So I am working on fixing up a the Bronco that my sister abandoned at my house. It is a 1987 with the 2.9L V6 Engine. She overheated the engine several times and the car has had some work done on it previously. To my knowledge, the radiator, water pump, and intake manifold have been replaced. The heads have been rebuilt. The bronco stalled numerous times and has barely any power. I am currently working on taking off the heads to see if they are warped or cracked. It would be a miracle if just the gasket was blown. My questions are:
1. Has anyone done this rebuild / inspection before?
2. If needed where can I get the new style heads that won't fail as easily?
3. If the engine block is cracked or warped, what other engines are easy swaps for this one?

Any input or advice would be greatly appreciated. I can post pictures on request and will do my best to answer questions you have for me. I am a fairly new wrencher and budget is limited. Thanks in advance.

 

Top end rebuild here (at least torn down heads, etc...) Not to bad of a job, but you'll need to shell out a few bucks for brand new head bolts, as the ones used are torque-to-yield types.

New style heads, best bet (again, I've used them with great luck) World Products 2.9 replacement heads. Thicker where needed to resist cracking again.

2.9's about the only one I'd recommend. In my area they are still pretty available in the bone yards.

Advise:

Compression test the engine before starting anything heavy duty.

TFI modules for their electronic ignition is favored to be a huge pain in the rear end, creating all kinds of problems.

Clogged injectors can also create stalling problems and little or no power. Might want to also pull the SPOUT connector and check base line timing.

S-

 

I will definitely get a compression test done, and someone else told me to do a "leak down" test. As for the new heads, is there a place online to get them? If the compression and leak tests turn out ok, ill check the other stuff. Not sure yet how to check the TFI or the injectors. I'll look into it, but if you have any good advice for these checks it would be nice. As for a replacement engine, what type of vehicle at the junk yard will have the engine i'm looking for?

 

86-90 Bronco II and 86-?(can't recall the last year they used it) Ranger. They started using the revised heads from the factory in 89 or 90. May have to swap a few parts, like the intake, to make a different year work. Some years didn't have an EGR valve.

 

Thanks, I will look further into the engine swap. So now I am confused. The engine passed the compression test, it read 180psi for 1,2,4,5 and 150psi for 3 and 6. The repair manual calls out a 101psi minimum spec. Thoughts?

 

im not sure but i heard the 2.9 and the 4.0 has the same motor mounts

 

So I put all the stuff I took off the Bronco II back on and threw in brand new coolant, and a reliable battery and turned the key. I used the half tank of old gasoline (5 years at least) and made sure it had enough oil. The bronco roars to life, but then tries to catch on fire. No flames were present, but smoke came from the passenger side of the engine. It is tough to tell where the smoke is coming from, but its not oil, or trasmission fluid burning. It idled fairly high (no tachometer, and i havent heard it run in a long time to determine high revving), for about 1 minute on four seperate occasions. Each time I turned the engine off due to the smoke issue. I noticed a large amount of rust coming out of the tail pipe. I am assuming this is due to the fact that the vehicle was outside for so long. One more point, every time I barely press the accelerator, the rpm drop drastically. I let off before it stalled, so I am not sure if the car will actually stall. I looked at Autozone for that leak down tester, but they don't have one. Any suggestions on where to find one to rent? Any suggestions on the smoke or accelerator issue?

 

150-180 for compression is quite good. That's giving signs of decent engine sealing. Honestly I wouldn't fork out mega bucks for a full leak down tester at this point. It might take a bit of work to find, but a simple air-hose adapter that connects to a spark plug threaded adapter normally is a quick and dirty method to check for leakage.

All you would do is get the cylinder at TDC (both valves must be sealed), screw the adapter where the plug would be...hook up the air hose..nail it with compressed air. Any leakage will be either seen or heard. (seen as in--massive bubbles coming out the radiator (need to test with the cap off, of course)...or heard from the intake/exhaust).

The engine wanting to stall just 'off idle' sounds more like the throttle sensor might have a dead spot in it. Cheap enough to test with a basic multimeter. A dead spot would mean when you start to push the pedal down? It hits a dead spot in the sensor, and sends the engine computer a bad signal. (it might be telling the computer it just went to wide open throttle, with the plates 'closed'. So it'll kick up the fuel, without enough air flow--result? starts to flood out to the point of stalling)

What color is the smoke? Any of the wiring touching the exhaust pipework? (it can be a nightmare to see, if the truck has the AC box). Whiteish smoke would point towards coolant. (rotted freeze plug seeping onto the exhaust). Blue tinted smoke is oil related..Black smoke is usually "Carbon" related. (get a truck running super 'rich'...blows black smoke out the exhaust--any crack or exhaust leak and it'll smoke outta both the tail pipe, and the leak.)

I know you said it's not oil, however that engine is famous for the valve cover gaskets failing (90% of the time? Incorrect installation is the fault) It'll start leaking out oil all over the exhaust manifold--and you'll notice a heat shield for the hot-air intake system clamped to the passenger side manifold. That can get fully caked up with dirt and oil---once it gets hot enough? That'll smoke like there's no tomorrow.

S-

 

I just did the tps test and it didnt have any dead spots, so that's not it. I tried depressing the accelerator slowly and now it seems to be gradually increasing rpm. It is a warmer day so maybe the near freezing temperature of last time caused it to act funny. I am still looking for a spark plug to air hose adapter to do the leak down test. The smoke is somewhere between white and grey, the smell of the smoke is very odd, never smelled something like it before. One thing i cannot figure out, is that when my sister used the bronco, she constantly had to add coolant to it. I wasnt given exact amounts but I get the feeling it took at least a gallon a week. I cannot figure out where the coolant is going. No one remembers seeing a coolant puddle underneath the vehicle. I did notice a small dripping of water or watery coolant, coming from where the coolant lines go into the firewall. I will try to send a picture of this location soon to give you a better idea. The dripping seems to have stopped, but i never really did anything to fix it. As far as the valve covers go, i will try to get some black rtv in there to tighten up the seal. I did follow the chilton repair manual method of installing the heads as far as torque patterns and specs. Let me know what you think. Thanks.

 

One thing I did note with ours, regarding the valve cover gaskets. The edges at the front and rear of the heads did seem to 'push' out from the valve cover itself. Almost like they where made to long to fit. We wound up backing the bolts off slightly and using a light coat of sealant on both sides of the gasket carefully pushing it back under the lip. Oddest thing, not what I would expect from a FelPro gasket by a long shot. If it did that trick on ya during the install? You'll be able to reach around and feel it at the back, and you'll physically see it sticking out at the front. Not saying this is what it is, just a suggestion.

Best bet with the cooling system at this point? I'd beg and/or borrow a "Slant Radiator Pressure Tester". Fill the system, install the adapter and then the tester...and pump the gauge up to the PSI noted on the radiator cap. (Yeah, do this while cold LOL) If the gauge won't hold the pressure, and the seal is tight to the radiator neck? This tool will allow you to maintain some pressure on the system and inspect for coolant leaks. Ours has a nice leak at the water pump for the heater hose. It's a badly dinged up fitting, and the hose will seep out coolant. The tester will do a lot to help figure out coolant leaks. (they can be quite expensive to purchase, a local shop or parts house may have them for loan?)

S-