drain89

iTrader: (10)

Since I'm converting to Holley MPFI instead of TBI but wish to use a 730 ecm, could I use the newer style ignition from a gen 1 vortec truck? It has a crank sensor and cam sensor. External coil and external module.
How hard would it be to adapt to this style of ignition?
Or would I be better off to stick with the small cap 87-95 style distibutor?

SSFiero

bump to the top. I'm looking to do the same thing, but I want to do this to fit on my intake better. The shorter dizzy allows me more room.

jwscab

I've kicked this around a bit before. the small cross-fire cap is nice to make some room, but you have to do some modifications to the distributor to work properly.

the distributor houses only a cam position sensor, really, all it senses is between engine revolutions, it has a hall effect sensor, and the shutter is 180 degrees window/180 degrees interruptor.

the nice thing is that the hall effect sensor is much like the old optical mallory kit that adapted the points distributors, you need power, ground, and signal out. you can use this to trigger a computer controlled ignition module externally mounted. that way, all you have done is changed the pickup type, and the ecm still thinks is a regular distributor.

the hard part would be to machine another shutter wheel(looks kinda like a hole saw, actually, might be able to use a scrap one, or just machine a steel cup on a lathe)

the shutter wheel should have 8 equally spaced notches, the width would be experimental though, I'm guessing, about 3/32" wide or so, should mimic the reluctor pickup signal width of a standard distributor.

if you get that all worked out, it should work fine. I have one to play with, just never got the time to make a new wheel and fire it up on the bench.

Dave_Jones

Or use the Vortec front cover, and 4X reluctor, to replace the pickup coil in the distributor.

Only catch is, you have to use a standard or single roller (i.e. ZZ4) timing chain, not a dual roller, so that the reluctor will fit, and shorten the crank hub by about .090" to account for the reluctor thickness, and maintain pulley alignment.

I also discovered that an 8" harmonic damper lays back over the timing cover far enough that it'd interfere with the crank position sensor. I solved that by switching to a Fluiddampr. I think a regular 6.5" damper would be OK, too.

I haven't finished the wiring yet (another project is currently occupying the garage) but I've talked to some Sy/Ty owners who have used the same strategy on their V6's, so I see no reason why it wouldn't work on a V8.

jwscab

so you've got a vortec front cover on an older SBC? interesting. hard to make work?

what ecm would you use that would convert the reluctor signal into somethign useable? does the vortec coil/module provide the signal conditioning? I can're remember what the schematic looked like, but I didn't think the module did that, the reluctor pickup went striaght into the pcm. i think the pcm also computes the required dwell and all advance(none built into the module), but I can't be sure.

sounds interesting though. any more details?

Dave_Jones

Not hard. I already had a ZZ4, so I already had the single roller timing chain. Otherwise, it's just a front cover swap, and finding someone with a lathe to trim the balancer slightly.

What some Sy/Ty guys have done is to wire the crank sensor into a regular HEI module, where the pickup coil would normally be connected. This gets a module back in the loop, so the ECM doesn't need to learn any new tricks.

BTW, my real reason for the vortec cam & crank sensors is ultimately for a CNP setup, but I may end up running it for awhile in single coil configuration in the meantime.

jwscab

duh, should have realized that....its a 4 pulse per rev, drive it into an ignition module, good thinkin!

should work fine in that case. for CNP, MSD makes a small cam position sensor, that drives the oil pump, with a reluctor pickup. that way, you wouldn't need a dummy distrubutor in place. dunno how much it costs though. thats my biggest dislike about the retrofit systems. something about leaving an unused part on the engine, just doesn't seem right to me, hah.

Dave_Jones

I'd heard of those, but I'm pretty sure they cost more than the $20 I paid for the Vortec distributor.

Besides, I figure if the looks bother me, I can grind the wire terminals off the vortec cap, so it's just a plain cover.

Grumpy

Why not use one of the old dual sensor GM distributors, that used a reluctor for cylinder firing, and the Hall for the cam synch signal.

Dave_Jones

Any idea what applications those might be found on?

SSFiero

I'd be interested in knowing what app that dist is from too.

What I'm trying to do is run a HSR with the top plenum reversed. Its in the back of a fiero, transverse mounted. The reason for the reversed plenum is for looks mostly, but also for a better/easier fit. The plenum is tall and just fits in the decklid without the TB.

I'm not against doing a CNP, but I was hoping to keep the cost down.

What type of signal does the ECM want to see to run? Would running a magnetic crank trigger, with a cam signal from the vortec dist. work? I have mitchell on demand, so getting schematics and wiring these parts together isn't a problem. I'm not familiar with what kind of signal the ecm is looking for. Maybe I'm making this more complicated than it should be.

SSFiero

Where would you mount the Module?

Can the module be remote mounted, or does it need to be in a dist? Reason I ask is, That bottom side of the module that your supposed to put the paste on, does it do anything? Like ground the module, or pick up some kind of signal?

Dave_Jones

The module can be remote mounted, in conjunction with some form of heat sink.

The Vortec and LT1/LT4 engines have the module mounted on the coil bracket, with a finned aluminum sink.

67 ss

I don't see how you could send the vortec crank sensor to an old hei module. The vortec crank sensor sends a square wave signal out, the hei module is looking for an A/C sine wave signal in from a pickup coil I don't know that the module would be able to understand?

SSFiero

thats what I was told last night as well.

What type of signal do the aftermarket crank triggers have? Or other factory crank triggers that give out an AC sin wave?

What can I used to measure the signals? oscilloscope? I haven't used one of those since High school. They aren't too pricey on ebay, if its something thats going to see some use.

Tell me if this sounds right.

If I have a crank trigger that has the correct signal, and wire that to a remote mounted ign. module. Then out of the module to the coil and ECM like in the factory setting. Using a vortec dist. Assuming all the sensors are adjusted properly, would this thing fire? I Wouldn't think I will even need the cam pos. sensor from the vortec dist. Unless I changed to CNP down the road.

That just sounds too simple.
thanks

67 ss

In theory it should trigger the hei module and if you wired it to the ecm in stock manner you should have timing control.

Rule of thumb a crank sensor with three wires is going to be a hall effect sensor producing a sqaure wave. A two wire crank sensor is going to be an a/c generator produceing a sin wave.

Though most a/c style crank sensor I have seen have the same amount of notches as cylinders to engine and I sync pulse for #1 cylinder. I don't know that the 4 pulses from the vortec setup is going to produce what is needed for the hei module to work correctly.

Don't get me wrong I have never tried any of this you would have to wire it up and see what happens.

Dave_Jones

Y'know, now you've got me wondering...perhaps the guy I was talking to was actually using an MSD crank trigger, not the Vortec CKP.

Damn brain cells, just ain't what they used to be.

Maybe adding in something along the lines of
http://www.electronics-lab.com/proje...rs_timers/003/
would make it work.

jwscab

the hei module can use a square wave as an input, I've done it on my test bench, and it works fine. Its not looking for a sine wave, it actually wants to see a zero-crossing from the reluctor pickup. I am feeding the signal differential, though, out of a flip flop, which has both an inverted and non-inverted output(Q, /Q), so when one is high, the other is low, and vice versa. You could do the same thing with an inverter IC, or even simpler, a transistor. then feed both signals into the + and - of the hei module. I would take the signal off of the hall effect sensor, run it into a nice project box, with the circuit in it, and run the signals out of that. then waterproof the whole thing, and put in a safe place in the car(maybe firewall or top of fenderwell, away from alot of heat/moisture.) then use the 4 position crank sensor from the vortec. The only thing I don't know for sure is how the duty cycle of the signal affects the software, for dwell and so forth, since the reluctor sends out 'pulses' rather than a 50% duty cycle square wave that the hall effect will.

Grumpy

Dunno if I'd want to add any capacitance to the ignition. You might disrupt the latency fired into the spark code. If you do something like that, I'd test run the engine with a timing light on it to make sure the actual timing matched what you thought it should be.

DJ406

Im was about to order an msd crank trigger for a ramjet 350 type motor to fire my FAST ecu but this factory crank trigger deal has me curious. Does anyone know where does it trigger on the rising edge ,at what degree ? I need it to be able to trigger somewhere around 50btdc. the reluctor ring is keyed to the crank and the pickup is fixed so I guess I could re cut the keyway in the reluctor if I had to. has anyone messed with the vortec crank trigger? it is just an inductive pickup isnt it ?

thanks
Doug

Fast355

iTrader: (2)

I wouldn't use the 730, it is junk compared to what I am using. I am using the Vortec PCM with my TPI swap. It was a match made in heaven with both units sharing 19 lbs/hr injectors. A plus side is you get the big MAF sensor. I am also running a 1998 (S10 4.3) 4L60E automatic with the swap. I have yet to do any tuning, but it runs awesome and is putting out 250 RWHP from a 305 with stock 081 castings on it and a LT1 roller cam.

305 TBI roller cam block
LT1 roller cam
Stock casting 081 heads
Flowtech 11500 Headers (1.5" primaries 3" collector)
2 1/2 Dual cats, into flowmaster 50 series, 3" single tailpipe.
New Vortec Timing cover and Crank Sensor
New Vortec style crank reluctor ring and timing set
Vortec style distributer and wireset
Vortec wiring harness from Painless off of Ebay ($150.00)
Vortec PCM from 1996 1500 Express with a 305 ($20.00 off Ebay 1997 down is without VATS/Passkey)
Lightly used MAF sensor from a 2004 Suburban 5.3 ($30.00 off Ebay)
Welded in 4 heated O2 sensors 1 before each cat and 1 after) $25.00 for the lot of 4 off of ebay from a 2004 Suburban 5.3
TPI setup from Speed Density 1992 Camaro 305 (Old style MAP sensor connector spliced into harness)
1996 LT1 Firebird Throttle Body (same IAC & TPS as Vortec
Intake Air Duct from 1995 LT1 caprice

The PCM has adapted very well to the engine combination and is fun to drive. It needs to have the EGR programed out as the linear EGR valve will not bolt to the TPI lower intake. Other than the EGR code, EVAP, and MISC others, it is running great and getting good fuel economy.

It is in a 1994 Chevrolet G10 Van, but it runs as well as a newer Express or Suburban with a 5.3.

It is sequential fuel injection now as well. The OBDII system is still in operation, my scantool hooks up perfectly, and the Hypertech programmer that I have laying around that I pulled off of my 1997 Chevy G1500 305 (swapped from destroyed 350 to used 305 and tuned it, then went back a year later to a 350) worked OK. Basically changed the shifts, raised the speed limiter, powertuned it, and recalibrated for the tires, gear ratio, set it up for a 170* thermostat, and firmed up the shifts.


Ignore the date on the camera, this was like 3 1/2 weeks ago (date resets when the battery goes dead).

The Vortec PCM will also do alot of extra stuff.

Automatic Transmission control (4L60E & 4L80E)
WOT A/C cut-off
Cooling Fan Control (454s used an auxilary electric fan output that can be changed programed)
OBDII Diagnostics (Missfire, Sensors, Catalyst, etc)
Freeze frame to store operating conditions when a code is set
Sequential Injection
Hybrid MAF/MAP operation
Underhood mounting

scuzz

I'm doing a similar swat as fast355 now. The thread is over at diyprom. I'm using Vortec engine/trans with Ramjet intake, ported heads, LT4 cam. I'm glad I finally found someone that has done it and know that it worked. Thanks Fast355 for telling us.
Ron

Fast355

iTrader: (2)

My only problem is that I didn't get TCII when I had the chance and JET wants WAY TOO MUCH for it. Then they slapped a crappy vehicle limit on it. I am still trying to get it tuned to eliminate the unecessary programming.

scuzz

I was in the process of ordering TCII when they sold the rights to jet. I got lucky and bought an original copy from a member on Monodax Homepage - TunerCat OBDII Scanner and Data Logger - MXScan Info-. I'm a ways from being done with my project.

Doctor J

The Vortec crank sensor is a Hall switch, which produces a square wave output.

By changing the keyway position you can get a rising or falling edge where ever
you want. I used one to feed a DRP to a 727 ECM for several years:

https://www.thirdgen.org/forums/atta...postid=1425055
https://www.thirdgen.org/forums/atta...postid=1425057

HTH

DJ406

Thanks Doctor J , I need to hit the junk yard and find a vortec motor to pilfer :-) thanks for the close up pix of the sensor , now I see it has 3 wires and Hall like you said which will still trigger my fast ecu. I still may just use an msd crank trigger because it will be a lot easier to clock but Id like to experimint with the factory trigger anyway.

thanks again

Doug (in Michigan )

scuzz

I've sent my harness to S10Wildside to re-pin for the 2001-2002 Express van pcm. It's the same as LSX and will run the L31 engine.

Ryan3834me

Sorry if this is redundant, or already answered elsewhere. The OBD II thread blew up. I saw Scuzz had an aftermarket intake with Vortec dizzy and it was tight.

Does the vortec dizzy fit a modified LT1 intake? I'm looking to swap both, corevette aluminum LT1 heads (10207643) and LT1 intake (modified for dizzy). It's a clearance question basically. (Specific to modified LT1 intake).

Thanks! you guys rock.

Mike Welsh

I have a 1987 monte carlo ss with 1996 chevy vortec with mod's done to it. I am running into the same problem of where to wire crankshaft sensor into. I know u said pick up coil but not sure where n how to do it. Thank u for any advice u can give me