks. I am likely overthinking this procedure, but I want to ask the question before I potentially cause major engine damage. I have a 2004 Glastron GS249 with a Volvo 5.0 GL carbureted engine. It has the EST distributor, for which I have purchased the "shunt". I have the updated "shunt connection method" as per a previous post by Don S. (thanks Don!)

With the engine running, I connected the positive wire of the shunt according to procedure. The engine proceeded to drop some RPM, and ended up in the 600 RPM range. To start, I set my advance timing light to 0 degrees, and for some reason the timing marks lined up perfectly. Knowing that this seemed strange, I then set my advance timing light to the required 10 degrees. Obviously, the timing marks no longer lined up properly. So far, it seems simple; you would think my timing was off. So I left the advance timing light at the required 10 degrees and turned the distributor. Now, I had the timing marks lined up perfectly.

Now, although I did not have to turn the distributor that far, it still seemed strange that the timing needed to be altered as much as it did. So without taking the boat out into the water, I came home and found this in the manual:


5.0GL-B/C/D/E Models1
Engine RPM. . . . . . . . . . . . . . . . . . . 89 AKI Fuel
Initial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10?
600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19?
800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22?
1200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25?
1600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26?
2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27?
2400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28?
2800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28?
4000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28?
4800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28?

So, my question is this: The manual shows an "Initial" timing of 10 degrees and then a "600 RPM" timing of 19 degrees. Am I correct in assuming that the 600 RPM timing (19 degrees) is with the shunt removed? Further, if I am correct, I guess this means that I could check "total timing" (28 degrees) at say, 4000 RPM with the shunt removed?

Just one more question: I mentioned above that the engine RPM dropped when the shunt was connected. What "should" the RPM be at with the shunt inserted while I look for an inital timing of 10 degrees?

Thanks!

 

[Don S]

Re: Delco EST Initial/Advance Timing Concerns

So, my question is this: The manual shows an "Initial" timing of 10 degrees and then a "600 RPM" timing of 19 degrees. Am I correct in assuming that the 600 RPM timing (19 degrees) is with the shunt removed?

First, you have to understand that when you are setting the timing with the shunt installed, the degree that you set it at has nothing to do with normal timing. When the shunt is installed, it locks the timing so it doesn't change. In order to get 19? of timing in normal mode, it has to be set at 10? when the shunt is installed.

The shunt just stops the timing from moving. nothing more. On the 3.0 engines, you set the timing at 2?ATDC just so you get 8 in normal mode. If you tried to set the timing without the shunt, the timing would keep changing on you and make it almost impossible to set the timing properly.

Adjust the timing at 600 to 800 rpm range and it will be fine. The timing is locked.

Did you see this information on setting the timing on Volvo engines? http://forums.iboats.com/showthread.php?t=271407

 

[propuckstopper]

Re: Delco EST Initial/Advance Timing Concerns

Thanks Don! I fully understand the procedure now. I was just a little worried that my timing appeared quite a bit off, but it is a new boat to me and likely has never been timed since 2004 when it was new. I did find the timing adjuster bolt somewhat loose, so that could explain everything.

So what I am going to do is this: Install the shunt, ensure RPM is between 600 and 800, and set my advance light to 10 degrees. I'll time it right there. Then, I can remove the shunt and rev the engine to 2800 RPM. I should see the timing at 28 degrees at that time, correct?

Thanks!

 

[propuckstopper]

Re: Delco EST Initial/Advance Timing Concerns

This project turned out perfectly. After I verified 10 degrees initial timing, I removed the shunt and verified 28 degrees total timing at 3000 RPM. We are going to take the boat out later today and see how it runs. Thanks.