Inline 6 on a 0411 pcm

[dave w]

I have both of those and that is what they measure with the deg wheel I have.

I think the 6x trigger wheel I make for the distributor will need to be the same.

I have also thought about just milling the harmonic balancer. It has a ridge around the front of it.
Attachment 17094

For a nearly perfect 100% CKP/CMP signal accuracy, maybe use the harmonic balancer for both CMP and CKP? Maybe the outer ring / larger ring the CMP? Maybe use the inner ring / smaller diameter ring for 3x CKP? If I'm thinking my engine math correctly, then maybe machine two 87.5 degrees segments (175 degrees CMP trigger wheel divided by two) from the outer ring? Custom CKP - CMP brackets required. Custom balancing for the I6 Harmonic Balancer required. The BBC 8.1 Liter CKP sensor will read the Harmonic Balancer modified 175 / 185 degrees.

Link for the BBC 8.1 liter Timing chain and gear set: https://www.carid.com/melling/engine...3-4sr50sc.html

dave w

[Thorwon]

For a nearly perfect 100% CKP/CMP signal accuracy, maybe use the harmonic balancer for both CMP and CKP? Maybe the outer ring / larger ring the CMP? Maybe use the inner ring / smaller diameter ring for 3x CKP? If I'm thinking my engine math correctly, then maybe machine two 87.5 degrees segments (175 degrees CMP trigger wheel divided by two) from the outer ring? Custom CKP - CMP brackets required. Custom balancing for the I6 Harmonic Balancer required. The BBC 8.1 Liter CKP sensor will read the Harmonic Balancer modified 175 / 185 degrees.

Link for the BBC 8.1 liter Timing chain and gear set: https://www.carid.com/melling/engine...3-4sr50sc.html

dave w

The CMP won't work off the crank. The crank makes one full revolution+185 deg. before the CMP gets a signal.

[2xls1]

I'm in no way trying to say it won't work. More just inquiring as I know of no OEM crank sensors that read anywhere but directly off the crankshaft. I hope you will keep this thread updated with whatever issues you run into. It will be interesting. And the cam sensor does not need anywhere near the accuracy of the crank sensor. It's just telling the PCM TDC either compression or exhaust. OEM vehicles using a P01 don't even need the cam sensor to run. Without a CMP signal on start the PCM will guess TDC on compression. If no start it will wait 180 degrees and fire the plug again. Once it starts it will sync on that position until the next key cycle.

[Thorwon]

I'm in no way trying to say it won't work. More just inquiring as I know of no OEM crank sensors that read anywhere but directly off the crankshaft. I hope you will keep this thread updated with whatever issues you run into. It will be interesting. And the cam sensor does not need anywhere near the accuracy of the crank sensor. It's just telling the PCM TDC either compression or exhaust. OEM vehicles using a P01 don't even need the cam sensor to run. Without a CMP signal on start the PCM will guess TDC on compression. If no start it will wait 180 degrees and fire the plug again. Once it starts it will sync on that position until the next key cycle.

That's what I love about this site, You can never tell when somebody will teach you something. I love learning and I didn't know that.

So if I put a CRP on the crank and drop a big cap HEI in this engine it'll run? That would be crazy.

All I really need is a way to run the fueling.

[dave w]

The CMP won't work off the crank. The crank makes one full revolution+185 deg. before the CMP gets a signal.

I'm not sure what will happen with both CMP and CKP on the crank without an oscilloscope.

What I know works . . . CMP and CKP in a distributor or dual trigger distributor works in a Chevy L31 V8 using 8x crank triggers and 1x cam trigger.

Likely everyone would agrees Inline 6 requires 3x crank triggers.

Likely everyone would agree that the engine math is two crankshaft rotations equals one distributor rotation. The camshaft timing chain gear is twice the diameter of the crankshaft timing chain gear.

So using the reverse logic to make a dual trigger Harmonic Balancer the cam signal would need to half the signal of the distributor mounted cam signal?

Let's say for simplicity reasons, the distributor mounted cam signal is 175 degrees, so half of 175 degrees is 87.5 degrees.

So now it's time to use an oscilloscope on a 4.3 V6 and reverse engineer a solution, or maybe not?

dave w

CKP_CMP_waveform_relationship_001.jpg

Crank Cam.jpg

[2xls1]

That's what I love about this site, You can never tell when somebody will teach you something. I love learning and I didn't know that.

So if I put a CRP on the crank and drop a big cap HEI in this engine it'll run? That would be crazy.

All I really need is a way to run the fueling.

I can't say for sure on a V6 OS which I think you'll be using but for sure on 4.8, 5.3, 5.7, and 6.0 will run without a CMP signal. You can get an extended crank while the PCM figures out compression TDC. One thing is do not disable the DTCs for the CMP sensor. The PCM has to see the CMP code set for it to run without the signal. I've just never tested it on a vehicle with the CMP in the distributor. The V8s have the cam reluctor either directly on the back of the cam or up front on the cam gear.

[Thorwon]

Full rotation of all 4 stroke engines is 720 deg on the crank and 360 on the cam.

Your math is correct but your thinking is wrong.

To get a 175 deg signal on the cam the crank has to turn 545 deg while the cam has turned 185 deg.

While 87.5 deg rotation on the crank will give you 175 deg on the cam but then you have to figure out how to get another 360 deg on the crank.

If you try to put the cam signal on the crank you will get 1 signal per revolution. A 1x cam signal is actually a 1x per every 2 crank revolutions.

[Thorwon]

I can't say for sure on a V6 OS which I think you'll be using but for sure on 4.8, 5.3, 5.7, and 6.0 will run without a CMP signal. You can get an extended crank while the PCM figures out compression TDC. One thing is do not disable the DTCs for the CMP sensor. The PCM has to see the CMP code set for it to run without the signal. I've just never tested it on a vehicle with the CMP in the distributor. The V8s have the cam reluctor either directly on the back of the cam or up front on the cam gear.

I may try it both ways and just see what I get. I'm going to use the 2002 Chevy S-10 L35 4.3L 4L60E (12212156) bin I posted in the start of the thread.

I've still got to swamp in a manual trans sec.

[2xls1]

Here is a stock 2002 Silverado 4.3L M5 Trans bin if that will help.

[Thorwon]

Here is a stock 2002 Silverado 4.3L M5 Trans bin if that will help.

Thanks, I'll take a look at it.

[dave w]

Full rotation of all 4 stroke engines is 720 deg on the crank and 360 on the cam.

Your math is correct but your thinking is wrong.

To get a 175 deg signal on the cam the crank has to turn 545 deg while the cam has turned 185 deg.

While 87.5 deg rotation on the crank will give you 175 deg on the cam but then you have to figure out how to get another 360 deg on the crank.

If you try to put the cam signal on the crank you will get 1 signal per revolution. A 1x cam signal is actually a 1x per every 2 crank revolutions.

For simplicity reasons lets look at the CMP signal @ 180 degree not 175, so perhaps we can agree the picture below is what a V6 CMP / CKP signal looks like with a 180 degree 1x distributor CMP Signal?

dave w

V6 CMP _ CKP.jpg

[Thorwon]

For simplicity reasons lets look at the CMP signal @ 180 degree not 175, so perhaps we can agree the picture below is what a V6 CMP / CKP signal looks like with a 180 degree 1x distributor CMP Signal?

dave w

V6 CMP _ CKP.jpg

Yes, I agree that's what it should look like.

[dave w]

I can't say for sure on a V6 OS which I think you'll be using but for sure on 4.8, 5.3, 5.7, and 6.0 will run without a CMP signal. You can get an extended crank while the PCM figures out compression TDC. One thing is do not disable the DTCs for the CMP sensor. The PCM has to see the CMP code set for it to run without the signal. I've just never tested it on a vehicle with the CMP in the distributor. The V8s have the cam reluctor either directly on the back of the cam or up front on the cam gear.

I don't know if either a V6 or V8 using the '0411 with a distributor mounted CMP will run without a CMP signal, that theory of operation will need to be tested.

What I've learned from the dual trigger distributors I've built is the alignment between CMP / CKP is CRITICAL. If the distributor mounted CMP is not accurately aligned with the CKP, the engine will not start.

dave w

[dave w]

Would it be an accurate statement to say the distributor mounted CMP is telling the '0411 computer that cylinder #1 is at TDC of the compression stroke?

Would it be an accurate statement to say the CMP signal is setting / resetting the injector firing sequence?

Would it be an accurate statement to say the '0411 computer that is using a distributor mounted CMP is adjusting the ignition timing via the Ignition Control Module based on CKP and MAF input?

dave w

[dave w]

I see the error in my thinking.

dave w

V6 CMP _ CKP_Crank.jpg