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Non-turbo IDI vs. PowerStroke vs. 460 gas?

51K views 27 replies 13 participants last post by  moosiah 
#1 ·
Hi Guys!

I'm glad I found this site, as I have a truck purchasing/ownership dilemma. Hopefully my ignorance does not get me flamed...I'm brand new to diesels, but a long time FORD lover.
I have found the truck of my dreams (not really, but in my price range) that I'm considering buying. It's a 92 F350 with 358k miles and from southern KY, so it is virtually rust free and in shockingly good condition body/frame wise.

My question concerns its 7.3 non-turbo engine. Is there a significant difference in performance, fuel mileage and longevity between the old IDI engines and the PowerStrokes? Can an OEM/aftermarket turbo be installed relatively inexpensively on the IDI, or should I continue looking for a newer PS equipped model?
Please don't laugh for asking this, but is a rebuilt 460 swap a straightforward enough process to be worth my while if the old engine is tired, or is that a cardinal sin if one already owns a diesel powered truck?

My dad had an identical truck with the 460, and hated the fuel mileage but loved the BB power. I wonder if the cost of repairing/maintaining an IDI or PS is worth any advantages held by the increased mpg? Seems to me, the horsepower and torque numbers for non-turbo IDI and 460 gas are virtually the same. So where are the "felt" differences.

Thanks for indulging me! :thumbsup:
 
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#2 ·
The 7.3 IDI is unbeatable for reliability, longevity, durability, and ease of repair. It's not a speed demon but I doubt it would ever leave you on the side of the road. Even if it does, as long as you have a simple set of tools you should be able to get going good enough to get to to the nearest service station.
 
#3 ·
yep the old idi is a great engine and yes you can install a turbo. you may have to find a used one but the ats 088? (not sure) or banks sidewinders are specific to this engine as a powerstroke turbo would blow the heads off. 10 to 12 psi max, and at those boost levels the idi-t will keep up with a stock/mildly tuned 94-97 psd. as or the 460, 6-8 mpg, when a 7.3 is 444 ci and in great shape can get upwards of 15-17, and if it ever goes down quite honestly youd probably come out cheaper from a junkyard getting another idi. they charge for the bbfs, but nobody wants to put a 7.3 into a mustang
 
#4 ·
Thanks for the replies! :thup:

During my research on the net, I stumbled onto statements about the IDI's having an issue with thin cylinder walls and pinhole leaks forming, causing eventual catastrophic engine failure. Is this nonsense, or a very real problem that was resolved later on with the PowerStrokes?

I'm still reading and learning, trying to get a fast education so I know weather this truck is worth what he's asking. I think it was a grocery getter, not a workhorse, given it's near new looking interior. My biggest concern is the high mileage and the potential for things to start failing right after I buy it. Is there anything specific I can look/listen for when test driving? I have bought many vehicles over the last 15 years, so I have the general stuff down, but not diesel exclusive points to monitor/inspect.

Comments and advice are truly appreciated. :icon_smile:
 
#5 ·
I just retired a 1990 E350 with 410,000+ miles on it. The IDI never even had a valve cover off. Other than a few sets of glow plugs a water pump or two it had no other repairs. The motor is still good, wanna buy it?
 
#6 ·
I had an '86 F250 with a 460/C6 that ate corvettes for lunch. I bought it new and over the years, made modifications to try to increase efficiency, and managed to increase HP more than anything. With the trailer in sig, I was seeing 7.7 MPG on the flat highways @70 MPH, it was a GAS HOG!!!

My current truck gets about 10.5 MPG with the same trailer hooked on @ 70 MPH. I wouldn't think of going back to the gas engine for towing.

Having had 9K+ lbs. of trailer hooked on to both a 460 and an IDI ( mind you mine is turbo'd) the 460 will get the load up the hill faster, but it needs a whole lot more fuel to go the same distance. Again remember that My 460 was not stock, but I have pulled that trailer with a stock 460/C6.

The IDI is about the most reliable engine as far as diesels go, and as long as the cooling system is cared for, cavitation is a non worry point in my opinion. repair costs for the IDI beat the PSD hands down. Injectors for the IDI are about $35.00/ea...PSD injectors are about $350.00/ea.

Bottom line: If you can get an IDI for the right price and add a turbo, that's the way to go!!
 
#7 · (Edited)
I can't really tell you how they compare to PS's, but I can tell you how my personal '91 F350 IDI dually with a service body compares to the gas engined service body trucks I regularly drive for a living and to more modern and smaller Japanese cars and trucks.

First off, these aren't really powerful engines, but they're adequate and they pull well. I never have any problem maintaining speeds between 55 and 70 on the freeway and they accelerate well enough that you're not going to slow down traffic. I used to have an International Traveller with a 3.0 Nissan Diesel in it and that was an utter slug in comparison. To me it compares to a full size with a straight six gas engine, but it tows better.

Maintenance wise, they don't really compare to a 2000 era Toyota. I've found lots of little things to fix on mine. On the bright side though, they are EASY to work on. They remind me of pre-emissions control gas engines in that regard. They're simple and you have lots of room to work.

As far as fuel economy goes, I just filled up and I went 178 miles on 13.7 gallons of diesel, making the mpg's almost exactly 13. That's mixed driving and I was hauling stuff on top and inside it for about 1/3 of that. probably 2/3 highway and 1/3 city. That's with a 7.3 IDI, 4x4, E40D, 4:10's, dually rear and a big service body. My best mileage results have been 16 mpg and the worst about 11.5 and I drive like a granny.

My usual work truck in comparison is a C3500 utility truck with a service body and a bucket lift on the back. I'm not sure the exact engine size in it, as it is a company rig, but it is a V-8. One thing I do know however is the kind of gas mileage it gets and that's between 6 and 7 mpg, as I figure it out every time I fill up and thank God for fleet gas cards. I don't recall ever seeing it get more than 7 mpg and it's a 2wd. In fairness however, I do a lot of city driving with it, probably 60%. My old work truck was a gasser F350 bucket truck and while it's been a few years I recall it getting similar mileage to my current company truck.
 
#8 ·
yea the cavitation eating holes in the cylinder walls is preventable with a quality diesel coolant additive. i think we all would recommend the idi engine as a first diesel due to their inherent simplicity and respectable power
 
#9 ·
Thanks guys!

These responses have been most helpful. I've been turning wrenches on gassers for years, so I like the idea of simplicity that you speak of regarding the IDI's. I am convinced that a 460 is out of the question based on my own experiences with my 351W and your mileage reports as well. I know my dad used to complain @ the 8 mpg. so I know that is a bitter pill to swallow.
I am mostly worried about the horror stories I've heard about diesels regarding the expensive injectors and pumps, water/fuel filters and crazy $ oil changes, double batteries and gelling of course in the winter. If all of these "issues" can be mitigated by simplicity of repair, low cost of ownership and better mileage than a gasser...I definitely want to jump on board the gravy train.

Please keep the comments coming. I would love to hear from as many of you current and previous owners of these IDI turbo'd and non-turbo'd engines. Anything I should look at specifically when I go to view/drive this truck. I will be going to look this weekend, and it's a long drive (3 hours each way.) I don't want any surprises or disappointments I could have avoided by being forewarned.

Love this forum! :thumbsup:
 
#10 ·
ShakeFreight2
If you are still considering that IDI, I would ask the seller if he/she kept the SCA's up on it, if he don't know what that means then walk away from it. SCA is "Supplemental Coolant Agent" that is the additive to the coolant to prevent cavitation "thinning of the cylinder walls". A well maintained IDI will go a million miles without too much trouble. Some call the IDI a Powerstroke, a true Powerstroke was not until 94.5 when the engine was computer controlled. Reference: Ford Power Stroke engine - Wikipedia, the free encyclopedia

The IDI's are a good work/towing truck 83-94, the hi torque range is in the low RPM 1600 to 2000, top RPM is governed by the Injector Pump somewhere around 3800. As far as fuel milage goes, 16-18 is very good, some claim 20-21. That F350 with dual wheels will more than likely be 12-16 city.
 
#11 · (Edited)
Oh, I should ad, this is a 4 door, 8 foot bed dually, XLT automatic with every factory option with original 2 tone paint, and 2 wheel drive. Only accessory that seller knows about is an electronic brake booster, which I assume means it has pulled something relatively heavy during its life. It does have the 5k Reese 2" receiver hitch too. I'm hoping it doesn't need a bunch of front end work which I know is very expensive because it's considered a heavy duty/commercial use vehicle. I intend on pulling a 7k pound tandem axle trailer (RV) during the summer, once a week 150 miles roundtrip. Does this truck sound like overkill, or just right?

:ford:

Edit: Thanks Bill...that's very good info. I will ask seller about SCA. And thanks for clearing that up for me. Again, much thanks folks!
 
#12 ·
No such thing as overkill..My mantra " better to have more than enough and NEVER need it, than to NEED it once and not have it"..

Front suspension/steering parts are not expensive, and if you have less than $100.00 worth of tools, you can do everything except the alignment. I did my ball joints in one day and the parts were like $75.00 IIRC.
 
#13 ·
With a good tape measure and ten bucks worth of string, you can probably do the alignment, too. Since there's no caster adjustment it's not exactly rocket science. For me the problem is finding flat ground...
 
#14 ·
Well injectors NEW can be had for $26 at the right places, have 8 brand new injectors in mine that cost that much and have no issues with them, they were all BB coded too I think. Injection pumps also aren't that big of a deal, yeah a bit spendy but not too bad. My '90 460 F250 that I had would get about 4mpg on a good day and about 4mpg on a bad day haha, always 4 no matter what I did but the IDI I have (with turbo) would flat out beat that thing in any race any day, the 460 is gutless compared to a well tuned turboed IDI. Dual batteries arent that much of an issue, its just one extra battery you have to buy but its NEEDED, you CAN start them on one battery for emergencies but thats not the best for the truck. They are dirt simple engines, simpler than a carb car since you dont need to fiddle with anything fuel related really, just keep it clean and do regular fluid changes. Like was said before these engines arent horribly powerful, your looking at a stock 7.3NA with 180 horsepower and 360lbft but that bumps up quite nicely with a turbo. These engines were designed by International to run at full throttle redlined for HOURS and not have issues, try that with a powersmoke and you will have a dead engine. In my opinion the IDI is WAY better than any stock 460 around and they can run on almost any sort of fuel oil besides diesel.
 
#15 ·
I also absolutely LOVE my truck!! Yes it doesn't quite have the get up the new ones do, but I love having a truck that's not computerized!!! The only thing I see different than everyone else is milage. I get 8 mpg while towing 11K worth of 5th wheel and 10 when unloaded. Granted I do have the pump turned up just a bit... Before that I sometimes got 12 unloaded, but never ever in 10 years have I ever got over 12 and I only have 64K on it :)
 
#19 ·
umm, if you want an idi youre gonna have to go farther back man. like 83-94.5 and hey if you wanna trade it for one, mines pretty nice for a 93 and has just under 239k on it....just sayin...
 
#17 ·
the 460 is gutless compared to a well tuned turboed IDI.
I have had both and I can tell you the 460 is a rocket off the line compared to a properly tuned turbo'd IDI... My '86 F250 would blow the doors off my current truck...

Same grade in Tehachapi, Ca...Same trailer...Gasser did it @ 45 MPH all the way up...IDI did it at 25 MPH...biggest difference was the gallons of fuel consumed to do it.
 
#20 ·
I had 3.08 gearing in my 460 from the factory LOL, it was slow as hell and couldnt pull anything, just goes to show engine isnt everything ;) My IDI on the other hand could keep up with a new at the time (06) Dodge 2500 with the Cummins.............granted he had 38s, a lift and a tune on it but I could keep up, axle hop was horrid though, mine just has the pumped turned up a bit, ok maybe a bit more than a bit. Like said before, the IDI when towing will get you there...........eventually, its not fast about it but you WILL get there.
 
#18 · (Edited)
like my sig says, dont worry about what the things gonna pull, worry about what itll stop, and everybody else has said this and i guess its my turn. a non turbo idi will pull whatever you want it to, just dont expect to get there right now. but itll make it every time as for the extreme cost of injectors and so on, thats mainly the psd's area. our injectors are 35 each compared to 350 each for 7.3 psd, and wayyy up there for the piezo units on the newer trucks. ive heard horror stories of $4000 injector r&r. anyway man, idi is a definite recommendation. cheap to work on, stone simple, and almost unkillable.
 
#22 ·
Thanks again everyone for your input!

I am definitely going to pursue this truck purchase after getting so much positive feedback here. I hope to see it this weekend if the holiday doesn't cause a snag with scheduling a view/test drive. I will let you guys know in another thread if I become a proud new owner.

Cheers!
 
#25 ·
Mine was an '86 and since it was tagged over 8700 Lb gross, It didn't have the unleaded restriction or a cat. It did have an EGR and when I donated it to the local hospice it still passed CA. smog.
 
#26 ·
I used to have a built 76 460 in my truck and put many miles on it, used to eat ricers, they get really pissed when a cc passes them, it would pass anything but a gas stop got about 6 loaded.

The 7.3 turbo I built will pull circles around the 460 loaded and the mileage has almost tripled.

My opinion on cavitation is if it hasnt yet it may never. But get the price low enough and figure in an engine later.
 
#27 ·
Odd, I can't even find the CR for the 460 in my Ford book. These books really are terrible. Finding anything in them is a nightmare. That alone might be enough to convince me to buy another brand next time. Guess I should see what Dodge manuals look like.
 
#28 ·
I looked and looked for a diesel van ( I haul bikes) finaly found one in San Fransisco '91, 7.3 e4od auto, didn't start well ,had tranny issues.... new glow plugs, filter changes took care of that.. I did swap out the tranny for a 5 spd.. now I'm getting 21mpg on freeway driving and about 18 city.. on summer blend fuel..it's getting a turbo this winter and a propane tank .. I like it , it's a keeper... :thup:
 
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