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Unread 02-13-2013, 11:30 AM   #1
voz
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1991 YJ Wrangler 
 
Join Date: Jul 2011
Location: Clayton, NC
Posts: 121
My Build/ Swap Thread.

I will be doing a 4.2 to 4.0 swap on my 89 YJ,
Would like to refresh the engine w/o a complete rebuild.
This is what I have so far.

92 4.0 out of a YJ, computer harness ETC, PO claimed only 148k on it.

New parts I have Purchased over the last 2 months.
Oil Pump
Head Gasket
Valve cover gasket
Timing chain kit, which includes gears, cover, gasket and damper
rear main seal
injectors
Spark plugs, wires, cap, rotor & coil
Crank sensor
Headers
new head bolts
POR 15 engine paint
intake temp sensor
Fuel filter

That's all I can think of off the top of my head,,,

Anything else I should be changing out? inspecting?

Thank You!

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Unread 02-13-2013, 11:37 AM   #2
A_Ninja_Racer
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Location: Tampa/Brandon, Florida
Posts: 123
Since you are taking off the Head are you at least planning to send it out to have it inspected and resurfaced?
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Unread 02-13-2013, 12:01 PM   #3
voz
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1991 YJ Wrangler 
 
Join Date: Jul 2011
Location: Clayton, NC
Posts: 121
Sir Yes Sir.
Local shop will do it for 60.00, (using my buddies discount)
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Unread 02-13-2013, 12:03 PM   #4
A_Ninja_Racer
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Then I'm Good!. It just seems Like almost a waist of time to do all that work to tear it down and not give the head a good once over.
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Unread 02-13-2013, 12:17 PM   #5
voz
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1991 YJ Wrangler 
 
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Location: Clayton, NC
Posts: 121
Valve seals? valve adjustments?
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Unread 02-13-2013, 12:17 PM   #6
JeepinJeremy
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1992 YJ Wrangler 
 
Join Date: Feb 2012
Location: , Colorado
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Might as well just rebuild it at this point. You dropped a ton of money on new parts whats another $600.00 to go through the lower end. Kind of a waste in parts and money on a motor with 148k.
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Unread 02-13-2013, 12:22 PM   #7
voz
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1991 YJ Wrangler 
 
Join Date: Jul 2011
Location: Clayton, NC
Posts: 121
My skills come up short when it comes to the bottom end..

I will inquire at my local shop
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Unread 02-13-2013, 12:40 PM   #8
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,004
Rebuild at 148k? Do you think it's necessary Jeremy? I dont eveb see a reason to pull the head IMO. Pull the valve cover and clean it up. Do a compression test. It takes you 10 minutes. If the valves and pistons all test good then leave it and put your effort into other things that make sense like the external slave, axle disconnect, etc. Do the things you do for routine stuff that are difficult with the engine in place like clutch, rear main, oil and water pump. Leave the rest alone. The engine will get you 250,000 easy if the compression test is good.
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Unread 02-13-2013, 01:15 PM   #9
JeepinJeremy
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No I don't think is is necessary but for the amount of money he put in new parts he might as well start fresh. I put in a 4.0 with 145k in my swap and only changed the valver cover gasket. Been running that for a year now without issue. My only point since he was going as far as he is he might as well just rebuild the dang thing. The only think I guess would concern me is that if he seen it in running condition before he bought it. What is prompting him to swap all the parts he is swaping and why?
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Unread 02-13-2013, 01:16 PM   #10
JeepinJeremy
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92 4.0 out of a YJ, computer harness ETC, PO claimed only 148k on it.


Did you ever hear or see it run?
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Unread 02-13-2013, 06:42 PM   #11
Que89YJ
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1989 YJ Wrangler 
 
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New jeep. More isn't always better.
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Unread 02-14-2013, 09:29 AM   #12
voz
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1991 YJ Wrangler 
 
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Location: Clayton, NC
Posts: 121
Jeremy, Yes I heard it run, Sounded fine, but since it was on jack stands I could not hear run it down the street.

I guess I'm changing parts, cause I don't want an issue down the road. I have it on an engine stand now. easy to change..
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Unread 02-14-2013, 10:20 AM   #13
Que89YJ
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1989 YJ Wrangler 
 
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I am just suggesting that you look at the mods that will save you time and heartache in the long run that are easier to deal with when you got it apart. I just don't see the point on some of them but others I agree 1000%. It's just my opinion. There are a few things that you can do that are easier to do while you are doing the swap like dealing with the axle disconnect and the internal clust slave cylinder that will help you more then replacing a good head gasket. The high lighted ones are the ones not necessary IMO.

Oil Pump
Head Gasket
Valve cover gasket
Timing chain kit, which includes gears, cover, gasket and damper
rear main seal
injectors
Spark plugs, wires, cap, rotor & coil
Crank sensor
Headers
new head bolts
POR 15 engine paint
intake temp sensor
Fuel filter
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Unread 02-14-2013, 11:00 AM   #14
Beachcruiser
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1987 YJ Wrangler 
 
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Location: Raleigh, NC
Posts: 375
If you are having the head surfaced, I'd tell them to put some new valve stem seals on it too....only a couple bucks more & well worth the peace of mind, IMO.
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Unread 02-19-2013, 12:45 PM   #15
voz
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1991 YJ Wrangler 
 
Join Date: Jul 2011
Location: Clayton, NC
Posts: 121
Thanks for the fellas...

Axle disconnect? please explain..
Also do you have a trick for the slave cylinder,
I also forgot to mention that I will be going from a 5spd to auto
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