Looking for opinions/advice 302 vs. 289 vs. Explorer 5.0

[thegreatjustino]

I have a '69 that I bought on this board a few years back as a non-running Bronco. The story I got was back in the early 90s a crate 302 from Ford was installed, the Bronco was driven very sporadically, and by the time the engine developed a rod knock at around 500 miles, the time had run out on the engine warranty from Ford. The Bronco was parked and has sat without being started for 20+ years now. I purchased it and had it transported to my house where it has sat for the past three years, nearly new 302 with rod knock issue still installed.

In my garage I have a 289 out of a '68 that I bought from 904Bronco here on the board. He pulled it out with what he believed to be 160,000 miles on it to install an explorer 5.0. I have long thought that removing the rod knock 302 and installing the 289 would be the cheapest and easiest way to get this '69 running even if the 289 does have 160,000 miles on it.

There is currently a complete '96 Explorer for sale locally (and listed on this board) with 250,000 miles on it. With the prevalence of the Explorer 5.0 swap with the engine itself, EFI setup, and front dress, this would be a good swap to do to get all of that stuff inexpensively.

My concerns here are I'm debating between:

A 302 that will for sure need to be taken to the machine shop to have the rod knock addressed - but is the lowest mileage of the three engines.

A decent running 289 that has 160,000 on it and could be on its last legs to begin with

An Explorer 5.0 with all the goodies but with 250,000 miles on it.

Cheap is always good, but it almost seems like I should take whatever engine I decide to use to the machine shop for some work before going to the extent of installing it.

I'm curious what everyone's opinions are who have done these swaps and have built engines in the past. I know the Explorer engine being a roller will be in better shape with higher miles, but at 250,000 it seems like that would be pushing it for just swapping it in and hoping for the best.

 

[suckerpunched]

I wouldn't run the 250k engine. I think you would be better off to buy one with less miles on it. I would probably tear down the rod knock engine and see if the rebuild on it could be salvaged. If so, I might repair it and use the explorer front dress. eh, on 2nd thought. buy a lower mileage explorer.

 

[bronconut73]

A lower mileage Explorer or pull the 302 apart.

That 302 may just have a top of engine knock like a collapsed lifter. At least tear it down to see. Maybe even if it is a rod knock perhaps it's an easier fix than we think.

 

[ransil]

I would do the 289, and get the bugs out of the rest of the bronco, as long as it runs . Then send the 302 out for rebuild and swap that in when done, sell the 289 while still installed so buyer can see it in running condition.

Sent from my SM-G920V using Tapatalk

 

[Broncobowsher]

I would take the 289 and do a quick rebuild. Heads off, check for severe cylinder wear. If only a little ridge, de-ridge it and take it apart. Dingle ball hone the walls. Inspect cam bearings, they are bad more often then not. This and heads would be the only thing I would pay someone to do. Drop the crank in with a fresh set of standard bearings. Don't even plastigauge it, you don't want to know. Even if the journals are wavy it will be fine (just not sharp ridges). Fresh timing chain and the cheap Summit house grind cam/lifter combo (204/214, .441/.472 or about so), the small one. High volume pump since the clearances will be on the wide side

So... Rings, bearings, timing, pump, cam. Dirt simple and cheap short block.

Steal the heads off the 302 or freshen up the 289, tough call. Need the casting numbers, what compression will each make up? The 302 heads will probably require a different set of pushrods (new rocker arm design has a different length). Hopefully the knock wasn't the rod bearing going so far away to be smashing the piston into the head. Or if you can find a local place that still does low cost work and just get the 289 heads cleaned up, knurled guides, quick grind, fresh seals, couple shims under the springs type of work. Really hard to tell which way to go with the heads.

I take it the 302 probably really has a bad bottom end. Wiped out bearing, that takes out the crank and that rod. Generates a lot of metal debris. But before you completely write the engine off, take the belts off the front (accessory drives can make bad noises) and take the fuel pump off. Make a quick cover plate for the fuel pump hole and try it. There is a spring inside the fuel pump that can go bad that will make the pump knock like a rod knock. You will have to rig a fuel supply (gravity feed works) to run the engine. You might fix the engine with just a fuel pump.

250K Explorers are hit and miss. If it is wrecked, it was running when it was parked. If it looks like it was just parked, nothing wrong on the outside, something is wrong on the inside. Sometimes that is still good, when the transmission or transfer case goes out it was a runner but parked for a reason. Still 250k is on the top end for one of these engines. There are the odd ones that will run 500k, but I don't expect the typical family car to be one of those.

 

[B RON CO]

Hi, I would find out what when wrong with the 302. Maybe it is the fuel pump, or a loose flywheel or?
I would put a breaker bar on the balancer bolt and see what it feels like. You may detect parts clunking.
Even if you have to pull the pan, you must be curious.
There are many engines that just got 1 rod and bearing changed.
You may pull the pan and find out all is well and the trouble is a piston pin.
In any event you have a lot of low mileage parts that probably need a good cleanup.
Good luck

 

[pcf_mark]

It is worth it to get to the bottom of the 302 knock. It could be very simple, easy and cheap. If not you only wasted a few hours doing some diagnosis.

If it was me:

1) Change the oil and cut apart the filter - lots of shiny stuff scrap it dont even try to rebuild get a 100k Explorer replacement. Clean? Proceed!
2) Isolate if the knock is "external" - is it from the bell housing or accessory drive? Take the belt off and see if it changes the sound.
3) Does the fuel pump on the engine work? I had a 302 the fuel pump eccentric came off the front of the cam it made a nice soft knocking noise for a short while I thought was a rod knock until the pump stopped working!
4) With the engine running remove one spark plug wire at a time from the coil. If your knock goes away or decreases you know the sick cylinder. It is probably a rod bearing, maybe a piston pin. Get Explorer engine. Did not stop?
5) Take the valve covers off and take a very careful look around. Check for anything loose, broken or shiny from rubbing. Any loose rocker arms? Ones not compressing a spring should have very little slop. Rotate the engine around on the starter and watch the valves. They should all move about the same amount. If not cam problem. You can replace it but I would go Explorer. If you have some loose rocker nuts (not uncommon on a new engine) and it has hydraulic lifters like it supposed to, you can just tighten the nut to 40-50 ft-lbs. I would buy new nuts if you have loose rockers they will loosen again. Easy fix! If not..
6) Still knocking you need to go deeper and it may be a main bearing

At this point you either found a minor problem and fixed it or you have written your engine off and are looking for an Explorer engine. Roller cam and EFI are the way to go before spending any $$ on a 289/302 rebuild.

 

[904Bronco]

Justin,

You just never know with an Explorer motor... I pulled one with 127K on it, thought I could run it. When I went in to change the timing gear and gaskets. I found that someone had been in it already. Further inspection revealed it needed to be gone through.
It all depends, on the maintenance when you start looking at over 100K mileage motor.

The 289 ran, the heads had been off it, and it used oil... But it ran...

 

[Broncobowsher]

Heads already done on the 289, even better. Dingle ball hone it and slap some new rings in.

 

[thegreatjustino]

Wow, a lot of good ideas here.

The guy I bought the Bronco from in Arizona was not a car guy. He bought it from the friend who had the crate 302 put it. As far as I know no diagnostic work was ever done to the rod knock 302. It could be one of those crazy stories where a $50 fix leads to a Bronco that runs for another 20 years.

Here's to positive thinking...

Anyone want to buy a 289? Doug's highest recommendation above ;D

 

[bmc69]

Were it me facing this...I would defer my final decision on the two motors in hand until I had torn them down to completely understand what I'm dealing with.

I bought an '89 Mustang 5.0 with verified 90K miles on it...ended up having to do a "minor" overhaul after I got it because it turned out to have really low compression due to annealed rings. Somebody was hard on it and didn't maintain it worth spit. On the flip side, I've gone through several 5.0 and 5.8 engines that had well over 200K miles on them and still met (barely) bore specifications....no oversize required, just a good hone.

 

[suckerpunched]

I did have a knock in a 289 once that I would have sworn was a rod, ended up being a fuel pump.

 

[blubuckaroo]

Were it me facing this...I would defer my final decision on the two motors in hand until I had torn them down to completely understand what I'm dealing with.

I bought an '89 Mustang 5.0 with verified 90K miles on it...ended up having to do a "minor" overhaul after I got it because it turned out to have really low compression due to annealed rings. Somebody was hard on it and didn't maintain it worth spit. On the flip side, I've gone through several 5.0 and 5.8 engines that had well over 200K miles on them and still met (barely) bore specifications....no oversize required, just a good hone.

X2.
Look at the bearings and journals. The crank and cam bearings on a roller cam motor wear out just as fast as in a flat tappet motor.