THS_Steed06

I just picked up a used 4.0 motor with 42k on it. Car was in an accident, but motor seems fine. I have been waiting to get a hold of an engine that I can build while still driving my car each day. Now I’m starting to plan the re-build!

https://mustangforums.com/forum/moto...o-rebuild.html

So I begin this "project x" with a lot of hope and not much money. In fact opposite of some guys out there it will be my intention to spend as little money as possible and re-use as many of the stock parts as possible. The truth is from most of what I've read and researched the 4.0 SOCH is really a good durable engine. Quirky…yes. Hard to service…yes, but out of the car it’s a different story. I'll use this thread to track the progress and hope this can be a reference for others who want to buil their 4.0's too.

The Explorer, Ranger and Mustang crowds have all beat these motors pretty hard and they hold up in stock form. Many even hold up to FI and Nitrous well (when properly balanced with fuel needs). I read a number of accounts of 100k+ miles of power adder engines still running well.*That said the used motor I bought has just 42k miles on it and is in good condition. So it should not need to be bored out, though that remains a faint possibility as it would net a decent HP gain over stock but requires buying new pistons, which I’d like to avoid.*

The loose goals I have in mind are the following:*

1. Build a smooth, quick revving v6 for daily driver duty and rare track use*on street summer performance tires.**

2. Try to achieve 250 HP and*290+*ft. lbs*of torque with stock internals on motor only. Build engine with plan to*safely &*reliably use 75-100 HP nitrous kit (will require different piston rings and possibly increased bore clearances and one range colder plugs). This use of nitrous may require new injectors too but hopefully I can retain stock fuel pump (TBD). I plan to work with BAMA performance on this project and may even drive the car to PA for dyno tuning (700 miles will be a nice “break” in period for the motor too). We’re going to start though with one of their email tunes to get me close and then dyno tune it the rest of the way and for the nitrous burns.*

3. I will keep the stock cams in an effort to try to retain decent fuel economy (19/28 is stock)*and drivability. Hoping to not decline by more than 10-15% for daily driving.*I assume that some of the efficiency improvements may help offset the power increase, but of course putting my foot down will kill those numbers pretty quick.*

4. Update to a spec. stage 2 clutch and spec. light weight flywheel, add*under-drive crank pulley. Against my better judgment I’m keeping the T-5 unless I find a dirt cheap TR-3650 & 8.8 rear end. When I blow it you can all say I told myself so*J.*

5. Stretch goal here, but It would be great if all this can get me into the 13’s!*Wish me luck, I'm gonna need it!


Engine plans:
Disassemble block*

-**********Send crank, rods, pistons and Spec. lightweight flywheel to shop for full balancing of rotating assembly.*

-**********Send heads out for decking (slight compression bump), flow bench testing w/minor int/exh porting and three angle valve job. Special attention to removing material from the valve guides (thin out) and smooth out the valve seat transitions. This should have a nice effect on increasing air flow.

-**********Re-use stock valves and have the stems swirl polished. I’m only planning mild porting since I have read that heavy porting hurts the bottom end so I really want to keep a good power band between 2-5k. As a note SSM’s 4.0L stage 2 heads flow 216 CFM and they claim their Cyclone 3.7’s can flow up to 300 CFM when ported. Since the stock 4.0 motor head flow results in 210HP and the stock 3.7 heads flows less than 300 CFM and are 305 HP, I think the power level I’m seeking should be achievable.*

-**********Send engine block to machine shop for decking (slight compression bump) and have block bore ridges reamed and cylinders honed down (depends on piston clearance recommendation to run nitrous). Have it checked for main bearing alignment (just to be sure it’s good).*

-**********I'll do a home porting kit to match the*intake & exhaust*manifolds up with the ported heads. I haven't found or read about headers that don't reduce low end torque, which is something I would like to keep similar to stock or accentuate where possible. So I think retaining the manifolds will help out there. I already have Dynomax x-pipe and dual exhaust kit which flows really well and sounds amazing and I also have an Airaid CAI too. I think the plan to move air through this motor will work well. My only concern is the 65mm stock TB, it may not be ideal and going up to the BBK 70mm might help it on the top end 4k-6k range. For comparison two valve heads on ‘99-04 4.6 GT’s use 65mm TB’s to make 260HP stock so the needed flow may already be there at 65mm.**

Assumptions:

-**********This engine will produce approx. 210 HP without any internal changes.*
-**********That flow porting improvements will net approx. 75% of the gains seen on small block 350 (10-20% hp bump) = 15-23HP/20-30 TQ*
-**********That a balanced engine assembly will free up parasitic losses similar to v8 engines and the 4.0 can realize about 75% of those gains (5-10% hp bump) 10-20 HP/10-20 TQ*
-**********That a 4.0 SOCH underdrive crank pulley will net similar gains as in past dyno testing (12 hp/16 ftlb torque).*
-**********That a 93 octane race tune will net 10-15 HP/10-20 TQ*
-**********That my Dynomax exhaust nets 5-7 HP (Dynomax claims 12HP) and Air raid intake nets 3-5 HP (Air raid claims 12HP)*
-**********Total conservative HP/TQ increase could be from 45-60 HP/40-60 TQ

Also note, please be patient with me. It will take months to save up money for the machine shop work and then longer to get everything put back together and the motor swap done. I’m expecting this will take me a year or more to complete.*

One final question for you guys who have done gears:*I’m on the fence about updating the gears this summer to 3.73. The reason is I want my 0-60 time to be a one shift exercise hopefully in the 5 second range (currently around 6.4-6.5s). Slightly worried if I go to 3.73 that I need to hit 3rd*to reach 60. Either way I'm most likely going to add the LSD this summer (ran out of funds last season).

With the motor, clutch & flywheel upgrades this car should really move out in 1st*– 3rd*gears. Here’s hoping the porting keeps everything breathing well above 80 MPH. We’ll see how it goes!*

I’ll try to post updates as often as I can and I'll post some pics of the engine now that I got her home and mounted on the engine stand (once I find a good place to host them).

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Thanks,*

Tom

jimkaray

The flip side of spending a lot of money is wasting a lot of money. IMO you should reexamine your goals and your plans because as I read it you're probably doing a little of both.
Here's why: Your performance goals are easily attainable without the engine work your talking about. You already have two perfectly good motors - so if cash is an issue then why spend the time and money where it will be least effective? Serious improvements will require the changes you are ruling out - heads, cams, pistons.
Start going faster now by adding the supporting improvements you mention - custom tune, rear, clutch, exhaust, etc and then nitrous or other power adder when you have the money. As noted the engine is stout so sell the spare and upgrade the real weak links - the rear & trans.
Good Luck!

tx_zstang

STOP!!!
You're wasting time and money. Your power goals do not warrant you to do all that work!
The small nitrous shot you mention won't hurt the stock engine, as long as it is tuned properly.

There's many many many of us running 350+ hp on the stock engine internals (turbocharged or supercharged).

You won't get to your power levels with your build plans without nitrous or f/i.

Stop and do a little more research!!!

Check out mustangcollective.com; we've done it all over there, to all kinds of 4.0L builds and f/i setups.

You're wasting your time and money!

THS_Steed06

Mike,

PM sent....

Thanks!

tx_zstang

PM replied. As mentioned (now that I've re-read your list, and for others reading this), do not assume you'll realize the cumulative gains you might otherwise expect. Do it all right, and you'll have a new engine, one that'll last well over 200k miles. That's the biggest benefit of what you are doing.

Regarding your gears, 373's is a good option, especially if doing a t-loc at the same time.

(..we all know what you mean by lack of funds..but try to not skimp and save a couple of bucks here and there by taking shortcuts and buying cheap parts; it's not worth the risk..)

Anyways, keep us posted with progress and pics!!!

THS_Steed06

Hi Mike,

Thanks, your PM did not seem to come through. Can you resend?

Also, yes I didn't want to cut corners ln cheap gaskets, rings or the new timing set. I'll post a parts list and sources soon. That way I can be sure to provide the info for others and make sure the parts I'm planning to get will have a good reputation before plunking down the cash.

Specifically I have to research the piston rings carefully. I think ln Gaylons build over at the collective he reccomended total seal rings for his FI setup. I think they might fit the bill for my plans to run the nitrous. Who knows maybe I can run a 100-125HP shot with the right set up!

Tom

tx_zstang

...you can run that shot of nitrous on the stock engine!...I'll check to see if I still have the pm and if I do, will resend it...