Installing a crank position sensor set up on stock trans?

[shanebo]

  I am doing the 4.0 EFI conversion. one of my many obsticles  is going to be installing the crank position sensor that does not exist on our ealges. I am not sure how to modify the stock Eagle trans to take the jeeps crank sensor....any help greatly appreciated.

Thanx
Shane

[amcinstaller]

drill, cut, make small bracket. others have also just drilled a small hole and plugged the sensor into the hole

[eaglefreek]

You will need the appropriate flexplate that matches the computer you will be using. If using an OBD1 computer and using an auto transmission you would need to use a flexplate and starter from a 91-95 Wranger because they use basically the same transmission as the Eagle. Another option would be to use a Wranger TF999 transmission that has the hole for the cps. If manual, you'll have to search the net about the proper flywheel.

[philotomy]

I believe mine is on the front bottom of my crank pulley,but it was part of that Hesco kit, a special pulley with that built into it.stock trans

[philotomy]

here's mine it has a plate bolted to the oil pan for support,its a bit dirty right now thanks to the rad quitting on me and I believe it has a special crank pulley/harmonic balancer just for this application

[Jurjen]

Here is a picture from Novak adaptors:
http://www.novak-adapt.com/knowledge/ford_to_amc.htm

[captspillane]

The Hesco kit is very expensive and very fragile. Hesco even suggests you buy their trail kit, which comes with an extra fuel pump and two extra CPS sensors. Its common to have them bumped or jarred, and then the engine won't run. It's worth trying to modify your old transmission.

Its been done two different ways. One is the square CPS sensor like a 1992 Jeep Cheroke would have. Another is a 1/2 inch round CPS sensor like a wrangler would have. I purchased two of the round version to try this. It should work slick in the sense that you just need to drill a hole. There are two externally identical round ones to choose from, you have to get the earlier version so that it accepts the correct voltage. OBD1 and OBD2 use different operating voltages.

Don't use an AW4 flexplate. Its 4mm different than the TF727 flexplate. The "32RH" is another name for the TF727, after they started putting the CPS sensor in. The Wrangler 32RH flexplate will look identical to your old Eagle one except it will have a ring around it with holes in it to work with the CPS sensor.

[philotomy]

hmm no problem here with mine and ran fine for 3 1/2 yrs in the snow and dirt roads,I'd check into the  link posted by Jurgen if you're not going with a "kit".

[eaglefreek]

Not that it matters, but the original post was from over a year ago. 

[philotomy]

yeah i had sent Shanebo all my conversion paperwork last year I believe in hopes that it would be of some help,but mine is the whole (expensive kit) while I think Shanebo is doing it with the Rambler mentality

[carnuck]

The Hesco kit is very expensive and very fragile. Hesco even suggests you buy their trail kit, which comes with an extra fuel pump and two extra CPS sensors. Its common to have them bumped or jarred, and then the engine won't run. It's worth trying to modify your old transmission.

Its been done two different ways. One is the square CPS sensor like a 1992 Jeep Cheroke would have. Another is a 1/2 inch round CPS sensor like a wrangler would have. I purchased two of the round version to try this. It should work slick in the sense that you just need to drill a hole. There are two externally identical round ones to choose from, you have to get the earlier version so that it accepts the correct voltage. OBD1 and OBD2 use different operating voltages.

Don't use an AW4 flexplate. Its 4mm different than the TF727 flexplate. The "32RH" is another name for the TF727, after they started putting the CPS sensor in. The Wrangler 32RH flexplate will look identical to your old Eagle one except it will have a ring around it with holes in it to work with the CPS sensor.

999 is 32RH and 727 is 36RH (Grand Cherokee 4 speed auto on 4.0L is 42RE, etc)

[carguy87]

I used the 42RE flexplate off the 4.0L from a 95' Grand Cherokee.  I also used the corresponding CPS that has one tab for a mounting bolt.  I cut a hole in the bell housing and made a bracket that crosses the two bolt holes and is held in place using the bell housing to engine block mounting bolts.  Then it is simply slid down into place, and bolted to the bracket.  Been like that for a year now as my daily driver in Michigan.

[captspillane]

I understand this is a very old post being revived. My main motivation for writing this reply is that I recently almost tried using a AW4 flexplate with a torqueflite transmission. I would have blown up the transmission. Thankfully I came across a post on a forum about it before I made that same mistake. I want this information to be readily available in the future.

999 is 32RH and 727 is 36RH (Grand Cherokee 4 speed auto on 4.0L is 42RE, etc)

To be more precise, there are four types of flexplates available for AMC Engines.

1) The automatic transmissions original to the AMC Eagle were the hydraulically controlled “Torqueflite” transmissions. These transmissions for a short time were produced by Chrysler with CPS rings on them before the newer electronically controlled four speed transmissions appeared. TF904, TF998, TF999, and TF727 all use the same flexplate without the CPS Ring. The exact same transmission was still produced after Chrysler changed their naming conventions. Early 90’s Wranglers had the exact same transmission as our Eagle does except for a very minor internal difference (TF998 vs TF999) and the addition of a CPS signal at the edge of the bellhousing. The CPS needed a ring with holes added to the flexplate. They named that “32RH” to mean it is a three speed, strength rating of 2, “H” hydraulically controlled transmission. If you find a rare 32RH transmission it is a direct bolt in solution with no modifications needed and no $350 Hesco CPS relocation kit required. The TF727 with its larger planetaries designed for truck applications became the “36RH” to mean three speed, strength rating of 6, “H” hydraulically controlled transmission. Unfortunately there was never a 36RH with CPS holes produced that will bolt up to an AMC Engine. All 36RH transmissions have a Chrysler bolt pattern. The only Jeeps to receive that transmission were the Grand Cherokees with Chrysler V8 engines.

2) AW4 flexplate. This flexplate is almost identical to the torqueflite version, but not quite. All Jeep XJ Cherokees had the AW4 four speed automatic transmission. I have read stories of people taking the AW4 flexplate and putting it in front of a 32RH transmission. It bolted together fine and the vehicle even drove for about 50 miles without signs of an issue. After a short time period, however, the 4 mm difference in backspacing caused pressure to destroy the input shaft of the transmission along with mortally damaging the torque converter. It looks like it works but it doesn’t.

3) 42RE flexplate. This flexplate may or may not be identical to the torqueflite transmissions. The modern Chrysler four speeds were designed using knowledge from the tried and true torqueflite transmissions Chrysler was already producing for decades. The new electronic four speeds do not look at all the same and do not share any compatible internal or external parts as the older hydraulic three speeds, but I’ve seen conflicting reports of them using the exact same flexplate. “Carguy87” just stated in the last post that he successfully used this flexplate with the TF998 and I believe him. The 42RE transmissions are light duty equivalents to the TF998. A stronger 46RE equivalent to a TF747 is not available for AMC Engines. The 42RE is several inches longer and don’t fit well under an Eagle. In stock form they are not nearly as strong as a TF727. In the aftermarket, however, a 42RE can be rebuilt using the rear overdrive assembly from a Chrysler 46RE or even the stronger 47RE found behind Cummin’s Diesel engines. Several people specialize in making the AMC 42RE as strong as a TF727 or 46RE.

In truth, the biggest complaint against the 42RE is that it has some very strong components mixed with weak components. The weak components make it just as weak as an AW4 but the inertia of the strong components make it lose fuel mileage in comparison to the AW4. The AW4 is better in stock form but the 42RE has greater potential. I personally wish to use the AW4 behind my 6 cylinder motors and I wish to use the modified 42RE behind an AMC V8 in the future.

4) TH400 flexplate. This flexplate is more Chevy than Chrysler. It was used in Full Size Jeeps and CJ7’s with a special casting of the TH400. The TH400 is a three speed hydraulically controlled GM transmission that is exactly as strong as the Chrysler TF727. Internally it’s the same as the Chevy TH400 transmission but externally the output is rotated several degrees, the output shaft is crazy long, and the bellhousing bolts to AMC engines only. An AMC TH400 is often a poor choice of transmission because of the length and limited transfer case options, but this flexplate can be used to adapt the 700R4 four speed electronically controlled Chevy transmission to an AMC Engine. The 700R4, unlike the TH400, is sometimes compatible with the New Process transfer cases suitable for our Eagles. Of course every transmission can be adapted successfully, but the adaptor cost is prohibitive. A rare version of the 700R4 came from the factory mated to the 6 bolt New Process pattern. I will use a 700R4 as an overdriven automatic strong enough to live behind a built AMC V8 if the modification of the 42RE is inadequate.

[captspillane]

I also used the corresponding CPS that has one tab for a mounting bolt. 

Its a pleasure to hear from someone with first hand experience. Your CPS was round, about 1/2" diameter, with a single tab for a mounting bolt, correct? Do you have pictures of this installation?

Thank you for the information you have. I'm about to attempt this with a TF727 with that style of CPS. I've only seen pictures of the square, two tab style so far.

[carnuck]

Somewhere in my piles of stuff I have a 999 trans case from a '00 Wrangler with 4.0L I was going to build it with Eagle internals (valve body was bad), but never got around to it

[eaglefreek]

My one major concern about using the CPS on the front damper, is that there is rubber involved and a chance of it slipping, causing your signals to be off. As I understand it, the CPS switches 5v or 8/9v ,depending on year, on and off in correlation with the notches on the flexplate. I wonder if you could use a toothed wheel attached to the center of the damper to keep the rubber out of the equation. I can't see the edge of the Hesco damper on their site, but I would assume they just drill holes in precise locations to mimic the notches in the flexplate. Here's an example of a toothed wheel attached to a crank pulley:

[eaglefreek]

I found a pic of a Hesco damper. Basically, you would just need to scale down the measurements from the flexplate and make sure you have the notches in the right spot on the damper in correlation with the flexplate. You could even make your mounting holes oblong to "play" with your timing. A little more work than drilling a hole in the bellhousing, but it is also an option.

[mach1mustang351]

So I was reading last night and I saw on Novak's website they said to call them for their 4.0 CKP sensor solution.  I called them today and they said for the cost of an hours labor (about $90) they would cnc machine a hole in the bell housing you mail them to accept the ckp sensor.  SO for $90 plus shipping in both directions you can have a nicely done stock setup and save some coin over the Hesco system.  Just thought I'd share.

[captspillane]

I wonder if Novak would still do that service if you sent them an empty TF727 front case instead of a bellhousing?

The potential problem with that service is that you then need to have CPS notches in the flywheel. On an automatic that is as simple as buying the proper flexplate. On a stickshift this means the 258 flywheel has to come off and a 4.0 flywheel put in its place. The 4.0 flywheel is a quarter inch thinner. The throw out lever should be able to adjust to account for that difference in flywheel width, but it will require adjustments not easily made on an Eagle. On a CJ7 or Spirit, the mechanical linkage has an adjustable spacer on the linkage. On our hydraulic system you don't have an adjustment, just a removable shaft. It might work just fine but have the "bite" point of the clutch at an awkard level in relation to the floor. The only way to know is to experiment with it.

Advanced Adaptors also sells a T5 bellhousing with both of the two different CPS sensor mounting holes already built into it. They currently ask $373 for it. That price is directly comparable to the Hesco CPS kit.

[eaglefreek]

Wouild an adjustable throwout bearing solve the issue of the thinner 4.0l flywheel? http://www.novak-adapt.com/catalog/clutches/adjustable_throwout_bearings.htm

[captspillane]

Oh dang that just earned you several eggs. I've never imagined such a beast. That really should account for the 1/4" difference without needing to adjust the linkage geometry. That is a big deal, since I'm pretty sure the linkage has a 2:1 mechanical advantage, meaning that a 1/4" difference in travel compounds to a 1/2" or more of linkage adjustment.

I really wish I had seen that a year ago. I beat my head against a wall trying to get the AMC Spirit mechanical linkage to work with a 10" clutch. A Spirit used a bizarre 9" clutch that isn't readily available anymore. The Spirit version of the mechanical clutch linkage looks alot like a CJ7 version, but it doesn't travel or adjust as far. This would likely add a necessary degree of adjustment.

[carnuck]

I wonder if Novak would still do that service if you sent them an empty TF727 front case instead of a bellhousing?

The potential problem with that service is that you then need to have CPS notches in the flywheel. On an automatic that is as simple as buying the proper flexplate. On a stickshift this means the 258 flywheel has to come off and a 4.0 flywheel put in its place. The 4.0 flywheel is a quarter inch thinner. The throw out lever should be able to adjust to account for that difference in flywheel width, but it will require adjustments not easily made on an Eagle. On a CJ7 or Spirit, the mechanical linkage has an adjustable spacer on the linkage. On our hydraulic system you don't have an adjustment, just a removable shaft. It might work just fine but have the "bite" point of the clutch at an awkard level in relation to the floor. The only way to know is to experiment with it.

Advanced Adaptors also sells a T5 bellhousing with both of the two different CPS sensor mounting holes already built into it. They currently ask $373 for it. That price is directly comparable to the Hesco CPS kit.

The HO and Renix tone rings (or notches on the std flywheel) are different. The flywheel itself is the same, but the tone ring was added and the starter ring was moved almost 1/2" closer to the motor so you have to use the 4.0L starter (not a deprivation there as it's a better design)
   For the auto you CANNOT use the AW4 flexplate. You need one from a Grand Cherokee with 4.0L for the HO system. It'll probably need to be custom made for the Renix setup.

As for the 727 bell CPS hole, it's pretty easy to mock up if you can borrow a 999 case from a TJ to make a template. I had planned to do that with the 727 I put in my Eagle but ran out of time before I could afford the flexplate and couldn't afford to pay storage anymore. I also moved my 999 case somewhere and haven't found it, the HEI I bought and a bunch of other AMC 6 performance parts including a header and cam.

[carguy87]

Here is a picture of the CPS on the bracket I made.  I had pictures of it installed in the trans, but they got wiped out when my memory card fried.  Oh well, hope this helps.

[mach1mustang351]

Oh dang that just earned you several eggs. I've never imagined such a beast. That really should account for the 1/4" difference without needing to adjust the linkage geometry. That is a big deal, since I'm pretty sure the linkage has a 2:1 mechanical advantage, meaning that a 1/4" difference in travel compounds to a 1/2" or more of linkage adjustment.

I really wish I had seen that a year ago. I beat my head against a wall trying to get the AMC Spirit mechanical linkage to work with a 10" clutch. A Spirit used a bizarre 9" clutch that isn't readily available anymore. The Spirit version of the mechanical clutch linkage looks alot like a CJ7 version, but it doesn't travel or adjust as far. This would likely add a necessary degree of adjustment.

This is good info.  I plan on running my 4 speed in my SX4 with my 4.0.  This will help solve a problem I didn't know I had yet.

[captspillane]

That picture does help. That's the round sensor I plan on using. The NSG370 6 Speed has a round sensor externally identical to that mounted on the side. The Flywheel looks identical to my 1992 AX15 flywheel, except that the tone ring is rotated to account for the sensor being on the side instead of the top like the square AX15 style. I've seen two threads in the Jeep forums where guys switched their 5 speed for a 6 speed or vice-versa and tried to use their old flywheels. The engine will not run.

The round CPS is available in both OBD1 5 volt or OBD2 8 volt. I plan on using the OBD1 sensor because its compatible with my 1992 era MPI system. For my TF727 I will drill a hole in the housing and mount it on top with a bracket similar to the one you just posted a picture of. On my 2006 NSG370, I hope the earlier round sensor will fit perfectly into the existing round hole in the bellhousing.