4.0 vs. 4.2 - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

Reply
 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 06-12-2000, 10:09 PM Thread Starter
Enthusiast
 
dennisuello's Avatar
 
Join Date: Jun 2000
Location: Reno, Nevada
Posts: 321
Thanks: 0
Thanked 0 Times in 0 Posts
 
4.0 vs. 4.2

what are pros and cons of both. i am looking at 1990 YJ with rebuilt 4.2L How does it compare to 4.0 engine

dennisuello is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 06-12-2000, 10:55 PM
 
Join Date: Sep 1999
Posts: 281
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: 4.0 vs. 4.2

4.2 blows in comparison. you get about the same torque in both but get 70 more(about that) HP in the 4.0 H.O. The only way I would get another 87-90 YJ would be if the 4.2 or 2.5 were bad or going bad so I could put a V8 in it. However, if you live in a state where emissions aren't strict there are plenty of things to be done to the 4.2 to match the 4.0. but for me, in Califorina, its not worth the money trying to get much more legal Hp out of the the 4.2.

Tas
'89 YJ 4.2L 5speed, flowmaster, Euro taillights....

YJ4LIFE is offline  
post #3 of (permalink) Old 06-12-2000, 11:07 PM
Can't Get Enough
 
Join Date: Sep 1999
Location: Cotopaxi, Colorado
Posts: 1,036
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: 4.0 vs. 4.2

http://forums.vmag.com/pm-0400/messages/1709.html

This was just a post I read, I think that the 258's horses are closer to 115, and the 4.0l's are more like 190. It seems to me that the 350 Chevy should be higher too, but can you believe that torque spec!



dorfs is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 06-12-2000, 11:24 PM
Keyboard Implanted
 
jeepgod's Avatar
 
Join Date: Jan 2000
Location: Wildomar, CA
Posts: 4,618
Thanks: 0
Thanked 3 Times in 3 Posts
 
Re: 4.0 vs. 4.2

ok.. you hold up them horses.. my book.. i would take the 4.2, why.. much more basic.. simplistic.. and that means less crap to break.. and if it does.. i can fix it.. hp? 70? i guess you believe everything you read.. like adding a K&n air filter gives you like 15 hp.. whatever.. 258 is a much stronger motor in my opinion.. 4.0 does have fuel injection and beats the 4.2 in mpg.. i myself would take the 4.2... do some mods.. ie. if you dont live in cali.. like an intake and carb, cam.... with some headers.. and you will beat the snott out of any 4.0 around.. granted you are talking some money.. but if you want to be better than something.. it always takes money.. i do love fuel injection.. so what you have to ask yourself.. is what do you really want.. i myself would give up the added mpg, and the better off road driving (up steep hills) and what not.. for the 258 for the upgrades.. but that is me... i like older things.. more simple.. KISS.. baby... and i do know how to work a clutch..


survival is instinct, but living takes guts

http://www.jeepgod.net
jeepgod is offline  
post #5 of (permalink) Old 06-12-2000, 11:52 PM
 
Join Date: Sep 1999
Posts: 281
Thanks: 0
Thanked 0 Times in 0 Posts
 
That is one sick 350

that is one choked 350. it has a lot of potential left in it while the 4.0 is stroked and maxed out.

YJ4LIFE is offline  
post #6 of (permalink) Old 06-13-2000, 02:55 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: That is one sick 350

Those readings are from the wheels, so readings will be reduced from the factory numbers that are normally taken from the engine itself, I wouldn't doubt the factory inflates numbers too. I do think thats crap about the stroked 4.0 kicking out 225 hp and 300+ torque atleast at the wheels, his numbers have to be off on that 350 too, isn't a tbi 350 a 5.7 L FI engine? and its kicking out 95 less horses and 77 fps less torque, then an engine that is around 4.5 L...*cough* Bull [censored] *cough*

post #7 of (permalink) Old 06-13-2000, 12:13 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: 4.0 vs. 4.2

Accurate Power is putting 4.6 stroker on dyno this week end and I will findout specs and post later. And will find out if at wheels or crank. Jeff

post #8 of (permalink) Old 06-13-2000, 04:57 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: 4.0 vs. 4.2

I am gonna have to side with Jeepgod on this one. While the torque values are similar, the 4.0 is at almost 4000 RPMs to get there, whereas the 4.2 is doing it at about half that. So if you are gonna crawl (what jeeps are designed for) then the 4.2 is much better suited to that use. The only thing I really like about the 4.0 is the injection, which is awesome compared to that crappy carb (which can be replaced with the MPI and 4.0 head to give you the best of both).

It's ALL good!
post #9 of (permalink) Old 06-13-2000, 06:13 PM
Can't Get Enough
 
beee240's Avatar
 
Join Date: Feb 2000
Location: Abingdon, MD.
Posts: 1,019
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: 4.0 vs. 4.2

You gotta love the "ballsy" sound that the 258 makes also.[img]/wwwthreads_images/icons/smile.gif[/img]
Bryan[img]/wwwthreads_images/icons/crazy.gif[/img]

beee240 is offline  
post #10 of (permalink) Old 06-13-2000, 06:28 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: 4.0 vs. 4.2

When it is said that 258 puts out max torque at 1800 what is it at crawlin rpms [like going over big rock at 600 rpm] would like to see torque curve from 500 rpm up and then compare that to 4.0 . Which I think has much flatter and longer curve than 258. Lets compare curve if somebody has it

Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome