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IDI Forum Frequently Asked Questions - FAQ

Discussion in 'IDI Tech Article' started by Agnem, Apr 22, 2005.

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  1. Agnem

    Agnem Using the Force! Staff Member Supporting Member

    Likes Received:
    Jan 10, 2005
    Delta, PA

    This post will attempt to address frequently asked questions not answered by the Technical Articles section. It contains contributions by many members, and edited into this single document, and will grow as donated material comes in. Individuals interested in contributing to this FAQ, are encouraged to write up the topic in Question and Answer style, and send them to the moderator in a PM. The topic will then be added to the appropriate section. Individuals looking for answers to FAQ's should use their browsers "find" function to assist in locating key words in this post. If you have a question which has not yet been answered, please feel free to start a new thread. Hopefully if the topic is FAQ worthy, it will be added here as a result.

    Many parts for your 83-94 model year Ford F and E series vehicle are still available from your Ford dealer. Sometimes they are available and the Ford dealer does not know it, because they have thrown away their old part number books and converted to the computerized system which does not have a complete parts database of older vehicles. See The Parts Bin Tech Article sponsored by Towcat, for those hard to find and sometimes forgotten part numbers. Remember that many parts were common through 1997 for body and trim, and even some F-600 and F-700 series trucks used our cabs and doors.

    Popular 3rd party vendors include:
    LMC Truck
    Dennis Carpenter
    Hammerdown says this about TABCO...
    Thanks Ray ;Sweet


    Q.What is a Road Draft Tube (RDT) and how do I make one

    A.Contributed by Argve...
    Since there seems to be an interest in how to make a Road Draft Tube (RDT) set up in order to bypass your Crankcase Depression Regulator (CDR) here is a way of doing it. I will warn you guys that if you live in an area that frown heavily on a truck emitting smoke/vapors from the end of a tube connected to your engine then this might not be the best idea/mod for you. For example let's say California or the like. Basically where ever there are tons of green tree huggers as a RDT will surely send them into cardiac arrest.

    The principal behind a RDT is you will no longer be routing your crankcase vapors into your engine, you will SEE these vapors. For example on The Enterprise when I stop at a stop light I can see a slight sheen of something coming from under the front passengers side of the truck (where my RDT exits). I have been told by unsuspecting folks that my radiator was steaming, I have also been told it looked like something was on fire. So be prepared to get questions and dirty looks.

    First step is to remove your CDR from the truck, then plug the port where the CDR mated to the intake system. For example on a non turbo this is on the back of the intake horn. You can do this however you want. For example when you add a banks turbo they include a piece of metal that will use the stock bolt holes meant for the CDR to attach to the intake horn then they include a thick piece of rubber to plug the hole (gasket). This seals off the intake so you won't be sucking in UNFILTERED air.

    Then you want to give a path directly from the crankcase to under the truck. I would probably keep this fairly short as you don't really want to run this from the engine to the rear bumper, the backpressure created from a tube this long might be a little too much in my opinion. But a tube that is less than 8 feet long would probably be OK. You choose where/how you want to run this tube. All your doing is giving a path for the vapors to escape the engine.

    On The Enterprise since I have a banks sidewinder turbo (aftermarket) banks included a cast piece that bolts onto the front of the injection pump gear housing cover, it's moves the oval access cover out about 2 inches, then has a large hose barb on it. This barb is for a 1 inch hose (or there abouts). I hooked a piece of clear rubber hose purchased at Home Depot to this barb then ran across the top of the engine headed towards the heater core area, then made a big sweeping curve and headed back towards the alt. Once it reached the alt area (towards the outside of the alt - basically between the alt and fender) I made another big sweeping curve down. Then the tube ends just below the steering componets. I held the tube in place with zip ties (wire wraps). When I first start up The Enterprise she emits zero vapors but as she warms up you can see the vapors start. Then once fully warmed up they are at their max which is sort of like a tea kettle. If you pass by the front of The Enterprise you can smell diesel oil, which you should be able to since you have a direct path to the inside of your power plant.

    The Moose Truck sport a little different design in that Mel installed a weed sprayer filter to help condense some of the oil out of the vapors before they exited the tube.

    I only get a drop or so on the ground if I let her idle for long periods of time in one spot. Might be one drop might be three, who knows. But it's very very little. The seepage from my oil cooler front header gasket produces more oil than the RDT.

    Q. What is cavitation, and test strips, and all that jazz?

    A. Contributed by Agnem...
    The say a picture is worth a thousand words, so Click Here, and then come back and read the rest of this paragraph.
    There is enough information on the web as to the causes of caviation, so I wont' get into it here. There is also additional info in our Tech Articles section. What is important is that you PREVENT IT through the use of supplimental Coolant Additives (SCA's) SCA's come in the form of chemicals which are added to the coolant, and monitored with test strips. Our IDI's require them, even though Ford doesn't acknowledge this fact very well. For normal Green low silicate coolant, the proper additive is Ford VC-8 or Fleetguard DCA-4, available from Diesel Injection Service, as well as other online sources. The test strips are also available there, and a guide for using the test strips is located HERE. An additional way of maintaining these chemicals is to install a coolant filter and use filters designed to dispense SCA's.

    Q. What kind of coolant should I use then?

    A. Contributed by Agnem...
    This has been a difficult to answer question. This THREAD discusses it pretty well.

    Q. Should I get my heads machined when rebuilding my engine or replacing head gaskets?

    A. Contributed by Icanfixall...
    Make sure the shop does not resurface the heads. For whatever reasons these heads have a min thickness measured from the deck to the top of the valve cover gasket machined surface. The min is 4.795 to 4.805. The intake valves MUST be recessed into the heads 0.042 to 0.054 deep and the exhaust valves MUST be recessed into the heads 0.051 to 0.063. Now the pre-cups can be recessed by -0.0025 or +0.0025. That's above or below the heads by 2 1/2 thousands. They are made from inconel material so they are very hard to machine. It takes a special cutter to clean them up with the heads being a softer cast iron. Some shops remove them because they can't afford the expensive fly cutters. Be careful when you talk stuff with the shop know-it-alls. Make them prove what they are going to do. Many shops will cut the heads because it looks good and they get paid to do it whether it needs to be done or not. They are in it to make money anyway they can off of you.. The customer. You have rights. Many members are running the 910 valve springs. BTW we run the same spring for the intake and exhaust. They both have the same open or closed pressure. Make sure the exhaust valve seals are pressed up under the valve spring keeper. they are not done on the valve guide like the intake is. Head surface flattness is 0.003 in any 6 inches overall.. Never allow any shop to knurl the valve guides. That's a temp fix and all it does is crushes the cast iron into the valve area. It mostly just chips off but some does swell in that area. Then they ream it to fit. It wears out quickly too.


    Q. Ok so outside of the obvious adding a turbo what else can be done to IDI's to gain more ponies? I know little to nothing on IDI's so any input would be appreciated.

    A. Contributed by Agnem...
    This is a very common question. There are Two aspects to consider. One is, maintanance of the engine. The other aspect is performance modifications. On the subject of engine maintanance, the most common cause of performance loss is degredation of the fuel injection system. Fuel injectors, and injection pumps have a lifespan which is not easily determined. In general, 100,000 miles is considered a reasonable service interval. However, injectors and pumps can loose performance while still working satisfactorily. For more information on this, Click Here. Sometimes refreshing the fuel injection system with new parts will revive a tired engine. If your engine is up to snuff, then performance mods are the way to go. The rule of diesels is Air + Fuel = Power. The amount of fuel available is determined by your foot. Various tweaks can be done which increase the fuel being delivered. However, this fuel is useless until there is air available to burn it. Consequently, most mods focus on getting the fuel to burn more effectively, usually by increasing the air (adding a new intake and ultimately a turbo, and intercooler), or by introducing propane to chemically alter the burning of the fuel to make better use of the air that is available. Other mods include water injection (lowers combustion temperatures so that the air is denser) or nitrous (not used often in non-turbo charged engines). Getting more air in, means facilitating a better way of getting the spent air and gasses out, so changes to the exhaust system are usually a must, and a few extra HP and reduction of EGT's (Exhaust Gas Temperatures) are usually achieved by a free flowing muffler and piping. Headers are an option for those not wishing to turbocharge. Many ask about porting and polishing of the heads. Unlike a gas engine that revs high and deals with variable amounts of air, the diesel is a lower RPM beast that benefits better from a turbo, then these passageway mods. However, they can still be done. It's just a question of cost versus benefit, and the specific conditions one wishes to achieve. Stock horsepower for the IDI's is generally in the 155 to 185HP range, depending on engine, year, and pump calibration. All 6.9 and 7.3 engines can easily make 185 with some simple tweaks. A turbo can add another 30 to 50 HP easily. The most common mods a new IDI owner makes, is a free flowing exhaust system, and a new air filter (possibly a K&N) or maybe one of the homebrew air cleaner mods which include various open element air filter styles or ram air setups. It is recommended that you install a pryometer (Exhaust Gas Temperature Gauge) as part of your instrumentation so that you can measure performance changes in a scientific way, rather than just by "the seat of your pants". This is especially true if you want to "turn up the fuel" on your injection pump.

    Q. OK. So if a turbo is the best performance mod, who's is the best, and why?

    A. Contributed by Agnem...
    First it is necessary to understand that turbochargers come in two styles, and that their are three manufactures of kits for our engines. It is also possible to use a turbo off of a Powerstroke Engine, but that is too advanced a discussion for this FAQ. The two styles of turbocharger are wastegated, and non-wastegated. Wastegated turbos are best for making more boost at lower RPM's, while non-wastegated turbos have more top end performance. How to choose which is best for you is always a topic of conversation, and it can be best boiled down to city versus highway driving. This is an oversimplification. There are trade-offs between the two styles. A wastegated turbo gives more boost earlier, but causes higher EGT's with added backpresure at higher RPM's, and it's boost is regulated with valves, linkages and other parts not found on the non-wastegated style, making it more complex and expensive to rebuild. A non-wastegated turbo can create unlimited boost in proportion to speed and load, so it is important that it is sized correctly to prevent overboost conditions from occuring. It also has more lag than the wastegated models. For a non-wastegated turbo, the only current choice is from Hypermax Engineering. Their "Pulse" system turbo is available for all IDI engines. Banks once made a non-wastegated turbo and is often refered to as the first generation Banks turbo. Gale Banks with their "Sidewinder" system and Advanced Turbo Systems, originator of the 93-94' Ford factory turbo, both offer wastegated only models. So there is no choice really for non-wastegated, but if you want a wastegated unit, you can choose between Banks and ATS. Both have their strengths. Banks is regarded as the most complete kit on the market, while choosing an ATS kit gives you the closest thing to a factory turbo that you can get. There really isn't a "Best" in this question. It's mostly a matter of personal preference and cost considerations. A Hypermax turbo is usually the least expensive of the three, and the Banks the most expensive. The early Banks and the Hypermax Pulse offer the cleanest layout, with no significant incursion to the glow plugs or injectors, making them as easy to service as before. The Banks Sidewinder and ATS take up a lot of space and make access to glow plugs and injectors more of a challenge. No matter which one you choose, all three will make you smile with the performance they provide.

    Q. What kind of horsepower can I expect from an IDI 6.9 or 7.3 diesel?

    Current IDI Horesepower and Torque Bests... 205.35HP / 461.59Torque

    A. Contributed by Heath Sutton...

    Editors note... These results are rear wheel SAE horsepower numbers achieved on a SuperFlow dynometer unit during the 2009 IDI Weekend in Bowling Green, Kentucky, and represent a large cross section of truck models and styles. Some Powerstroke engines are listed for comparison. Most were modified.

    Name - Horsepower - Torque in ft/lbs

    Non turbo results

    John Herbert 143.9 261.3
    Marnin Gehman 137.4 257.1
    Heath Sutton 123.2 218.7
    Matthias Agne 108.8 229.1

    Average Horsepower of a normally aspirated stock IDI.... 128.3
    Average Torque of a normally aspirated stock IDI... 241.55

    Turbo results

    Heath Sutton- DPS inj 185.1 404.0
    Heath Sutton MM's 178.7 387.9
    Joe Perry 172.5 313.6
    Suzi Agne 151.9 284.2
    Steve Reitner 150.0 300.3
    Chris Barber 148.7 278.8
    Jared Witmer 136.0 304.1

    Average Horsepower of a turbocharged lightly modded IDI...165.55
    Average torque of a turbocharged lightly modded IDI...324.7


    Gary Russell 302.8 557.2
    Aric Hornsby 301.9 543.7
    Bonnie Young 181.8 373.3

    Average horsepower and torque for a Powerstroke...262HP/491.4

    Additional turbo equipped dyno numbers that were achieved individually...

    A comparison of Propane versus no Propane fumigation courtesy of Darrin Tosh
    First pull, no LPG - HP 183.15 Torque 325.45

    2nd and 3rd pull with LPG - HP 205.35 Torque 362.64, HP 205.51 Torque 361.55
    Bests average turbo IDI by 39.8 HP and 37.94 Torque

    So a 22.96 increase in HP and a 37.19 increase in Torque when using propane.

    Results of a truck equipped with Moose Mister injectors. No intercooler, #2 only, courtesy of Heath Sutton
    With a Moose Pump - 204.75HP and 461.59lb/ft torque
    With a DPS Pump - 178.7HP and 387.9lb/ft

    So a 26.05 increase in HP and a 73.69 increase in torque using a Moose Pump.
    Bests average turbo IDI by 39.2 HP and 136.89 torque

    Q. Are there other mechanical modifications to the engine that may improve performance?

    A. Contributed by the users...

    Read this discussion on alternate cams.


    Q. I have problems shifting into gear on my manual transmission. What is the problem?

    A. Contributed by Agnem...
    This is a common problem with manual transmission trucks, and the common solution varies somewhat between body styles, but all causes can be shared by any model year. Let's start with this TSB...

    Parts used in this TSB include
    The big plate kit, E3TZ7K509B about $126.90.
    The small kit(E3TZ7K509A)is only $16.25.

    This only addresses one of the symptoms, and not the cause. High pedal effort is the result of the throw out bearing not sliding properly on the tranny input shaft sleeve, often due to a lack of grease or galling of the sleeve. Proper lubrication of the TOB is a task that must be carried out on a routine basis. An upgraded TOB with a zerk fitting is available as part number F1TZ-7548-B. Slave cylinder cracking, and other hydraulic issues can often be traced back to problems with the TOB or presure plate. On later model year trucks, problems with the actual clutch pedal linkage can contribute to clutch problems. See the tech articles section. For even more information, check out the full 1988 TSB HERE.

    Q. I need to find out what my axle gear ratios are. How can I tell?

    A. Contributed by The Warden

    Ford service manuals for each model year indicate what axle code goes with what ratio, and if they are limited slip or open differentials. While it is not practicle to list each code for each model year, it is relatively safe to assume that codes didn't change much, at least among the 3 model families based on body styling. Editor

    Code Manufacturer Rating Ratio Notes (jaluhn's, not f/r book)
    13    Ford        3750    4.11 Ford 9"???
    14    Ford        3750    3.00
    16    Ford        3750    3.50
    17    Ford        3750    2.47
    18    Ford        3750    3.08
    19    Ford        3750    3.55
    22    Dana        5300    4.10 Dana 60?
    23    Dana        5300    3.54
    24    Dana        5300    3.73
    26    Ford        4050    3.55 Unknown
    31    Dana        6250    3.07 Dana 61
    32    Dana        6250    4.10
    33    Dana        6250    3.54
    72    Dana        6300    4.10 Dana 70 3/4 ton
    73    Dana        6300    3.54
    42    Dana        7400    4.10 D70 Dully???
    43    Dana        7400    3.54
    52    Dana        7400    4.10 Why not same as above?
    53    Dana        7400    3.54
    62    Dana        8200    4.10
    63    Dana        8200    3.54
    L/S axles
    H3     Ford        3750   4.10 9"?
    H4     Ford        3750   3.00
    H6     Ford        3750   3.50
    H7     Ford        3750   3.08
    H8     Ford        3750   3.55
    B2     Dana        5300   4.10 D60?
    B3     Dana        5300   3.54
    B4     Dana        5300   3.73
    C2     Dana        6250   4.10 D61??
    C3     Dana        6250   3.54
    G2     Dana        6300   4.10 Definetly a D70
    G3     Dana        6300   3.54
    D2     Dana        7400   4.10
    D3     Dana        7400   3.54
    Note the similarity between the ls and non l/s codes. The only axle id's I am
    sure of would be g2 being a dana 70-2u, and 31 must be a dana 61. Others
    are strongly suspected based on rating. Confermation would be helpful. Also,
    I beilive the same codes were used at least through much of the 80's.
    GCWR Ratings:
    Manual Trans:
    Engine Rear end ratio GCWR
    4.9    2.47           5450
            3.08           6450
            3.50           7800
            3.54           7800
            3.55           7800
            3.73 L.D.     7800
            3.73 H.D.    10000
            4.10           10000
    5.0-2 BBl 3.08      6450
                 3.54      7800
                 3.55      7800
                 3.73      7800
    5.0-EFI   3.08      6450
                 3.54      7800
                 3.55      7800
                 3.73      7800
    5.8         3.50      7800
                 3.54      7800
                 3.73      7800
                 4.10      9000
    6.9         3.07     9000
                 3.54    13000
                 4.10    14000
    7.5         3.07    9000
                3.54    11500
                4.10    16000
    Note: 3.54 & 4.10 w/ 6.9 add 1000# w/ T-19 wide ratio.
    Automatic trans:
    4.9 3.08 9000
    3.50 10000
    3.54 10000
    3.55 10000
    3.73 10500 - note 2
    4.10 - note 1 11000
    5.0-Carb 3.50 10000
    3.54 10000
    3.55 10000
    3.73 11000
    4.10 11000
    4.11 11000
    5.0-EFI 3.50 11500
    3.54 11500
    3.55 11500
    3.73 12000
    4.10 12500
    4.11 12500
    5.8-2 BBL 3.50 10000
    3.54 10000
    3.73 11000
    4.10 11000
    5.8-4 BBL 3.50 10000 - note 3
    3.54 11500
    3.73 11500
    4.10 12500
    6.9 3.07 10500
    3.54 12000
    4.10 14000
    7.5 3.07 12000
    3.54 15000
    4.10 18500
    1. Heavy duty engine only - 8500+ gvw
    2. 10500# for heavy duty (8500+ gvw) only. Light duty (8500- gvw) 10000#
    3. F-150 4x2
    Note: Max trailer frontal area is 60 sq ft. Devalue 2% for every 1000ft
    Interesting notes: (mine, not the book)
    1. 7.5 gcwr is much higher than the 6.9. Is it over rated, or the 6.9
    underrated, or is there really that much differnce in power?
    2. Gcwr is idepandant of vehicle type, exept for constrainst based on
    drivetrain avalibility.
    Originally posted by jaluhn here.

    Here is from late 85, with the Sterling axles listed:
    13 Ford 3750 4.11(This is likley a 9")
    14 Ford 3750 3.00(9")
    16 Ford 3750 3.50(9")
    17 Ford 3750 2.47(8.8")
    18 Ford 3750 3.08(8.8)
    19 Ford 3750 3.55(8.8)
    22 Dana 5300 4.10(60 semi float?)
    23 Dana 5300 3.54
    24 Dana 5300 3.73
    25 Ford 5300 4.10(10.25 semi float I'd assume)
    26 Ford 4050 3.55(not a clue on this one)
    27 Ford 5300 3.73
    29 Ford 5300 3.55
    31 Dana 6250 3.07(D61)
    32 Dana 6250 4.10(D60 FF)
    33 Dana 6250 3.54
    35 Ford 6250 4.10(10.25 FF, 2.5" brakes)
    38 Ford 6250 3.08(didn't think the 10.25 was ever offered this tall)
    39 Ford 6250 3.55
    72 Dana 6300 4.10(D70 FF SRW 2.5" brakes)
    73 Dana 6300 3.54
    42 Dana 7400 4.10(D70 FF SRW 3" brakes)
    43 Dana 7400 3.54
    45 Ford 7400 4.10(10.25 FF, 3" brakes)
    49 Ford 7400 3.55
    52 Dana 7400 4.10(maybe narrow brake D70 dually?)
    53 Dana 7400 3.54
    62 Dana 8200 4.10(Wide brake D70 Dually I'd assume)
    63 Dana 8200 3.54
    65 Ford 8200 4.10(3" brake 10.25 dually)
    69 Ford 8200 3.55
    Limited Slip:
    H3 Ford 3750 4.11
    H4 Ford 3750 3.00
    H6 Ford 3750 3.50
    H8 Ford 3750 3.08
    H9 Ford 3750 3.55
    B2 Dana 5300 4.10
    B3 Dana 5300 3.54
    B4 Dana 5300 3.73
    B5 Ford 5300 4.10
    B7 Ford 5300 3.73
    B6 Ford 5300 3.55
    C2 Dana 6250 4.10
    C3 Dana 6250 3.54
    C5 Ford 6250 4.10
    C9 Ford 6250 3.55
    G2 Dana 6300 4.10
    G3 Dana 6300 3.54
    D2 Dana 7400 4.10
    D3 Dana 7400 3.54
    D5 Ford 7400 4.10
    E2 Dana 7400 4.10
    E5 Ford 8200 4.10
    F9 Ford 8250 3.55
    Originally posted by 82F100SWB, same thread. I know some of these codes changed at some point. I have a G3, and it is a 3.54 LS. I also have been told that for newer trucks the drivetrain site is right with their ID of 4.30 LS. This also doesn't show 12.
    Just the facts, ma'am ;Sweet


    Q. My firewall is cracked where my clutch master cylinder is mounted. What can I do to fix this?

    A. Contributed by Krawlr
    Ford offers firewall repair/reinforcing kits in two flavors. The price difference between the large and small kit is not trivial, so choose the kit that addresses the severity of the crack.

    Small kit:

    Use reinforcement kit E8TZ-7K509-A on these trucks. The only part in this kit is the special reinforcement for these trucks. To install it, proceed as follows:

    1. Remove the two clutch master cylinder attaching nuts (13 mm) from inside the truck.

    2. Position the reinforcement in place over the clutch master cylinder studs.

    3. Re-install the two master cylinder nuts, Figure
    6. Tighten to 9.5 - 14.9 N-m.

    Large kit:

    Use reinforcement kit E3TZ-7K509-B on all 1983-1991 Bronco/F-Series trucks with hydraulic clutch controls. The kit consists of the following items:

    A main reinforcement or doubler, with a plate having two studs to clamp the doubler through the cowl inner.

    Two additional pieces with three threaded holes:
    One plate helps attach the main doubler through the dash inner tunnel. The other large piece is placed inside the front of the cowl, with bolts driven through from the engine compartment side of the dash reinforcement, see Figure 7. (sorry no picture here).



    Q. My headlights blink on and off, and don't seem that bright. What can I do

    A. Contributed by PaFixItMan

    The Headlight switch is problematic in that it conducts the full current of the headlamps. A well respected modification is to install relays that take the load off of the headlight switch, resulting in longer life for the switch, and better lighting all around. A couple of good article links to this are Here and Here. Note that Summit Racing is now offering pre-made wiring harnesses and relays specifically for this application. Hope this link doesn't go bad too quick -> Summit's Relay Upgrade Kit --> New link


    There are smatterings of official manuals and other documents in various places on the web. Please report any bad links to the moderator.

    The Diesel Files - Many different downloads here.

    ZF-5 model S5-42 Documentation (Requires free Adobe Reader )

    Everything you could want to know about Dana 60 front axles (courtesy Pirate 4X4)

    Various 6.9 related documents Moose Truck library
    Electrical Schematics for F series 1986 Moosestang Library
    Various 7.3 related documents Lady Moose Library

    The Gale Banks memorial library (Banks turbo manuals and such).

    For more of this FAQ, CLICK HERE to go to PART 2.

    End of the FAQ at this time. PM me to contribute! - Mel
    Last edited: Dec 4, 2017
    Jake60, papadiesel, Trevtron and 3 others like this.
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