1984 Bronco II rebuild the 2.8 or swap in a 302


ranger1911

Member
Joined
May 6, 2009
Messages
36
Reaction score
9
Points
8
Location
Southern AZ
Vehicle Year
85
Make / Model
Ford
Engine Size
V6
Transmission
Manual
I bought my Bronco II sometime around 2010 and it's been a great 2nd vehicle. I live in the desert and it's a great little offroader too...

On the way home from work last summer it stalled out on me (happens frequently when coming up to a stop sign) and I pop started it and something happened, loss of power and a rattle. I was less than a mile from the house and made it home ok.

Working on getting the engine pulled since it's not really possible to pull the oil pan and poke around. Already peeked under the valve covers and nothing obviously wrong. I figure the problem is probably something like a bad rod bearing, but it's all speculation until I can pull the 2.8.

I was reading about engine swaps and happened to find a 1974 302 on craigslist for 75 bucks (no intake manifold or carb). The guy said the engine would only rotate about a 1/4 turn and then it stopped. I bought it anyways and pulled the heads, the cylinders were pretty damn dirty (carbon buildup) but one had some rust on the valves and valve was stuck. Crankshaft rotated nicely with no heads on it... Squirted some oil on it and a couple of light taps with a mallet got it moving again, put the heads back on and now it all rotates like it should.

I'm not going to do much more than some cleaning on the 302 until I get the 2.8 pulled and opened up and find the problem. If it's gonna be a pricey rebuild I will most likely condemn that engine and put my money into the 302 instead and track down the parts I need to make it work with what I have. Based on the list of stuff on the 302 swap page it's not an overwhelming amount of stuff to find but I could be wrong! If the 2.8 looks like it's not too bad I will try to do a quick and dirty rebuild to give myself a little time to work on the 302 so I can drive it in the meantime. It's just a bit cheaper to drive around than a 3/4 ton diesel.

I was curious if anyone has been in a similar situation where their 2.8 crapped out on them and what they did (rebuild or swap in a different engine) and had some thoughts about pitfalls or things they wish they had known beforehand.

Thanks :)
 


Rock Auto 5% Discount Code: 4FF3E9EEA14805 Expires: October 1st, 2020

franklin2

Active member
Joined
Dec 24, 2019
Messages
574
Reaction score
185
Points
43
Location
Virginia
Vehicle Year
1984
Make / Model
Bronco II
Transmission
Manual
I am building more and more respect for the 2.8 since I started running mine about 6 months ago. I am finding out it's just like the 300 six in the 1984-up f150's. Both of these are great little engines, saddled with a very complex and failure prone engine computer control system. Get rid of that, and the engine underneath is given a new life.

You didn't say why you think your 2.8 is terminal and needs to be pulled. If it has bad mechanical noises that is one thing. If it just doesn't run correctly, that is probably the engine control system.
 

ranger1911

Member
Joined
May 6, 2009
Messages
36
Reaction score
9
Points
8
Location
Southern AZ
Vehicle Year
85
Make / Model
Ford
Engine Size
V6
Transmission
Manual
I am building more and more respect for the 2.8 since I started running mine about 6 months ago. I am finding out it's just like the 300 six in the 1984-up f150's. Both of these are great little engines, saddled with a very complex and failure prone engine computer control system. Get rid of that, and the engine underneath is given a new life.

You didn't say why you think your 2.8 is terminal and needs to be pulled. If it has bad mechanical noises that is one thing. If it just doesn't run correctly, that is probably the engine control system.
I did say :)

I pop started it when it stalled out and it did start, but with a major loss of power and an intermittent rattle coming from what I think was the lower end. I was only a mile from home so I drove home and tried to figure out where the noise was coming from, I think the bottom end. Not 100% sure as I didn't want it to run and cause more damage. At the very least I need to pop off the oil pan which looks impossible with the engine still in.

The 2.8 is just about ready to come out, everything detached and it's resting on the motor mounts. Ran out of time yesterday to get it out. Will pull it this weekend.

I did intend on doing a Duraspark conversion on it but never got around to it; If the engine isn't tore up and it's not expensive to get going again, I will do so. The 302 will then be a long(er) term project.

Side note: We had a late 80's F150 with the straight six, it was a good truck. I was using as a work truck during the summer and it was good to me; Those vent windows were a lifesaver with no A/C in the desert summer. I ended up getting a Ford van later (with AC). We sold the truck after I sold the van and bought a F250.
 

Shran

Junk Collector
Forum Moderator
Supporting Member
Article Contributor
V8 Engine Swap
Solid Axle Swap
Joined
Mar 4, 2008
Messages
5,124
Reaction score
668
Points
113
Location
Rapid City SD
I hate 2.8s and am all for seeing every last one put down, melted in the depths of hell and recast as LS blocks but I dunno if I'd be putting much faith in that $75 302. At a minimum I'd have the heads checked and cleaned up and tear down the rest, have a look at the crank, cylinder walls, etc... you may have a worn out turd.

V8 swap involves a significant amount more work than I think you're aware of... you need a transmission, transfer case, both driveshafts, motor mounts, radiator, and a ton of little things.

Your easy button is to fix the 2.8. Could be something simple. I've had distributor issues with them before, the timing jumps and then it won't run or won't run well.
 

19Walt93

Well-known member
Ford Technician
V8 Engine Swap
Joined
Nov 13, 2018
Messages
1,380
Reaction score
786
Points
113
Location
Canaan,NH
Vehicle Year
1993
Make / Model
Ford Ranger
Engine Type
V8
Engine Size
351
Transmission
Automatic
2WD / 4WD
2WD
My credo
If you don't have time to do it right will you have time to do it over?
I'd tear the 2.8 down and see what you're up against before deciding because it sounds like the 2,8 works for what you do with it. If you end up doing the 302 swap a 73-76 302 is a poor candidate, they used rail rockers and had severe valve guide wear as a result, the timing gear was nylon teeth on an aluminum hub which was just as unreliable as it sounds, and in order to drop the compression for emissions reasons Ford increased the deck height by .023" so the pistons sit deep in the holes. I'd recommend a later 302, they got a 1 piece rear main seal and a lighter block in 82, Mustangs got a roller cam in 85, and other models later. Even if you leave it stock, the roller cam reduces friction and drag, which will free up a little power, and you won't need to worry about adding ZDDP to the oil to protect a flat tappet cam. It's my understanding that T birds and Explorers have more compact drive belt system for an easier fit. A Bird or Explorer is unlikely to have had as many "hot suppers" as a Mustang or worked as hard as and F150 so a rebuild will probably be cheaper. No 2.8 to V8 swap is going to be really cheap.
 

ranger1911

Member
Joined
May 6, 2009
Messages
36
Reaction score
9
Points
8
Location
Southern AZ
Vehicle Year
85
Make / Model
Ford
Engine Size
V6
Transmission
Manual
I've read the V8 swap article, I'm aware of what needs done. Is it incorrect? It says I can use the bronco manual transmission with a 1984 f150 bellhousing and adapter plate. It's not going to be a hotrod engine. There is already a dual core radiator in the bronco. Motor mounts are simple from the looks of it (either buy the stock mustang ones and flip them, or make custom plates for the ranger mounts. I'm a machinist, drilling 3 holes in a flat piece of plate is simple.) V8 pulleys for alternator / power steering. I know it's a lot of work. I'm not in a huge hurry. It's been sitting for a year.

Regardless I will check out the 2.8 first. if a rod bearing went out and scored up the crank, I doubt I will to pay to have that block and crank machined for new bearings (and whatever else needs done, it was a oil leakin son of a gun). I'd have to do the duraspark conversion because the EGR system is a total piece of crap, along with all the other vaccum operated garbage.
 

franklin2

Active member
Joined
Dec 24, 2019
Messages
574
Reaction score
185
Points
43
Location
Virginia
Vehicle Year
1984
Make / Model
Bronco II
Transmission
Manual
A main bearing problem on the crank is a very heavy faint thump thump noise, like one of those kids going by with one of those stereo systems.

A rod bearing problem is higher and usually a little louder, more like you are actually taking a hammer and hitting the side of the engine.

Rattling and ticking is usually a valve train problem.
 

CUracing

Member
V8 Engine Swap
Solid Axle Swap
Joined
Aug 10, 2007
Messages
105
Reaction score
2
Points
18
Location
Millersville, MO
Vehicle Year
1986
Make / Model
Ford
Transmission
Automatic
I would do 4.0 swap out of first gen explorer or ranger or do v8 swap
 

Shran

Junk Collector
Forum Moderator
Supporting Member
Article Contributor
V8 Engine Swap
Solid Axle Swap
Joined
Mar 4, 2008
Messages
5,124
Reaction score
668
Points
113
Location
Rapid City SD
I've read the V8 swap article, I'm aware of what needs done. Is it incorrect? It says I can use the bronco manual transmission with a 1984 f150 bellhousing and adapter plate.
Can and should are different things, I don't know why they even make adapter plates to use the RBV manual trans behind a V8. Most of those early transmissions didn't hold up well behind a V6 let alone even a stock V8. A half ton F150 or larger truck transmission is a necessity, IMO the ONLY RBV transmission that is usable behind a V8 is a hard to find C5 auto and even then you need a C4 bellhousing and torque converter (but you get to keep your stock t-case.)

If I was doing it again, I wouldn't use the Mustang motor mounts either. I think you could build some that allow the engine to sit lower. Lots of things would have worked better if that was the case.
 

ranger1911

Member
Joined
May 6, 2009
Messages
36
Reaction score
9
Points
8
Location
Southern AZ
Vehicle Year
85
Make / Model
Ford
Engine Size
V6
Transmission
Manual
Can and should are different things, I don't know why they even make adapter plates to use the RBV manual trans behind a V8. Most of those early transmissions didn't hold up well behind a V6 let alone even a stock V8. A half ton F150 or larger truck transmission is a necessity, IMO the ONLY RBV transmission that is usable behind a V8 is a hard to find C5 auto and even then you need a C4 bellhousing and torque converter (but you get to keep your stock t-case.)

If I was doing it again, I wouldn't use the Mustang motor mounts either. I think you could build some that allow the engine to sit lower. Lots of things would have worked better if that was the case.
See, this is the kind of information I was hoping for when I posted this. Thanks very much for your reply. I will do some more research into transmissions, would like to stick with a manual if at all possible. Not a fan of automatics.
 

Shran

Junk Collector
Forum Moderator
Supporting Member
Article Contributor
V8 Engine Swap
Solid Axle Swap
Joined
Mar 4, 2008
Messages
5,124
Reaction score
668
Points
113
Location
Rapid City SD
No prob. There are lots of choices for manuals - I have a NP435 four speed in mine with a mid 80's bellhousing, the trans itself came from a '76 F150 as did my 205 t-case. If a four speed will work, you can also use T18s and T19s from F series trucks. If you want an overdrive gear, you can use a M5R2 trans from an F150 or a ZF 5 speed from a F250 although they are quite large and heavy.

Two more things to keep in mind there, you cannot use your small, compact RBV transfer case, you must use one from a half ton or larger truck to be able to bolt onto your new transmission... and you have to pick one that will fit between the frame rails, and not all will.

Further, the shifter on the old four speeds is not really in an ideal place for RBVs. I had to cut a notch out of my dash to clear the shifter and that was even after heating it up and bending it. The 5 speed options are better in that regard.
 

franklin2

Active member
Joined
Dec 24, 2019
Messages
574
Reaction score
185
Points
43
Location
Virginia
Vehicle Year
1984
Make / Model
Bronco II
Transmission
Manual
This site claims a Mazda M50D-R1 will hold up behind a v8. Couldn't he get one of those transmissions, use an adapter, and then use his original transfer case behind that? Driveshafts probably would need modified correct?

Hopefully there is nothing much wrong with the 2.8.
 

ranger1911

Member
Joined
May 6, 2009
Messages
36
Reaction score
9
Points
8
Location
Southern AZ
Vehicle Year
85
Make / Model
Ford
Engine Size
V6
Transmission
Manual
I got the 2.8 out last night and pulled the oil pan, no evidence of anything bad in there. Just a bit of sludge at the bottom, but it has been sitting with the oil drained out for a few months so that's not much of a surprise. No wiggles in any of the rods except for the minute amount of side to side clearance that's supposed to be there. No chunks stuck in the pickup screen. All the pistons look to be ok....

I will do a compression test on all the cylinders and see how that looks before I pull the heads. Was looking at parts for the Duraspark conversion, looks like around 300 would get all the parts. Might be the route I go if there is nothing wrong with the 2.8. It would give me plenty of time to work out exactly what I want to do with the V8 :)

The local pull a part yard has at least a dozen F150's from the 80's (and a Bronco II!!!!) so I may end up making some trips there. The first trip will be to scavenge stuff off the '84 BII. I'd love to get a factory center console. Need the front body panel the holds the turn signals too.
 

bobbywalter

TRS Technical Staff
TRS Technical Advisor
TRS Banner 2012-2015
TRS 20th Anniversary
Joined
Aug 9, 2007
Messages
20,036
Reaction score
995
Points
113
Location
woodhaven mi
Vehicle Year
1988
Make / Model
FORD mostly
Engine Size
BIGGER
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
sawzall?
Tire Size
33-44
My credo
it is easier to fix and understand than "her"
theres no way in hell i would swap an 80's engine into that thing.


there is just way too much cool shit out here these days. i wish i was 16 again....
 

85_Ranger4x4

Forum Staff Member
Forum Moderator
Article Contributor
OTOTM Winner
TRS Banner 2010-2011
TRS 20th Anniversary
Joined
Aug 7, 2007
Messages
23,068
Reaction score
3,539
Points
113
Location
SW Iowa
Vehicle Year
1985
Make / Model
Ford
Engine Size
5.0
Transmission
Manual
This site claims a Mazda M50D-R1 will hold up behind a v8. Couldn't he get one of those transmissions, use an adapter, and then use his original transfer case behind that? Driveshafts probably would need modified correct?
No, the M5ODR2 is for a V8. Kinda, 97-04 4.2 (which is a V6) F-150 fits the best, the shifter is the same place as a Ranger trans (earlier R2's has the shifter farther ahead) The 4.2 has the same bellhousing pattern as a SBF, just needs the holes enlarged slightly. Then it is fullsize t-case and custom driveshafts.

I have an M5ODR2 out of a 2004 4.2 F-150 in my truck.
 


Top