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87 YJ 4.2 -> 4.0 swap questions



 
 
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  #1  
Old September 3rd 06, 08:19 PM posted to rec.autos.makers.jeep+willys
bobvonbob
external usenet poster
 
Posts: 38
Default 87 YJ 4.2 -> 4.0 swap questions

have an opportunity to pick up a 4.0 engine with under 50k for $500 -
it comes out of an 88 cherokee and comes w/electronics, transfer case,
AT, wheels, tires, etc etc basically everything minus the steering
column and a few other bits i'm not interested in.
what i want to know is this: can i bolt up the 4.0 directly without an
adapter for the transfer case?
and in the event that i want to replace the POS Peugeut tranny
(synchros are worn) with the AT from the cheerokee, can i still use my
current driveshaft?
ideally i would like to have both the 4.0 motor and the AT but i am
currently rather cash poor and limited in terms of workspace...
what's the scoop? can i do it without too much expenditure? my 4.2 is
on its last legs, and if i never see that @#$** Carter carb again it'll
be too soon...
it seems like a good deal to me - private owner not a parts/junk shop.
thanks in advance,
bennett

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  #2  
Old September 3rd 06, 08:44 PM posted to rec.autos.makers.jeep+willys
bobvonbob
external usenet poster
 
Posts: 38
Default 87 YJ 4.2 -> 4.0 swap questions

also - one more question - the suspension on my YJ is pretty well shot
as well - esp the front leafs which are bent with frozen bushings - can
one use the front springs from a cherokee on a YJ? how about the rear
ones?
thanks.
bennett

  #3  
Old September 3rd 06, 09:55 PM posted to rec.autos.makers.jeep+willys
Earle Horton[_1_]
external usenet poster
 
Posts: 222
Default 87 YJ 4.2 -> 4.0 swap questions

You will need a fuel tank with the electric FI fuel pump in it, or an
equivalent external pump. External pumps are problematical, because the
suction side typically doesn't work right and is very very sensitive to
leaks. You will need some way to fit a crank position sensor. Advance
Adapters has a bell housing for this purpose, but I don't know how many
models are available or whether there is an AT version. There is also a
crank pulley CPS adapter available.

Your transfer case input shaft spline count and depth will be different from
what the Cherokee AT uses. The quickest way to solve this problem is to
change the TC input shaft, which requires disassembly of your TC. Don't
know about the drive shaft, but I'll bet the AT from the Cherokee is longer
than what you have now.

Earle

"bobvonbob" > wrote in message
ps.com...
> have an opportunity to pick up a 4.0 engine with under 50k for $500 -
> it comes out of an 88 cherokee and comes w/electronics, transfer case,
> AT, wheels, tires, etc etc basically everything minus the steering
> column and a few other bits i'm not interested in.
> what i want to know is this: can i bolt up the 4.0 directly without an
> adapter for the transfer case?
> and in the event that i want to replace the POS Peugeut tranny
> (synchros are worn) with the AT from the cheerokee, can i still use my
> current driveshaft?
> ideally i would like to have both the 4.0 motor and the AT but i am
> currently rather cash poor and limited in terms of workspace...
> what's the scoop? can i do it without too much expenditure? my 4.2 is
> on its last legs, and if i never see that @#$** Carter carb again it'll
> be too soon...
> it seems like a good deal to me - private owner not a parts/junk shop.
> thanks in advance,
> bennett
>



  #4  
Old September 3rd 06, 10:59 PM posted to rec.autos.makers.jeep+willys
Troy
external usenet poster
 
Posts: 94
Default 87 YJ 4.2 -> 4.0 swap questions

I hear that you can't fit the transfer case with full time 4 wheel drive
into a wrangler. I forget the exact name, is it Selectrac?

Troy


"bobvonbob" > wrote in message
ps.com...
> have an opportunity to pick up a 4.0 engine with under 50k for $500 -
> it comes out of an 88 cherokee and comes w/electronics, transfer case,
> AT, wheels, tires, etc etc basically everything minus the steering
> column and a few other bits i'm not interested in.
> what i want to know is this: can i bolt up the 4.0 directly without an
> adapter for the transfer case?
> and in the event that i want to replace the POS Peugeut tranny
> (synchros are worn) with the AT from the cheerokee, can i still use my
> current driveshaft?
> ideally i would like to have both the 4.0 motor and the AT but i am
> currently rather cash poor and limited in terms of workspace...
> what's the scoop? can i do it without too much expenditure? my 4.2 is
> on its last legs, and if i never see that @#$** Carter carb again it'll
> be too soon...
> it seems like a good deal to me - private owner not a parts/junk shop.
> thanks in advance,
> bennett
>



  #5  
Old September 3rd 06, 11:10 PM posted to rec.autos.makers.jeep+willys
bobvonbob
external usenet poster
 
Posts: 38
Default 87 YJ 4.2 -> 4.0 swap questions

thanks earl - a few questions then:
can i take the fuel pump out of the cherokee and install it into the
YJ? and what if i was to swap out my entire engine/TC/trans with the
one from the cherokee?
wouldnt that eliminate the need for installing a CPS and the adapter
plate? i suppose i'd need a different driveshaft... and perhaps front
drive shaft?
and the springs?
thanks for your help...
bennett

  #6  
Old September 3rd 06, 11:38 PM posted to rec.autos.makers.jeep+willys
DougW
external usenet poster
 
Posts: 911
Default 87 YJ 4.2 -> 4.0 swap questions

Troy wrote:
> I hear that you can't fit the transfer case with full time 4 wheel
> drive into a wrangler. I forget the exact name, is it Selectrac?


The full time is Quadratrack. It has only 4hi-N-4lo


--
DougW


  #7  
Old September 3rd 06, 11:52 PM posted to rec.autos.makers.jeep+willys
Earle Horton[_1_]
external usenet poster
 
Posts: 222
Default 87 YJ 4.2 -> 4.0 swap questions

The fuel tanks are different, so you can't put the pump from the Cherokee in
the Wrangler tank. Now I don't know whether the Cherokee tank fits in the
Wrangler, but I do know that you need an FI tank to make the 4.0 work. An
external aftermarket pump will "work", but as I pointed out they are
problematical.

Before thinking about swapping the entire drive train, you'd better get out
a tape measure and see what is what. The Wrangler drive shaft is too short
as it is, as people find out when they install lift kits. If the Cherokee
engine mount to TC tail shaft distance is longer, then it won't fit. If
it's a Selectrac, it "really" won't fit. I haven't made this measurement
myself, but I am pretty sure that you will find out, that the Cherokee drive
train is too long.

Wrangler springs from www.4wd.com are not too expensive. The stock springs
on a Wrangler are pretty flat, so your existing springs may not be as bad as
you think. The best way to get the old bushings out is with a gas wrench.

Earle

"bobvonbob" > wrote in message
ups.com...
> thanks earl - a few questions then:
> can i take the fuel pump out of the cherokee and install it into the
> YJ? and what if i was to swap out my entire engine/TC/trans with the
> one from the cherokee?
> wouldnt that eliminate the need for installing a CPS and the adapter
> plate? i suppose i'd need a different driveshaft... and perhaps front
> drive shaft?
> and the springs?
> thanks for your help...
> bennett
>



  #8  
Old September 4th 06, 12:21 AM posted to rec.autos.makers.jeep+willys
bobvonbob
external usenet poster
 
Posts: 38
Default 87 YJ 4.2 -> 4.0 swap questions

thanks all.
Earl - can i ask you to clarify some things?
1st off - i am clueless as to the nature of the 'Selectrac' and
'Quadratrac' so what l do i need to look for to detemine their
presence? 2nd - besides the driveshaft length - which is pretty
obviously different i would imagine - can't i just swap my tired old
Peugeut 5sp with the AT that comes with the Cherokee? since this is the
tranny and TC that comes with the motor, it would thus eliminate any
need for adapters for the CPS, as well as the problem of pilot bushing
mismatch, and for finding a 4.0/5sp manual computer... isnt that right?
all i would need would be a YJ driveshaft with the correct spline count
yes? i assume my stock (5sp) shaft wont fit - correct?
sorry for all the questions, trying to figure out if this is a good
idea...
cheers,
bennett

  #9  
Old September 4th 06, 12:21 AM posted to rec.autos.makers.jeep+willys
RoyJ
external usenet poster
 
Posts: 388
Default 87 YJ 4.2 -> 4.0 swap questions

www.4wd.com wants $110 (front) and $120 (rear) for stock springs.
www.quadratec.com wants $74 for stock rear springs, doesn't sell the
fronts in OEM version but does sell the Trail Master fronts for $80

Earle Horton wrote:

> The fuel tanks are different, so you can't put the pump from the Cherokee in
> the Wrangler tank. Now I don't know whether the Cherokee tank fits in the
> Wrangler, but I do know that you need an FI tank to make the 4.0 work. An
> external aftermarket pump will "work", but as I pointed out they are
> problematical.
>
> Before thinking about swapping the entire drive train, you'd better get out
> a tape measure and see what is what. The Wrangler drive shaft is too short
> as it is, as people find out when they install lift kits. If the Cherokee
> engine mount to TC tail shaft distance is longer, then it won't fit. If
> it's a Selectrac, it "really" won't fit. I haven't made this measurement
> myself, but I am pretty sure that you will find out, that the Cherokee drive
> train is too long.
>
> Wrangler springs from www.4wd.com are not too expensive. The stock springs
> on a Wrangler are pretty flat, so your existing springs may not be as bad as
> you think. The best way to get the old bushings out is with a gas wrench.
>
> Earle
>
> "bobvonbob" > wrote in message
> ups.com...
>
>>thanks earl - a few questions then:
>>can i take the fuel pump out of the cherokee and install it into the
>>YJ? and what if i was to swap out my entire engine/TC/trans with the
>>one from the cherokee?
>>wouldnt that eliminate the need for installing a CPS and the adapter
>>plate? i suppose i'd need a different driveshaft... and perhaps front
>>drive shaft?
>>and the springs?
>>thanks for your help...
>>bennett
>>

>
>
>

  #10  
Old September 4th 06, 02:21 AM posted to rec.autos.makers.jeep+willys
Earle Horton[_1_]
external usenet poster
 
Posts: 222
Default 87 YJ 4.2 -> 4.0 swap questions

The big problem you are going to have is that I am 98% sure that the AT you
want to use is too long. If the Cherokee has a Selectrac, then the
combination is definitely too long. Look at the 4wd shift knob on the
Cherokee. If it has 2h-4h-n-2l like your Wrangler, then it is Commandtrac,
which is the manual option. This means that the TC is not too long, but you
still have to worry about the transmission. If it has something else that
looks like full time four wheel drive, then it is Selectrac. The difference
is that the Selectrac has an interaxle differential in it, which is real
good for slick roads, but adds too much length to fit in a short wheelbase
vehicle like the Wrangler.

What you need to do is first measure from the back face of the engine block,
where it bolts to the transmission housing, to the back end of the
transmission, where it bolts to the transmission case. If this dimension is
longer on the Cherokee, then the transmission will not fit. Then make
another measurement, to the end of the TC where the rear drive shaft sticks
into it. It is important to realize that the rear drive shaft on the
Wranglers cannot be any shorter than it is, without increasing the
likelihood of problems such as vibration. People have installed longer
transmission/transfer case options, but not without welding a custom
driveshaft or resorting to expensive constant velocity joints or slip yoke
eliminators, that seem like they would be way out of range of your budget.

The spline count I am talking about is on the shaft between the transmission
and the TC. You would have to change this, if you decided that you could
use the transmission but not the TC. As far as I know, the output splined
shaft is likely to be the same. In other words, your existing drive shafts
will work, but only if the transmission/TC combination is exactly the same
length as what you have now. Otherwise, this is not a good idea for you.

You can get more information from the Advance Adapters Jeep Conversion
Manual, http://advanceadapters.com. The Conversion Manual is $10, and they
have gone to the trouble of measuring a number of different Jeep
transmissions and transmissions that might fit in Jeeps.

Earle

"bobvonbob" > wrote in message
ups.com...
> thanks all.
> Earl - can i ask you to clarify some things?
> 1st off - i am clueless as to the nature of the 'Selectrac' and
> 'Quadratrac' so what l do i need to look for to detemine their
> presence? 2nd - besides the driveshaft length - which is pretty
> obviously different i would imagine - can't i just swap my tired old
> Peugeut 5sp with the AT that comes with the Cherokee? since this is the
> tranny and TC that comes with the motor, it would thus eliminate any
> need for adapters for the CPS, as well as the problem of pilot bushing
> mismatch, and for finding a 4.0/5sp manual computer... isnt that right?
> all i would need would be a YJ driveshaft with the correct spline count
> yes? i assume my stock (5sp) shaft wont fit - correct?
> sorry for all the questions, trying to figure out if this is a good
> idea...
> cheers,
> bennett
>



 




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