4.0 SOHC Performance Motor Build

I've been helping the mustang crowd come up with a decent set of rods to use in place of the stock forged I-beam rods and I've found a couple different options out there. I want to use this thread for documentation purposes for all the options found and eventually, there will be info about all things needed to build this motor along with the estimated cost. Finally, after the research is done I'm going to put a motor together.


The Objective

A 4.0 SOHC that will consistently hold 500HP and 600HP at the drag strip. (for a decent cost) - in other words, if this can't be done for a certain price, then a different motor is a better option.


Stock 4.0 SOHC INFO

Deck Height 8.858
Bore 3.953
Stroke 3.31
Rod Length 5.748
Piston Pin Height 1.44


Cylinder Bore
Diameter 3.9530
Out-of-round limit 0.0010
Taper 0.0010


Piston / Rings
Standard DIA 3.9520 3.9528
.5 MM OS 3.9716 3.9724
1 MM OS 3.9900 3.9910
Piston to bore limit 0.0012 0.0020
Compression Ring end gap (top) 0.0080 0.0180
Compression Ring end gap (Bottom) 0.0180 0.0280
Oil Ring Snug Fit


Crankshaft and connecting rods
Crankshaft endplay 0.0020 0.0126
Connection rod journal DIA 2.1250 2.1260
Out-of-round and Taper limit 0.0003
Bearing oil clearance (desired) 0.0003 0.0024
Bearing oil clearance (allowable) 0.0005 0.0020
Connection rod endplay 0.0036 0.0106
Main bearing journal DIA 2.2430 2.2440
Out-of-round and Taper limit 0.0003
Main bearing oil clearance (desired) 0.0008 0.0015
Main bearing oil clearance (allowable) 0.0005 0.0020


Valves and related
Intake
valve seat angle 45 Degrees
valve seat width 0.0600 0.0940
valve seat runout limit 0.0020
Stem diameter standard 0.2740 0.2750
stem to guide clearance 0.0010 0.0020
valve face angle 45 Degrees
valve face runout limit 0.0010

Heads
68CC cambered

Camshafts
lobe lift (intake and exhaust) 0.2590
Allowable Lobe lift loss 0.0050
endplay 0.0003 0.0070
Journal DIA (ALL) 1.1000 1.1040
Bearing Inside DIA (ALL) 1.1020 1.1040
Journal-to-bearing (oil) clearance Standard 0.0020 0.0040
Journal-to-bearing (oil) clearance Service Limit 0.0060

Rods

Rod Option 1

The first rod option is a Forged H-beam Manley rod that states it holds 700-800HP on a 4.6 V8. We v6 dudes have to overkill here because 500 HP on a v8 is different for 500HP on a v6.

4.6 L Stroker w/ 22 mm pin and a 2.000" crank journal
Part No. 14044-8
Center-to Center 5.850"
Big End Bore 2.125"
Big End Width .940"
Pin End Width .940"
Pin Bore .8671"
Gram Weight 612


Here is the rod.



With this rod option, the rod journal (big end with the lip) will have to be narrowed by .064" per side. It should only be the little lip you see sticking out. The chamfer will then have to be re-cut and this should be it.

This rod is longer than the stock 4.0 SOHC (Stock is 5.748" and this one is 5.840") this means the custom piston being made needs to have a shorter pin height.

Custom pistons with floating pins will then need to be made to whatever compression you want. These rods go for around $579.50 for a set of 8. This means if you buy 3 set's for a v6, the fourth set is free. Furthermore this means the rod cost per rod will be $72.44 (Not counting the machining cost) If we estimate the machining cost, say 150.00 per set of 8, we come up with $91.19 / rod.

The H-beam rod option already available for the 4.0 SOHC is $125.00 per rod so you can see we've already beat that.

So, to recap this option.

Estimate $91.19 / Rod
Estimate HP the rod can handle is 700-800HP

This should be good for 500HP on the 4.0 SOHC


Rod Option 2

SBC rods.

UPDATE (9-5-2009) - I've decided to go this route for rods. The first option is still available; however, the cost was the deciding factor.

The second rod option is a SBC eagle H-Beam rod that is 5.7" long from center to center. The stock 4.0 sohc rod is 5.748" so this rod is .048" shorter. This means the custom piston being made needs to have a longer pin height depending on the compression desired. The rod journal bore on this rod is 2.1" where as the stock 4.0 SOHC has a 2.125" rod journal. This means the bore has to be opened up. The cost per a set of 8 is lower for this rod ($359.00) so this puts us at $44.87 / rod. The machining cost will offset this and I'll update the thread when I get the info.

The good about this option is the ARP rod bolts are 7/16" where as the first option has 3/8" rod bolts.



Pistons

Compression Ratio for boost

UPDATE (9-5-2009) - I've decided to go with a 9.5:1 compression ratio (custom forged piston) and then get the piston tops coated.

Here is a formula for helping pick a compression ratio for a boosted engine. Anything between 16:1 to 18:1 is what to shoot for on a street set-up. Anything above 20:1 is race car country.

((boost psi / 14.7) + 1) x motor compression = effective compression.

Here is the 4.0 SOHC with 9.7:1 compression running 14 LBS of boost...

Effective Compression
18.93809524

Here is the 4.0 SOHC with 9.5:1 compression running 14 LBS of boost...

Effective Compression
18.54761905

Here is the 4.0 SOHC with 9.5:1 compression running 16 LBS of boost...

Effective Compression
20.25782313

Here is the 4.0 SOHC with 9.5:1 compression running 50 LBS of boost...

Effective Compression
42.69319728
(Okay, this is a little much)


A motor with 8:1 compression running 18 lbs boost VS a 9.5:1 compression motor running 12 lbs boost will have almost the same effective compression and about the same peak power. The big difference will be where you see the power, and how much of a demand will be placed on the supercharger/turbo. Obviously, the 9.5:1 motor is going to have far greater torque and low end power as the boost is only starting to come in. It is also going to be much easier to find a blower/turbo to survive at only 12 lbs of boost -vs- one that would have to put out 18 lbs of boost. It is now very easy to see why a higher compression motor with lower boost is becoming so popular.

Assembly Instructions

Download SOHC_Engine.pdf from FileFactory.com

There's still a BUNCH of work that needs to be done here so this should be considered "A work in progress" until I remove this line from the thread.

 

[Jakee]

Cool deal.

It looks like their in the same state as me and I like the stuff that's "MADE IN THE USA".

"Located in Austin, Texas, Turbowerx is a premier automotive research and development organization, with special emphasis on products for Porsche automobiles. We utilize state-of-the-art technologies for the most thorough research and testing. With top-tier engineering and manufacturing, TurboWerx delivers unique, industry leading products."

 

[Jakee]

The good news - The pump stopped making the noise...

The Bad News - The pump doesn't come on. It's gone...

 

[Spdrcer34]

Have you watched any of the TRUCKS! shows recently?

They are dropping a 4.6 DOHC Aluminator into a Mazda B-series Truck (read: Ford Ranger).

It is called project 'Rolling Thunder'....as a play on words towards the F-150 Lightning...

At one point in the build, they had to address the steering shaft being moved closer to the drivers side fender....you might wanna check out the show, they mention it in the first episode, and then in the next show they actually show him doing the work to the firewall, and show the parts that were used to move the shaft away from that HUGE engine!

Ryan

 

[Limited02]

I have caught parts of that show in the past. Are you sure it's an Aluminator? I thought it was a Mercury Marauder engine that eventually gets worked over in later episodes?(never saw the end of it)

Either way, it'll be a fun tire smoker!

 

[Jakee]

I managed to drill and tap the oil pan in the vehicle for a new oil return right beside the oil filter and above the oil level. There is a spot on that side (passengers side), once the lower pan is off you'll see, that seemed to be a good spot for the debris to fall thru while drilling. Also is a good spot for oil to come back into the pan. This will take around 3 to 4 feet off my oil return line and around 2 feet of vertical taken away which should make it much easier on the pump. When I drilled thru, the pan was not as thick as I thought it would be (maybe ¼” or less). I went thru with a ¼” first, then 3/8” and finally .562” for a 3/8 NPT thread. The holes had to have a angle because it’s tight in there. I then used a 3/8 NPT Tap and a socket wrench with an 8 point socket to turn the tap. You can get the tap pretty straight this way by resting the rounded socket head on the motor mount. I ran the tap about 75% of the tap threads in before calling it good.

I’m still concerned a little about the thickness of the oil pan here but when I threaded the fitting in, it felt pretty good and got plenty tight. I used ARP thread sealant. We'll see how it works out. If it doesn’t, the oil pan will have to come off and get a bung welded in. But it can’t hurt to try, right?


All this took about 20 minutes.


Standard NPT Tap Drill Sizes

NPT Size Tap Drill Size (in.) Decimal Equivalent (in.)
1/16 - 27 "C" 0.242
1/8 - 27 "Q" 0.332
1/4 - 18 7/16 0.438
3/8 - 18 9/16 0.562
1/2 - 14 45/64 0.703
3/4 - 14 29/32 0.906
1.0 - 11•1/2 1•9/64 1.141
1•1/4 - 11•1/2 1•31/64 1.484
1•1/2 - 11•1/2 1•23/32 1.719
2.0 - 11•1/2 2•3/16 2.188
2•1/2 - 8 2•39/64 2.609
3.0 - 8 3•15/64 3.234

 

[Mountaineer1113]

There is a spot on that side, that seemed to be a good spot for the debris to fall thru while drilling.

A little trick to drilling: Lube the front of the drill bit up with some grease. The shavings stick to the grease so they don't fall in the pan.

Awesome work! Thanks for the references on taps.

 

[rocket 5979]

I managed to drill and tap the oil pan in the vehicle for a new oil return right beside the oil filter and above the oil level. There is a spot on that side (passengers side), once the lower pan is off you'll see, that seemed to be a good spot for the debris to fall thru while drilling. Also is a good spot for oil to come back into the pan. This will take around 3 to 4 feet off my oil return line and around 2 feet of vertical taken away which should make it much easier on the pump. When I drilled thru, the pan was not as thick as I thought it would be (maybe ¼” or less). I went thru with a ¼” first, then 3/8” and finally .562” for a 3/8 NPT thread. The holes had to have a angle because it’s tight in there. I then used a 3/8 NPT Tap and a socket wrench with an 8 point socket to turn the tap. You can get the tap pretty straight this way by resting the rounded socket head on the motor mount. I ran the tap about 75% of the tap threads in before calling it good.

I’m still concerned a little about the thickness of the oil pan here but when I threaded the fitting in, it felt pretty good and got plenty tight. I used ARP thread sealant. We'll see how it works out. If it doesn’t, the oil pan will have to come off and get a bung welded in. But it can’t hurt to try, right?




All this took about 20 minutes.


Standard NPT Tap Drill Sizes

NPT Size Tap Drill Size (in.) Decimal Equivalent (in.)
1/16 - 27 "C" 0.242
1/8 - 27 "Q" 0.332
1/4 - 18 7/16 0.438
3/8 - 18 9/16 0.562
1/2 - 14 45/64 0.703
3/4 - 14 29/32 0.906
1.0 - 11•1/2 1•9/64 1.141
1•1/4 - 11•1/2 1•31/64 1.484
1•1/2 - 11•1/2 1•23/32 1.719
2.0 - 11•1/2 2•3/16 2.188
2•1/2 - 8 2•39/64 2.609
3.0 - 8 3•15/64 3.234

With steel sheet metal oilpans you open the hole a bit with a drill and then finish with a metal punch. This provides for more threading and sealing surface to minimize leaks. Most are ok if just drilled though.

 

[Jakee]

Well, drilling and tapping the oil pan on the vehicle didn't work. It's leaking.....I could probably JB weld it but you guys know I don't roll like that.

The pan has to come off....

 

[Mountaineer1113]

Well, drilling and tapping the oil pan on the vehicle didn't work. It's leaking.....I could probably JB weld it but you guys know I don't roll like that.

The pan has to come off....

Good man. You try to cheap out now instead of doing it the right way you'll most likely regret it in the long run. Not too familiar with using JB Weld but I've heard that sometimes it works for a while and sometimes it doesn't even hold up.

 

[CDW6212R]

Most epoxy type repair products need perfectly clean and prepped parts, which is not easy to do some times.

Jake, take your time R&Ring the upper pan, it's important to get it sealed up and not leak. You don't want to do the work to fix the one leak and end up with another one.

 

[rocket 5979]

Well, drilling and tapping the oil pan on the vehicle didn't work. It's leaking.....I could probably JB weld it but you guys know I don't roll like that.

The pan has to come off....

My guess is you may have tapped it too deep. Pipe fittings, and thus their taps too, are tapered. To properly determine how deep to run the tap while making the threads you have to measure the diameter of the brass fitting with machinist calipers where it enters the oil pan and then measure the point on the tap whose diameter coincides with this. Then just tap it to that depth or a little shallower and you will have perfect fit pipe fittings with proper depth and good seal everytime.

 

[Jakee]

My guess is you may have tapped it too deep. Pipe fittings, and thus their taps too, are tapered. To properly determine how deep to run the tap while making the threads you have to measure the diameter of the brass fitting with machinist calipers where it enters the oil pan and then measure the point on the tap whose diameter coincides with this. Then just tap it to that depth or a little shallower and you will have perfect fit pipe fittings with proper depth and good seal everytime.

Yap, it's usually around 75% the length. I'm pretty sure when I drilled from an angle, the hole enlarged or actually egged just a tad. I then tried to straighten it out while tapping and thought I did. But it's leaking and I tried tightning it up. I guess I could tighting more cuss I have plenty of threads left. I'm nervous I'll crack the pan. Yes, that can happen with cast aluminum. I don't think there's enough meat for the taper. It's probably like .125 thick.

If the pan was flat where I drilled I could use a bulk head fitting. But its not. I don't think theres anyway around it but to take the upper pan off. All the manuals state you need to pull the engine in order to get it off. I know I can jack the engine and not have to pull the motor but I'm not looking forward to doing this. Half of me wants to just pull the motor and continue this thread like it started (a performance motor build) even if it takes 2 more years to complete.

The good news is I think the new PCV evac system worked pretty good. I'll have to post some pics up of this little creation. I need to get a vacuum gauge on the catch can to see how much vacuum (if any) I have @ WOT. THe one time I said screw it an hit the gas, It was detonating like crazy so I couldn't tell.

 

[rpcaster]

Jakee,
What about a pipethread fitting with 0-ring?

 

[CDW6212R]

I pulled my upper pan by lifting the engine off of the mounts slightly, exhaust attached. The diff. has to be out, but not much else. You can do it.

 

[rocket 5979]

Yap, it's usually around 75% the length. I'm pretty sure when I drilled from an angle, the hole enlarged or actually egged just a tad. I then tried to straighten it out while tapping and thought I did. But it's leaking and I tried tightning it up. I guess I could tighting more cuss I have plenty of threads left. I'm nervous I'll crack the pan. Yes, that can happen with cast aluminum. I don't think there's enough meat for the taper. It's probably like .125 thick.

If the pan was flat where I drilled I could use a bulk head fitting. But its not. I don't think theres anyway around it but to take the upper pan off. All the manuals state you need to pull the engine in order to get it off. I know I can jack the engine and not have to pull the motor but I'm not looking forward to doing this. Half of me wants to just pull the motor and continue this thread like it started (a performance motor bbuild) even if it takes 2 more years to complete.

The good news is I think the new PCV evac system worked pretty good. I'll have to post some pics up of this little creation. I need to get a vacuum gauge on the catch can to see how much vacuum (if any) I have @ WOT. THe one time I said screw it an hit the gas, It was detonating like crazy so I couldn't tell.

How far below the flange did you locate your fitting and where is this in relation to the top of the oil?

 

[Jakee]

It's above the oil level about 2 to 3 inches in the upper part of the windage tray. Next to the oil filter. I may just drill and tap the oil filter and be done with it...LOL

The problem was getting a drill in there.

The pipe thread with an o-ring may work? hmmm

 

[rocket 5979]

The pipe thread with an o-ring may work? hmmm

Doubtful. There will be no real shoulder for the o-ring to rest against in the fitting. And there will be no recess cut into the pan metal to allow the o-ring to seat inside and press-fit to a good seal.

If I were you I would just use some RTV on it. Take the fitting out,splotch some RTV on the threads, and tighten her back in. It might be enough to take up that little extra space and seal the leak. After all, according to your fitting placement, it should be more of a passive leak than a persistent one.

 

[Jakee]

Doubtful. There will be no real shoulder for the o-ring to rest against in the fitting. And there will be no recess cut into the pan metal to allow the o-ring to seat inside and press-fit to a good seal.

If I were you I would just use some RTV on it. Take the fitting out,splotch some RTV on the threads, and tighten her back in. It might be enough to take up that little extra space and seal the leak. After all, according to your fitting placement, it should be more of a passive leak than a persistent one.

It doesn't leak when cold or just idling. I went for a 5 mile trip, then crawled under to find a good bit of oil, so it's when I'm driving and the engine oil is warmed up. Can't hurt to try RTV. I guess I'll take the fitting out, clean really good, and re-seal with RTV. Good idea.

Hind site is 50/50...Using the below would have given the room to do this right. I guess, if nothing else works, I could go to the next sized larger and use a right angle drill attachment to get it straight.

 

[rocket 5979]

It doesn't leak when cold or just idling. I went for a 5 mile trip, then crawled under to find a good bit of oil, so it's when I'm driving and the engine oil is warmed up. Can't hurt to try RTV. I guess I'll take the fitting out, clean really good, and re-seal with RTV. Good idea.

Hind site is 50/50...Using the below would have given the room to do this right. I guess, if nothing else works, I could go to the next sized larger and use a right angle drill attachment to get it straight.

View attachment 61943

50/50 hindsight huh? Lol

 

[CDW6212R]

50/50 hindsight huh? Lol

That's about what my eyesight is now, 20/50 or so.

Try the Ultra black or copper and see if that does it, I love the stuff.