Phishincruisin gets a vortec
- Thread starter phishincruisin
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ntsqd
technerd
The signal that a good pick-up will send out will look exactly like the tooth profile. Some ECU's are particular about the signal shape (want square wave, semi-square wave, or sinusoidal). It would be good to emulate the tooth shape of the OE tone ring if at all possible.
I'm hoping that the shop that epoxied something in place epoxied a threaded bung for a sender rather than the sender directly. Would make replacing the sender a bit of a problem. I can see using epoxy for the bung since welding on thin aluminum castings is a crap-shoot as to if you warp it or not. You really don't know if it will warp until you try it, and if the parts is expensive or hard to find....
Was it you who built a VSS on the end of the input (rear side) of a Split-case? I dimly recall someone epoxying a gear to something to use as a tone ring. Seems like that would be an ideal location. I don't know about the problems in securing the tone ring.
I'm hoping that the shop that epoxied something in place epoxied a threaded bung for a sender rather than the sender directly. Would make replacing the sender a bit of a problem. I can see using epoxy for the bung since welding on thin aluminum castings is a crap-shoot as to if you warp it or not. You really don't know if it will warp until you try it, and if the parts is expensive or hard to find....
Was it you who built a VSS on the end of the input (rear side) of a Split-case? I dimly recall someone epoxying a gear to something to use as a tone ring. Seems like that would be an ideal location. I don't know about the problems in securing the tone ring.
- Thread starter
- #123
I tried doing that, but didn't epoxy it. I machined the gear so that it was a tight fit on the stake nut on the shaft, but the set screws weren't enough to hold it on, which is why i'm trying to figure a better method.
The gear I used is ordered from mcmaster, and should give a signal very close to a square wave. mwdubs used the same gear for a setup that he built in his swap and it worked well for him.
ntsqd
technerd
Cool! Just didn't want to see a bunch of work go into something that the ECU would reject.
My split-case is gone, so I've no reference for the design details. From what I could find in pictures on the net it looks like there is a nut on the rear of the input shaft that clamps a bearing & possibly more onto the shaft. Seems like a 'washer' with a tube welded to it's OD could project back and carry a welded/bonded-on tone ring. The tube would need to have an ID large enough for the socket for that nut to fit inside of, and that might kill the idea. Dunno. Something like the attached?
My split-case is gone, so I've no reference for the design details. From what I could find in pictures on the net it looks like there is a nut on the rear of the input shaft that clamps a bearing & possibly more onto the shaft. Seems like a 'washer' with a tube welded to it's OD could project back and carry a welded/bonded-on tone ring. The tube would need to have an ID large enough for the socket for that nut to fit inside of, and that might kill the idea. Dunno. Something like the attached?
- Thread starter
- #125
Awesome idea. I hadn't thought of something like that, but it should work really well. And it will be an easy install as well. I'll have to look into the dimensions of the nut and socket and such, but I think it should. I'll have to model the part and see what I can get for prices locally to do the machine work. I'm not at school right now so I don't have access to any machine tools
rover67
SILVER Star
That's what I am running on my truck. I got the VSS and reluctor ring from Downey when they were in buisiness. Same part that you show there plus a different cover that holds the VSS close to it.
have you checked Jags That Run for VSS stuff? They have lots.
www.jagsthatrun.com
I just bought a couple of parts from Parts Mike, a driveline rotor and a mechanical caliper for said rotor. The rotor has provisions for providing a defacto VSS signal, it just needs the sensor lined up with the holes in the rotor. So if you're not running the Cruiser axle and you need a an E-brake, you might be able to kill two birds with one stone. Just a thought.
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- Thread starter
- #129
I haven't updated this in a while, so here goes:
In August I built myself a VSS, and it has worked pretty well so far. I press fit the 40 tooth gear from McMaster that mwdubs found onto the nut on the rear of the transfercase input shaft, and secured it with 3 safety wired SHCS. On the nut I drilled small set holes where the SHCSs would seat to give me more interference. For one of the screws I drilled through the nut into the keyway, thus securing the nut in place with that SHCS. I used my earlier sender housing, and adjusted the clearance. This took a couple tries, and still isn't 100%. I purchased a ScanGauge II to see that the computer saw my VSS, and up to about 45 mph it is good, and then it jump around a little. I think either the sender needs to be closer, or the profile on the teeth needs to be a little different. It still performs its required functions for my setup, and I've been happy with it.
The ScanGauge II was another cool addition to the LSx swap. It allows me to monitor every sensor the PCM sees, and it even calculates your HP for you! It is neat to watch the temp hit 200F and then hear the fan come on, and the temperature drop right away. Definitely a great feature to have with OBDII engines.
Sometime during the fall, pulling into my driveway after an afternoon of biking, my clutch went out. Somehow the slave cylinder over extended causing the clutch fork to end up lodged in the bellhousing and brake fluid all over the driveway. I determined that my using the LS1 flywheel was actually incorrect for this application, due to the difference in flywheel mounting location between LSx motors and a SBC. The use of the larger pilot bearing allowed the input shaft to be located and supported properly, unlike the small pilot bearing the old SBCs had. The purchased conversion flywheel had a face offset of .400". This put the clutch assembly in the same position relative to the bellhousing mounting surface as the SBC, so now everything fit how it should.
Here is the difference in flywheels:
In August I built myself a VSS, and it has worked pretty well so far. I press fit the 40 tooth gear from McMaster that mwdubs found onto the nut on the rear of the transfercase input shaft, and secured it with 3 safety wired SHCS. On the nut I drilled small set holes where the SHCSs would seat to give me more interference. For one of the screws I drilled through the nut into the keyway, thus securing the nut in place with that SHCS. I used my earlier sender housing, and adjusted the clearance. This took a couple tries, and still isn't 100%. I purchased a ScanGauge II to see that the computer saw my VSS, and up to about 45 mph it is good, and then it jump around a little. I think either the sender needs to be closer, or the profile on the teeth needs to be a little different. It still performs its required functions for my setup, and I've been happy with it.
The ScanGauge II was another cool addition to the LSx swap. It allows me to monitor every sensor the PCM sees, and it even calculates your HP for you! It is neat to watch the temp hit 200F and then hear the fan come on, and the temperature drop right away. Definitely a great feature to have with OBDII engines.
Sometime during the fall, pulling into my driveway after an afternoon of biking, my clutch went out. Somehow the slave cylinder over extended causing the clutch fork to end up lodged in the bellhousing and brake fluid all over the driveway. I determined that my using the LS1 flywheel was actually incorrect for this application, due to the difference in flywheel mounting location between LSx motors and a SBC. The use of the larger pilot bearing allowed the input shaft to be located and supported properly, unlike the small pilot bearing the old SBCs had. The purchased conversion flywheel had a face offset of .400". This put the clutch assembly in the same position relative to the bellhousing mounting surface as the SBC, so now everything fit how it should.
Here is the difference in flywheels:
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ntsqd
technerd
I don't know what type of sensor is used for the VSS, but what I have observed with an oscilloscope and inductive sensors is that the output signal looks exactly like the tooth profile. Say that you machined the tips of the teeth of a sprocket off, an inductive sensors output signal will have the radiused 'bottom' of the tooth profile, but also have the slightly squared off tip profile too. It will look exactly like as if you had "unwound" the teeth and pulled them out straight.
With a Hall Effect type sensor this may be different as I have not (yet?) done that experiment. Nor have I done the experiment with any other type of sensor. What I recall reading is that early GM ECU's (early TBI's & TPI's) wanted one type of VSS input signal, but that later ECU's want a sinusoidal signal form (late TPI's). I do not know if this is still true of the ECU's used with the LSx series.
So if the sensor used is outputing a square wave and the ECU is expecting a sinusoidal wave (or vice versa), that might be the source of the issue.
With a Hall Effect type sensor this may be different as I have not (yet?) done that experiment. Nor have I done the experiment with any other type of sensor. What I recall reading is that early GM ECU's (early TBI's & TPI's) wanted one type of VSS input signal, but that later ECU's want a sinusoidal signal form (late TPI's). I do not know if this is still true of the ECU's used with the LSx series.
So if the sensor used is outputing a square wave and the ECU is expecting a sinusoidal wave (or vice versa), that might be the source of the issue.
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yes... I know that the different GM 5.7 engines with fuel injection don't all use the same VSS. As stated above I think that clearly you have to use a VSS signal that teh PCM expects to see. On my 99 5.7 I run the stock GM flywheel...without issue. At present I use a GM VSS sensor with downy adapter.
djawahir
SILVER Star
Hey Phishin',
I'm not sure I'm following what you did to the flywheel? Did you shave it .4"? I'm having a problem with my clutch slave not engaging/disengaging as nicely as with the 2F/4spd. (I have a Vortec V8, Marks adapter, H55F setup now.)
I'm not sure I'm following what you did to the flywheel? Did you shave it .4"? I'm having a problem with my clutch slave not engaging/disengaging as nicely as with the 2F/4spd. (I have a Vortec V8, Marks adapter, H55F setup now.)
ntsqd
technerd
I suspect that it isn't just the sensor that is important, but that the trigger wheel (reluctor) also have teeth of the same shape as the original reluctor. Even better if you can use the original reluctor somehow. I'm thinking that you already know this, but I'm stating it just to be clear.
- Thread starter
- #134
I understand how the signal is gathered with this system. The PCM wants to see a square wave, 4000 PPM. Since I don't run an auto, the PCM just really needs to see that the vehicle is moving, and it does that. When I get a chance I'll get it working just right, but its not high on the priorities at all.
- Thread starter
- #135
djawahir, I didn't do anything to the flywheel, I just had to order the right one. What flywheel are you running in your setup? The .400" is additional thickness to the flywheel, so that the flywheel surface, where the pressure plate and clutch are mounted, is in the same location relative to the bellhousing mounts as a earlier SBC. Since all the kits out there are designed for SBC not LSx motors, this adjustment should be made in every situation where an LSx motor is used with SBC adaptors.
Elbert, you can use the stock flywheel as you have a 5.7 Vortec, not an LSx Vortec. the 5.7 still has the usual SBC locations.
djawahir
SILVER Star
Oh, I thought you machined your flywheel to look like that. The flywheel I'm using is the one from man-a-fre: part #700120. Looks like the one in the first picture.
Your truck looks great so far! If you have any questions about the electrical stuff, let me know. I did a custom wiring job on my V8 conversion and I've got HPTuners software.
Your truck looks great so far! If you have any questions about the electrical stuff, let me know. I did a custom wiring job on my V8 conversion and I've got HPTuners software.
Moby
GOLD Star
5.7 "vortec" truck engines are not gen III/IV blocks (they aren't the same block as the 5.7 LS1 even though the displacement is the same). 4.8/5.3/6.0/6.2 "vortec" truck engines are gen III/IV blocks and require a different flywheel or spacer to mate to a transmission designed for a gen I block. They otherwise bolt up the same (except for one inconsequential missing bellhousing bolt in the gen III/IV).
agree
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- #139
Moby
GOLD Star
me too. thanks for reiterating what I already said...
Wow, sorry, it seemed like there was some confusion from other folks. Sorry if I offended you guys. It took me some time to understand that "vortec" didn't mean gen III/IV for truck engines and that the 5.7 was actually a gen I.
