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She’s So Positive My 6.9


1983-87 Global/Ford 6.9L IDI

-Devoted to the past due Terry Hankins, IH/Navistar Engineer

Public and governmental outcry after the oil shortages of the early ‘70s pressured U.S. auto, mild truck and business truck makers in opposition to economical diesel energy. Inroads had already been made getting extra diesels into the Elegance 3 thru 6 business medium vehicles, and the upper GVWs had excellent protection, however Elegance 3 and four had been nonetheless ceaselessly powered by way of little greater than beefed-up passenger automotive engines. To that point, there wasn’t a lot incentive to expand diesels for Elegance 3 and four for the reason that thrifty consumers of the ones vehicles, most commonly in-city brief hoppers, weren’t desirous about the standard 20% value top rate. Emerging gasoline prices modified the ones attitudes however cheaper price diesels had been had to push the theory around the end line.

From 1980, right here is likely one of the prototype 6.9L diesels. Evaluate it to the1983 symbol somewhat farther on. Having a look to the proper of the image, you notice a unusual sq. nook. This was once the Section 1 oil cooler, which was once a fancy plate-type design. For manufacturing, a extra compact tube-bundle taste was once used. Observe additionally the variations within the higher timing equipment duvet. At 780 kilos dry and with out ancillaries, it was once a slightly mild diesel.
That is the 1982 Global model of the 6.9L, dolled up with chrome and snazzy blue paint. To start with, Global had two scores, 155 horsepower at 3000 rpm and 305 lbs-ft at 1600 rpm or 165 horsepower at 3300 rpm and 310 lbs-ft at 1800, either one of the ones with the early 20.7:1 compression ratio. For ‘84, the typical IH scores had been 155 horsepower at 3000 (305 lbs-ft @ 1800) and 165 horses at 3000 with 321 lbs-ft at 1600 rpm. Scores as much as 170 horsepower at 3300 in vehicles had been allowed. Marketed was once a 180 horsepower ranking for marine engines. The 6.9L had oil cooled pistons, four-bolt mains, curler tappets, oil cooler, equipment pushed cam and injection pump, inboard combustion chambers (injectors at best of engine), exhaust valve inserts and sure valve cooling. The crankshaft was once a cast unit and the block was once solid of nodular iron. The heads had been tied down with 5 bolts for each and every cylinder.

Gasoline economic system considerations quickly was an element with Elegance 1 and a pair of mild vehicles (half of to one-ton) as smartly. Diesels had been a part of the solution there too however there have been few appropriate diesels to be had and the business addressed it in a short-sighted, haphazard method. Examples of that within the mid-late ‘70s incorporated the 80 hp 3.3L Nissan in Global’s Scout SUV and pickup strains, the 100 hp 4.3L Mitsubishi inline in Dodge D/W150-250 vehicles and the notorious 120 hp 5.7L Olds diesel in half-ton GM vehicles. Within the early ‘80s, GM stepped ahead somewhat with the 130 hp 6.2L diesel however you’ll be able to see the typical theme. A top buy-in for the privilege of proudly owning a gutless surprise.

The Ford model of the 6.9L differed in different respects from the Global. The secondary gasoline filter out was once fastened at the engine at the back of the alternator. The main filter out/water separator was once fastened at the firewall subsequent to the ability brake booster. Additionally, the Ford had a vacuum pump fastened below the alternator (now not proven right here) for the vacuum boosted brakes. Ford used a decrease profile air filter out to suit below the decrease pickup hood. Normally, the ‘83 fashion 12 months Fords had been rated at 161 horsepower at 3300 rpm and 307 lbs-ft at 2000 rpm. With the compression spice up to 21.5:1, that ranking went as much as 170 horses and 315 lbs-ft at 1800 rpm. The compression spice up to 21.5:1 will have come earlier than the ‘83 Ford fashion 12 months was once over, however we haven’t showed that but. Engine with serial numbers from 59209 and up had the upper ratio and a few of the ones are stated to have seemed in 1983 manufacturing. We’d like to ensure that.

Few knew that Global Harvester was once operating on a brand new diesel that replied the desires of truck homeowners from Elegance 2 thru Elegance 6 (6,000 to 26,000 pound GVW). IH was once in the middle of company upheavals and pink ink however their medium-duty line was once a top spot worthy of an funding. A brand new low cost diesel was once a kind of investments. Like maximum medium-duty strains, the decrease GVW finish of the IH line was once populated with fuel V8s, a lot of the ones legacy engines from the ‘50s. Past the gasoline economic system attitude, they had been virtually past hope of assembly long run emissions rules and being constructed on tooling that was once wiped out.

Goal Specs

The engineering goal was once for a quite priced V8 diesel within the 400-450 cubic inch vary, making 165 internet horsepower at 3200-3500 rpm. After engineering and advertising defined the fundamentals, professionals licensed the venture in 1977. The intense design paintings began in March of 1978 with a function of beginning manufacturing in March of 1983. The advance had a excellent shortcut, the just lately advanced medium-duty MV404 and MV446 fuel V8s supposed to ultimately change the outdated V-345, V-392 or even older V-478. The brand new diesel borrowed probably the most elementary MV structure and allowed the brand new diesel to be constructed at the similar new tooling. The proposed 420 cubic inch diesel used the similar stroke because the MV-446 however had a smaller 4.00 bore (0.125 inches smaller).

When the fits come to pose, you are aware of it’s a completed deal. Right here, from left to proper, are 3 VPs; G.D. Aravosis from Advertising and marketing, W.A. Wallace from Engineering and V.P Spedale Basic Supervisor but even so one of the vital prototype engines. The picture accompanied an October 31,1980 press free up from the IH Parts Crew, which included the Indy Engine Plant. The Indy plant had lengthy been IH’s fuel engine manufacturing facility and diesels had been constructed up at Melrose Park, Illinois. As fuel engine manufacturing slowed, more room was once to be had and diesel manufacturing was once ramped up at Indy till all of the gassers had been long gone. Indy constructed all of the mild and medium-duty diesels for company use and the ones offered to Ford into the 6.4L generation. The Indy plant closed in 2009.

In that generation, Oblique Injection (IDI) was once the straightforward solution to assembly upcoming diesel emissions necessities and it additionally delivered higher gasoline economic system than the DI engines of the day. Most likely the principle reason why was once low value, the IDI requiring a far more cost effective injection machine. In the ones days, the Ricardo Comet Mark V swirl combustion chamber was once the fashion. Sir Harry Ricardo had advanced the elemental design in 1931 and although advances in gasoline injection era would quickly tilt the benefit to direct injection, the Ricardo Comet V was once a viable solution for the Nineteen Eighties and was once utilized in many engines of the day.

First Engines

The primary prototype engine was once finished in August of 1979 and 160 extra adopted. Early checks highlighted the will for higher injectors. The primary ones attempted had been an outward-opening poppet injector that didn’t ship anything else close to the objective energy point and failed temporarily. A brief leap forward was once accomplished by way of putting in a suite of two-orifice nozzles from some other IH software, getting them in the course of the preliminary checks and into box trying out. It took some time to determine the correct mix of injector, injector focused on, combustion chamber location and compression ratio. The orifice nozzles proved non-optimal from an emissions point of view, and so they had been sooting up, so new inward opening pintle injectors had been designed and so they built-in smartly with the Stanadyne DB2 rotary pump.

The 6.9L owes it’s elementary structure to the 1975 MV-404 (2 and 4-barrel) and MV-446 (4-barrel) fuel engines. No, the 6.9L was once now not a “fuel engine with diesel heads” however the engines shared many options, the similar elementary dimensions and a few portions. New tooling have been constructed for the MV engines and IH sought after to make use of it for the 6.9L.  The 6.9L and MV-446 crankshafts had been just about an identical, although within resources let us know the warmth treating was once other. The MV engines had two-bolt mains and the diesel had four-bolt. Each the fuel and diesels used the similar equipment drives for the cam and oil pump. The MV heads had been tied down with 4 bolts in keeping with cylinder and the 6.9L with 5. The rocker equipment is the same as had been the valve covers. The MV sequence engines had a slightly brief lifestyles, simply seven years (1975-81) to the track of 120661 404 and 446 engines. This may be a dressed-up display engine. Most often, they had been painted pink.

A complete of 21,000 dyno take a look at hours had been collected at 3300 rpm, complete load, height energy and a few 52,000 take a look at hours overall. Beginning in September of 1980, prototype engines had been put in into vehicles and box examined, with over 813,000 take a look at miles collected. As soon as all of the insects had been found out and handled, they constructed 10 preproduction engines at the new line and a few had been examined an additional 1,000 hours at complete energy at the dyno after which out within the box. Precise manufacturing began in August of 1982, beating the unique timeline estimate by way of seven months.

Input Ford

As soon as the concept that was once confirmed and trying out smartly underway, IH started actively buying groceries the engine round. Global wasn’t inquisitive about supplying different medium-duty producers however light-duty was once some other topic since they’d discontinued their very own mild line by way of then. Ford Motor Corporate was once at the hook virtually from the beginning. Being handiest relatively better and heavier than their current 460 bigblock V8, it was once a positive have compatibility in Ford mild vehicles. Ford opted to provide it handiest in mild vehicles with an 8,500 pound GVW, or extra, that means F250HD and F350 fashions. That incorporated the Ford E250 and E350 vehicles however now not Ford’s medium-duties. It all started a industry courting that lasted 30 years, although it ended badly.

The ‘84-87 Ford sea point and top altitude energy graphs display a flat torque curve from idle to about 1800 rpm. The 1400-1800 rpm vary is the candy spot for those engines.

Ford began putting in 6.9L engines in August of 1982, first on the Dual Towns Meeting Plant and at all of the related truck vegetation in a while thereafter. Till about March of 1983, you must handiest get it with a handbook trans till the tooling was once able to mount the C-6 at the back of it. Ford marketed 161 horsepower at 3300 rpm and 307 lbs-ft at 2000 with a 19.7:1 compression ratio. Those specifications come from Ford Knowledge Books, brochures and Ford Information Books dated August and September of 1982. The early mag checks indexed those specifications as smartly. Global paperwork from the similar generation display the engine with a 20.7:1 compression ratio and it’s very most likely the nineteen.7:1 ratio indexed is both a initial quantity that was once modified or mistaken. Because it was once, the 20.7:1 ratio delivered chilly beginning problems and it was once higher to 21.5:1 for 1984 with piston and cylinder head adjustments.

Have an effect on on Historical past

Within the medium-duty marketplace, the 6.9L added an entry-level diesel into Global’s 1600, 1700 and 1800 strains, each busses and vehicles, with GVWs as much as 26,000 kilos. That was once excellent for Global’s final analysis however it didn’t rock the medium-duty international and different producers adopted go well with with an identical engines. It sounded the demise knell Global’s medium-duty fuel engines, together with the slightly new MV sequence. Manufacturing of gassers at IH (later Navistar) dwindled into the masses of engines by way of the mid ‘80s and had ended totally by way of 1988.

The decrease finish may be very stout for the generation. Proven is a 1986 engine right through an overhaul. You’ll see the four-bolt mains and power drives.

The 6.9L was once changed by way of the 7.3L IDI in 1988, which obtained turbocharging in it’s ultimate 12 months of manufacturing, 1994. A complete of 436,868 6.9L engine had been constructed from August of 1982 to August of 1987. The HEUI diesel emerged in ‘94, referred to as the T444E by way of Global, and Powerstroke by way of Ford. Through then, Global Harvester have been damaged up. The Motor Truck Department, together with the engine production part, was Navistar Global.

The weakest hyperlink of the 6.9L are the top gaskets and head bolts. Fashionable head gaskets with an ARP head stud package remedies this weak point.

The 6.9L had extra importance within the light-duty marketplace and speaking about it forces us to possibility inciting GM as opposed to Ford contention. GM beat Ford to the punch with the intro of the 6.2L diesel for 1982. It was once a some distance higher engine than the 5.7L it changed however was once nonetheless low on energy. The 1982 6.2L GM diesel emerged with 130 horses and 240 lbs-ft. (135 hp in HD emissions) and stayed at the ones scores till later within the ‘80s. The 6.9L emerged for ‘83 at 161 horsepower and 307 lbs-ft however was once as much as 170 horses and 315 lbs-ft by way of 1984. The 6.2L was once to be had in all GM vehicles into the C/Ok 30 realm and did lovely smartly within the half-ton strains. It was once much less stellar fastened in hard-working 3/4 and 1-tons the place low energy delivered mediocre loaded efficiency and a few important degradation in reliability.


Two 1986 Ford F-250HDs. Left: What was once completed. Proper: What Gale Banks did and Ford/Navistar will have to have completed to rock the arena. Banks got here out with a non-wastegated turbocharger package for the 6.9L in 1984. It made about 10 psi spice up, and Banks marketed 255 horsepower and 550 lbs-ft. The primary era package at the proper was once put in by way of the unique proprietor when the truck had 7,000 miles. It’s nonetheless there and will nonetheless put 200 horses to the rear wheels.

The buy-in was once nonetheless lovely top for each engines (vs a large block which was once round a $500 for each FOrd and GM) so getting better the ones prices from gasoline and upkeep financial savings may just take some time. The 1983 GM 6.2L diesel choice was once $2375 ($1334 engine plus $1041 for the desired diesel apparatus bundle). For ‘83, all the Ford 6.9L choice at  $2225 for the 4×4 and $2543 for the 4×2. Making an allowance for the ability distinction, which was once the easier deal? To not disparage the 6.2L, however in taking a look again, and the use of boxing metaphors, you must say the 6.2L was once a light-weight or welterweight in it’s output and development. The 6.9L was once a forged middleweight or perhaps a gentle heavyweight. The GM 6.2L was once a excellent and economical selection in a half-ton however when you towed or hauled, the Ford 6.9L was once the easier selection.

These days, maximum would sneer at a 170 hp NA diesel with 315 lbs-ft, however within the early ‘80s the ones numbers gave you some braggin’ rights.

The publish She’s So Positive My 6.9 seemed first on Diesel International.

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