Bronco Engine Suggestions

[dccarpenter]

I picked up a '94 Bronco Eddie Bauer with a nice interior and brand new wheels and tires for the cost of parts. Lights and climate control all work. It was running quite rough, got it running a bit better and then had a local garage look at it as it was misfiring badly under load. He says compression is very bad to none on cylinder #7. I was able to drive it around at 30-40mph and it only shook bad on uphills , etc.. so suprised that it was that bad. It idled like an old car...not terrible though there is a lot of shake to it when viewed. Plug and wire were changed on it.

I've done engine swaps on carburated old trucks but with a bum shoulder and heavy work schedule I don't think I have the time to attempt a EFI motor swap , got quoted $5500 for a Jasper motor + install. I'm guessing a junkyard motor if available will run at least $1600 if put in by the yard.

I could grab one of the $1800 Autozone remans and find a local shade tree guy to put it in, I'd probably be out $3000 by the time it was said and done.

Exterior of the truck is 'ok' other than the cut wheel wells and rusted tailgate, frame and hangers are all in good shape.

Anyone gone the junkyard engine route and had luck? Or a Jasper vs parts store reman experience?

I drive a $400 Ranger around as my only other vehicle so I tend to be very frugal with vehicle expenses, old Broncos do seem to be going up in price though and a rust free frame and spring hanger/coil bucket one isn't a bad starting point. My Ranger's a 4 cylinder regular cab so I do sometimes run across towing tasks or rainy day transport tasks that I wish I had another vehicle for.

 

[bobbywalter]

What engine? 302 or 351? What was the oil psi doing?

Bad valve or piston or head gasket on number 7?....or wiped lobe?...block broke?



Running 351 engines value 400 to 1k dollars at my local yards...engines on shelf ready for pickup....mostly from 1 ton trucks.


The 302engines...run about 250 to 700 dollars.

And yes your rolling the dice.

I assume they did a full leakdown and determined the block toast or you would not be looking to swap.


If it just needs gaskets .. you can do that in a weekend.....IF EVERYTHING on the emissions components DONT BREAK....and the manifolds are not grown to the bolts.

 

[dccarpenter]

What engine? 302 or 351? What was the oil psi doing?

Bad valve or piston or head gasket on number 7?....or wiped lobe?...block broke?



Running 351 engines value 400 to 1k dollars at my local yards...engines on shelf ready for pickup....mostly from 1 ton trucks.


The 302engines...run about 250 to 700 dollars.

And yes your rolling the dice.

I assume they did a full leakdown and determined the block toast or you would not be looking to swap.


If it just needs gaskets .. you can do that in a weekend.....IF EVERYTHING on the emissions components DONT BREAK....and the manifolds are not grown to the bolts.

Thanks for the input, they did not do a leakdown test just a regular compression test so it could just be a valve or head gasket.

It is a 351.

I can get a 105k 351 engine for $1100 and or a 176k for $550. Will run me about $1000 to have either put in.

Cylinder 8 had 20lbs compression on a standard compression test. It drove acceptably the 5 miles home at 50mph , didn't like accelerating on the one hill but otherwise passable performance. Idled fine at startup, poorly after the 5 mile ride. I might hail mary it by putting some seafoam in the oil and letting it run for a few hours and then changing the oil. Then use straight 40 as the new oil and a can of Restore, it could make it a passable 55mph and under vehicle for a few months.

 

[bobbywalter]

It's a pia to pull the valve cover...but may be worth it. May be a bad spring...

If you have an air compressor....and a compression tester...pushing some air to it for a quick check is usually pretty easy.

Usually issues that seafoam helps are sticky valves and lifters and they make particular noises....but it is definitely worth the effort if it frees up a wobbly valve ..

 

[dccarpenter]

I've got tomorrow morning free so I'll pickup a compression tester at autozone, I do have a air compressor.


At the pricing I'm seeing for new heads on Google plus gaskets and head bolts plus a day or two off work to do it, the 105k mile engine for $1,000 is starting to sound better. The current motor has 220k on it. I'll have to see what the testing tomorrow yields.

 

[bobbywalter]

Running engines are a coin toss if you can't hot test them. But I have had the best luck doing that.

 

[dccarpenter]

I was unable to hunt down a leak down tester at the auto part stores near my house. They were all out.

So after wasting way too much time thinking about engines and looking stuff up on google I remembered the engine was down almost a gallon of coolant when I got it. The oil looked fine so I hadn't suspected head gasket. I read that bad head gasket could cause compression drop on a single cylinder. I went the mechanic in a bottle route and let her idle for an hour with 2 cans of Blue Devil head gasket repair. I've had luck with the Blue Devil product in the past, it worked great on both trucks I used it on before.

Major increase in compression, I went from 20lbs compression on the last test to 120lbs on the new test on cylinder 8. Of course the vehicle rewarded me by promptly having a break line burst as soon I pulled out for a test drive. It still has a bad surging idle but I am changing the throttle position sensor today to see if it helps with that as well as the ECT sensor. IAC and MAP sensors already changed along with plugs/wires/rotor.

 

[dccarpenter]

So if it's not one thing it is another with these old trucks. I fix the leaking brake line, I pull the thermostat and get the new tps sensor in.

Surging idle improves quite a bit..not all the way still probably have a vac leak or some outdated smog nonsense is messing up but it is definitely better.

Then..on cue... the water pump starts a slight leak after I turn it off. Leak is very slight at the moment...might try K-Seal mechanic genie in a bottle for that one. If I pull the water pump I might as well do fan clutch..if I do that I may as well do timing chains, timing cover, thermostat..and on and on. All on a block band-aid'd together with Blue Devil gasket repair.

At a certain point I stop putting new things on this block and get the junkyard 105k runner that they tested and go all out putting new injectors, gaskets, all new sensors and PCM, everything on it pre-install and plop it in.