Alright, long time no post here, but I need to ask you fine people for a little help and advice before the truck goes to the scrap yard.

To summarize:

• 1987 F-150 5.0 was burning and leaking so much oil that I would have to put in 2-3 quarts every 50 miles or so. Power steering pump was leaking bad, and exhaust manifold gaskets were full of holes.
• Bought a 1993 F-250 parts truck with a good running 5.8 but a bad frame and bad body
• Made a deal with a family member (red flag, bad idea, yeah I know) that if he did the engine swap he could scrap or sell all the leftover parts and keep the money
• 5.0 was removed, 5.8 was bolted up to mounts and transmission. But that was it. Nothing was labeled, no accessories changed over, no wiring reconnected. He gave up, because there were too many differences in the sensors and wiring. Then to add the icing on the cake, the parts truck got scrapped before I could tell him not to. So there went all of the extra bits and pieces we probably needed.

I don't have any time or space to do the heavy work, which is why I gave it to someone else in the first place. So, I searched around for a mechanic crazy enough to take on a project in this state. I found one who accepted the challenge, and things seemed promising. He said he'd work on it in his spare time to keep costs down, and that sounded great to me.

First problem found was, the distributor on the '93 5.8 wouldn't connect to the 5.0 harness. Called around and found a 5.8 distributor at a salvage yard for a 89-91, and it fit just fine. Brand new plugs and wires too. Got a call today that he buttoned up a bunch of the other work, and got the engine to the point where it would turn over and try to start. But all it will do is backfire (shoot flames) through the exhaust. The mechanic did some research and came to the conclusion that there is NO WAY to use a 1993 5.0 in a 1987 truck because the firing order is different and the 5.0's computer can't compensate or be changed. He's reached the end of the road, understandably so, and I thanked him for his time and efforts.



Fast forward MORE THAN ONE YEAR after my [barely] running truck left my driveway, and this is where I'm at.


Is it true, that when it comes down to it, it was never going to work in the first place because the 1993 5.8 is just plain incompatible with the 1987 truck? Or is there a special way to connect the spark plug wires to compensate for the different firing order?

Or ?????


I have already prepared to cut my losses and either take the truck to the scrap yard or sell it to someone for parts. If we can get it going again, that would be super awesome. I miss the truck. But I have little to no expectations and any progress would be a bonus at this point. Thank you!

 

Oh wow. Just wow. They say say too many cooks & all that but sounds like "they" can't boil water.

Let me guess. family member is a chevy guy.

Firing order does not matter with speed density fuel injection. This should have been accomplished in a weekend.

You do need a roller cam steel gear on the salvage yard distributor. Depending on how much time is on it there, could be cam damage if not changed. (I'd bet not, changed that is)

First question, how much of the original wiring 87 exist?

People here will talk you through it if you got the patience & stick-to-it-ness required.

Somebody might take it off your hands if they'er close & price is right.

Sorry & good luck.

 

Yes, they did change the firing order, but all you need to do is move the plug wires around on the cap.

The 302 firing order is 1-5-4-2-6-3-7-8 and the 351 order is 1-3-7-2-6-5-4-8

The computer doesn't care beyond that.

 

Bummer- if you still had the '93, it's 'not too hard' to
swap the entire harness, distribution box and ecu, and splice in the dozen or
so wires to the 87. But if all the ancillaries are gone,
that's a bit of a project. Lots of people convert early
trucks to later distributors, so THAT is not the end of the road.

The 5.8 has a different firing order than a 5.0, so it
sounds as if that's part of the problem.
The internet will sift that out for you pretty easily,
and THAT might just be the worst of it.

hth

t

 

Yep, Chevy (diesel) guy currently, but has had Fords just like this in the past and was confident in his abilities at first.

I will have to look into the differences between the cam gears. I never actually laid eyes on the new or old distributors - had it shipped right to the mechanic and he told me it was the "right one" and I believed him. Is that just a difference between the year the distributor came from (88-91 or whatever) and the 1993?

100% of the original '87 wiring exists. I guess I forgot to mention that. I was able to pull the original '87 5.0 harness off the junk engine before it was scrapped. That included all the injector wiring and various other things. Mechanic removed the '93 harness from the 5.8 and installed the '87 harness onto it. As far as I can tell at this point, there is no '93 wiring at all, except the new harness that had to be made for the alternator and battery connections.




Good to know. I will give him a call and see if he tried that. I'm not actually sure which firing order he attempted to use. I guess I should ask you, which one SHOULD I use? 5.0 or 5.8 firing order?





Yeah, too bad, it's all gone. I even tried to buy the truck back from the scrap yard, or at least some of the parts, but they had already shredded it.

 

You need to use the 351W firing order on the 351W.

The flat tappet cam cam is made different than the roller cam. The gear on the distributor and / or camshaft will be damaged if they are not compatible materials.

 

Yup I think you need to use the updated 1993 firing order. In that case, you need a 93 or later ECU and plug wires!

just like cast gears and roller cams, Diesel guys and ignition systems don't mesh! So, verify if you have a roller cam or not. 1993 cam be either. If you have a roller, I belive you need to get that dizzy out or at least swap with a steel gear. Somebody please correct me if I'm wrong.

Also, verify your timing and marks are correct, you may be very close to having a running truck. Pull plug 1, verify TDC and all that jazz, harmonic balancers slip. Make SURE to remove SPOUT when timing!

To recap:

1. Get proper 1993+ 351w ECU computer if you have a stick shift, get one from a stick and vice-versa
2. Change distributor gear to steel if necessary
3. Change plug wires to 1993+ 351w firing order
4. Verify timing markers are correct by finding TDC, and then remove SPOUT and set base timing to 10 degrees BTC
5. Unplug battery for an hour to clear whatever codes you've racked up

 

I dont think he needs to swap distributor gears. He says it's a 351 pre95 and a 89-91 351 distributor. So they both should be set up for flat tappet cams.

Swap plug wires for a 351w order and try to start see where you are at.

What trans do you have? Flexplate offset may be different and you can smoke a transmission with the wrong flexplate.

I have done this swap 95 351 into an 88 150 when I was a stupid teenager and it took 3 days. These guys are giving you the runaround man.

 

Some say 1993 was the first year of roller, either way it pays to check. Still needs proper firing order and ECU--especially if the transmissions are different.

 

Roller lifters start in 1994 in stock 351 Windsor engines excluding Lightning engines.

Considering you are talking about junkyard engines and swaps the best way to know what you have is to get in there and find out.

 

The 302 changed to the 351W firing order but hasn’t the 351W always been the same?

 

Yes, correct. During development Ford found that the longer stroke engine had a harmonic they didn't like, so went from their first choice firing order, to what became known as the "351" firing order instead. Which many of the other engine families use as well.
Once some of the 302/5.0 engines started using that same order (because it was felt they were spending more time at the track and at higher rpms where it was more important) it became known as the "351/HO" firing order. For the 5.0 HO that started using it first.
All they did was change the camshaft and the wiring order back before computers. If you look at the two strings of numbers, they simply swapped the 2,3 and 6,7 positions in the order and voila! If I remember correctly, it was largely to keep cylinders 7 and 8 from firing next to each other.

This is a good reason to always verify if an engine is unknown. Because the camshafts are literally the same dimensions, and some companies still stick with the old 302 firing order on their cams (or vice versa) a previous cam swap can mess with you while you're tuning if you think it should have the other firing order.
Regarding compatibility, an engine will run passably well if the computer thinks it's got one firing order and shoots the injectors at the wrong time, and if you're lucky it just runs a little rough at idle and misses out on some efficiency. And weren't the 5.8 systems batch-fir for the Speed Density setups anyway? I'm not sure about that, but the others will know.
By the same token though, it'll run like absolute crap if you get the spark plug firing order wrong. If it runs at all!
So injectors and fuel delivery? Not as big a deal as ignition spark, when it comes to matching components. But it really is best to make sure they all match.
Important to remember if you end up using the ECU from another engine. Which also is a tuning thing because it's expecting a smaller engine and perhaps smaller injectors and a different throttle body and all that stuff. Would definitely be nice to have a proper 5.8 computer I would think.

 

All of the motors involved here would have had flat tappet cams so there should be no compatibility problem with the drive gears. The electrical connections at the distributor changed around '92 when Ford moved the TFI module off the dizzy to the fender, but by using a distributor for an older 5.8 you solved that problem. You don't absolutely need a 5.8 PCM, the motor will run on the 5.0 PCM. This is possible because '87 predates all the electronically controlled transmissions, the only options were C6, AOD, or a manual and the PCM has nothing to do with any of those.

That is the best news in this thread so far and it means this motor should run fine when the plug wiring is sorted out. The spark plugs must be routed for the 351w firing order but the distributor has to be stabbed with cyl #1 at TDC on the compressio stroke, and the person doing all this must know that Ford cylinder numbers are nothing like Chevy or Dodge otherwise it'll be all wrong.

The other outstanding issue I see is what flexplate is between the engine and trans? If the truck has C6 then the flexplate that was on the 5.8 will be fine, but if the truck has an AOD you need to stop all work RIGHT NOW and change that flexplate. The AOD requires a unique flexplate with a different offset than the C6 and E4OD versions, those will push the TC back too far into the trans oilpump causing grinding and metal fragments to be sent throughout the trans, it will be fatally damaged before the engine warms up enough to take it's first drive... it happens that quick.
Also note that the 5.0 and 5.8 have different counterbalance weights so the 5.0 flexplate or flywheel cannot be used either.

 

So help me I saw 95 up there where it clearly says 93.

Jeeze, can't do anything right these days. Sorry for the un-needed confusion.

Don't know if the 93 distributor has remote ICM vs 87?

 

Alright guys, I got a little behind on my replies, but here's what I understand so far.

1. The cam gear on the distributor is PROBABLY ok, but it will probably be worth checking anyway. I bought the '93 parts truck from the second owner, who bought it from the first owner with only 15k miles back in 1995, and he did tell me that no major engine work was ever done on it. But I have no idea about any of the history or specifics on the junkyard distributor.

2. The '87 5.0 electronics should run the 5.8 just fine, as long as the firing order gets sorted out. I suppose it could be a timing issue too, though I don't see how the timing would have changed. Also worth ruling out. Since it is backfiring, that tells me that fuel and spark are both present, resulting in some sort of ignition. That's all a good sign.


I definitely need to weigh in on the transmission concern here. The transmission in my truck is the NP-405 (4 speed manual and 4 wheel drive) and the '93 parts truck had a 5 speed manual and 2 wheel drive. No automatic transmissions whatsoever in this project.

I did buy all new clutch components and new flywheel, which my relative installed during his part of the work. The parts I ordered were all for the 1993 5.8.

I also bought a new 130A alternator for the 5.8. The mechanic had to build a new wiring harness for it because all of the plugs were different on the '87 truck.