'Bulletproofing' an IDI?

[towcat]

When you start getting near or above what the rig is rated for towing you make lots of trouble for yourself and others. Say you have 5.13 gears and are actually hauling 18,000 lbs with ease. Now think about attempting to stop that much weight. Its the brakes that really limits us as to what we can SAFELY haul. I recall some members mentioning hauling around 30,000 to scales... Tugging that much weight can be done but the truck can't handle that much on its back. I have hauled our fully loaded 5th wheel at about 12,000 lbs with 3.55 gears. The grapevine north from la is done around 55 mph where the Cajon pass to the south is done around 40 mph. My tandem trailer brakes are set up tight too. Being electric brakes that means tight brakes are dragging more than normal.

i've been all over the western and southern USA with my 1989 F450 with non-turbo'd 7.3 never worried about over heating when I hit the hills with the truck. legal loaded GVW is 15k/lbs real GVW was often 17-19k/lbs. gearing makes all the difference in the world. 60-65 no problem. 85 was my max top speed.

 

[Can30Diesel]

Being able to stop and control the weight is just as if not more important than being able to move it around. If it was my truck I would seriously consider installing an exhaust brake in addition to the other addons mentioned already.

The IDI was designed to be worked hard, and if it is understood that they cannot always keep up with the newer diesels, they will surely and reliably do all the same work at a slower speed.

 

[C_Luft]

It's all about how much you want to spend. For me I am the kind of person who likes to do things once, rebuilding an idi engine I would have the engine blueprinted and balanced, cryo treated, tops of pistons ceramic coated, 7.3 rockers if you have a 6.9, ford oem headgaskets, arp head studs, moose misters(injectors) or marine injectors (if you can find them), 90cc to 120cc injectionpump with a smoke puff limiter, upgraded turbo, type4 camshaft ,intercooler, maybe water injection, a oil filter bypass system or a oil centrifuge, and of course gauges, (boost, egt, water temp, oil pressure, ect).

 

[Andertusa]

Well, thank you guys for the info, your input has been greatly appreciated.

 

[jaluhn83]

Head studs, ceramic coat pistons, deck pistons ~0.015", typ4 cam. WG turbo set for 10-12 psi boost and matching pump fuel rate. IMHO special injectors don't do much for you so just a good set of stock ones. Intercooler. Decking/ceramic costing pistons isn't really necessary for ~10 psi boost but can't hurt and gives you the option to boost more later. Pyro/boost gauges and use them.

Learn to drive less like a gorilla.

For towing that heavy I would for sure want an exhaust brake and hydroboost and would be very careful doing it - that's a lot of weight.

IMHO roller rockers, and balancing woln't get you much of anything. These engines don't rev high enough for roller rockers to do much at all, and are heavy enough that precise balancing isn't needed. Makes it feel smoother sure, but I doubt that translates into anything worth the extra cost. Definetely use the later 7.3 style - I lost a fresh rebuilt engine due to a failed early style rocker.

 

[BDCarrillo]

An absolute bulletproof build oughta have the roller rockers just to keep the valve guides happy and get about a 1% power gain by reducing friction losses.

Balancing is a very good idea to keep from deforming bearings and wearing it out early... You don't want goofy radial point loads beating up fresh bearings. If you're slapping new pistons in I'd weigh the old ones and see if they're all matching.

Or, and just hear me out, don't F with it and don't pull absurd loads. These things are built stout already

 

[jaluhn83]

I doubt very much that you'll get that much of a frictional loss decrease with the low rpm that these engine run at and the size/mass of everything else. Much more effect on high rpm low friction engines. Would possibly reduce value guide wear, but on the other hand these engine don't have a severe guide wear problem.

Same with balancing - sure it's nice, but at the low rpm range of these engines and how heavily they're built it's not that critical.

How often have you heard of a idi loosing bearings? I've never heard of one that didn't have issues from something else, ie improper clearance or contamination.

IMHO, both are nice to do things, but something I'd say is worth a minimum of time/money.

It's worth remembering that much of the high performance gas engine knowledge is not directly applicable to a diesel due to the significant difference in construction and operating rpm.

 

[03wr250f]

The only thing I see that others have not added or I differ from a few of there opinions, but everyone is entitled to theirs. My suggestion is upgrade your rear brakes to disk brakes, get a really good brake controller and with an exhaust brake you can safely run the same amount of backpressure as you can boost without floating valves. which would be 10-15 psi of backpressure befor you overcome the exhaust valve springs. I have heard of people swapping in heavier duty powerstroke springs. But like many said it is more important to stop the load than haul it. You don't want to kill the bus full of pregnant nuns. I have hauled 20k with an idi and it was not fun. You have to plan ahead for the idiots of the road and grades are nerve wracking especially when they are 5% or better. Stopping is crucial. To keep things cool an aluminum radiator may not be a bad idea especially towing that heavy. Only ford Thermostats if your going to do a cooling system refresher. And for that heavy of towing everyday a zf6 may be better because 1st gear and 6th are the same ratios as azf5 but 2,3&4 are closer together allowing you to stay in the powerband better for towing. it also has an internal oil pump which can allow you to add a cooler later on if you choose. And the shafts in them are designed to tow more weight.
Oh final thing a finned diff cover may not be bad to.
Hope this helps.

 

[burt]

The only thing I see that others have not added or I differ from a few of there opinions, but everyone is entitled to theirs. My suggestion is upgrade your rear brakes to disk brakes, get a really good brake controller and with an exhaust brake you can safely run the same amount of backpressure as you can boost without floating valves. which would be 10-15 psi of backpressure befor you overcome the exhaust valve springs. I have heard of people swapping in heavier duty powerstroke springs. But like many said it is more important to stop the load than haul it. You don't want to kill the bus full of pregnant nuns. I have hauled 20k with an idi and it was not fun. You have to plan ahead for the idiots of the road and grades are nerve wracking especially when they are 5% or better. Stopping is crucial. To keep things cool an aluminum radiator may not be a bad idea especially towing that heavy. Only ford Thermostats if your going to do a cooling system refresher. And for that heavy of towing everyday a zf6 may be better because 1st gear and 6th are the same ratios as azf5 but 2,3&4 are closer together allowing you to stay in the powerband better for towing. it also has an internal oil pump which can allow you to add a cooler later on if you choose. And the shafts in them are designed to tow more weight.
Oh final thing a finned diff cover may not be bad to.
Hope this helps.

Where would you tap in for a back pressure gauge? I always use my exhaust brake sparingly because it always sounds like people are saying it's a little sketchy on an idi. Although I've never heard of somebody actually floating a valve with one.

 

[Waystro]

You don't want to kill the bus full of pregnant nuns.

Wait they get pregnant?

 

[Black dawg]

Or, and just hear me out, don't F with it and don't pull absurd loads. These things are built stout already

This.

I do think though, any altitude at all needs a turbo to clean up the smoke.
A cheap and easy bulletproof idi truck to me, would be,
7.3 or studded 6.9
wastegated turbo to mild psi, maybe 7?
wide ratio zf (for the low 1st)
4.56 or more gear ratio
us gear OD. for gear splits and double od when it would pull it.

intercooler would be nice, but adds complexity and cooling system strain.
exhaust brake would be a nice touch too.

 

[jaluhn83]

I've used an exhaust brake without any trouble. The one I have is the US Gear that has a pressure regulating feature, they offer a 35 & 50 psi setup, mine is 35 psi. Would be caution if you have one of the other types that doesn't really regulate, but I've had no issues at all using mine on a stock idi. Wouldn't hurt to put stronger spring on of course, and is simple and easy to do.

The exhaust brake makes a huge difference towing.

Not sure I'd mess with a trans swap - extra gear would be nice, but once you get to that point it makes just as much sense to not even mess with the idi and go get a PSD F-450 which is already going to come with heavier/stronger running gear & more power.

Don't think the intercooler really adds any strain to the cooling system, at least not an air to air unit. Yes, you're dumping more heat and providing somewhat more restriction to cooling air flow, but you're also going to significantly reduce exhaust and combustion temps, which means less heat dumped into the coolant to begin with.

 

[Black dawg]

You are probably right on the intercooler, especially at the power level that I was describing. The power level I am describing is basically using the turbo for "normalization" at altitude.

I agree on the exhaust brake, and 30 psi bp should be safe (or has been for me for a long time). One of these days I would like to research exhaust valve springs, it would be nice to step up to 60psi braking.

 

[jaluhn83]

When I rebuilt mine last time around I got some stronger springs from Russ (typ4) and put shims under them per his recommendation. Not sure I'd want to go for 60 psi though - that's a fair amount of pressure. Would be worried about blowing out exhaust joints and gaskets myself, also not sure about that amount of backpressure on the turbo - 35 isn't much, but 60 is probably above what it would be designed for.

 

[laserjock]

Where would you tap in for a back pressure gauge? I always use my exhaust brake sparingly because it always sounds like people are saying it's a little sketchy on an idi. Although I've never heard of somebody actually floating a valve with one.

BD and Pac Brake both have a port on the brake for a gauge to set the thing up. If you do a search BD has a brake that is "universal" that is listed for the IDI and they also have a table somewhere listing the manufacturer safe back pressure so you can set it. I actually just bought a Pacbrake unit today that I listed over in the marketplace area.