Any questions you have before you begin buying, building and installing.
#61902
Thinking about this some more, I think I said adjust the distributor. Since you have not moved the distributor, I would do the following:
Lock timing at the value indicated in the manual for your engine (usually 8 or 10 degrees)
Check timing
Adjust trigger angle to get correct timing

This should avoid any problem with rotor phasing and replicate the indmar setup.
#61942
So I managed to get my hands on a timing light and make some adjustments to the settings. I'm struggle to understand the relationship between 3 settings:

Trigger Settings
Trigger Angle (Deg)
Mine is set to 0
Apollard's is set to -27

Spark Settings
Cranking advance Angle (Deg)
Mine is set to 5
Apollard's is set to 0

Spark Settings
Fixed Angle (Deg)
Mine is set to 0
Apollard's is set to -127 (although it is greyed out)

I've set Enabled Fixed / Locked timing to On and experimented with the Fixed Angle (Deg) value without changing any other values. My understand is that once the timing is locked the Cranking advance Angle (Deg) and Trigger Angle (Deg) values are overwritten....?

I started with Fixed Angle (Deg) at zero and then moved in 5 degree increments in either direction. Starting the engine becomes slightly worse the further I go from zero in either direction. The engine will not start beyond 15 degrees or beyond -10 degrees.

Each time I change the Fixed Angle (Deg) I jump down into the engine bay and check with the timing light. I've got the timing mark painted with a bright whiteout pen so it is easy to see. Despite the engine bay being in the shade I'm yet to see the line come into view. I'm measuring from the stern / starboard corner of the engine which is spark plug one.

I found the Indmar manual for my engine and it indicated 10 degrees BTDC which I assume translates to -10 on the settings described above.
https://www.manualslib.com/manual/87849 ... d=1#manual

I'm wondering which of my assumptions are incorrect at this point?
#61945
Izzy46 wrote: Sat Mar 18, 2023 9:17 am So I managed to get my hands on a timing light and make some adjustments to the settings. I'm struggle to understand the relationship between 3 settings:

Trigger Settings
Trigger Angle (Deg)
Mine is set to 0
Apollard's is set to -27

Spark Settings
Cranking advance Angle (Deg)
Mine is set to 5
Apollard's is set to 0

Spark Settings
Fixed Angle (Deg)
Mine is set to 0
Apollard's is set to -127 (although it is greyed out)
The trigger setting is when the distributor tells the ECU it's at TDC of #1 cylinder. It is almost never zero, because you want to allow time for the ECU to do the calculations necessary, etc. The GM engineers setup the 8 pin EFI distributor to be around 20-30 degrees BTDC. Speedy needs this value in ATDC, hence my (-)27 figure. -27 ATDC (which is 27 BTDC) can also be expressed as 333 ATDC – all are pointing to the same place in the engine rotation. What's important here isn't how it's entered, but understanding the concept - Speedy has to know when TDC is to do almost all of it's work.

Cranking advance angle sets a fixed ignition timing when in the cranking zone. If set to zero like mine, Speedy uses the spark table, not a fixed angle. Right now, you want the fixed angle. After trigger is set, you can use the table or the figure Indmar gives (10*). I find it easier to use the table and keep setting in one place.

Spark settings Fixed angle forces speedy to use a fixed timing setting when running. The "Enable" setting above it determines if this value is used. Yours is turned off (like mine), so the spark table is used, not the Fixed angle value. Cranking advance angle overrides this setting AND the spark table during cranking.
Izzy46 wrote: Sat Mar 18, 2023 9:17 am I've set Enabled Fixed / Locked timing to On and experimented with the Fixed Angle (Deg) value without changing any other values. My understand is that once the timing is locked the Cranking advance Angle (Deg) and Trigger Angle (Deg) values are overwritten....?
Trigger angle is used for calculation of all timing events – ignition, fuel injectors, etc. It is never overwritten.
Cranking is always active when cranking .
Izzy46 wrote: Sat Mar 18, 2023 9:17 am I started with Fixed Angle (Deg) at zero and then moved in 5 degree increments in either direction. Starting the engine becomes slightly worse the further I go from zero in either direction. The engine will not start beyond 15 degrees or beyond -10 degrees.

Each time I change the Fixed Angle (Deg) I jump down into the engine bay and check with the timing light. I've got the timing mark painted with a bright whiteout pen so it is easy to see. Despite the engine bay being in the shade I'm yet to see the line come into view. I'm measuring from the stern / starboard corner of the engine which is spark plug one.

I found the Indmar manual for my engine and it indicated 10 degrees BTDC which I assume translates to -10 on the settings described above.
https://www.manualslib.com/manual/87849 ... d=1#manual

I'm wondering which of my assumptions are incorrect at this point?
Looking at the internet pictures of Indmar engines, it looks like your distributor should be toward the Bow. If that is the case, then you have #1 identified correctly. You say you are not seeing the mark. Is the light flashing? I ask because I’ve had problems getting timing lights to flash given the small plug gap involved on these engines. I loosen the plug wire to force the spark to jump further to make the light pickup the spark. Also, be sure you have the correct mark. Some dampners have more than one line on them.

If the light is flashing, you have the correct mark but you can’t see the mark, that means timing is off a good amount. When you say it won’t start at 15*, is it backfiring, kicking back, dragging (slow cranking)? These are clues to the timing error direction. However, the GM distributor you have was built have correct rotor phasing with the trigger angle around 20-30* BTDC (variations in tolerances and electronics cause the range). So, Indmar had to have it somewhere around that.

I would Enable locked timing, set it at 5 degrees for now. Then change the trigger angle to see if you can find the timing mark. I would start with -5, -10, -15, -20, etc for now. By -20 you should at least see the mark. If not, you can try the other way (ie, +5, etc). It should be negative. You want to adjust the trigger angle until what you read with the light matches your 5 degree locked timing value.

Note that the RPM will drop and the engine won’t sound as good as you lower the timing to the correct range. Engines idle well (but at high RPM) when timing is highly advanced.

If this doesn’t work:
1) Note what other engine characteristics you see at the trigger settings (dragging starting, backfires, kickbacks, etc
2) Post a picture of the dampner and timing marks, just so we can see what you are seeing
3) Post your tune again so we can see where you are now with settings.
@David and Josh, please correct me if I have anything wrong about how speedy works.
#61948
I would Enable locked timing, set it at 5 degrees for now. Then change the trigger angle to see if you can find the timing mark. I would start with -5, -10, -15, -20, etc for now. By -20 you should at least see the mark. If not, you can try the other way (ie, +5, etc). It should be negative. You want to adjust the trigger angle until what you read with the light matches your 5 degree locked timing value.

I did as suggested going in -5 increments, at -25 the mark popped into view. I adjusted the trigger angle until it was on the mark, although it did seem to hunt around a little bit, maybe 0.5 to 1 degree around the actual mark. The mark on the crank moved in a clockwise direction with every -5 adjustment to the trigger angle.

The engine starts easily but is pretty smokey and sounds a little rough and grumbly. At this point I didn't have the TPS or the MAP sensor hooked up so I didn't rev the engine at all.

I guess the next step is to work with the spark, VE and AFR tables until I get a nicer idle....?

Is it worth copying your tables as a start point Apollard?
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Last edited by Izzy46 on Sat Mar 18, 2023 3:03 pm, edited 1 time in total.
#61950
Your next step is to connect all the sensors .
No point doing any further tuning until they are connected especially tps and map!
#61951
That is fantastic, and about where I would expect it since it was designed to have around that as the trigger point BTDC. some movement or hunting is normal on these systems. You would see the same on any setup like this at idle. I find it becomes more stable at higher speeds.

So at the -30 trigger angle, the timing read exactly 5* ?

It's grumbly, smelly and smokey because without the MAP hooked up, it thinks you are at low RPM with the throttle wide open, so it is putting way too much fuel in (MAP will read 100 without a sensor connected). Like dazq said, hook up all the sensors and calibrate them (each one must be calibrated under Tools menu).

You can use mine as a guide, but my engine is a 7.5 liter with a performance cam, so it won't be the same. Later I'll take a look at your tune and see if you are way off somewhere. But don't do anything more than run it on the hose without at least the MAP connected - MAP is integral to getting the correct fuel and timing. TPS is needed for acceleration enrichment, which will be tuned after the base tune is done.
#61956
OK, another day and a little more progress. I got the o2, MAP and TPS sensors hooked up and calibrated. Now she starts first time every time and sounds reasonably good. Currently the idle sits pretty high at around 1200 rpm even when warm.
So at the -30 trigger angle, the timing read exactly 5* ?
Apollard, I'm not exactly sure what you mean by timing read exactly 5*....? With the settings I have and the timing locked the timing mark on the harmonic balancer hovers around the mark on the engine block. Is there something else to look for here?

At this point I have lots of wiring to tidy and tuck away as well as install some gauges that should be arriving any day now. :D :D :D

What is the next step to get the tuning on point?
Attachments
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#61957
Awesome progress :)

Do you have CLT hooked up? Otherwise it is likely to default to 20*, and be permanatly in warm up.

Have you calibrated all the sensors?

Edit

just re read your post :D

just CLT question then :)
Last edited by LPG2CV on Sun Mar 19, 2023 1:04 pm, edited 1 time in total.
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