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Spooner
07-15-2008, 07:41 PM
Can anyone tell me if a 1987 Jeep YJ 4.2l bolt right into a 90 YJ? The 90 is a 4.2l aswell. Is it a straight swap and are the parts off the 87 and 90 the same?

Kinslayer
07-15-2008, 07:44 PM
get a 4L

Jeep Victim
07-15-2008, 08:18 PM
Fucking hell are you kidding?????Tell me you're kidding

Nutbar
07-15-2008, 09:27 PM
If the 87 has the plastic valve cover on it (early 87 and prior) you have to make sure that you use the flywheel from your 90 engine so that the starter will work other than that they are pretty much the same engine and will bolt directly in

Spooner
07-15-2008, 09:45 PM
get a 4L


I know nothing about Jeeps I am just trying to help my brother out. Whats better about the 4l then the 4.2?

Spooner
07-15-2008, 09:46 PM
If the 87 has the plastic valve cover on it (early 87 and prior) you have to make sure that you use the flywheel from your 90 engine so that the starter will work other than that they are pretty much the same engine and will bolt directly in



Thanks for the info

Nutbar
07-15-2008, 09:55 PM
I know nothing about Jeeps I am just trying to help my brother out. Whats better about the 4l then the 4.2?

The 4.0 is a multi port fuel injected engine and the 4.2 is carbed the 4.0 makes more power more efficiently but is one hell of a wiring and mechanical conversion and in most cases not worth the cost of the upgrade.

Spooner
07-15-2008, 11:04 PM
The 4.0 is a multi port fuel injected engine and the 4.2 is carbed the 4.0 makes more power more efficiently but is one hell of a wiring and mechanical conversion and in most cases not worth the cost of the upgrade.


Oh ok thanks yea I dont think he wants to start getting into rewiring it. I think he is more or less looking for drop in and go type of deal. Thanks for all your input Nutbar.

Josh_M
07-15-2008, 11:42 PM
The 4.2ls arent THAT bad. We just sold a YJ with a webber on the 4.2 and it had good power and ran really well. On the other side of the spectrum i know a kid with a 4.2 Yj and it gets awful mileage and runs horrible with NO power.

Greg82
07-18-2008, 04:10 PM
v8 it. Like said above it will work.