V6 Dead, Replace with 3.8, 4.2, Cologne...?

Doc Hawk · 11-03-2009, 08:14 PM

New Mustang owner here. I had a chance to buy a '99 V6 convertible (auto) in good shape with a grenaded motor on the cheap, so I couldn't resist owning my first pony. I am looking for my options for replacing this V6. I am a race driver, but this is a DD for my wife so it needs to be smooth and reliable. I will not be adding boost or power adders.

I am going to pull the dead motor and replace it. I would like to know what my best option is for dropping in another motor with a minimum of fuss, while still taking advantage of the fact that I've got to pull/replace the motor, anyway.

Should I look for an 01-04 (internally balanced), or do I need to stick with a 99-early 00?
Could I use an 05+ 4.0 Cologne V6?
Should I be looking for a 4.2 swap instead?
Is there another option that I am not thinking of?

I have done a day of searching on several forums but haven't found what I'm looking for. I see lots of V8 swaps, and people upgrading from a 94-98 V6 to a split port from a 99-04. I don't see many people messing with a New Edge split port V6. While I do appreciate that I could now move forward with a V8 swap, that will force me to do a speedo replacement and the entire drivetrain to the rear end, plus exhaust. Unless someone tells me differently, that doesn't seem particularly cost effective.

I am tending towards the 4.2 swap. Get a running JY motor, drop the entire long block in, pop my Mustang upper intake on there, and ride off into the sunset, right? Will the truck flex plate match right up to my Mustang stock auto tranny?

Thanks for any help,
David in San Diego

This ad is not displayed to registered or logged-in members.
Register your free account today and become a member on Mustang Forums!

robinson209 · 11-03-2009, 08:28 PM

There is a thread all about the 4.2 swap. It has almost everything you need to know. I thought it was a sticky but I can't seem to find it. Maybe someone here knows where it is.

crysalis_01 · 11-03-2009, 08:40 PM

You'll also want to skip the 'stang upper and throw on a Windstar GL upper while you're at it.

Shaunmac9128 · 11-03-2009, 08:45 PM

I don't think hes too worried about power. Just a reliable dd. The 4.2 will offer you a more torquey engine and I believe around 20hpish over a 3.8. So if you can find one for around the same price as a 3.8 I would say go for it. The 3.8's are very reliable motors though, just an fyi.

LilRoush · 11-03-2009, 09:30 PM

Either the 99-00 or the 01-04 will drop right in for ya. Personally, I prefer the 99-00 do to the lack of runner controls built into the lower intakes on the 01-04 cars.
The 4.2L is a nice upgrade, but if you don't need the extra power, don't waste the time/money to do it.
Short and dirty of the 4.2L is you'll need the Mustang upper intake and the 01-04 3.8L oil pan to clear the larger crank.

Doc Hawk · 11-03-2009, 10:13 PM

Thanks for the replies, everyone. I value and respect your opinions; nothing replaces the knowledge of guys who have been wrenching/researching a platform for a long time.

I am not too worried about power, agreed. However, I do have a baseline expectation of what a sporty car should be, and (no offense - I bought one!) the stock V6 does not meet that expectation. Before buying this fixer, I did shop some GT's and V6's, and I got to know the car a little bit. Especially under the power curve, the V6 was very disappointing to me.

All opinions about what "adequate" power is are purely relative to individual experience, so what is adequate to one person is MAD TITE SPEEDZ to another, yet underpowered and gutless to a third. For me personally, with a stable that currently hosts an 11.8 CR full race Datsun 240Z, another Z with a 550 RWHP 350 Vortec Small Block Chevy driving all 2300 lbs, and a little built Miata, the stock V6 Mustang didn't quite do the freeway merge test the way I would like. My wife is certainly less of an adrenaline junkie than I, but she does know how to get on it and likes to be able to drive as fast as her car looks.

If I was buying a running car, honestly I'd just leave well enough alone and let her drive it. It's still a fun car. But since I have to swap a motor anyway, I don't want to miss an opportunity to bump the power a little bit. The labor is 90% the same.

LilRousch, you said don't waste the time or money, but really, can you tell me what time and money I would be wasting? I have to buy an engine, anyway. The difference in price between a used 3.8 (~$300) and 4.2 (~$500) just doesn't seem like it has any significance. The time for this project is like 10 hours of engine swapping, and add 1 extra hour of intake and oil pan swapping if I do the 4.2.

What am I missing? Will the ECU adjust? Do I need a new flexplate or will a 4.2off an automatic mate up to the Mustang's auto tranny?

BTW many posts I have read say the stock 4.2 clears the '99 Mustang cross member. Anyone know for sure that it does not?

LilRoush · 11-03-2009, 10:22 PM

I was just thinking that if it's not needed, the extra tq isn't worth the time/money of the larger motor and swapping parts. If you're ok with spending a bit more, the 4.2L is a great way to go. Look into the Windstar upper intake as well, much better flowing, and worth it if you're going to swap an intake on anyway.

Everything on the 4.2L should line up, if I remember right. You should double check abouut the flex plate, I've only done the swap on 5 speed cars.

Doc Hawk · 11-03-2009, 10:32 PM

Quote:

Originally Posted by LilRoush

I was just thinking that if it's not needed, the extra tq isn't worth the time/money of the larger motor and swapping parts. If you're ok with spending a bit more, the 4.2L is a great way to go. Look into the Windstar upper intake as well, much better flowing, and worth it if you're going to swap an intake on anyway.

If we were talking about a crank swap or heads, I would agree with you. But dropping in one block vs. another externally identical block just doesn't seem like any extra work to me. Is there something about the Ford V6 intake that makes swapping it a pain? I do full motor builds on everything from Japanese straight 6's to American V8's, and intakes and so forth are pretty much a 10 minute job. That's why I keep asking the question - not to prove you wrong, but to ask "What am I missing? It seems like a no-brainer."

A couple hundred dollars extra on a different used motor for ~15 HP/ ~30 TQ is some of the cheapest power you could ever buy for a car. That's what I'm trying to take advantage of in this motor replacement.

Quote:

Originally Posted by LilRoush

Everything on the 4.2L should line up, if I remember right. You should double check abouut the flex plate, I've only done the swap on 5 speed cars.

So were you good using the (internally balanced) F150 flywheel on the MT cars? And by everything do you mean the 4.2 oil pan will clear the '99 crossmember?

Thank you both for the recommendation on the Windstar upper intake. I had not heard that before. I'll skip it for now since I have the Mustang intake in hand, but I will keep my eye out to junkyard one in the future and bolt it on.

Doc Hawk · 11-03-2009, 11:21 PM

Quote:

Originally Posted by l_shizzle_l

You will need the 4.2L shortblock(you could even leave the heads on because the F150 heads and 3.8 heads are the exact same, at the same time saving yourself $100 or so for new head gaskets), don't even open the timing cover cause the F150 cam is a little better than the 3.8, so just leave that in there. The main caps on the F150 block are taller in the rear, so you will need a 01+ oil pan(the 4.2 oil pan will not work with the mustang k-member). Everything else will be reused from your 3.8.
Here is the balance issue. The 4.2 is a internally balanced motor(the balance weight is on the crank) and your 99 3.8 is an externally balanced motor(balance weight is on the harmonic balancer and flywheel) so you will need the trucks(or 01+3.8(they switched the balance to internal then)) harmonic balancer and then you will need to buy a netural balance flexplate for your auto. If you had a manual then you could use the netural balance flywheel from the truck but you don't. Got it?

Pretty good info.

LilRoush · 11-03-2009, 11:22 PM

Haha, sorry, I'm not used to V6 owners spending extra money when asking about mods I guess. It is more or less a drop in and go situation for you.

You'll need the 01-04 3.8L oil pan. The 99-00 pan won't clear the 4.2L crank, and the 4.2L pan won't clear the Mustang K member. The F150's 4.2L upper intake won't fit under a stock hood. Most use the Mustang upper, but since you'll swap it anyway, the Windstar is one of the best flowing out there (equal or better than a cut/ported aluminum upper). Swapping the upper is a 10 -15 job.

I used the F150 flywheel on my car.