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Discussion Starter · #1 · (Edited)
Does anyone know anything about this 4.2 liter in the f-150 trucks? To me it looks just like a 3.8 with a goofy intake. What if I wanted to swap this in my 95 sc and put the supercharger and my heads on it. Would it work? If not, why?

I also have a question: what size mafs ans throttle body do the 95sc's have?
 

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I don't know what all is different but the 4.2 liter crank is probably not forged steel like the SC crank and wouldn't take boost very well. Also I believe the SC block is much beefier for the same reason...much boost.
 

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Interesting question.
Several guys on the V6 Mustang message boards
have swapped to a 4.2 short block,
some with Vortech blowers,
and they're surviving, so far;

but DrFred4.3 opinions that the cast 4.2 crank
with the eaton SC blower is a formula for a hand grenade.
I'm not sure why, if it works for the Stangs,
but I'd think DrFred should know.

One problem is, seems the SC knock sensor can't "hear" the 4.2 knock [different frequency] and adjust the timing accordingly.
Therefore, plan on lots of EEC tuning time.

I've heard Morana has put together some 4.2 SC engines,
but never heard any correspondence or details from any such owners.

So, if there's any more stroker SCs out there, let's hear it!
 

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the MAF is a 70mm and TB is a 66mm if I remember correctly.
-Jeff

PS - I also know that the 3.8 SC block is different from the NA 3.8 block. It was beefed up to handle the stress, and torque that a super charged motor puts out. For this reason, I don't think it would be a great idea to do it. However..I do NOT claim to know exactly, I'm sure there are many other people who could answer the question more knowledgebly than I.
-Jeff
 

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Go For It!

Has anybody PROVEN that the 4.2 CAN'T accept Supercharging? No Yet!

As I see it, the only thing that might stop 4.2 experimentation, is that we don't know if the SC top end will bolt on to the 4.2 bottom end!

Curious 68COUGAR
 

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96-98 4.2 heads are exactly the same as 3.8,
SC top end is a bolt on.
Later 4.2s are split port,
like the 3.8 Mustangs & minivans,
but the single port heads still bolt on;
the block is unchanged.

4.2 rods are longer, piston height shorter,
but i don't have the #s handy right now.
Rods are powder metal,
so that might be a real weakness for SC duty.

This all according to posts i've read on
http://www.v6power.net/cgi-bin/ultimatebb.cgi
http://www.3.8mustang.com/forum/
and corral.net forums/sixshooter
 

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The 4.2L looks similar because Ford built it by boring out a 3.8L. The motor sucks as a whole. I seen guys swapping them, however I give them 30K miles until it says "good by". The 4.2L is such a problem motor ford has dicontinued it on the new
F-150. At our shop alone we've replaced 4......yes 4, 4.2L motors in F-150, due to bent rods, broken cranks, and two other internal probems over the past two years. If you get one I think your dumb, but do what you wish. I don't think you want to proove the supercharging seeing that it can't hold itself together N/A.
 

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I just gotta say

OMG THAT IS A HUGE SIGNATURE
 

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BlownMerc said:
The 4.2L looks similar because Ford built it by boring out a 3.8L. The motor sucks as a whole. I seen guys swapping them, however I give them 30K miles until it says "good by". The 4.2L is such a problem motor ford has dicontinued it on the new
F-150. At our shop alone we've replaced 4......yes 4, 4.2L motors in F-150, due to bent rods, broken cranks, and two other internal probems over the past two years. If you get on I think your dumb, but do what you wish. I don't think ytou want to proove the supercharging seeing that it can't hold itself together N/A.
Seems at least one of the guys on this Mustang board believe the 4.2s are only bad because of a production error - (http://www.v6power.net/ubb/ultimatebb.php?ubb=get_topic&f=1&t=003241) Apparently on the '97 and early '98 models the timimg cover bolts weren't torqued correctly and eventually let coolant into the crackcase leading to bearing failure. Those of us that have head gaskets go know about coolant in the lower end....

Maybe some of you mechanics can confirm (or deny) this?
 

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doodaa said:


Seems at least one of the guys on this Mustang board believe the 4.2s are only bad because of a production error - (http://www.v6power.net/ubb/ultimatebb.php?ubb=get_topic&f=1&t=003241) Apparently on the '97 and early '98 models the timimg cover bolts weren't torqued correctly and eventually let coolant into the crackcase leading to bearing failure. Those of us that have head gaskets go know about coolant in the lower end....

Maybe some of you mechanics can confirm (or deny) this?
I can confirm this, even though im not a mechanic. I have a 98 f150 that had the coolant leak. She was a strong engine up until she let loose at 84,xxx miles. I also had this question for an SC 4.2. Instead ill just buy the sc bird.
 

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First of all the pistions will fail being very weak compaird to sc pistons. I have both pistions sitting in front of me one with a broken skirt due to berring failure. not pretty
Also the compression is a little higher and could not handle 15 lbs. boost. Ever wonder why ford droped the compression to 8.2? under boost you get higher compression so your cranking comp. needs to be lower. Next the cast crank will go south very quickly. It can be done but you will need some extensive machineing and a ton of money. Nows the time to buy a engine out of a lighting. Much cheaper and more bang for the buck.
 

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1# reason the 4.2L LASTS with a vortech, NO boost under 2500rpm where as the supercoupe is making [email protected] 2000rpm.

the 4.2L is a 3.8L STROKED to 3.75" throw, ALL 4.2L's have SPLIT PORT HEADS, and the 97-early 98's had the front cover leak problem. Also the 97 will not work becuase it has a FULL length main bearing girdle, then 98+ only has the gridle on the 4,3, and 2 main bearing caps so It will fit a car oilpan.
 

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Stroked

I have searched for something on the stroking of the 3.8.
Can anyone point me to something on the web?

Rodney
 

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Ok a bit more information

I know the SC 3.8's had forged cranked and forged pistons. Are the connecting rods forged as well (unlikely but tell me I am guessing).

Once I pull this dude apart I will have a better idea of what all the dimensions are but until then.

Rodney
 

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Not that I want to do a swap of a 4.2

I don't really want that. I am in the process of rebuilding and since I am in there I might as well do what I can to improve.

Looks like a good quality rebuild and a head job might be the ticket.

R
 

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Re: Stroked

rbrown said:
I have searched for something on the stroking of the 3.8.
Can anyone point me to something on the web?

Rodney
If you're talking about stroking a 3.8 you're talking about a 4.2, that's what a 4.2 is, a 3.8 with a longer stroke crank (cast). Unless you're just going for a minimal thing like offset grinding or a full custom, the threads about the 4.2 swap contain the info you asked for, that's all I was sayin'
 

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Thanks

Any and all information is appreciated. I am in the gathering stage. I don't think I really need to stroke this thing just improve on what is there.
Got to get it on the road right now.
 
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