M90 rebuild (rudy) | Page 11 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

M90 rebuild (rudy)

well figured i would start a new thread.just a quick background.did the whole build on my explorer but built it using stock head gaskets and head bolts.did it really as a safety net and i just couldnt afford head studs at the time.well to say the least i blew the head gaskets off from it wile i was in the mountains on a forum trip about two years later.

i picked up a 1994 ranger,its got the 4.0 OHV and is a 5 speed 2wd.the plan is to pull the motor out of the explorer and rebuild it.

this thread will basically cover the rebuild and build up of the new ranger.it will basically end up as a street race truck.ive named it Rudy:D:D so let the fun begin.

new motor specs
BORE: 4" JE asymmetrical pistons (custom over bore)


RODS: 6.058 Manley (longer rod)

VALVES: IN-1.8 EX-1.5 Manley heavy duty (.150 over)




Transmission:T5 hybrid from a 2006 Mustang and 93 Fox
HEADS: 93TM HEAVILY ported with custom brass guides and copper gaskets/O-ringed with ARP studs
CAM: 422 Comp cams with 988 springs and Toms custom lifters,push rods and 1.7 roller rockers
Complete blueprint and balanced internals
GM M90 supercharged with one 1" intercooler plates with ASP 8 rib belt conversion. .
pushing 16 lbs of boost with small shot of NOS
Running on E50
Dyno tuned by Dyno Tune Performance outa Virginia using SCT

old thread and pic
3800 M90 Build
ported and polished gm 3800 gen 2 m90
Water to air intercooled
port matched 76mm inlet and intake tube
mustang 75mm race tb
90mm maf
36lb injectors
255 fuel pump
sct 5bank dyno tuned
2.7" pulley 10lbs of boost!!;)



and the new 1994 ranger 4.0 OHV 5 speed 2WD with 115,000 miles on it.o and i only paid $1,000 for it:shifty_ey


Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

Nice build. I wish I knew how to even start doing some of the stuff that you have already completed. Where did you learn to do engine work. I'm always to scared to take it apart in fear that I can't put it back
I hope you get that job with your engineer, I personally love working on CAD drawings.

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

So been keeping an eye out for a cheap trans to throw in the ranger so I can get it running again..driving the explorer is costing me wayy to much to drive and its just not a dd or street legal. ...

Well I found one Friday. .its a jasper rebuilt unit.I bought it from a shop, said it came from a first gen explorer.they replaced it and not long after the truck came back in with motor problems. It was scrapped so they kept the trans.they broke the rear mount putting it in the rack, I just swapped rear tail sections from my old unit.paid $350 for it..

Towed the truck down Friday and tore the trans, exhaust and manifolds off from it..once I had the trans out I could tell it was rebuilt and also it had a name and 9/2000 wrote on the top of it.pull the plug and it barley fit out the hole it had so much metal on it.oil was black and thick as tar..opened it up and all looked good, nothing jumped out but im no trans guy for damn sure...the clutch was also replaced so im not going to replace it..it sat for 3 years plus ive had it for awile, so has low miles on it.so does the trans so I dont know what really happened to it.unless he just replaced the clutch and put steel plugs in the trans, which is possible.

Putting the headers on to take some measurements for angles to order mandrel bends.as soon as they come in ill be doing the dual exhaust, probably about 3 weeks.I also ordered a v8 swap radiator for I can have more cores and still use my fan.from the measurements I should have plenty of room, ill post pictures later when it comes in..o and my valves are at Manley and should be done in 3 weeks..

Old plug



Still had all the stickers


Out with the old and in with the new;)


Well Manley called back and the valves are paid for.he ran into one issue though, the super duty valves cores have hardened tips on them but my valves are so short that the tips would be cut off to where its not hardened anymore.so I gota run lash caps and they add .080 to the top of the valve.not a real issue just rather not have to run them.so means the pushrods need to be even shorter...it all came to $489!!!:(they will be done in 3 weeks......

He also said he just glanced over my request for pistons and they will have to be one off also..he quoted me a price of $97 and I about passed out...hope that includes pins, locks and rings for that price!! :( he said they are 6 weeks behind on them and as soon as the valves are done he would take a closer look at my specs and call me back....


take it like a lamb.


Well the ranger is about 90% back together, hopefully it will be running again by tomorrow. ;)

Got my V8 swap radiator in today, looks really good.think its gonna work out great.the stock one is 1 core and measured(core dimension) 1.25X18X16.75 and the new one is 2core and 2.25X16X16.75 but the tanks are huge compared to the stocker.my fan is ruffly 16x16.ill post some pictures of the fan mounted to it and it mounted in the truck tomorrow. .




Well she is back up and running! !!! Thank god the trans fixed it!!! Everything went pretty well.the v8 swap radiator worked perfectly, I have tons of room and it keeps my truck super cool.my fan really doesn't even really run anymore and when it does it kicks off in like less than a min.

Headers fit great and I got my mock up pipes bent to the right angles. The drivers side is going to be very tight tho.the clutch line is right there and the collector comes out at a funny angle. Im going to wrap the headers and I guess im going to have to wrap up to the cutouts.also wrap the clutch line, it has a heat wrap boot on it now.

But o wow how I miss driving the ranger!!;)time to save some money for pistons! !


You can see its totally tucked up under the support and I have tons of room now



Almost look to good to wrap but keeping heat down is more important



awesome fit of that rad fan. Nice big fan.

Nice to hear your coming along with your project nicely. A lack of money has demotivated me on mine. I'll get moving soon.

Keep going!

I should have cleaned the fan off or something. Lol looks like crap on a nice polished radiator. Still has mud on it from where it was in the explorer.but MANNNN that thing moves some air!!!!

Hey JD

I don't get over here much but just happened to stumble across your thread here when I was searching for something else. First off thanks for the help you gave me on the other forums over the last few months, motor is back together and running like a champ so far (only ~200 miles on it). This was my first rebuild on a 4.0L so lets hope I got it right. Like what you've got going on here, it's kinda similar to what I'm doing with my 86 Ranger, except I'm doing the V8 instead of 4.0L. Had to swap for either and found a great deal on the donor.

On your BII tank swap what are your plans for a forward cross member? I would like to get my hands on a matching cross member, but no local yards are willing to pull one for me and the u-pull-it yards are a good 1.5 hour drive and a two day trip. Three of them in about a 30 mile radius, can easily spend half a day in each, and I can't resist hitting them all.

I'd be interested in hearing more on your thoughts about this:
I honestly think the fel pro super duty may be just fine..I really only think I blew the stock fel pro ones because of the TTY head bolts.

So got started on the tear down today.tore it all down in a couple hours and found it is a blown head gasket.its pretty obvious, I also put some stop leak in it to try and get back from the trail to spikes house.you can see the build up from the stop leak and even left a flake/chunk hanging off the edge of the top cylinder lip where it blew.



I can't tell you the miles on my new heads, but I know I've gone through at least two (possibly three) head gaskets on them before rebuilding the engine. Each time the head gaskets went out exactly like what you show above. In my case it was more like a slow erosion of the gasket and it was on the other bank at the back, but same corner of the head.

It wasn't an issue brought on by the new heads either, I replaced head gaskets maybe twice for the same reason on the old heads. Had to replace the heads due to a crack that I believe was caused by a broken heater valve. This recurring gasket issue was 95% of the reason I rebuilt the motor, same problem multiple times on 2 sets of heads, only thing left to check was the block. Machine shop found nothing wrong with it.

Until this rebuild I just did I always used FelPro Standard Duty gaskets and new FelPro TTY head bolts. This time I also used the FelPro head bolts, but used the Severe Duty head gaskets, the head bolts also had different torque instructions than what we recall seeing on previous sets. Hoping that it's fixed this time, but if it happens again I'm liable to drop some leak stop in it and trade it off. Just curious if you think it's a problem with gaskets, bolts, torque specs or something else entirely.

Sorry for the long post, but seeing your pics got my curiosity piqued.

I dont run a front crossmember on my tank.the front straps attach to the bed and the rear attach to the frame crossmember. I did this to help distribute the weight of the tank to the bed.I plan to run a c-notch and didnt want all the weight to be hanging off the back of my frame

If your blowing gaskets then the tq wasn't done right or the block and heads need to be milled.I only blew one because of the amount of boost I was running and the TTY bolts.I now run the super duty on the explorer and recommend it for any build. On my ranger motor I run head studs and copper gaskets.

Makes sense. Not doing a C-notch myself so frame will have full strength back there. Guess my other question would be, have you got plenty of ground clearance have you got with the back dropped that much? I'm probably only going to drop my back about 3 inches since I want to keep the raked look.

I was kinda wandering if if the boost accelerated a common issue with these heads gaskets. As mentioned it's the same type of blow out and in the exact same spot relative to the head, except mine is on the opposite bank. Seems like quite the coincidence. Block and heads are flat, no machine work needed per machine shop. Just got crank journals polished and bores honed. While block was on stand I chased and cleaned the head bolt holes, the corner bolt hole where my blow outs occurred was dirty, but so were some others that didn't have a problem. I can't see a torque issue happening repeatedly on the exact same spot, but I suppose it was possible. If it was a torque issue (or anything else) hopefully it's fixed now.

Ive got plenty.it sits above the spare tire holder/bar.im dropped about 4.5ish in the rear but I plan to drop it another 1.5-2 inches but need the cnotch.

If it blows in same spot typically I would think its not flat.I ALWAYS have the block and heads milled anytime I start a rebuild even if the heads are new.I didnt obviously mill the block again this last time but the heads were.I think the SD are just better gaskets, I honestly think its the TTY bolts that lead to most blowouts.that spot is just where its probably the smallest section/weak spot also.

So got some stuff done.im moving my battery to behind the passenger seat so got all the wires and everything ran for that, ill post some pictures once I get the new battery. While I was at it I took one of the amps outa my explorer and mounted it on the back cab wall.then took and mounted two subs in the throw seats in the sides.pulled the back of the seat apart and filled the wall with "fiber fill".last i got a flip out deck with digtal tv and all that bs.ill get a video once I install new door speakers.

I then got the pipes mock up and ordered mandrel bent pieces, they are pretty backed up so no progress for now.

Last I got the valves in.he called before he shipped them and told me he would need more specs for the pistons and sent a form to fill out..I gave him every single spec besides for the rings..I asked him what rings would work best as they make off the shelf 4" rings..he told me he couldn't suggest anything. ..so guess ill need to go back to the machinists and see what 4" rings he suggest. .just pisses me off because it bumps me to the end of the 6 week waiting list..came to $506 shipped:(

Valves look great tho, dont like that I have to run lash caps but it is what it is..they are really close together but its within the specs my machine guy told me so..I just hope they fit and dont hit a water jacket.the intake will be fine but the exhaust is gonna be close.they are IN 1.8 & EX 1.5



Used a old head for contrast;)







Those valves are huge. I never really thought there would be a physical size difference like that. The pics really show the difference.

Those valves are huge. I never really thought there would be a physical size difference like that. The pics really show the difference.

The intake isnt much bigger ( .100 bigger) but the exhaust seems wayyy bigger (.150) in person there is huge difference in them, not just head size.pictures honestly dont do any of their parts justice. ..they are 100% top notch built valves for a forced induction motor.they are pricey but every part I have gotten from them has just been astonishing and just makes me feel even better about pushing the limits;) im getting pretty excited, few are as STUPID as me to actually go through with this project! ! Hha:D


few are as STUPID as me to actually go through with this project!

I guess you can't call it stupid if it is what YOU want to spend YOUR money on. It is extreme, but I think it is cool to see this kind of build.

There are worse ways to blow money: drugs, alcohol, and hookers to name a few.

This is a cool build, no doubt.
Its obviously the intent to do something that few are willing to do.

I think its awesome.
Btw, I took my black 4.0 sc explorer to work the other morning, and I had forgotten how hard it pulls with all that torque down low. I can hardly wait to start hearing your results as you bring your motor to life.

This is a cool build, no doubt.
Its obviously the intent to do something that few are willing to do.

I think its awesome.
Btw, I took my black 4.0 sc explorer to work the other morning, and I had forgotten how hard it pulls with all that torque down low. I can hardly wait to start hearing your results as you bring your motor to life.

Just hope everything comes together and works, there is no returns in the custom world:(
yea my buddy came over yesterday with his 5.0 explorer, he's the one that just got the EE SC.makes me miss mine SOOOO bad!!haha

Traction is going to be a serious issue. .I did some 1/4 runs the other night, did 4 total but some reason the only one that got recorded was my very first one.runs 1,2&3 I could not get a good launch to save my life.even line locked and warmed the times up each time.I only has 3 gallons in the tank tho, need to redo it with about 10-12 gallons and make sure it records. .

1st and second was just worthless. The last run I left easy then hit it, spun thro most of first but caught at the end and in second. It definitely was wayyyy faster of a run, couldnt see time but the app told me when to stop and I was well over 85 (max dash speedo).my first run that it recorded was a 16 flat at think 78 mph.was absolutely the worse run tho, last run I would have guessed it was in low 15 easy.

also just about hit red line in 5 gear that night, speedo hit the stop pin for ""0mph"" and I still had about another 1,500 rpms left..felt absolutely stable and planted the whole time.the brakes also impressed more and more each time.where I was running wasnt much longer than a 1/4 before a turn..lol

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

Finally got all my bends and parts for my dual exhaust.its all mandrel bent 2.5" with flowmaster suv 50 mufflers. Wired the cut outs up so all we have to do is mount and plug them in.hopefully sometime next week when my boy has time we will throw it up on there and see how it sounds.I went with the 50 suv over the 40 I have in the explorer in hopes it wont be as loud, after all I have cut outs when I want it loud.yes im gonna have a tune written for when they are open.

I got a tripple piller guage pod im going to try and fit, it may not.but need to get my wide band mounted and wired before we install the exhaust so thats the plans for this weekend;)