4.0 OHV as an overland engine

[ecgreen]

Hey guys,

I am building an 89 Bronco II for overlanding and the 2.9 is so tired. I just re-did the the entire driveline and I really want to put some serious miles on this little truck. But the idea of leaving the state with a 2.9 seems a bit sketchy. So I am at the point where I need to make a decision. Rebuild the 2.9 for reliability or swap something else in. a 302 would probably be the best idea, because I could essentially go new. However, I don't need that kind of HP (nor do I want it) and I don't want to spend all that $$$ (and don't tell me I can do it on the cheap, we all know what happens "on the cheap").

So that leaves me with the 4.0 OHV. In my area there are a ton of sub 170,000 mile explorers out there for sale for less than 1,000. My question is this: what could I expect in terms of reliability from a high mileage 4.0? Could I get another 100,000 out of one of these engines provide I go through it before install (i.e. changing seals, water pump, etc.)?

Sean

 

[JOLENE_THE_RANGER]

theyre pretty okay engines. way better than the sohc in terms of life expectancy. make sure its not leaking coolant from the head gaskets and try to find one with the least noticeable lifter tick and youll be good to go. the steering pump will be louder than your exhaust if you plan to use it offroad but thats fine. lol

 

[Shran]

Keep the cooling system in good condition and change the oil and they'll last forever. I know of one that has 350,000 miles on it and still going strong... seen many others that have well over 200k that are in great shape. 90-92 supposedly have weaker heads... 93-94 Explorer would be a great donor for your truck.

I've put about 30k on my Explorer in the last four years and it has taken me all over the southwest, more or less trouble free, aside from a few leaks and one transmission failure that may have been my fault anyway. I believe it's got around 185k on it now, hard to say with the 5 digit odometer but I definitely trust it and would not hesitate to drive it across the country and back right now.

 

[85_Ranger4x4]

Projected lifespan for an engine this old (anything not just 4.0) is hard to guesstimate. It has been in the lower end of the pool for regular maintenance for awhile, most people with 25-30yo SUV's are adding oil when it starts to make noise not necessarily changing it every 3k miles religiously like the first 8 owners. IMO luck of the draw on that.

 

[MikeG]

My 97 still going strong, pushing 300K miles. But, I'm the original owner, and have documented every oil change.

Good luck.....

 

[RonD]

+1 ^^^^

4.0l OHV is very reliable, my 1994 is still going fine at 420,000......kilometers so 260k miles

These are prone to cracked heads at the slightest overheating, so keep the cooling system in good working order, and PULL OVER if temp gets above 3/4 on the gauge, DO NOT try to "make it home" or to the next exit, PULL OVER
Let it cool off then limp to where you need to go in short heat up cool down trips
Head job costs minimum $500 all in if you do it yourself, so even if it takes you 5 hours to get to "home" or parts store, you are making $100/hour for your trouble and not having to replace the heads

 

[ecgreen]

Thanks for all the input guys. I know there are some die-hard 2.9 guys out there, but after 2 years of messing with them, I am loosing faith. Sounds like a 4.0 OHV my be my solution.

 

[Shran]

I don't think the 2.9 is a bad engine... must not be that bad since the 4.0 OHV is based on it. I think it got a bad rep because people neglected the cooling system and then the "upgraded" heads weren't really a bulletproof fix. Then they did the same thing again on the 4.0, weak head design the first few years. Personally I feel that the 4.0 is a big upgrade in terms of power, but a somewhat marginal upgrade in terms of reliability.

Kinda funny, I mentioned this in another thread, my buddy had a 1992 4.0 rebuilt. I pulled it from an Explorer that I saw run and drive - seemed to be a solid engine, other than a thick layer of oil and dirt on everything. Both heads ended up being cracked in multiple places. Would have never known that without having them checked... it ran pretty good and there were no obvious indications of failure.

 

[Roert42]

I think the SOHC is a fairly robust engine. People poo poo on them because of the chain tensioners, but they are easy to change. Add another 30 minutes to an oil change every 70K to change them. It may be easier to find a lower milage sohc then an ohv, so I wouldn't write them off just because of the tensioners.

 

[Uncle Gump]

 

[gaz]

ec,

This is a good question with more than one answer, fortunatly your BII weighs 600lbs less than an Explorer ..)


I feel you, I feel your regard for reliability the most. That said, I would expect A LoT from a donor 4.0L OHV, mostly crap.
Good news is that the solution is mostly painless, do an "inspection of prudence" before installaltion, to include the following:

-lose the crankshaft driven fan/clutch
-have a professional valve job done
-thoroughly disassemble, inspect and clean the entire valve train, replace all out if spec components
-check the cylinder lip and walls
-install a new oil + water pump
-install new timing set
-new rear main seal/wiper
-proper tune up
-second transmission cooler
Probably around $800 not including the donor components.

I believe a V8 conversion is a SOLID move for this application.

A fresh rebuilt 2.9l with 4 system changes:
1) -no crankshaft fan/clutch + electric fan
2) +86/87 throttle body
3) remote engine oil filter and cooler
4) 4x4 automatic Explorer 2 core radiator
If you could do all the work except the machining, not the cheapest move but $1,100 to $1,500 including new heads.

My bust, you have an automatic, #5;
5) add second transmission cooler.

 

[RonD]

Another aspect is parts
2.9l was used from 1986 to 1992, 6 years
4.0l OHV was used from 1990-2000, 10 years
302 was used from 1968 to 2001, 33 years

There will "probably" always be parts available "almost" any where for the 2.9l and 4.0l, but no "probably" for the 302/5.0l....there will ALWAYS be parts for that engine, stock and/or upgrades, and in any town, IMO

 

[ecgreen]

Another aspect is parts
2.9l was used from 1986 to 1992, 6 years
4.0l OHV was used from 1990-2000, 10 years
302 was used from 1968 to 2001, 33 years

There will "probably" always be parts available "almost" any where for the 2.9l and 4.0l, but no "probably" for the 302/5.0l....there will ALWAYS be parts for that engine, stock and/or upgrades, and in any town, IMO

Solid logic and it is probably the best choice for a high mileage overland rig in the end. If budget is a concern, I think 4.0 is the way to go.

 

[Shran]

I guess I kinda feel like an "overlanding" rig should be as close to stock as possible, at least in the drivetrain department. Nothing is worse than breaking down somewhere and trying to track down pieces for multiple vehicles that you used as donors instead of what came with the truck in the first place...but an Explorer donor is just such a good donor for your B2... that's the beauty of a 4.0 swap in a 2nd gen truck, you just buy parts for an Explorer instead of a B2 and that's the end of it.

I really do love my V8 swapped truck but the thought of leaving about a hundred mile radius of my house with it makes me very nervous. I used parts from sooooo many vehicles, some of which I don't even remember now...that's why I built my Explorer for out of state travel... everything is either stock '92 parts except the rear axle.

 

[ecgreen]

I guess I kinda feel like an "overlanding" rig should be as close to stock as possible, at least in the drivetrain department. Nothing is worse than breaking down somewhere and trying to track down pieces for multiple vehicles that you used as donors instead of what came with the truck in the first place...but an Explorer donor is just such a good donor for your B2... that's the beauty of a 4.0 swap in a 2nd gen truck, you just buy parts for an Explorer instead of a B2 and that's the end of it.

I really do love my V8 swapped truck but the thought of leaving about a hundred mile radius of my house with it makes me very nervous. I used parts from sooooo many vehicles, some of which I don't even remember now...that's why I built my Explorer for out of state travel... everything is either stock '92 parts except the rear axle.

Thats a good point!