Major potential stumbling point retrofitting an LS7 :>(
Major potential stumbling point retrofitting an LS7 :>( Evidently it has been confirmed that unlike the LS1/2/6 the LS7 will use a 58x reluctor wheel to determine the crank positioning as opposed to the current 24x system. This makes it sound like only an LS7 PCM will work with the motor.
Anyone out there have the expertise to tell us options here short of dissassembling a brand new LS7 motor to retrofit a 24 tooth reluctor wheel on the crank in order to use currently wiring and software? Thanks!
Anyone out there have the expertise to tell us options here short of dissassembling a brand new LS7 motor to retrofit a 24 tooth reluctor wheel on the crank in order to use currently wiring and software? Thanks!
Last edited by John B; Jul 6, 2005 at 09:15 PM.
Originally Posted by John B
Evidently it has been confirmed that unlike the LS1/2/6 the LS7 will use a 58x reluctor wheel to determine the crank positioning as opposed to the current 28x system. This makes it sound like only an LS7 PCM will work with the motor.
Anyone out there have the expertise to tell us options here short of dissassembling a brand new LS7 motor to retrofit a 28 tooth reluctor wheel on the crank in order to use currently wiring and software? Thanks!
Anyone out there have the expertise to tell us options here short of dissassembling a brand new LS7 motor to retrofit a 28 tooth reluctor wheel on the crank in order to use currently wiring and software? Thanks!
BTW, the reluctor wheel is just one of a couple of potential show stoppers for retrofit into a GENIII based GM vehicle.
Well. This might be harder to figure out.
There is this thread where a guy Transplanted a Gen III into a C6 and the sensor worked
https://ls1tech.com/forums/showthrea...ight=48X+crank
The crank gear is a 24X reluctor in the GEN III.
http://www.hsvdriversclub.co.uk/ls1.pdf
Goto the Crankshaft position sensor. That shows the digital output from the 24x reluctor.
There is this thread where a guy Transplanted a Gen III into a C6 and the sensor worked
https://ls1tech.com/forums/showthrea...ight=48X+crank
The crank gear is a 24X reluctor in the GEN III.
http://www.hsvdriversclub.co.uk/ls1.pdf
Goto the Crankshaft position sensor. That shows the digital output from the 24x reluctor.
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From: Berkeley, California
Originally Posted by John B
Anyone out there have the expertise to tell us options here short of dissassembling a brand new LS7 motor to retrofit a 28 tooth reluctor wheel on the crank in order to use currently wiring and software? Thanks!
Rather than fit a 24X reluctor wheel in place of a 58x (or 60x), it should be possible to electronically convert the new signal to 24x. This would only require inserting a bit of circuitry in the line from the LS7 CPK sensor.
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Originally Posted by Gary Z
Rather than fit a 24X reluctor wheel in place of a 58x (or 60x), it should be possible to electronically convert the new signal to 24x. This would only require inserting a bit of circuitry in the line from the LS7 CPK sensor.
The 24x is a nother story all to together. It has a more random pulse (not really but looks like it) and would be harder to transplant on to the signal. It would almost be a Signal Generator. Not a simple Flip-Flop like I hoped.
I'm still looking into this.
CRANKSHAFT POSITION SENSOR
The Crankshaft Position Sensor (CKP) is mounted
in the right rear of the engine block behind the
starter. The CKP sensor works in conjunction with
a 24X reluctor wheel mounted on the rear of the
crankshaft. The CKP sensor has a battery power
supply, an earth, and a signal circuit.
As the crankshaft rotates, the reluctor wheel teeth
interrupt a magnetic field produced by a magnet
within the sensor. The sensor's internal circuitry
detects this and produces a signal which the PCM
reads. The PCM uses this signal to accurately
measure crankshaft position and engine speed.
The reluctor wheel is mounted on the rear of the
crankshaft. The 24X reluctor wheel use two
different width notches (12° and 3°) that are 15°
apart. This pulse width encoded pattern allows
cylinder position identification within 90 degrees of
crankshaft rotation. In some cases, cylinder
identification can be located in 45 degrees of
crankshaft rotation. This reluctor wheel also has
dual track notches that are out of phase. The dual
track design allows for quicker starts and accuracy.
The Crankshaft Position Sensor (CKP) is mounted
in the right rear of the engine block behind the
starter. The CKP sensor works in conjunction with
a 24X reluctor wheel mounted on the rear of the
crankshaft. The CKP sensor has a battery power
supply, an earth, and a signal circuit.
As the crankshaft rotates, the reluctor wheel teeth
interrupt a magnetic field produced by a magnet
within the sensor. The sensor's internal circuitry
detects this and produces a signal which the PCM
reads. The PCM uses this signal to accurately
measure crankshaft position and engine speed.
The reluctor wheel is mounted on the rear of the
crankshaft. The 24X reluctor wheel use two
different width notches (12° and 3°) that are 15°
apart. This pulse width encoded pattern allows
cylinder position identification within 90 degrees of
crankshaft rotation. In some cases, cylinder
identification can be located in 45 degrees of
crankshaft rotation. This reluctor wheel also has
dual track notches that are out of phase. The dual
track design allows for quicker starts and accuracy.
Last edited by Richiec77; Jul 5, 2005 at 09:45 PM.
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Joined: Nov 2004
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From: Reno, NV
Originally Posted by John B
Now we're talking potential options! What does this involve?
Originally Posted by Builder
As Gary Z indicated, it won't be too hard. It would require measuring and capturing the 24-tooth sensor output and the 58-tooth sensor output, building a translation table (in a PIC, for example), and packaging it to handle the under-hood environment and to fit somewhere near the existing circuit.
This is much trickier than it looks. In a lab, this isn't too hard to figure out, In the real world, other factors will make it harder to be acurate.
Go here and look @ the Crankshaft Sensor. It has the logic output for the 24x reluctor.
http://www.hsvdriversclub.co.uk/ls1.pdf
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From: Reno, NV
Originally Posted by Richiec77
That would be a simple fix, but won't easily happen.
What I find weird is that when GM released the part number for the LS7 engine no other good info was released. If the motor REQUIRES a new PCM wouldn't GM have released that info when they released the part number? That might make too much sense.
Another thing, block pic I've seen shows the dip stick boss present but not machined for a dip stick tube.
Also, we do not yet know if the crank snout is different (length and perhaps diameter) in order to accomodate the twin rotor oil pump... this might make the reluctor wheel a moot point.
Watch the Motortrend mock assembly video and you'll see for a split second the new reluctor wheel on the crank... and I had heard that GM might still use the older reluctor wheel for a bit longer. DAMN! http://www.motortrend.com/av/112_050...nebuild_video/
I'm also wondering if the (corporate) reluctor wheel change has something to do with future displacement on demand... and perhaps the need for increased or different signaling from the crank.
Another thing, block pic I've seen shows the dip stick boss present but not machined for a dip stick tube.
Also, we do not yet know if the crank snout is different (length and perhaps diameter) in order to accomodate the twin rotor oil pump... this might make the reluctor wheel a moot point.
Watch the Motortrend mock assembly video and you'll see for a split second the new reluctor wheel on the crank... and I had heard that GM might still use the older reluctor wheel for a bit longer. DAMN! http://www.motortrend.com/av/112_050...nebuild_video/
I'm also wondering if the (corporate) reluctor wheel change has something to do with future displacement on demand... and perhaps the need for increased or different signaling from the crank.
Originally Posted by Frizzle Fry
Just out of curiosity here; if someone has the $$$ to buy the LS7, then why not just buy the LS7 ECM? Or, are there other issues there such as no edit capability yet?
Also, Is the LS7 MAF or MAF-less? I haven't seen the sensor in any pictures I've looked @.
Originally Posted by billreid1@***.net
What I find weird is that when GM released the part number for the LS7 engine no other good info was released. If the motor REQUIRES a new PCM wouldn't GM have released that info when they released the part number? That might make too much sense.
Another thing, block pic I've seen shows the dip stick boss present but not machined for a dip stick tube.
Also, we do not yet know if the crank snout is different (length and perhaps diameter) in order to accomodate the twin rotor oil pump... this might make the reluctor wheel a moot point.
Watch the Motortrend mock assembly video and you'll see for a split second the new reluctor wheel on the crank... and I had heard that GM might still use the older reluctor wheel for a bit longer. DAMN! http://www.motortrend.com/av/112_050...nebuild_video/
I'm also wondering if the (corporate) reluctor wheel change has something to do with future displacement on demand... and perhaps the need for increased or different signaling from the crank.
Another thing, block pic I've seen shows the dip stick boss present but not machined for a dip stick tube.
Also, we do not yet know if the crank snout is different (length and perhaps diameter) in order to accomodate the twin rotor oil pump... this might make the reluctor wheel a moot point.
Watch the Motortrend mock assembly video and you'll see for a split second the new reluctor wheel on the crank... and I had heard that GM might still use the older reluctor wheel for a bit longer. DAMN! http://www.motortrend.com/av/112_050...nebuild_video/
I'm also wondering if the (corporate) reluctor wheel change has something to do with future displacement on demand... and perhaps the need for increased or different signaling from the crank.
Cool. I never looked for the dipstick boss being casted in place. So it would seem that the LS7 block can be used in a traditional GEN III build. Good news.
You have a damn good point about the crank snout. Seems like we are all so excited, but there will be issues to combat.
I have to assume that this crate engine whould be for both DBW (drive by wire) TB and Cable TB. The PCM needs to be included for this engine to work.
The switch to the 60(-2) standard just shows that GM is going to a more proliferated design. More engines use the 60(-2) design than any other type, by a Really large factor. I believe it was implemented by Bosch 1st and has been for a long time. Makes for less RD work when designing a Product to use a Standard that is/has been working for a while.
For now, We'll have to wait and see what is actually there. I don't know who would want to open an assembled engine though.
Regarding the reluctor wheel, if all else fails I would think one could purchase the older reluctor wheel and have it installed prior to installation of the motor into the car. Assuming the reluctor wheel would not change the balance of the crank and the mounting diameter is the same then this mod wouldn't be all that expensive in the scheme of things.
Regarding the cable TB, doesn't the FAST 90MM intake manifold have the same bolt pattern as the LS2/7? I am still asumming at this point that the LS2 and LS7 share the same DBW TB. If so, then FAST already has a 90MM cable TB available. Ya, a bit more of an expense... but... no one ever said this retrofit would be cheap.
I know... alot of assumptions... but I'm just pointing out what I see along with some speculation and just trying to stay optimisitc that this motor won't require cost prohibitive mods to install.
At first glance it looks like the LS7 does not have a MAF... but a closer look reveals what looks like it has one. I have seen an 01 Duramax Diesel MAF and it is basically just a "sensor head" that mounts into the intake tract... the pic shows basically the same thing.
Bill
Regarding the cable TB, doesn't the FAST 90MM intake manifold have the same bolt pattern as the LS2/7? I am still asumming at this point that the LS2 and LS7 share the same DBW TB. If so, then FAST already has a 90MM cable TB available. Ya, a bit more of an expense... but... no one ever said this retrofit would be cheap.
I know... alot of assumptions... but I'm just pointing out what I see along with some speculation and just trying to stay optimisitc that this motor won't require cost prohibitive mods to install.
At first glance it looks like the LS7 does not have a MAF... but a closer look reveals what looks like it has one. I have seen an 01 Duramax Diesel MAF and it is basically just a "sensor head" that mounts into the intake tract... the pic shows basically the same thing.
Bill
Last edited by billreid1@cox.net; Jul 6, 2005 at 09:22 PM.
Ok. I'ver heard about the sensor head, just never saw it due to the angle being 180deg out from that picture.
So, TB is pretty much done, The reluctor is still the issue I see. You can put the 24x on the crank, but you'll have to diasemble the engine to due so. Kind of defeats the point for buying the Crate engine. I have an idea that may work, but i'm iffy if it'll work under the hood. I thought this would be a simple fix, but has become a tricky one to solve.
So, TB is pretty much done, The reluctor is still the issue I see. You can put the 24x on the crank, but you'll have to diasemble the engine to due so. Kind of defeats the point for buying the Crate engine. I have an idea that may work, but i'm iffy if it'll work under the hood. I thought this would be a simple fix, but has become a tricky one to solve.
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The new reluctor ring is a new corporate standard for all GM engines. The biggest advantage to them is its divisable by all engines 4,5,6,8,10 cyl etc.
The inhearant drawback of it is the extended cranking till it figures out cyl #1.
Dave
The inhearant drawback of it is the extended cranking till it figures out cyl #1.
Dave
Originally Posted by 99Fbody99
The new reluctor ring is a new corporate standard for all GM engines. The biggest advantage to them is its divisable by all engines 4,5,6,8,10 cyl etc.
The inhearant drawback of it is the extended cranking till it figures out cyl #1.
Dave
The inhearant drawback of it is the extended cranking till it figures out cyl #1.
Dave
The new reluctor ring is a new corporate standard for all GM engines. The biggest advantage to them is its divisable by all engines 4,5,6,8,10 cyl etc.
The inhearant drawback of it is the extended cranking till it figures out cyl #1.
The inhearant drawback of it is the extended cranking till it figures out cyl #1.
Originally Posted by billreid1@***.net
Hmm... maybe thats part of the reason why GM put in the smart start where you just rotate the key (or push the button) for a split second and have the computer complete the starting routine... interesting...
And the use of the 60(-2) does cut down on costs. That is something I wasn't even paying attention too.