'91 ex budget build, 4.0 or 4.0?

[trueblue02]

Hey guys, I've been reading up a bit on different swaps and builds but am having trouble deciding on what course I should take. So I'm going to be getting a '91 ex as a planned daily/road trip car as my mustang has become too impractical since I took out the back seats. There would be some light towing as well with a 1500lb boat trailer. The car in question is an old team car that was used to take our sports team to events, and it was a blast to drive although it was not maintained, which led to it being run sans coolant on the freeway at 75 with a trailer. It did not survive long and overheated.

I was looking through my schools surplus registry and saw the exploder, I checked it out and it has service records for years, and everything is in fairly good shape besides the engine. I need a second vehicle and I could but the truck as is for $200.

The only question is what to do with the engine, I was originally planning on swapping in another 4.0 OHV, finding one on eBay or at pick n pull, but I'm not sure anymore. I would like to do a top end rebuild on the current engine with 93T or 95T heads, and a 410 cam for a bit more power while towing, but I have little to no engine experience and am trying to save money on labor as it is expensive here and finding the right shop is a nightmare. I do all the maintenance on my mustang, oil, tranny fluid, brakes, etc. But don't have engine experience

Should I do a rebuild, or would I be better off swapping a used OHV? If I'm swapping would it be worth it to put in a SOCH 4.0? My buddies ranger is a 98 and it pulls the boats like they're not even there. My total budget is in the range of $1000-$1500, which is why a SOHC swap seems like a lot. What do you guys think?

 

[EMBRACETHEHATE89]

The SOHC motor will fit, but you will lose all of your AC stuff.

 

[Anime]

Depends how long it was run when it overheated. If it was seriously abused, as in, it was driven until the engine seized up from overheating, it's likely not worth rebuilding the engine, compared to getting a good motor that runs and was never abused.

If it was not abused, then the damage may only be the usual cracked heads, which you replace on a rebuild anyway. You can replace a lot of the common top end stuff and be within your $1000-1500 budget.

If you can get it for $200, I'd say go for it, then work on getting the engine out and taking it apart to see what the extent of the damage is. If it's seized or has damage to the block, look at getting another engine.

I'd say just put in another 4.0L OHV. It's a reliable motor, will tow 1500lbs like it's not even there, and will be a direct swap. If you get a 4.0L OHV from a 93-94 instead of a 91-92, you'll want to swap in the ECM (computer) as well.

 

[trueblue02]

It was running when it got put on the flatbed, the inspection report from university fleet services said that it had burnt spark plugs, which were replaced and then it was compression tested which was found bad on multiple cylinders.

as for a rebuild, this is a list of what i think i would need, any additions?


95Tm Heads - http://www.ebay.com/itm/FORD-EXPLOR...sories&vxp=mtr&hash=item27aca4d2da&rmvSB=true $300

Head Gasket - http://www.ebay.com/itm/Head-Gasket...nd-Rover-Mazda-4-0L-V6-SOHC-12v-/281620092356 $90

Rocker arms - http://www.rockauto.com/catalog/raframecatalog.php?carcode=1119608&parttype=5656 $72

Lifters - SummitRacing - $84

410 cam - http://www.summitracing.com/parts/cca-49-410-8/overview/make/ford $278

for a total of $825 before labor, unless i did it myself which i was hoping i would be able to do. as i have said i am not very experienced in engines however i am a quick learner and can follow a guide well. However with the cost being a good part of my budget i am leaning toward finding a used engine, I have seen ones on ebay for $300 or so and if i could find one in that range at the junkyard that would be an easier swap.

I am selling my mountain bike tomorrow to get the cash for this project, so hopefully i will have the truck by next week.

 

[Anime]

If you buy heads, you might as well buy them complete, with valves and springs and seats and seals installed. If you haven't done engine work, you don't want to be fooling around with precision stuff like seating valves or trying to transfer used stuff over to a new head.

Personally I'd say stick with the 93TM heads, the increased compression with the 95TM heads is not really worth it unless you are building up a performance motor. Not something I'd suggest doing on a budget.

I'd also suggest NOT getting a $90 generic engine gasket set on ebay. Either get OE Ford gaskets (they sell those on ebay, too), or some kind of brand name like Fel-pro, Victor Reinz, something.

Rocker arms, sure, the Melling's aren't great but they are better than damaged originals.

Where are you getting lifters for $84? Is that for a set of 12? You can get 12 lifters on ebay for $99, but they are aftermarket and unknown quality. Keep in mind you can rebuild the factory lifters if you want to, but a new set for $84-99 might be ok.

Like with the heads, I'd say forget the 410 cam for now. The cam is going to cost you more than you paid for the whole vehicle and isn't going to do squat until you do a LOT of other mods.

You are better off spending any surplus money on an air filter/cold air intake and/or a catback exhaust or just a muffler like a Dynomax Super Turbo.


I would invest in basic, needed parts first, the heads, gaskets, spark plugs, ignition wires (especially if the ones on it are original), thermostat, fluids like oil, coolant, etc.

I'd say hold off on the cam for now, perhaps you will find one later on from someone on here parting out or upgrading to a 422.

If you are planning to spend more money on the engine doing performance mods in the future, then sure, go ahead and get the 95TM heads, but be SURE they are 95TM heads - there's a LOT of info on here about places selling 98TM heads as 95TM heads.

It also wouldn't be a bad idea to scour or call salvage yards, or check their inventory online, and check your local craigslist and any other places that you can find vehicles. You may find a good 4.0L OHV to throw in, or even find another inexpensive Explorer and pick the better of the two and use the other as a donor.

If you do find a motor, consider swapping it in but keeping the original as a project motor - you can work on rebuilding it while using the other in the vehicle, then put it back in when it's done. Great way to learn about engine work without the hassle of vehicle downtime.

 

[EMBRACETHEHATE89]

Put them cam in now, if ya got the cash why not? Its a pita to do one while its in the vehicle.

Have someone assemble everything or you gonna be up **** creek before ya know it. Save more money.

 

[natenkiki2004]

Since Anime touched on gaskets...

I recently did the lower intake set and got mine from Magnum. They were cheaper than Fel-Pro and look to be much better made. All made in the USA with premium materials. I wouldn't hesitate going with them for a head gasket either. Heck, I probably will in the future

 

[trueblue02]

I bought it! It was $250 when it was all said and done, a little more than what I hoped but I jumped it and it ran! Its definitely got a misfire and runs rough at idle, but smoothed out at bit at 1k rpm. Hoping its in good enough shape to get to my house, which is 5 miles from where it's parked, mostly downhill with a little up at the end. From the sound of it I'm thinking it might just need a new head & gasket.

Can you replace a head without pulling the motor?

I do not have a lift, was looking at one from harbor freight and I could get it shipped for $200, which would leave me about $300 to get the motor from the cash I have at the moment.

Thinking if I could get an assembled 93tm or 95tm for less than $500 that would be easier, and less gas $$$ to pick up the engine with my housemates ranger. I would have to make sure there is no damage to the block however.

 

[natenkiki2004]

Pulling heads can be done pretty easily without pulling the motor. The hardest part might be the exhaust manifolds. If it were me though, I would rattle off the 2 bolts attaching the manifold to the y-pipe and then get the head & manifold out. Then you can PB Blast the manifold easier and get a much better shot of the studs with an impact gun. You could even grind them off if the head is toast.

 

[mr cribb]

Yes you can do all of the head work with the block still in the truck. I have done it twice.

Soak the exhaust manifold bolts for several days before you attempt to remove them. I wound up cutting my y pipe to get my old heads off. I also had a little bit bigger budget to play with on mine.

Things that are a MUST buy:

HEAD BOLTS (two sets, because one set does one cylinder head)

HEAD GASKET SET (this will include intake and valve cover gaskets <-- I trashed the cheap valve cover gaskets and bought the fel pro rubber gaskets) (extra expense for rubber valve cover gaskets)

TORQUE WRENCH (my mid grade wrench from autozone worked for me)

CYLINDER HEADS (I bought mine from Clearwater cylinder head, and that cost $600)

FLUIDS (Fresh oil and oil filter change, 1 gallon of coolant, then top off radiator with a gallon of water)

SPARK PLUGS and WIRES (Motorcraft platinum plugs, and motorcraft wires if you can find them.)

Totals:

HEADS $600
GASKET SET $75ish
HEAD BOLTS $60-80
TORQUE WRENCH $30 (If you can buy a combination set from like harbor freight so you have one that does inch pounds, it is a guess for inch pounds if you don't have the correct tool)
FLUIDS $50 if you use good oil
SPARK PLUGS $36 ($6 each)
SPARK PLUG WIRES are an easy $30

Just by my figures alone with my list you are at $855 - $875 for repairs. This is all dependent if prices are up or down since I bought the stuff.

I reused my old pushrods and rockers without any issues.

Things that are worthy of replacing because of age or unknown condition or just good practice or ease of access:

RADIATOR HOSES ($25 for both) *Don't forget new hose clamps*

THERMOSTAT (cheap one with gasket $10 <-- has a 3 month warranty, failsafe brand is $12 has gasket and a 1 year warranty and sticks open in the event of a failure)

HEATER HOSES ($5 to $10 for both because it is x amount per foot) *Don't forget new hose clamps*

WATER PUMP ($25 to $35)

FAN BLADE AND FAN CLUTCH (Blade is $25 and clutch is $40 or so) <--accurate pricing I just bought these a month ago

LOANER TOOL FROM PARTS STORE FOR FAN CLUTCH $75 in my area, harbor freight may be cheaper or if you have a buddy that has one use theirs.

SERPENTINE BELT $25 ish

So there's at minimum of another $225 to $250 in just wear out parts.

As a mechanic I recommend the replacement of these items if they look questionable to YOU.

Hoses, thermostat, fan blade and fan clutch are ALL known contributors to the 4.0 overheating game. Spend money now even if it takes a little longer to get the truck on the road, or do it all again later because of an oversight or laziness the choice IS ultimately yours.

BTW I'm not trying to come across as a donkey, I was just trying to express the fact of do it right do it once. Also in reality by replacing all the stuff I mentioned, most of these parts are likely to outlast the truck itself.

 

[trueblue02]

So i managed to drive it down to my house today, and its sitting in my garage. Here it is in all its glory http://imgur.com/YoKanf2 barely fits in the garage.

mr cribb, thanks for the helpful list of parts, didn't really think about a couple of those. the serpentine belts have been replaced within the last two years and look in good shape to me. the fan is cracking which is common for these ive heard, and the water pump may have failed, on the drive back i filled the radiator overflow tank and not a drop of that circulated to the radiator. new hoses would be good too.

as for heads, i found an assembled set from this thread http://www.explorerforum.com/forums/showthread.php?t=338500

which would be $680 after shipping and i would not have to deal with swapping the valves or pushrods. i am going to start taking the intake manifold off this afternoon and hopefully ill get to the heads by the end of the week. after i see the damage extent i will see if a full engine swap is necessary.

 

[EMBRACETHEHATE89]

Looks like the paint is pretty good, id throw some money into it. Have ya a fun toy. I really only drive mine on the weekends, and mainly its offroad.

 

[mr cribb]

I know what you mean about the serpentine belt, and again if things look good to use then use it.

The thermostat is easier to replace with the fan clutch assembly removed. However, since the intake is coming off the it doesn't get any easier than that.

I made that list because even as a mechanic, I have missed a few of those things in the past, and put this list together, because it very well could help someone else.

 

[trueblue02]

UPDATE: Ive made it to the valves! heres some pics http://m.imgur.com/11JhZjV,80eqQRf,FG3zQ4F,5zcLaRV

i believe that i need to take of the lower manifold/fuel rails next, however there is a specific torx socket i will need for that, ive looked around and am having trouble finding the right size i will need. it also looks like i will need a torx driver to remove the cylinder heads.

the valves seem to be in pretty good shape, no evidence of damage that i can see so far... should i remove the heads piece by piece or take them off as an assembled unit? i am planning on buying assembled heads but if the valve assembly is in good shape would it be better to reuse it?

also will i need to remove the power steering pump to get access? id rather not have to deal with draining the fluid.

 

[natenkiki2004]

The rocker arm shafts will come off with 3 bolts. You don't have to refurbish them or replace them, as long as they're not excessively worn. Check the pads and check the bowls/sockets on the rocker arms. The pads will have indents and the sockets should be polished to a mirror. If the sockets or pushrod tips look like brushed metal, they need replacement.

I don't know what torx size you need but you'll want to get an impact style, as thick and as strong as you can.

The power steering pump does have to come off but you can set it aside without draining it. I did it this way when I pulled the engine. Just don't let it fall, maybe zip-tie it up somewhere.

 

[mr cribb]

T55 is the torx.

I found it more reasonable to buy the whole torx bit set, because you never know when you will need another size. I think the price difference was about 10 dollars between buying one socket and buy a whole set.

 

[mr cribb]

Yes take off the lower intake manifold and fuel lines.

You undo the braided fuel lines, one is a 19 mm and I think the other is a 17.

Lower intake is secured by 10 or 13 mm bolts.

You will need to remove the rocker arms from the heads to remove the push rods.

When it comes to the push rods remove them one at a time and get a piece of cardboard to hold them.

I did mine #1 I for intake and #1 E for exhaust etc.

 

[trueblue02]

UPDATE 2: I got the heads off, well at least one. when taking off the rocker arms i took a look at the push rods and they seemed to be a little worn, the rocker arms looked in good shape though. after getting the head off i found the source of the misfire and main damage to the engine. http://m.imgur.com/a/CF8aI as you can see there is some pretty bad damage to the valve and the piston has some damage as well. What would cause this? it is clear that the piston and the valve collided at some point would that be from overheating?

its pretty clear that i would need to swap the engine at this point... any tips for getting that done? gonna get an engine lift next week from harbor freight.

 

[jd4242]

It probably cracked between the valves causing the valve seat to come loose and jam the valve open ..you have better pictures of the piston?? Being its a non interface motor plus the fact even if the valve stayed open at the max lift of the stock cam,it still shouldn't hit the piston..

 

[jd4242]

Aww wait. .it appears the valve seat contacted the piston, not the valve..is there damage to the cylinder wall??