Another 4.0 Swap question...head swap vs. full engine swap - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > Another 4.0 Swap question...head swap vs. full engine swap

FS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitFlowmaster's Force II Axle-back exhaust system for the 201FS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 07-27-2009, 03:31 PM   #1
Mol
Disclaimer: I'm Polish
 
Mol's Avatar
2008 JK Wrangler 
 
Join Date: Mar 2009
Location: Columbus, OH
Posts: 7,625
Another 4.0 Swap question...head swap vs. full engine swap

I just got a text message from one of my friends. He is swapping a small block for his 4.0 HO, and he wants to sell his 4.0 and ax-15. I'm still waiting to hear what he wants to sell everything for, which may be a determining factor.

What are your opinions on a head swap with howell kit vs. head swap with weber vs. swapping for the full motor.

He has had issues with his yj, and he seems to think that it is either a bad sensor in the tranny or a sensor in the wiring harness? If its a bad tranny, that's fine, mine is great. He is not a close friend, so I really don't know what his exact issues have been, just that it intermittently bogs down real bad and is almost completely devoid of power.

Swap for the motor or continue to build my 258?

Mol is offline   Reply With Quote
Unread 07-27-2009, 06:05 PM   #2
warhog-06
Registered User
1997 TJ Wrangler 
 
Join Date: May 2009
Location: Indiana
Posts: 138
If it were mine I would do the head swap w/ weber carb (which is actually what I am getting ready to do). Sounds like there is some trouble somewhere, by just using head you eliminate all electronic issues, etc. Changing the head, adding weber carb, and removing emissions (if possible), should gain you 40 - 50hp. Just spend a few hundred bucks and have the head decked (if needed), valves ground, etc., before installing. Nothing worse than going through the trouble to change head and then find out it is warped or the valves leak.
warhog-06 is offline   Reply With Quote
Unread 07-27-2009, 06:12 PM   #3
Mol
Disclaimer: I'm Polish
 
Mol's Avatar
2008 JK Wrangler 
 
Join Date: Mar 2009
Location: Columbus, OH
Posts: 7,625
Yeah I have already bypassed emissions. Thanks for the input, you have affirmed my thoughts exactly with the potential troubles with his setup. What should I offer him for the head? I see people asking between $120-$200...but we all now what people ask and what they net are two entirely different things
Mol is offline   Reply With Quote
Unread 07-27-2009, 06:19 PM   #4
warhog-06
Registered User
1997 TJ Wrangler 
 
Join Date: May 2009
Location: Indiana
Posts: 138
Hard to say. Some people would want to charge you more to take the head off (more work for them). Most wouldn't want to remove because they want to sell the engine as a whole. However, try getting it cheap (since you know there are issues), and you have to have it machined. Maybe he will bite (pull it your self?).
warhog-06 is offline   Reply With Quote
Unread 07-27-2009, 06:26 PM   #5
Mol
Disclaimer: I'm Polish
 
Mol's Avatar
2008 JK Wrangler 
 
Join Date: Mar 2009
Location: Columbus, OH
Posts: 7,625
yeah pretty good chance I can get it for a good deal...he has a mutual friend do his work, and I am the only other jeeper he knows. He wouldnt have anyone to sell it to otherwise. I'll give it a shot at $50 and see what he says
Mol is offline   Reply With Quote
Unread 07-27-2009, 06:34 PM   #6
warhog-06
Registered User
1997 TJ Wrangler 
 
Join Date: May 2009
Location: Indiana
Posts: 138
Now your talking. If you get it for $50, I'll buy it from you for $60. LOL
warhog-06 is offline   Reply With Quote
Unread 07-27-2009, 07:37 PM   #7
Mol
Disclaimer: I'm Polish
 
Mol's Avatar
2008 JK Wrangler 
 
Join Date: Mar 2009
Location: Columbus, OH
Posts: 7,625
Think I'm safe using the exhaust manifold and intake manifold from his motor? Or do I look at buying new?
Mol is offline   Reply With Quote
Unread 07-28-2009, 03:06 PM   #8
warhog-06
Registered User
1997 TJ Wrangler 
 
Join Date: May 2009
Location: Indiana
Posts: 138
I would go ahead with his. There isn't much to go wrong with them, just clean and check everything over good. Definitly new gaskets. Good luck.
warhog-06 is offline   Reply With Quote
Unread 02-26-2010, 04:41 PM   #9
green89yj
Registered User
1989 YJ Wrangler 
 
Join Date: Nov 2008
Location: Georgia
Posts: 1,340
So you have to get a new 4.2 head gasket and JB weld in the extra water jackets. Which pushrods and stuff do you use?
__________________
Build
Herc.Custom Green paint. RC 4". 5 Goodyear 33X12.5 MT/R w/Kev. Cragar V5's. Corbeau Moab seats. Optima Yellow.XRC8 Comp Winch. XJ 4.0/AX15
WTT: 4" springs for 6"
WTS: 4.2 parts. Fuel lines, pump, block, head, accessories, just ask
green89yj is offline   Reply With Quote
Unread 10-17-2010, 05:36 PM   #10
lclark2074
Registered User
1990 YJ Wrangler 
 
Join Date: Nov 2008
Location: RI
Posts: 681
to keep the carb you will need the intake from the 4.2 and the ext from the 4.0
__________________
night crew 226
http://www.jeepforum.com/forum/f12/f...l-box-1471348/
lclark2074 is offline   Reply With Quote
Unread 10-17-2010, 06:27 PM   #11
ThisGuyUKnow
Registered User
1985 CJ7 
 
Join Date: Jul 2008
Location: Harleysville, PA
Posts: 517
If you are getting the whole drive train and want to keep the 258with the 4.0 head why not use all the fuel injection components? That way you get the benefits of MPFI over a carb.....

You will also have the parts between the 2 motors to make a 4.6 stroker which is basically a 4.0 with the rods and crank (if you want it to run off 87 octane you need to have the head worked on to change the compression a bit) it could be run with the stock 4.0 computer or a carb since the 4.2 intake will bolt to a 4.0.
__________________
1985 CJ7 Laredo, 4.0, NV3550, D300, 3.31 AMC 20 w/trac loc
ThisGuyUKnow is offline   Reply With Quote
Unread 10-18-2010, 04:11 AM   #12
wendell
Registered User
1987 YJ Wrangler 
 
Join Date: Aug 2006
Location: grafton ohio
Posts: 3,292
On my 4.2, I swapped on a 4.0 HO head, comp cam, rollor rockers, offy intake, holley 470 TA 4 barrel carb, header, DUI and MSD. It romps and there's no sensors or computer to worry about. EFI is great, but it's not the only solution for the 258. The holley TA series 4 barrels are made for off road and will take some extreme angles and there dependable as well as easy to work on. I'm very happy with the power and simplicity of a carbed 258. It makes more power than a 4.0 at a little lower rpm to boot.
__________________
1987 wrangler, 258 I-6, 5-speed.
2007 liberty sport 4X4, automatic
2009 ford ranger 4x4 FX4 OFF/ROAD, 5-speed
wendell is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.