Today I went down to the junkyard and came home with a 4.0L V6. I plan on rebuilding it for the Explorer. Just how I'm going to build it is yet to be determined. I might just build it up with high compression and make the E85 motor that I'm always talking about.

The motor appears to have come out of an Aerostar van. The outside is very clean; no oil leaks and the paint is still on the parts. So I'm hoping that it's in good condition inside. We'll see.

Anyway, this is just the beginning. I'll let everyone know how it goes. This is the winter project, for installation next spring.

 

Cool! What year Aerostar did it come out of? Did you get to hear it run and check oil pressure, etc. before it was pulled?

 

This is a rebuild motor for sure. The junkyard owner says it came out of a 1990 Aerostar. He says it ran good, but the Aerostar was wrecked. That's the good news.

Bad news is, it was sitting outside for a year. I found it covered in weeds. It will have to be taken down and gone through for sure. But he did give me a deal on it, so that's good. Plus, he says if it's a complete wreck I can bring it back.

 

Well, that's good anyway. It might be in good shape and you could get away with just rings/bearings/gaskets.

 

Competition Cams makes a couple different profiles for 4.0's. That and a SCT chip and custom dyno tune, it could be a real torquer!

 

This I know! Nothing like the FE in my truck I'm sure, but still I'm sure it will do good.

Here's my current plan, subject to change:
Port the heads and intake (yes, I've ported heads before)
Comp cams 49-422-8 (270HR)
Slightly larger valves. It doesn't look like theres much room, but a slight improvement should be doable.
Headers (cheapie Hedman)
Silvolite 3155hc pistons. These are a flat top piston, and should significantly up the compression with my T ('90-'94) heads.
E85 (105 octane) fuel.

I have yet to determine wether I want to track down a set of U ('95-'97) heads, with the smaller combustion chamber. I need to order myself a tool so I can measure good things like combustion chamber volume, so I can calculate compression ratio. What I do know is that this motor came with a compression ratio of 9.3:1, with pistons with a good sized dish. I would think a flat top would significantly raise that.

I also think I may run into problems with piston to valve clearance, with that cam and piston selection. We'll see.

I did get the heads off today. One of the cylinders still had the cross-hatch pattern visible, while the others have no ridge that I could notice. A simple re-honing may be all it needs. The valve covers were very clean inside, and there were no oil leaks. The interesting part was that some of the fins on the fan clutch were broken off. This leads me to believe this was a low mileage motor that was involved in a crash. Bad for them, good for me.

OBTW, think it'll rev to 6000?

 

Rev depends on the cam. My stock 4.0 cam, 1993 motor, peaked HP at 4K on the dyno. It goes to 5 then rev limits but you can feel the power droppng off quickly after 4.

It does get a little tricky matching compression to cams. The longer the cam is open, the more A/F is dumped out the exhaust before compressiona ctually starts. I follow your thought on going from dish to flat to save compression. And even more so if you're going to do some porting because that helps the flow as well. But I just don't have the experience to say what a good combiunation is.

I did read somewhere too about the valve clearance to the piston....you might have some issues on the flat tops...better do some research before you invest in the pistons. But if you end up dropping a little compression, the cam will more than make up for the power and you can get by on cheaper gas without pinging.

All this work you will need a custom fully programmable chip. I tired a SCT one...the entire experience sucked becaust SCT advertised a 21 HP gain and we only ogt 4 HP out of it. That is all a completely different story. But the chip is fully programmable (if SCT enters all he tables which they didn't do for my PCM) and with this custom motor, you will need the adjustments to dial in your tune and spark curve.

I would estimate about 200 HP at the rear wheels once you're done. Mine is putting down 134 without the chip. Cold air intake, Granatelli MAF, borla headers, flowmaster cat back exhaust.

 

Well, I finally got a backdoor way to figure compression on my motor. See here:
http://webpages.charter.net/beckracing/slvpg45.htm

According to that, the stock 4.0L pistons have a 18cc dish. By that, to get the stock 9.3:1 compression, it must have 54cc combustion chambers. Now, if we install the flat top pistons, taking into account the slight difference in compression height, we get 11.25:1 static compression. I'll know for sure when I get the heads cc'd and magnafluxed.

Oh, and Mr. Ski, gasoline will not be a problem. I will be running 105 octane E85 in this thing. There's a local pump, and last I saw it was $1.819 per gallon.

I would go for more compression if I could. Unfortunately, that would mean I'd have to hunt down a set of 95TM heads, or get custom pistons (not happening).

I may even go with the smaller 410 cam for more dynamic compression for increased efficiency. Still thinking about that one.

Edit: I do like the idea of a fully programmable chip. With the number of deviations from stock this thing is going to see, I'm highly doubtful the stock program would be anywhere near adequate. Tell me more.

Re-edit: I measured the crankshaft a few days ago. It was in perfect condition. Maybe 1 ten thousandth wear in places, but no out of round, no taper, on any of the journals. The thrust surface was fine, and end play was .008". No need for regrinding here. New bearings and go. The crank has a barely noticible ridge, you can barely feel it. I need to measure it though, to see if it needs to be overbored though. I saw in the book that the spec for taper is .001", which is kind of tight IMO, but for what I'm doing, I'll follow it.

 

The crank journal spec is all about bearin longevity. If you don't care about another 300K miles, .001" out of round is nothing.


I thought you were going for an aftermarket cam. If so, you will need a programmable chip. The whole thing including the custom tune on a dybo will run you about $500. You can gove it a shot with out and limp it to the tuners (if you don't fry a piston) but when he's done, you'll realize the difference

 

I dont believe desktop dyno anymore. I modeled this thing in Desktop Dyno 2000. Here's the parameters I entered:

Bore X stroke: 3.974" X 3.32" (measured bore size, figuring block has already been bored .020" over)
Low performance heads, pocket porting, 1.75 X 1.4" valve sizes (stock)
11.49:1 compression ratio
600cfm induction flow (guess)
Tuned Port Injection intake manifold
Ethanol fuel
Large tube headers with mufflers
Comp 49-422-8 cam, using standard "hydraulic lifter" valve acceleration rates (least agressive)
IVO: 27
IVC: 63
EVO: 78
EVC: 26
Lift: .5"

The results are 269hp @ 5000rpm, 314ft-lbs @ 3500rpm. Keep in mind this is at the flywheel. I didn't think these things could make that much power?

This is where actual flow data would be real useful.

 

yeah and stock they are rated at 160 at the fly. With the mods I did I got 134 HP at the rear wheels, 16% less.

You might be a little aggressive with the CFM. That's the same sized carb I had on my 350 HP 302.

But even at 250 fly HP and 16% less, that's 210 at the rear wheels and I guesed 200 so either the computer program and I are both full of it or both just lucky. Go build it already!

 

I'm still alive!

I got the heads back from the machine shop. No cracks. Now I can do the port work, so I can take 'em back up to the machine shop to have valve seats ground.

He said it looks like most of the exhaust valve seats are pounded out, so inserts may be necessary. Anyone know how these heads handle inserts?

Bad part is I forgot to have him CC the heads.

 

You will be able to make enough power with this engine to put it in your F100! E85 in Sioux falls has been hanging at $1.62 gal.

 

Ha! A 4.0L in an F100... That would be a first! Even the way I want to build it, this thing will still be struggling to make half the HP of the 390.

Since I've been having some pinging problems with the 390, I may be trying E85 in there too. I do have that programmable fuel injection system on it, so it should be simple.

Edit: E85 around here was $1.839 a couple days ago.

 

Ford used the old 240 inline for years in the F100 making only 129 HP and 234 torque. If you get any where close to the projected "The results are 269hp @ 5000rpm, 314ft-lbs @ 3500rpm. Keep in mind this is at the flywheel. I didn't think these things could make that much power?" 5speed trans and 3.73 rear gear should be a nice combo. I don't know how heavy your F100 is but my 65 long box with the 300 6 weighs 3900#
Dan