Engine Swap Leessons Learned, Do's, Don'ts & Wished I Would Haves

[Steve Mikkelson]

Blown 5.0 EFI in F250 4x4 1986 and planning to swap in a 5.8 EFI from 1995. Before swapping them, I plan to enhance the 5.8L as it already needs a valve job before it goes in the 1986. The '86 is more of a toy that spends more time cruising than anything else, but it will see more time pulling a trailer than throwing sand up in the sand dunes. I would like to build the 5.8 engine with both thoughts of towing and throwing sand in mind.

Please share any thoughts, articles, past threads or your lessons learned. I would love to hear them even if it is, "don't swap in that 5.8!"

1. I would like the engine to rumble, sound good and impress me with its performance and durability. Durability wins moderately over performance when performance could lead to repairing the drive train.

2. I won't be machining or assembling any bit of the engine myself so please share your thoughts on upgrades from the stock engine. I will be hiring a pro so throw your crazy ideas my way.

3. Thoughts on the swap. My gut tells me the wiring & emission differences will be troubling.

4. Budget is $3,500, but I could be talked into to spending a much as $5,000 if I cut cost away for the aesthetic improvements.

 

[Rembrant]

...planning to swap in a 5.8 EFI from 1995.

Oh nice. Didn't the 351 have a roller cam in 1995 or 1996? That would be a nice engine to build up imho.

I've seen a couple 351 roller blocks pop up for sale around here and they sell so fast I barely get to read the ads before they're gone.

 

[Gary Lewis]

First, you need to figure out if the 5.8L's EFI system is EEC-IV or EEC-V. If from a truck the odds are that it will be EEC-IV.

The difference is that most EEC-IV systems are speed-density, and those systems assume that they know how much air is ingested into the engine based on throttle opening, RPM, and load/manifold vacuum. But, if you change much, like the cam, or heads, or exhaust then the computer won't know how much air is ingested and all of its calculations will be off and the engine won't run correctly.

The EEC-V systems are mass air flow systems, meaning they have a mass air flow sensor and the computer really does know how much air is ingested because it is measuring it. On these systems you can make significant mod's and the engine will still run correctly.

Something in the back of my mind tells me that some of the late EEC-IV systems might have been MAF, but I don't remember exactly. However, Bill Vose/85LebaronT2 should, so maybe he will chime in.

[Steve Mikkelson]

First, you need to figure out if the 5.8L's EFI system is EEC-IV or EEC-V. If from a truck the odds are that it will be EEC-IV.

The difference is that most EEC-IV systems are speed-density, and those systems assume that they know how much air is ingested into the engine based on throttle opening, RPM, and load/manifold vacuum. But, if you change much, like the cam, or heads, or exhaust then the computer won't know how much air is ingested and all of its calculations will be off and the engine won't run correctly.

The EEC-V systems are mass air flow systems, meaning they have a mass air flow sensor and the computer really does know how much air is ingested because it is measuring it. On these systems you can make significant mod's and the engine will still run correctly.

Something in the back of my mind tells me that some of the late EEC-IV systems might have been MAF, but I don't remember exactly. However, Bill Vose/85LebaronT2 should, so maybe he will chime in.

Thank you Gary.

Looks like a blind squirrel found a nut. Both the '86 5.0L & the '94 5.8L have 60 pin connectors, which my research tonight if it is correct showed a 60 pin connector is an easy why to determine an EEC-IV. 104 pin connector would equate to an EEC-V. Now the question to me becomes, is this now simply swap and use the existing '86 5.0L wiring harness for engine coming in from '94 5.8L.

[Steve Mikkelson]

...planning to swap in a 5.8 EFI from 1995.

Oh nice. Didn't the 351 have a roller cam in 1995 or 1996? That would be a nice engine to build up imho.

I've seen a couple 351 roller blocks pop up for sale around here and they sell so fast I barely get to read the ads before they're gone.

Rembrandt, I will need to look at the engine block number above the starter for an indentifiaction number to determine if it is a roller cam. I read that some late '93 have it but it started in '94. Being that this truck is a '94, I bet it could fall either way. I understand if the identification number starts out with "F4TE...". Here is a pic...

[Rembrant]

Rembrandt, I will need to look at the engine block number above the starter for an indentifiaction number to determine if it is a roller cam. I read that some late '93 have it but it started in '94. Being that this truck is a '94, I bet it could fall either way. I understand if the identification number starts out with "F4TE...". Here is a pic...

Well that's nice then. I believe the roller block 351 engines are fairly desirable as SBF's go.

Can't help you with the actual swap much though.

What transmission is in this truck? I don't think you can re-use the flywheel from the 302, so you'll need the one for the 351 (in case you haven't already sorted this part out).

You'll have to change the exhaust as well?

 

[Steve Mikkelson]

Well that's nice then. I believe the roller block 351 engines are fairly desirable as SBF's go.

Can't help you with the actual swap much though.

What transmission is in this truck? I don't think you can re-use the flywheel from the 302, so you'll need the one for the 351 (in case you haven't already sorted this part out).

You'll have to change the exhaust as well?

Thanks Rembrandt. I didn't know about the fly wheel or the exhaust. With the truck having lived it's life entire in California, there are quite a few catylatic converters that need to be gone so the exhaust is going to need some work.

I have the AOD tranny with no electronic shift. I thought about the C6 swap, but I have been influenced that the AOD will be appreciated with the fuel savings.

[Gary Lewis]

Thank you Gary.

Looks like a blind squirrel found a nut. Both the '86 5.0L & the '94 5.8L have 60 pin connectors, which my research tonight if it is correct showed a 60 pin connector is an easy why to determine an EEC-IV. 104 pin connector would equate to an EEC-V. Now the question to me becomes, is this now simply swap and use the existing '86 5.0L wiring harness for engine coming in from '94 5.8L.

Hopefully you have the ECU/ECM for the 5.8L as the firing order is different - I think. But other than that it should work. However, the wires to the injectors might be short as the 5.8L is wider, but using the '94 engine harness should fix that.

But you also mentioned eliminating the cats. I'm not sure you can do that and keep the computer happy. Is there an O2 sensor aft of the cats? If so, I think it is going to detect that the cats are gone and throw a code.

However, I'm not an expert on this, so will let others guide you.

[Steve83]

Hopefully you have the ECU/ECM for the 5.8L as the firing order is different - I think. But other than that it should work. However, the wires to the injectors might be short as the 5.8L is wider, but using the '94 engine harness should fix that.

But you also mentioned eliminating the cats. I'm not sure you can do that and keep the computer happy. Is there an O2 sensor aft of the cats? If so, I think it is going to detect that the cats are gone and throw a code.

However, I'm not an expert on this, so will let others guide you.

The EEC has nothing to do with firing order - it doesn't control the ignition system directly. And the injectors are bank-fired, so the firing order still doesn't matter. The difference in distance between the injector banks is smaller than the slack in the harness, so it'll fit either engine. No downstream HEGO until '96, so even though deleting the cats is a bad idea, the EEC wouldn't know about it.

[Steve Mikkelson]

The EEC has nothing to do with firing order - it doesn't control the ignition system directly. And the injectors are bank-fired, so the firing order still doesn't matter. The difference in distance between the injector banks is smaller than the slack in the harness, so it'll fit either engine. No downstream HEGO until '96, so even though deleting the cats is a bad idea, the EEC wouldn't know about it.

With this being a California truck, what are he "bad" effects if the cats were eminated?