cam/crank correlation with vortec dist?

[Aloicious]

Okay, so I'm working on the 24x conversion in my L31 vortec. how are you working with adjusting the dizzy for a correct cam/crank correlation? are you just stabbing the dist as you would normally with #1 at TDC for the intake and having the dist point where #1 would be, then logging the CMP Retard offset (vortec) to get it +- 2*? or is there a better way to get a correlating crank/cam signal with the 24x LS type setup?

[S10Wildside]

Okay, so I'm working on the 24x conversion in my L31 vortec. how are you working with adjusting the dizzy for a correct cam/crank correlation? are you just stabbing the dist as you would normally with #1 at TDC for the intake and having the dist point where #1 would be, then logging the CMP Retard offset (vortec) to get it +- 2*? or is there a better way to get a correlating crank/cam signal with the 24x LS type setup?

24x Documentation at http://www.eficonnection.com/24x/24x_Documentation.htm

Shortcut to the information you need at http://www.eficonnection.com/24x/documents/24xSmallBlockChevyInstallation.pdf. This document is included with every 24x purchase for non-LT1 applications.

What are the symptoms of incorrect cam/crank correlation?
- P1345 Cam Sensor Alignment
- extended cranking before starting
- engine backfire while cranking

[Aloicious]

24x Documentation at http://www.eficonnection.com/24x/24x_Documentation.htm

Shortcut to the information you need at http://www.eficonnection.com/24x/documents/24xSmallBlockChevyInstallation.pdf. This document is included with every 24x purchase for non-LT1 applications.

What are the symptoms of incorrect cam/crank correlation?
- P1345 Cam Sensor Alignment
- extended cranking before starting
- engine backfire while cranking

I did get that, I must have completely skipped that part though. thanks Mike. I may have more questions upcoming, I'm still prepping the block for the new heads.

[Aloicious]

okay, after re-reading that link I do remember it, however I'm mainly wondering what PID I log to while adjusting the distributor while it is seated to get its position correct, with the old 4x setup it is the CMP retard offset (vortec) which is logged while running to adjust the distributor correctly, and get it to within +- 2*. I'm assuming that is what I want to log to set it, or since that PID is designated "vortec", which I believe means it relates to the 4x, if there is a corrected PID I should be logging that will correlate with the 24x crank sensor.

[S10Wildside]

okay, after re-reading that link I do remember it, however I'm mainly wondering what PID I log to while adjusting the distributor while it is seated to get its position correct, with the old 4x setup it is the CMP retard offset (vortec) which is logged while running to adjust the distributor correctly, and get it to within +- 2*. I'm assuming that is what I want to log to set it, or since that PID is designated "vortec", which I believe means it relates to the 4x, if there is a corrected PID I should be logging that will correlate with the 24x crank sensor.

The L21 installation procedure for the cam sensor (distributor) is basically as provided in the previously mentioned document. GM doesn't even mention monitoring a PID while adjusting the sensor.

[Aloicious]

The L21 installation procedure for the cam sensor (distributor) is basically as provided in the previously mentioned document. GM doesn't even mention monitoring a PID while adjusting the sensor.

thats odd, considering its the same cam sensor as the vortec. they require the CMP offset to be +- 2* from zero. and its real touchy. I'll play around with it when I get it running and see what I can find, I'm just too OCD to not set it to something.

anyone know what the CMP Retard offset (vortec) PID is actually physically monitoring? (i.e. does the crank signal play any role in it? if not we could still use that one.)

[hquick]

Juc,
just from playing with the 'non' COP setup, if you're at +/- 2deg I reckon you'd be good to go. (Jeff agree's...Lol!).
The adjustment is 'super' sensitive to the point where tightening the hold down clamp can throw it out.
Oh...and a question you might be able to shed some light on (being a current trailblazer).
If you were to install the 24x reluctor wheel and then go to {G1207} Vehicle Platform Options and change 'Low Resolution Crank' to NO...will it run the dizzy and one coil? Ie...stock application???

[Aloicious]

Juc,
just from playing with the 'non' COP setup, if you're at +/- 2deg I reckon you'd be good to go. (Jeff agree's...Lol!).
The adjustment is 'super' sensitive to the point where tightening the hold down clamp can throw it out.
Oh...and a question you might be able to shed some light on (being a current trailblazer).
If you were to install the 24x reluctor wheel and then go to {G1207} Vehicle Platform Options and change 'Low Resolution Crank' to NO...will it run the dizzy and one coil? Ie...stock application???

yeah I've adjusted it alot in non COP setups, but since the PID is specifically labeled as "vortec" I'm not sure if the 4x crank signal has any part of the PID since that is a big part of the "vortec" setup. heh. so since I have to restab the dizzy (heads/intake off currently), and it is so sensitive, I'm looking for a way to set it with the 24x reluctor in already, or if I should just stab the dizzy and let it be like Mike is talking about. but I'm WAY too OCD for that, you know how that is...heh

I'm not sure if you could run a 24x reluctor, and single coil/dizzy that easy or not. I need to look at B1207 closer, but I'm not sure it works that way.

[Lextech]

Hey Justin,
We (Howard and I) don't know if it will run this way either. We were just curious if it would. That way you could put in the 24x wheel and get the truck running and then finish off the full CNP deal. Mostly just curiosity--But, we would really like to know of it would work.

Jeff---and Howard

PS: Howard (HQuick) and family are here in the states for a month and are staying with my family for several days--We are having a great visit.

Jeff

[Aloicious]

Hey Justin,
We (Howard and I) don't know if it will run this way either. We were just curious if it would. That way you could put in the 24x wheel and get the truck running and then finish off the full CNP deal. Mostly just curiosity--But, we would really like to know of it would work.

Jeff---and Howard

PS: Howard (HQuick) and family are here in the states for a month and are staying with my family for several days--We are having a great visit.

Jeff

yeah, it would be interesting if it would run like that, the main problem with me finishing is I keep getting called into work, and since I work graveyards it kinda screws up plans for the following day as well. but job security is good. heh.

I'll see if I have time to test it but I'm not sure if I will or not. right now I'm prepping the block for the new heads. and modifying the intake manifold to be boost friendly. I may get it running with the CNP first, and do some tuning with the new heads and 24x setup first, then add the whipple later. It kinda just depends on how it all goes.

[S10Wildside]

I'd like to throw in a little experience here just to avoid confusion for the reader who may be reading this thread and thinking that distributor orientation has anything to do with ignition timing.

Distributor orientation does not affect ignition timing.

From both the service manual and experience with the 24x signal from a distributor (prototyping only), the PCM is monitoring the 24x crank signal to determine crankshaft position. However, this is not enough for the PCM to know when to fire the injectors/coils. The PCM uses the 1x cam signal to determine engine stroke (intake or exhaust). If no cam signal is present or the cam signal is not in proper orientation, the PCM will attempt to start the engine as long as it sees the 24x crank signal (engine rotation is present). If the engine does not start (no increase in RPMs), the PCM will assume opposite stroke in an attempt to start the engine (extended cranking and typically backfire).

So don't get too caught up on the distributor orientation. Follow the instructions provided (as per GM) and expect reliable starts 100% of the time.

There's nothing wrong with knowing for sure that the cam sensor orientation is 100% accurate...but GM does not reveal this information. Probably because it's not critical.

Of the several vehicles already up and running with 24x, no one has had startup issues or DTCs indicating improper camshaft orientation.

[Lennart]

I am planning to convert an old inline-6 (292) Chevy to EFI. To keep the look as
original as possible I prefer to keep the distributor. My plan is to install the 1x cam
position sensor in the inline distributor and add a 3x crank reluctor from a 4.3L.
Obviously I will need a custom timing cover, question is how the crank pos. sensor
needs to be oriented. The inline crank is the same dia. as a small block/4.3L, not sure about the relation keyway to TDC #1.
On the V-6/8 motors it seems the sensor is placed 45° off center or parallel to the cylinder bank. Would I need to place the sensor parallel to my cylinders as well?

If I wanted to run a high resolution crank signal on an I-6 would that even be possible? 18x reluctor??

Thanks,
Lennart

[S10Wildside]

I am planning to convert an old inline-6 (292) Chevy to EFI. To keep the look as
original as possible I prefer to keep the distributor. My plan is to install the 1x cam
position sensor in the inline distributor and add a 3x crank reluctor from a 4.3L.
Obviously I will need a custom timing cover, question is how the crank pos. sensor
needs to be oriented. The inline crank is the same dia. as a small block/4.3L, not sure about the relation keyway to TDC #1.
On the V-6/8 motors it seems the sensor is placed 45° off center or parallel to the cylinder bank. Would I need to place the sensor parallel to my cylinders as well?

If I wanted to run a high resolution crank signal on an I-6 would that even be possible? 18x reluctor??

Thanks,
Lennart

Hi Lennart,

You might want to create a new thread as this thread is unrelated to what you're trying to accomplish.

I don't have details available for sensor/reluctor orientation for your project, but I can tell you that GM never wrote a calibration for a high resolution crank reluctor with the V6. You will be stuck with a single coil and distributor using the 3x crank and 1x cam signal.

Hope this helps,
Mike

[Aloicious]

forgot about this thread. just a post install update for anyone interested, the CMP retard offset PID just logs a constant zero, Mike is correct, that as long as the cam is installed correctly, there is no offset to adjust.

[evilstuie]

forgot about this thread. just a post install update for anyone interested, the CMP retard offset PID just logs a constant zero, Mike is correct, that as long as the cam is installed correctly, there is no offset to adjust.

Not sure if you're still monitoring this Wildside, but I'm having some issues with my setup and have started to wonder if this is related to the placement of the vortec dizzy on my 0411PCM conversion of a SBC 24x.

I'm getting horrible stuttering/backfiring and surging, more prominent (permanent) in low revs and extended cranking before it starts.
You mentioned the alignment is not critical, but would this be a still be the case if the dizzy used for 1x cam signal was off by 180 degrees?
Alternatively, if it is off by 5/10 degrees could it still cause this or it doesn't matter where it is, so long as it's present?

One other quick question, does the vortec distributor have a different pinout config to the LSx cam signal sensors or are they same?
I assume it's the same otherwise I wouldn't have a tacho reading, but I had a problem with the crank sensor when the vortec pinout was different to the LS1 pinout.