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Discussion Starter · #1 ·
Will the 4.2L crank fit with the factory oil pan? i was courious bc their is something wrong with my engine.

the starter is barly able to crank over the engine then the starter like freewheels. and the motor will not start.

(i hope it is not the engine though)

but if the engine is toast then i am thinking about a 4.2L, p&p, cam, forged piston rebuild. does any one make a forged 4.2L crank?
 

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That's a good question, nobody knows if it will fit yet. One issue is block strength.. The 4.2L truck engine, 3.8L Split port engines (mustang and windstar) all use beefed up blocks to support the extra power and tq over the 140hp 3.8L models.. Much in the way the 89-95 Thunderbird SC block was made stronger.

Some of the pre-99 mustang guys are spinning rod bearings due to lack of block rigidity under boost, or high compression, or the extra stroke of a 4.2...

Get yourself an SPI windstar block to start with, or work with what you have.. I would suggest if you intend to keep your stock 3.8L block that you add some supercoupe main caps, and have a custom main girdle made to help anchor the mains together, then hope it all fits under the stock oil pan! The windstar pan is deeper, because it uses a windage tray in some years. It holds 5 qts of oil vs 4.5 qts like ours do. IT may or may not fit in the subframe.

You'll need much better flowing heads.. These heads are insufficient for 3.8 Litres let alone 4.2 litres... You also will need a longer duration cam, with an increased LSA to make up for the longer stroke.

Its doable for sure, but it won't be cheap, especially if you go with forged stuff.

The extra stroke won't gain you much if you can't supply it with enough air. Same goes for getting it out.. The whole taurus exhaust system was never designed for a 4.2L engine.

Fuel also, no way stock fuel pump and injectors are adequate. This requires a larger injector and a mandatory tune (chip, or EEC tuner, etc..)

So, lots of stuff to think about besides if the crank will fit.

I still want to do this myself someday, but I just dropped a ton of cash on my supercoupe (new show quality paint job, and 18" chrome wheels and tires..) So the taurus is on hold until cash flow gets in the positive again!

Jeramie
 

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also, you would not need a forged crank unless you are running high boost from a roots blower. The roots blower is hell on the crank because it creates so much low rpm torque.. Mustang guys run 15psi from a centrifugal blower on a cast 4.2 crank all day long with no problems though.

There are two 4.2L forged cranks that I know of. Christopher Wise in the Thunderbird SC world had a cut and welded crank, as well as Dr. Fred here in Denver. Fred snapped his crankshaft and went with a $4,200 custom one off billet crankshaft... Not very affordable, but necessary for making over 600 hp at the crank from 6 cylinders..
 

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Everything he just said :D

If you're going to do it you might as well get a new camshaft in there too. I'm not so sure that the mounting points on the windstar/f150/stang engine are the same, let alone the chance of it bolting up to the Taurus Tranny. If only the deepest part of the pan is different on the 4.2 you shoudlnt have any problems hitting the frame.

Its still not clear if any of the RWD engines will even bolt up, that obviously eliminates the 4.2 from the list, you might however be able to just swap crank/rods/pistons/pan and gain that extra displacment.

Its all just a matter of someone with access giving it a try.
 

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The bolt patters are definitly different. The SPI windstar block is the same as our early taurus blocks as far as bolt pattern goes.

X, did you also use the SC main caps when you put your SC crank in?
 

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Naa, I didnt think to try and find a set of those. Could they be that much better than the n/a caps though? What I'd REALLY like to get my hands on is one of those main stud girdles to tie the bottom end together. While i havent had any problems down there (yet), when I get around to upgrading to one of the better m90s it may cause some trouble.
 

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The tall main caps are believed to add nearly 40% structural rigidity to the bottom end.

Hmmm, maybe these blocks aren't as weak as we think, I KNOW your engine has seen more tq than a 4.2 will
 

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How much torque do those 4.2s make? I still havent gotten around to dynoing mine so my 315lb/ft is nothing more than an estimate (thats theoretically what I should be getting at about 7psi, and I'm running at 11)

Remember I had that craptacular transmission though so God knows how much power was wasted on slippage, AND the tires would always burn furiously on a hard launch attempt, perhaps these conditions helped relieve the stresses on the block itself?




What is it about those sc main caps that makes them so much stronger? I dont remember seeing any extra holes for 4 bolt caps (if thats the case).



Also... a thought that just occured, the windstar is FWD, I wonder about the possibilities of using a complete windstar engine/pcm/tranny. If the mount points on the block line up then 90% of the hardwork is done, making a tranny mount cant be all that difficult when all you need is just a spot to attach it (no holes to worry about lining up )
 

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Discussion Starter · #9 ·
the windstar upper wil not fit bc it is way to tall. the mustang upper might fight. i don't think anyone has messured yet.

if the 4.2 crank can't hold up to the mp90 i might have to just find a sc 3.8 crank.

if i have to tear apart the engine then i was thinking about atleast cam, and heads for the mp90. the shop cam and towed the car today to see what is wrong with it. i am thinking the starter slionid is bad ( hopefully). so i willn't need the rebuild. Yet. eather way i am probly going to start assembling for the rebuild.

i heard about the post 99 windstar blockings being stronger and with the girtel. humm if i get the block i could measure the distance from the center of the crank to see if the 4.2 crank will fit.

oh dmx what pullies are you using for the 8 rib belt setup?
 

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The SC caps are taller, so there is more clamping force on the main journals.
 

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Taller huh, just learned something :)

Its always said that the supercoupe guys have to machine down thier main caps a good amount to get the girdle to fit. If they are so much taller than ours we may need only some longer bolts, and it'll clear the pan.


For the eight ribs:
I just used an sc alternator (110Amps), although just swapping one of thier alt pullies onto our stock would work just the same.
Same goes for the ps pumpm stocker would work with the supercoupe ps pulley, i swapped the whole unit in to replace my worn out one.
Stock Waterpump pulley works fine, its plenty wide for 8 ribs (maybe even 10), all I did was weld on 2 thin washers behind the 4 mounting holes for a <1/4" offset and all was well.
For the Crank pulley, I cut into that huge boat anchor supercoupe crank pulley. Its has the 8 rib front section and 7 rib back section (jackshaft side), I just cut off the front piece, cut my stock crank pulley down to the hub, ground down the excess so the offset would be the same, carefull welded them together and all was well.
The 8rib ribbed tensioner pulley I got from BTM (supercoupe parts store), I bet you can you can find one in the local parts store catalogs (avoid napa though thier selection sucks). The smooth idlers I found in the Dayco catalog at Advance auto parts, i'll have to look around to find the part number again, but they are just 3inch (76mm) 8 rib pulleys.

Other than that its just trial and error. I'll try to remember to get closeup pics of the crank pulley and metal bracket thing I welded up to hold the idler pulleys.
 

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What you need to do is, if it will fit, drop in an F-150 4.2 and use an 01 V6 Mustang oil pan and it will bolt right up. The main caos are different on the 97 4.2 thanthey are on the newver ones, but the 01 V6 Mustang pan wil always clear.

Also, as far as I know, there are no TRUE forged 4.2 cranks readily available and readily affordable...but this is not the weak-point if pallning to run the Eaton. The cast crank will withstand a lot, and, at the 500rwhp mark, the block becomes an issue anyway.

The 3.8 Mustang and Windstar engine are the exact same...and the truck 4.2 is the same exact block as the 01 V6 Mustang, so where one fits and botls up, so does the other, and the bolt patterns are the same, since they are the same block. The MUstang block was made stronger just in 01, while the 4.2 block has been this way since 1997, with some revisions in 1998. They all have the same heads and by the way.

If you can re-use all of your wiring and ignition system, I would use the stock PCM and hacve us flash it or make a chip for it.


I am actually running a Supercharged 4.2 F-150 engine in my Mustang. I've got some dynosheets on our site about what those things put out in a Vortech at 10-12psi with our tune, so you can get an idea. This car is getting a built 4.2, heads and a cam andmore boost within the next 2 months. Should make a lot more power. The heads and cam are really the restriction, and although as you can see, I agree with getting heads and a cam, it has nothing to do with a need just because of the longer stroke. As noted prviously, the 3.8 Mustang and 4.2 F-150 have the same heads. Now this isnot teh same as oging from3.0L to 4.2L, but what you reallyneed to see if what your heads flow...heads are not necessarily matched to displacement in that way.

If you are going to run the Eaton, you need to convert to single-port heads, obviously. What will you do for fuel?

If you are interested in torque, the 4,2 is what you want, but if you only want high-end, then youwant the3.8L, whcih will always make more high end power.

Anotehr thing to note, when looking at the dyno sheet on our site for that car, is that this particular Mustang was converted to IMRC (this was only standard in 01+) and this gave it an additional 30 ft/lbs under 3k RPM (where Ihave them open). that is, an additional 30 over the 20-25 ft/lbs it picked up with the 4.2 over the 3.8L...low end is the main difference with the 4.2.
 

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Discussion Starter · #15 ·
actualy thier is a difference between the fwd motors and the rwd motors. the bellhousings patteren is different. fyi the fwd motors are stamped FWD and the sc motors are stamped SC (the heads too for the sc)

i would probly upgrade to the new windstar block and the 3.8 in the taurus was never offered in the split port or the returnless fuel lines. so that part is not an issue.

i am interested in power from about 2k - 5k or 6k
 

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Of course the bellhousing is different! That is not part of the engine really.

But the actual blocks of the ones I mentioned are the exact same, i,.e Windstar, 4.2 F-150 and V6 Mustang. The supercouple block is different, but the same size. It is stronger.

What makes it split port is not the block itself, it is the heads and intakes. You can run either setup you want, if you can make it fit. The rest is all in the tuning.
 

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But the bellhousing bolt pattern is different. You cannot bolt up an AX4S transaxle to a RWD block. And you cannot bolt up an AOD/4R70W to a FWD block.

The engine mounting points are different also.
 

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I was told they are different, but if you can prove me wrong I would like that very much!!!

That would simplify the project greatly!

Jeramie
 
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