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4.0 engine swap in a Gremlin

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Forum Name: AMC 6 Cylinder Engine Repair and Modifications
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Topic: 4.0 engine swap in a Gremlin
Posted By: RamblinAMC
Subject: 4.0 engine swap in a Gremlin
Date Posted: Jan/10/2009 at 7:30pm
What would be involved in swapping a 93 4.0 into a 73 Gremlin? How would it bolt up to the stock auto trans? Or would it be better to use a Jeep 2wd trans?

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1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401



Replies:
Posted By: poormansMACHINE
Date Posted: Jan/10/2009 at 7:53pm
If you're moving the controller over so you can keep the injection then the Jeep tranny has 2 benefits over the torqueflite.
The  electronically controlled Jeep trans has the provision to mount the crank sensor and has an overdrive.


Posted By: purple72Gremlin
Date Posted: Jan/10/2009 at 8:07pm
Originally posted by poormansMACHINE poormansMACHINE wrote:

If you're moving the controller over so you can keep the injection then the Jeep tranny has 2 benefits over the torqueflite.
The  electronically controlled Jeep trans has the provision to mount the crank sensor and has an overdrive.
And the OD from what I have heard is a very good transmission, I would run the Jeep transmission. and as PMM says, its got a place to mount the crank sensor.


Posted By: RamblinAMC
Date Posted: Jan/10/2009 at 10:48pm
Will the 4.0 bolt right up to the stock trans I have now? And are the motor mount locations the same on the 4.0 and 258? I have access to a Jeep trans,not sure on the price yet.That will have an effect on doing the swap.Unless mating it up to mine is more of a pain than it is worth.

-------------
1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401


Posted By: poormansMACHINE
Date Posted: Jan/10/2009 at 10:58pm
All of the 72 and up 6 cylinders share the same bolt patterns. Same pattern used on the V-8's from 67 and up.
If you're using the injection, you need a crank position sensor. The jeep has it positioned on the bell housing with a trigger tooth wheel incorporated into the flywheel/flex plate.
If you bolt it to the torqueflite, you will need a means to trigger it accurately since it is your initial timing. There is an aftermarket harmonic balancer and trigger/sensor that mounts up front and I believe it runs about 275 bucks.


Posted By: RamblinAMC
Date Posted: Jan/10/2009 at 11:38pm
I picked up the flex plate today.The 4.0 is still at the tow yard in the Cherokee,which I intend to bring home and remove everything.So do you think there is a way to fab some type of mount up for the crank sensor to use on the stock trans?
 
And where is the balancer mount sensor availible? Might just look into that.


-------------
1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401


Posted By: poormansMACHINE
Date Posted: Jan/11/2009 at 12:03am
Rigging it up on the stock bell housing requires a bit of precision.
It has to run close enough to the flex plate to read and not get hit.
The clock position is your one shot at setting the initial timing since it's not in the distributor as you're accustomed to dealing with on a conventional distributor.
http://www.hesco.us/shop.asp?action=details&inventoryID=43098&catId=7902 - http://www.hesco.us/shop.asp?action=details&inventoryID=43098&catId=7902


Posted By: RamblinAMC
Date Posted: Jan/11/2009 at 12:08pm
If I use the auto trans from the 2wd Jeep,will I still be able to use the trans shift linkage that is in my Gremlin now?Or will it need to be changed? I have the column shift and would like to keep everything at least looking original.Is the Jeep auto a 3 spd like the 904? I know nothing about the later model Jeep trans.

-------------
1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401


Posted By: poormansMACHINE
Date Posted: Jan/11/2009 at 12:49pm
The trans is an Aisin Warner AW4. It's a 4 speed overdrive with a lockup torque converter.
Not sure on the shifter.


Posted By: farna
Date Posted: Jan/11/2009 at 6:57pm
It should work with the shifter, but you may have to monkey around with the adjustments and the shift arm length on the trans. If the arm on both trannys are the same length then it will work with no problem at all. The Jeep shifter only has three positions, there is no way to hold it in first gear -- the first position is 1-2, not L (1-2/D/OD/N/R/P).

You can mount the sensor on the old bell. There are a couple ways to do it, but you need to look at an original bell to figure out the clock position. I did that for my first one, which used a manual trans. I measured from the nearest bell bolt over to the center of the CPS on the stock Jeep bell and mount the CPS from there. Mine was one of the early conversions -- 1999. I had a hard time getting it started because of the CPS position. Thought it should have about a 1/16" gap, but it needs to be about 0.16" (about the same as points). What I ended up doing was turning the ring around to a high spot under the CPS, then pushing it down until it touched. At that point I raised it just enough that the engine would turn without touching the CPS. Fired up then! We now know there's an easier way! Super glue a thin piece of cardboard to the tip! Not index card, think something like a matchbook cover thickness. Remember the old trick about setting points with a matchbook cover? The cardboard won't interfere with the signal and will just wear off. The HESCO relocation kit comes with a sensor that has a piece of such cardboard already on the tip. Speaking of which, I like the Advance Adapters kit better -- it uses the stock CPS, the HESCO kit uses a custom CPS.

There are a couple different ways to mount the CPS. Rather than try to describe one, I'll let you look at an original then look at the CPS itself and see what you can come up with.

One more thing when using the 998 or 904 trans. You have to make darn sure the torque converter doesn't push too far into the pump when mounting the 904/998 converter on the AW-4 flexplate. If it does, you'll trash the pump. One of the guys on here put one in an Eagle and did just that, discovered that he had to do something to mount the converter closer to the flexplate. I forget what it was, and don't recall how the two mount. Of course you could go to the local Jeep dealer and order a flexplate for a 91-95 Wrangler with 4.0L and 998 or 999 transmission. That has the correct flexplate to mount  the converter and has the signal ring for the CPS. You'd still need to mod the bell and/or sensor.


-------------
Frank Swygert


Posted By: RamblinAMC
Date Posted: Jan/11/2009 at 8:25pm
Thanks guys for all the great info!!! The first 4.0 I bring home this weekend is going into my 73 Jeep Commando.The next one that comes in will go into the Gremlin.A friend of a friend has a tow company and seems to get alot of Cherokees.He has 2 now,but one is spoken for.
 
Are the motor mount bosses on the block of the 258 and 4.0 the same?Can I use the stock mounts.I don't have the 4.0 here to compare but from looking at it yesterday,they look like they are close.
 
I am going to check out the AA setup too.


-------------
1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401


Posted By: farna
Date Posted: Jan/11/2009 at 8:32pm
YES -- the engine plates of the side of a 232/258 will bolt right onto a 4.0L. The front hole on the left side may be drilled and tapped for a larger size metric bolt. Just get a bolt to fit and drill the hole in the plate out. At least that's the way it was on the 87-90 4.0L block. That hole may not be drilled and tapped on the 91+, but should be. 

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Frank Swygert


Posted By: kirkwood
Date Posted: Jan/12/2009 at 11:09am
This is what I did for the CPS. I grafted a 42RE bellhousing section into my Lockup 998.







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AMO Newsletter Editor


Posted By: RamblinAMC
Date Posted: Jan/13/2009 at 12:03am
That looks like a good way to do it.How did it work out?
 
So which trans do I have in my 73 with the 258? A 904 or 998?


-------------
1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401


Posted By: farna
Date Posted: Jan/13/2009 at 8:55am
It's a GOOD way, but you have to have the Jeep transmission. I just drilled a 1/2" hole in the old bell in the correct position and mounted the CPS over/through the hole. I then cut the brackets on the CPS down and tapped a couple of the small holes, and made little angle brackets to hold it in place. I slotted the holes in the angle brackets so I could adjust the depth of the sensor. The angle brackets were held to the bell using a couple self drilling hex head screws. If I had to do it again, I'd use a 93 Wrangler (YJ) sensor. It's round (I had to whittle the square plastic casing of the XJ sensor down a bit) and has one mounting screw. The bell is just drilled and tapped on the back side, should be easy to mount on an older bell. Wish I'd known the YJ was different back then!  Just make sure the hole for the CPS is in the right relationship to the screw hole. My mod worked, but this is much easier! You'll have to see it -- here's a pic from the 93 service manual:




-------------
Frank Swygert


Posted By: billd
Date Posted: Jan/15/2009 at 5:52pm
How would one do this with a stick, and will the 4.0 accept an earlier flywheel/clutch, etc.
How would the sensor work on the stick flywheel?
Say for an eagle with a t5?


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Posted By: purple72Gremlin
Date Posted: Jan/15/2009 at 7:00pm
Originally posted by billd billd wrote:

How would one do this with a stick, and will the 4.0 accept an earlier flywheel/clutch, etc.
How would the sensor work on the stick flywheel?
Say for an eagle with a t5?
Billd, I would assume you would have to get a flywheel with the pickup ring on it, and maybe get a YJ stick bellhousing? it would already have the hole and all that.......but problem is would the T-5 fit?


Posted By: farna
Date Posted: Jan/15/2009 at 8:49pm
The same sensor will work on a stick or auto, doesn't matter. The signal ring is made onto the flywheel or flexplate, and both are the same. The computer makes any adjustments. There is a manual and auto computer, but they can be interchanged. I'm using a manual engine computer with an auto now, but there ARE differences. The timing curve may not be the best, the only thing obvious though is the lower idle of the manual computer.

You can use either method to change either type of bell. The sensor just needs to be centered over the ring and all but touching it. If the sensor has the thin cardboard on the tip from the factory (should if you get a new YJ type as shown in the diagram) then you set it to lightly touch a high on the ring.

I modified a 79 multi-pattern manual trans bell (about 77-83 manual bells should all be multi-pattern) by drilling a 1/2" hole over the ring in the right clock position. You can be off about 1/16" to either side and it will run fine. Measure the center of a sensor on a YJ or XJ over to a bell housing bolt -- something that is in the same position on all AMC engines (since 72). That will tell you the clock position. Then bolt the flexplate or flywheel on and measure from the bell mounting face on the engine to the center of the tone ring.

The multi-pattern bell mounts a T-14, T-96, T-4, T-5, and SR-4. The hole in the center is SR-4/T-4/T-5 size, however. I mounted a T-96 on one and had to change the beraing retainer. I used one from a junk SR-4 and drilled it to fit the old T-96. I'm not sure is the T-14 used the same size retainer as the T-5 or T-96, or had a different size. I suspect it's the same as the T-5 though, the T-96 has a small one!


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Frank Swygert


Posted By: purple72Gremlin
Date Posted: Jan/15/2009 at 9:05pm
Originally posted by farna farna wrote:

The same sensor will work on a stick or auto, doesn't matter. The signal ring is made onto the flywheel or flexplate, and both are the same. The computer makes any adjustments. There is a manual and auto computer, but they can be interchanged. I'm using a manual engine computer with an auto now, but there ARE differences. The timing curve may not be the best, the only thing obvious though is the lower idle of the manual computer.

You can use either method to change either type of bell. The sensor just needs to be centered over the ring and all but touching it. If the sensor has the thin cardboard on the tip from the factory (should if you get a new YJ type as shown in the diagram) then you set it to lightly touch a high on the ring.

I modified a 79 multi-pattern manual trans bell (about 77-83 manual bells should all be multi-pattern) by drilling a 1/2" hole over the ring in the right clock position. You can be off about 1/16" to either side and it will run fine. Measure the center of a sensor on a YJ or XJ over to a bell housing bolt -- something that is in the same position on all AMC engines (since 72). That will tell you the clock position. Then bolt the flexplate or flywheel on and measure from the bell mounting face on the engine to the center of the tone ring.

The multi-pattern bell mounts a T-14, T-96, T-4, T-5, and SR-4. The hole in the center is SR-4/T-4/T-5 size, however. I mounted a T-96 on one and had to change the beraing retainer. I used one from a junk SR-4 and drilled it to fit the old T-96. I'm not sure is the T-14 used the same size retainer as the T-5 or T-96, or had a different size. I suspect it's the same as the T-5 though, the T-96 has a small one!
I have a bellhousing from an eagle that was a T5.  its not a multi pattern.  those multi pattern bells are hard to find as well as any T5 AMC bell. I know, took me awhile to find one. and I was surprised to find one here where I live, it came out of a 1982 SX-4 and my car has a T-14 in it now, and if the T5 would fit, it would be known by now, but I believe the  newer 3 speed bell will work with the T5, but I dont know.....


Posted By: billd
Date Posted: Jan/15/2009 at 9:35pm
I was concerned about the flywheel, if it would fit, #1, and then if the flywheel could have a sensor added since I'm pretty sure this Jeep is a 2wd auto, so if I get crazy and jump to a 4.0, I'd not be getting the rest of the drivetrain.
Just curious as if the thing could be adapted to the older stick flywheel and bell.
I've got a couple photos of a really clever method of putting the sensor in almost any bell, nice bracket, etc. Just would need the exact clock position and to get the trigger on the flywheel.


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Posted By: poormansMACHINE
Date Posted: Jan/15/2009 at 9:43pm
The old flywheel doesn't have a trigger wheel so nothing to adapt to it. Without it the only alternative is the aftermarket harmonic balancer and sensor.


Posted By: billd
Date Posted: Jan/15/2009 at 10:02pm
Is the trigger made into it, or bolted on?
By the time you pay shipping, you have 300 into the adapter to move it to the front. YIKES!
I could probably find a flywheel that would work for that if it's not bolt-on.
There's an 87 4.0  for the price of their adapter.


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Posted By: poormansMACHINE
Date Posted: Jan/15/2009 at 10:10pm
Looks like this
http://cgi.ebay.com/ebaymotors/Jeep-Wrangler-TJ-Flywheel-4-0L-Manual-Transmision-97-04_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem250350939388QQitemZ250350939388QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories#ebayphotohosting - http://cgi.ebay.com/ebaymotors/Jeep-Wrangler-TJ-Flywheel-4-0L-Manual-Transmision-97-04_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem250350939388QQitemZ250350939388QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories#ebayphotohosting


Posted By: billd
Date Posted: Jan/15/2009 at 10:15pm
Ah, so the flywheel itself is "notched".

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Posted By: poormansMACHINE
Date Posted: Jan/15/2009 at 10:25pm
You could probably use one of these and mod yours.Wink



Posted By: billd
Date Posted: Jan/15/2009 at 10:32pm
I won't say the term I was thinking.
I was thinking more like a mortising jig.
 


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Posted By: poormansMACHINE
Date Posted: Jan/15/2009 at 10:41pm
Is that any relation to Mortimer Snerd?



Posted By: purple72Gremlin
Date Posted: Jan/15/2009 at 11:08pm
Originally posted by poormansMACHINE poormansMACHINE wrote:

You could probably use one of these and mod yours.Wink

LOL It would make nice notches!


Posted By: billd
Date Posted: Jan/16/2009 at 6:33am
I doubt my normal carbide tip router bits would be much good, however.
I wonder if a dovetail jig would work out with diamond bits?


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Posted By: farna
Date Posted: Jan/16/2009 at 6:36am
Well, the only thing about "rolling your own" (using any method) is that the notches have to be precisely placed, and a precise width.

The 4.0L flywheels have notches, the flex plates have a ring welded perpendicular to the plate with square holes where the notches would be. You can use a 4.0L flywheel or flexplate with an earlier six (as early as 72) with no problem -- bolts right on. The stick is easy, just use the 4.0L pressure plate and get a clutch disc the right diameter to fit the trans shaft. Not hard at all, though might take a little research. The older model clutch may fit also. I don't recall what disc I used for the T-96, think it was a standard 4.0L clutch disc... may have been for an earlier Jeep. If necessary I still have the paperwork in a folder and could look it up.

For an auto you have to be careful that the torque converter isn't pushed back in the trans pump too far. When using an AW-4 flex plate with a 904/998 converter you have to shift the converter forward about 3/8". There are some nuts on the flexplate or converter that can be removed. I haven't done it, someone else relayed that info (after destroying the first pump -- changed pump, made the mod, and carried on in an Eagle). Or you can get a TJ flexplate and be done with it. They used a 999 which has the same style TC and flexplate as teh 904/998, but has the ring on the flexplate. For $75-$100 that's the way to go for an auto (http://cgi.ebay.com/ebaymotors/Jeep-Wrangler-TJ-Flywheel-4-0L-Automatic-Trans-97-02_W0QQcmdZViewItemQQ_trksidZp1742Q2em153Q2el1262QQcategoryZ33732QQihZ008QQitemZ180317718104).

Measure for sensor clock position as I've already explained in earlier posts.

Note that the 87-90 Renix flywheel/flexplate is notched differently than the 91+ H.O. system parts. Renix has notches all around evenly spaced. The sensor doubles as an engine speed sensor as well as crankshaft position.


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Frank Swygert


Posted By: 71gremmy
Date Posted: Jan/16/2009 at 7:35pm
I am doing this swap in a 82 spirit with a 95 jeep grand cherokee 4.0. I am running a 89 mustang t-5 with the stock amc t-5 bellhousing. I drilled a hole in the bellhousing for the cps and then made a plate with two spacers. The spacers move the plate out over the notches in the flywheel (a stock 95 jeep part) and the sensor mounts to the plate. The spacers happen to be the same thickness as the specal intake/exaust washers on 4.0 and 258 six cylinders. The plate and spacers then mount using two bellhousing bolts using longer bolts. Be aware that you must use a 4.0 starter with the 4.0 flywheel or flexplate, and the old big ford starter with the 258 etc flywheel or flexplate. The ring gears are in different places, it bolts up but won't ingage.

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71 Gremlin X,360,t-5,8 3/4 rear axle
66 Rambler Classic, 232,auto


Posted By: 71gremmy
Date Posted: Jan/16/2009 at 7:41pm
I forgot to mention vist this website, it is for cj jeeps but they have a whole area deicated to 4.0 swaps. There is a lot of info and they are very helpful. Almost everything will cross over to our cars.
http://www.cjoffroad.com/forums/forum.asp?FORUM_ID=24 - http://www.cjoffroad.com/forums/forum.asp?FORUM_ID=24
 


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71 Gremlin X,360,t-5,8 3/4 rear axle
66 Rambler Classic, 232,auto


Posted By: RamblinAMC
Date Posted: Jan/21/2009 at 3:17pm
That is some very useful information.Thanks!

-------------
1963 Rambler American 330

1971 Hurst Jeepster

1972 Commando 4.0

1972 Commando 258

1975 Jeep J20 401


Posted By: billd
Date Posted: Jan/21/2009 at 3:21pm
Some of this will be useful for my project - a 94 Grand engine going into a 82 Eagle.

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Posted By: 71hornet6
Date Posted: Nov/24/2012 at 9:30pm
This sounds rad! Did you ever make it happen?


Posted By: Pdok
Date Posted: Nov/24/2012 at 9:45pm
It's AALIIIIVVEE!!  The 3 year old thread, I mean...

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76 Grem X 258/904,4.0 head/MPFI, Comp X250H cam, Hughes springs, Clifford header, serpentine swap.


Posted By: 71hornet6
Date Posted: Nov/24/2012 at 10:10pm
http://www.cardomain.com/ride/3212775/1972-amc-gremlin/

This guy actually did it, which is a lot cooler than just talking about it


Posted By: Wrambler
Date Posted: Nov/25/2012 at 2:02pm
Guys, this thread is way ancient news...there are quite a bunch of 4.0L powered amc's out there now.
Look at the section above in the six area.

And YEA, it is much better than just talking about it!
B.T.D.T. (did not get a t-shirt) I've lost track of the exact date mine hit the road, but it's been quite a while now.


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Wrambler
69 AMC Rambler
4.0L, 5 speed
2015 Grand Cherokee Limited
2019 Chrysler 300


Posted By: farna
Date Posted: Nov/25/2012 at 6:15pm
Mine hit the road about October 1999... Wrambler wasn't too far behind me...

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Frank Swygert



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