The 6.9 IDI is not what you think... 

Slave lake has at least, tens of horse powers! Almost a hundred horse power on the ether!

I worked as a Ford tech in the late 80s early to mid 90s in the midwest. I worked on countless 6.9 and 7.3 IDIs. Nine times out of 10 cold star issues were weak batteries, bad cables, dirty connections or operator errors.

My favorite thing about 6.9 IDI’s is that the displacement of 6.9 liters corresponds to 420 cubic inches. Absolutely amazing... Also, always good to have a couple of spare dump IDI’s around the shop. I got one off a guy named mr love who lived in a trailer, we call it the love motor. Only the Highest quality power for these trusty Stallions

I’ve built IDIs. What it’s missing is lower compression to get actual horsepower from intercooling/turbocharging it. At that point pistons are too weak to handle heat. They are however cheap and underpowered enough to last forever. Good farm truck. I know their limitations but I like them.

I worked as a truck mechanic at a Ford-only truck dealership from '81-'04. I was jazzed when they announced the upcoming diesel truck in 82 and couldn't wait to get one. Mine is an early production '83 (yeah, thin block) F250 XLT 2wd with a/c and 3.54 limited slip as the only options. I've had it 40 years in mid-March. It has given me great service but only has 140k miles on it (I always commuted to work on motorcycles). I put 3 injection pumps, two water pumps, a vacuum pump, one set of glow plugs, one thermostat, a set of valve cover gaskets and one fuel return kit on in that time. Still has the original injectors. The power steering pump, gear, hoses and fluid are original and don't leak (I hope I'm not jinxing the thing by mentioning all this). I added a coolant filter and for several years had a spin-on Luberfiner bypass oil filter installed (just cause I could- I've since removed that). While I was at the dealership I scrounged exhaust tubing and a muffler from a medium duty 7.8L truck and fabricated a low restriction exhaust. Ran it on our chassis dyno before and after- picked up about 10hp (!) LOL. Got all the way to 120hp at the wheels. 4 speed with 3.54s it returned exactly 20mpg on a vacation pulling a 13' travel trailer (the segment was 700 miles round trip from Flagstaff to Albuquerque to Flagstaff at the same pump). I was happy with that, but it could definitely use a little more grunt. All in all it's been a great truck and definitely paid for itself.

My 94 7.3 turbo idi runs up to 18lbs of boost and starts whenever I tell it to. You're dead on with the fuel return lines, a good pump and good glow plugs. Your biggest tip is the starter. Parts house starters suck for these engines.

I worked for Ford dealers back when these were new. They were good engines that had very few issues. The occasional block crack in the first models around the block heater were handled in most cases under warranty. The early glow plug controllers were less than ideal but they did work, but we converted many over to the new style. The occasional bad lift pump or injection pump, or leaking return o rings were all we saw. In 25 years at Ford dealers I think I only had to replace two of those motors, one had 361k, the other over 700k. I had three 6.9L engines, one in an '86 F250, the second in an early 1987 F350, and one in an '84 Ford Cutaway motorhome. (I also had two IDI 7.3 engines, an '88, and a '94 before buying my first Powerstroke in 1997). Power wise the turbo charged DI engines have win hands down but for reliability under any condition the IDI would be my first choice of the two types. I only wish they had gone a different route both for the cold start options and the fuel return lines. If they had gone to a common rail system with an intake heater we'd have had a much simpler easier to start engine.

Fantastic job on this video Colt! This was totally different from what you normally do. But that being said it was great to learn about the 6.9 idi. I always loved learning the history of how things came about. Pretty neat how these old engines came factory with lots of goodies. I also think the 54 international getting a 6.9 is very fitting. Not to mention how awesome it's going to look rolling coal through the streets! Keep up the awesome content Colt. Cheers 🍻

Great video! I myself have a ‘93 F350 Dually with the 7.3 IDI NA mated to a E40D trans and it certainly has a special charm to it that my other trucks don’t. It rides like a log wagon and you can turn the steering wheel from 12 to 3 before ever turning but that’s more on Ford than International. On mine I built a custom Fuel Filter -> Holley Red Electric Fuel Pump -> Fuel Filter mounted on the frame rail that turns on with the ignition. So much easier to start compared to the lift pump on the block. Also rewired all the glow plugs and bypassed the relay in the back to a new one that connects to a button on the dash. Most summer days I don’t need to even use them down here in TN. In the winter I just plug it in. Have a block heater and battery tender all wired up together and just cycle the plugs twice and fires up immediately. Save yourself the misery and always go with Motorcraft plugs too! The Autolites swell up and are a PITA to extract. Ask me how I know… As of now the new return lines aren’t leaking but once they do i’m considering getting some billet aluminum ones. Also had to put a new injection pump and 2 re-manned injectors. The only leaks are the valve cover and the oil pan gasket. My dad bought it in 1996 and I hope to keep it alive and well long enough for my kids to enjoy! Though I would like to buy a clapped out one to beat up like good ole Slave Lake!!!

I found a company that makes billet single piece return rails for the 6.9/7.3. They were a pain to get on, but don’t leak and never will! 220 bucks.

Your video is really good. Who ever did the editing did a great job. Keep it up.

Very well done video. Glad to see a lot of solid information put forth for once instead of the usual myths. Also glad to see I made the video lol. I still have a lot of these things but I have not done much with them in recent years. Once life isn’t so busy I want to get back into building some crazy stuff.

This was a great video, loved learning more about the 6.9 idi

I had 3 of these! They are Incredible pieces of engineering. Loved that engine so much.

1986 f250 6.9 diesel was my first diesel i bought it for $400 and used it for 7 years to start my tree bussiness and i loved that truck , i put a easydump on it with a wood box and chipped into it although i needed more springs in the rear , but needless to say i fell in love with diesel motors and had every international engine from 6.9 idi to 7.3 idi then the turbo idi 7.3 then im curently driving a 2000 excursion 7.3 , most reliable diesel ever built imo....

😮 You da Mann !!! Just Inheirited a Reg. cab 84 dually 4wd 6.9 4spd " Hasnt started for 10 yrs. Superb Vid..& channel !" Your Info. was Exactly what ive been looking for !" 😁👍" Thanks Friend !" & Keep up the Great Work !" ❤👍

Actually, Navistar was the result of the breakup of International Harvester. The truck and engine division became Navistar International while the farm machinery division merged with J I Case to become Case IH.

Awesome video! I bought an 87 F-250 last year with the original 6.9 and 4 speed. What a great truck. Mine has a well maintained starting system and barked right off in single digits last year unplugged. Kinda made me wonder what the fuss was about with them being cold blooded. I ended up doing the injectors and return lines and I was shocked to find what I believe were the original injectors still in the truck. The date stamp on the vin tag in the door shows the truck being built in may of 87, the injectors were all stamped 2-87. Looking forward to more IDI content down the road!

Dang, that -50c start is -58f impressive. I bet thinner oil would really help the starter.

Man I love this channel already thanks peg for putting me onto this dude.

I love these idis they sound mean, loud and they smoke alot if your into that, but they just wont make much power bud but itll be interesting to see what you can max out of the thing

Well done. Great info about the old coal roller

Awesome video. Makes me regret selling mine. but those were dark times. I will buy another. Had an 86 f250 xlt auto 2x4

Love the editing. Well played sir.

Someone may have already mentioned in the comments, but that hypermax built idi drag truck popped back up on a forum last year and is supposedly making a comeback. Guy was known as "Dadiesel" or something like that

Dang, tons of IDI info and generous amounts of memage? Subscribed!

Just purchased my first 6.9L IDI ('87 250) and this was super helpful re. what work I know I'l be doing in the future!!

You mentioned your idi is 2° advanced on the static timing, how much did you turn the pump over towards the passenger side? I've been told to go a dimes width, I've been wanting to advanced my 6.9 a bit to help with better acceleration, recently I was in a rush and took off to work with my cold timing advance still on and the truck felt way better and when it kicked off it went back to being a dog lol feels like I'm always pulling a trailer, so I'm hoping advancing the pump a bit will give me a similar feel and more pep, 86 6.9 C6 4X4, awesome work on the video I loved it 🍻

Starter speed is critical for ANY diesel. No mater if NA or turbocharged, only boost system that makes boost on the starter is a blower. To slow of a piston speed allows too much time for the cylinder walls and piston to cool the air below combustion temperature. Had trouble with my starter in my Cummins not spinning fast enough required touching the throttle to fire off. 3 starters in I discovered the crimp on the lug was not tight going to the battery.

The 88 - 92 Ford trucks are my favorite body design but I've seen so many warnings about the diesel motors every time I researched them I started looking at swaps. Never pulled the trigger on one though. I did own a 89 with a 460 that was a great truck. My dad owned a 85 Ford diesel and it couldn't get out of it's own way. That was the last truck he bought new

I had an 87 one ton with the 6.9… I loved that truck. It wasn’t fast but it would drag anything I put behind it. Great engine.

Dude I have run across your videos before But Man you got me. Love the way you put this together. Love the information, it looks like you really did your research. and it explains why my 88 7.3 idi gave up the (I ain't got no money for maintenance) goat and quit on me.

Awesome video man! Love my 6.9 in my 84 F-250, wanting to put one in my 76 highboy but not sure I have the mechanical ability to take on that project. Keep up the good work and good luck on the International project!

Ran a 6.9 for years with no glow plugs,tiny shot of ether in morning. Started great rest of day.

This is actually pretty dang cool. Thanks for the vid.

I use to have a 7.3 idi that put out 800 hp and 1200 Flt.Lts. shame it got stolen and found later burnt to a crisp and blown up But it was not that hard the only issue was keeping them from going Kaboom after 2-3 runs but you can make the 6.9 and 7.3 idi Runs very well and Safe at 290 hp 555 ftlbs with no issues as daily driver

Very interesting, ingormative and well produced!

Great vid! Been following your channel ever since I got one myself.

I had a 83 6.9 for 5 years it notoriously kept my wallet empty but when it ran right it was a beast my happiest Day was the day I sold it

Never had the 6.9 but have had 7.3 turbo since 97 with 468k miles and ill never own any other truck LOL!

I love working on the ol IDIs. Bought a 7.3 F250 that had a dropped lifter and chewed cam lobe. Did an in frame and custom grind on the cam and woke that sleepy girl up. Then I did a 12v Cummins swap

I had an 86’ F350 with the 6.9L. It turned 98 hp to the rear wheels with maximum normal aspirated tune. I installed a Banks turbo kit which brought that up the 198 hp with optimal tune(not to much smoke). I sure do miss it. It had 325k on it when I sold it. I wish it had been a crew cab.

The 6.9l v8 non turbo stands out strong like the great 4.9l 300ci . These are trucks that will probably outlast most of the junk coming out of the factories today. Simplicity, reliable and easy to work on and affordable. People who actually need pickups.

I have a 1985 6.9 idi swapped along with its original chassis underneath a 1964 c20 custom long bed and cab its a real dope truck

i had a early 90s crew cab dually, 7.3 IDI. hadit tuned up to pull horses, a local diesel injection shop re do the pump, banks turbo kit with an air to air, granny shifting the ZF 5 spd it went 13s. 400,000 miles later it still runs, just use it as a parts/lunch runner, is still fun stop light to stop light.

"Fix your electrical" smoke detector beeps.

I knew max lagod of hypermax . Max was crazy about racing along with his dad. I am still good friends with a fella who works at hypermax in the injection room. I bet I can find out if that motor is still around.

Got a 91 w/ the 7.3 w/ 5sp ZF5 & 2wd. Can get about 21 but gotten as high as 23. An OP put 3in (might be 4) straight pipe on it. Converted the GPs to manual by bypassing the automatic side of the controller which had died. Thing is just parked at the moment. I like the sound of that thing...kinda miss driving it too.

They had fine power from the factory, I’ve owned dozens of 6.9 7.3 and Chevy 6.2 and 6.5s and the 7.3 with an e4od was perfectly fine as a work truck in stock form. I later got a 94 powerstroke that must’ve had a detuned fleet engine or something, because it was WEAK!

A IDI that handle's 147psi? Yet my last IDI I owned Didn't last a full week with just a few pound's. I added a Banks Sidewinder and after one weekend the both heads were literally cracked in half

The detroit 6.2 idi was pretty amazing. Fuel mileage was awesome, weight to power ratio was not great, that is why it was reliable.

Lmao I know nothing about diesels but the memes are on point with this video and now I know a little.

I had a 1987 ford f250 with zf 5speed. .with a 6.9. With ats intake with garet turbo. .i put a 7.3. And took every thing from the 6.9 and bolted it all on to the 7.3. That truck was fking sick

Good video! Love my 68 F250 highboy with a 6.9L turbo and zf5.

I always thought the hypermax story was BS. Most dynos couldn’t measure that much power and torque in the early 90’s. I don’t doubt the possibility of that power. But you had more info than I’ve ever seen about that truck on the forums in the last 20 years, and the pics! Never saw pics before, that makes it seem way more credible than I’ve ever thought.

6.9L 420ci, it couldn’t get any better

R&D IDI performance would be a great website to visit. Justin is a good guy

Awesome Video Man!! Loved the American Psycho clip!

I'm a fan of Ford design remote relay, I convert all my rigs. Run a #10jumper from the power to the start pin,run som 00 or0000 cable from power to relay where it's easy to get to for maintenance purposes like bumping the motor over settin valves, my 91.5 bump starts on the first compression cycle on the key. Plus when a shop gets instructions DO NOT START . They'll have hell trying to not follow instructions( especially when they refuse an introduction to a customized truck, they thought the motor had to be running to make the cable shifter work¿. Crushed oil pan into rotating assembly ,cault shop with a vom tryingto find the trigger wire and helped them push it into the shop. They still refused an introduction, week later they said pull the cab to get the Allison unbotled and 3k more. So i did the oil pan my self.)

I have an 03 f350 with the dreaded 6.0, going to engine swap it. Was set on a 12v swap, but the prices on a clapped out 12v needing a rebuild is sky high these days. So i was thinking about an IDI swap as i had one back in the 80's, it wasn't fast but was pretty much bulletproof and one can be found fairly cheaply to rebuild. Thanks for the video

My favorite moment with this engine was in Fringe where an EMP from a device that David Robert Jones is using to colapse the town and it's alternate universe version, doesn't do jack versus a mechanical diesel powering an old schoolbus.

You know what i was thinking that could make this video better the whole time? Clips of movies and other videos along with memes. You should put some in

I had an 84 f350. Never plugged in never failed to start quickly

I've also heard the legend of the 1200hp IDI. I never really believed it to be true, but I'd certainly like it to be

I love my 6.9. Just got her board out by .020" and am waiting to get some boost to her

Fucking LOVE seeing ppl building IDIs. I have a 7.3 factory turbo F250 with a ZF5 and I love it.

I have a 1985 F250 6.9 4x4 manual that runs great. My issue is all the crumbling wiring. I need to completely rewrite the entire truck. Oh and can’t forget the play in the steering wheel.

Really Great info, I knew nothing of this engine and learned a lot. I could really do without the film clip cutaways though. 😊

I had the misfortune of having my first 6.9IDI be low on compression. Replaced all the fuel return lines, injection pump, batteries, cables, glow plugs, controller. Only for it to struggle to start at room temperature. It had crank speed! And pumped copious amounts of white unburnt fuel out the tailpipe while doing so. It just didn't have very much compression I think. Burned about 2.5 gallons of oil every 500 miles, barely had enough power to go uphill unloaded at 30mph in 3rd gear and overall was just a bear to start. I bought it for $1000, put $3000 into it, and then sold it for $500. Oh to be a dumb teenager.

My first truck was a 1986 f250 rwd, when the glow plugs are wore out and the fuel pumps are on the way out the door and the fuel issue going back to the tank. Squirting some gasoline in the breather always wprked but on occasion i had to put out a hood fire when it backfires. Just dont add too much or it trys locking up and takes a few key cycles to start. As for the batteries just stick a chunk of penny in between the battery terminal so the penny will oxidize before the terminals.

I had one of each of the International gas motors and they were stout.😊

I love those motors.

I have a 7.3 turbo 1994 international / navistar / mercruiser this engine is in a 28 foot speed boat baja hull coupled to a bravo 3 . Super cheap on fuel and tons of reliable power 👌

IDIs don’t get enough love!

I have an 89 7.3idi in my 71 F250. My previous truck with this engine was a 69 F250, but the chassis just couldn't handle the weight and torque. This current one is on an 85 chassis that originally had a 6.9 and four speed, along with 3.07 gears. I had planned on swapping out to a 3.54 gearset, but having put a few thousand miles on this I think the high gears will stay. It does 80-85 all day turning in high teens to low 20s.

the edits in this video is great

PS: I had found a time slip from the truck years ago, it was a picture of the time slip laying on the hood/fender of the truck. I will see if I can track that down

My 1983 6.9 was one of the very first to be produced and had a fatal flaw. The glow plug system had an additional relay that was eliminated in later versions. Although it used the same controller/components otherwise. It was never made clear to me what the additional relay controlled. After untold numbers of cold start problems with multiple changes of (I thought) all of the components, the system started coming on going down the highway and of course melted the glow plugs and destroyed 3 cylinders. At the time these were very expensive to repair and it was pulled in favor of the 460. I still own the truck in very good condition and have a Cummins/Allison replacement for the gas hog.

Great video!

My grandpa put a banks turbo kit on his 84 f250. He was the coolest.

Better make sure you have the proper amount of sca additives in the coolant and a good radiator cap o prevent cylinder wall cavitation erosion

Very nice video!

I've never seen a 6.9 idi under 1k...but I have seen many 6.0 ls with wiring harness for well under 1k

My idi had the sts turbo…. Absolute perfection for me

Well.......that was entertaining!

In the late 90’s I Banked and aftercooled a 7.3IDI. Would out pull any 7.3 Powerstroke. But the block cracked at 105,000 mile due to how thin the cylinder walls are. Sleeping to a 6.9 is the only way to keep them alive.

ohh hey that old 7.3 idi that I used to own must of been that 1,200 h.p engine and i didnt know it as it took 3 full cans of ether to get to start on a 80f day

If this dude didn't use so many movie clips, this would be much easier to watch!

What video editor did you use ? And can it add the memes too??

Had two of these turds, an '86 and an '87. Oil consumption problems from new, injector pump failures from the timing advance control, the '86 ate glow plug relays like Doritos. On and on it went.

So Hypermax did at one point make a P-pump for the IDI engine. That would be compound Garrett turbos not twins. A six inch girdle doesn't make sense neither does the rubber expansion plugs. I believe if they were having that much block flex they would have filled the block to solve that issue.

Check out my 6.9idi ranger! She gets around just fine , with all of the boost and fuel hahaha

This was a good motor in school busses it was under powered so nothing ever broke

I have a 94 7.3 IDIT. I put in new injectors and had the pump rebuilt and had it running good but was still fighting air intrusion. I bought some R&D billet return rails for the injectors and had it running but had some leaks. So I took everything back apart and replaced some torn o-rings. Once I had it all back together it would not start whatsoever. To be certain that fuel was getting to the filter housing and to the injection pump I put an electric lift pump and deleted the mechanical. Still won’t start, fuel is not getting past the pump to the injectors at all. Took a look at the fuel shut of solenoid and replaced it to be sure and still nothing. Ran a hot wire from the battery to the positive on the solenoid and still nothing. New battery’s and starter as well. Sort of an SOS if you see this. Hoping the pump I had rebuilt didn’t take a dump some how.

in the age of garbage tik toks showing up on my facebook and youtube shorts, the little patrick bateman clip and the culvert cleaning clip made me legitimately laugh out loud like nothing else has. Great info too love the vid P.S. change the battery on your smoke detector they save lives you know

6.9 has smaller head bolts that will stretch. Even with studs they're not as good as the 7.3. 7.3's have cavitation issues that can pinhole the cylinders, so the best for performance is a 7.3 block sleeved down to 6.9. Then it doesn't matter if there's any pinholes - the sleeves take care of that. They are super fun and can make good power but they're not a power stroke or a cummin's so if you want crazy HP look elsewhere. One fun thing of note is you can pin them on the governor for ever and they'll just run and run and run... They don't care. Just keep them cool. 6.9, 110cc pump, 15-20lbs boost and studs is probably 300hp/700tq from memory. As long as you have enough cooling it will run all day and all night on the pin...

I'm a GM guy, but I'll give Ford credit they don't f around with performance and strength (at least back then). The problem with GM is that the guys in suits aren't directly tied to the companies. Chevy is the top dog in GM, not GMC or Cadillac. Ford IS the top dog in Ford, so they don't have to regulate anything to make it fair for their posterchild because THEY ARE THE POSTER CHILD. When GM screwed up with the early 6.2 Diesel's that was their fault, not Detroit Diesel. DD had a stronger crank in the original design plans but GM dropped it because of cost. Ford didn't F around to find out what would happen, so they built it tough as shit and called it good.

So is the mechanical glow plug controller a pre 1987 part? I’m doing the system right now and I bought both the solonoid type and the mechanical. I’m pretty sure I don’t need the mechanical one.

Good content

Tons of power? They’re absolutely gutless