Is a 4.0 OHV a 4.0 OHV regardless of year?

[hungryhunter]

I'm buying a 1993 4 dr with a manual trans and manual locking hubs. It's going to be my mud project with front and rear lockers. One problem is that it sounds like it has a rod knock coming from underneath the engine. Will "any"
4.0 OHV fit this application? The reason i ask is that there are plenty of 4.0 OHV engines on ebay for later years but every time I'm told that they aren't compatible with my year. What the hell. Isn't a 4.0 OHV a 4.0 OHV?

 

[Gadget X]

I think the biggest difference is going to be the stuff that's hooked to the 4.0 from later years. If you can, find a 4.0 from a 91-94, and it'll bolt right up! Good luck with it!

 

[littlebro294]

http://www.ebay.com/gds/DOHC-SOHC-OHV-valvetrains-whats-the-difference-/10000000002220885/g.html

not sure if this will help you but it helped me understand a difference in DOHC, SOHC and OHV engines.

 

[Maniak]

I'm buying a 1993 4 dr with a manual trans and manual locking hubs. It's going to be my mud project with front and rear lockers. One problem is that it sounds like it has a rod knock coming from underneath the engine. Will "any"
4.0 OHV fit this application? The reason i ask is that there are plenty of 4.0 OHV engines on ebay for later years but every time I'm told that they aren't compatible with my year. What the hell. Isn't a 4.0 OHV a 4.0 OHV?

Sort of...

1991-1994 is very similar. The heads changed (to fix cracking) in 1993 (called 93tm heads) and in 93/94 (depending on options, where it was made for etc) it can/will have SFI instead of batch injection, EGR/DPFE and Cam sensor... But in general, they are very close..

in 1995 the piston/heads changes and use the 95tm heads.. Smaller chamber head but dished piston.. plus odb-II from now on (well, 1996+)

in 1997, IIRC, they changed the heads again for emissions (smaller exhaust ports).

I can't remember "when" but they also changed the # of bolts on the crank.. It was somewhere in the 2nd gen I think (1995-2001).. I'm not 100% positive on this.. I've never "seen" it myself.. only remember posts about it.

So, No, a 4.0 ohv isn't a 4.0 ohv isn't a 4.0 ohv... but many parts were the same...

If you find a good 1991-1994 motor you can easily change/remove/add the part you are missing from your old motor.. worst case you swap over exhaust or plenum.

~Mark

 

[vq5speed]

I swapped in a 95 4.0 into my 91 when i cracked my head for the 2nd time. I got the whole motor complete but took everything off around the engine from the heads up. Put all my parts from my 91 onto it.

 

[hungryhunter]

I swapped in a 95 4.0 into my 91 when i cracked my head for the 2nd time. I got the whole motor complete but took everything off around the engine from the heads up. Put all my parts from my 91 onto it.

One more question; Can I put a powertrax locker up front and with 4x4 engaged leave one hub unlocked for 4x3 stability in the snow and ice? This option is a lot cheaper than an elocker or an ARB. You'll have to excuse my ignorance. I'm a sbf guy from way back but never did much with my explorers but drive 'em. That's a testament to how good they are.
Well now I've discovered some places to go off road and want the ability to have 2 wd, 3 wd (spartan locker in rear), and true 4x4 with a locker in the front as well. Hence the purchase of a 1993 with manual locking hubs that will be needing an engine soon. I understand the changes made to options or emmisions that might be attached to an engine but a 4.0 ohv should be a 4.0 ohv underneath all the crap. It just seems like there are a lot more late 90's 4.0 ohv's than 1991-94, especially "low" mile ones.