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Well on to Question 5: The restricted air paths inside the engine compartment of the Gen III and the Gen IV E-series has really bothered me for some time. There are a few solutions: A. add a hood vent at a high pressure zone under the hood, but at low pressure zone above the hood. B. Close off the underside under the radiator by extending an air dam past the front suspension crossmember to create a low pressure zone to dump the air exiting the radiator. or C. Apply a series of airflow smoothing panels inside the engine compartment to form a duct for the radiator outflow. Add to this a couple of simple inflow ducts to shape the airflow into the radiator.
Solution A is possible with a long (wide) vent that has to be placed right behind the radiator support bar and near the edge of the flat section of the hood. The "atop the hood" low pressure zone is only about 3" long. This opens up water inflow and cost as I have found nothing remotely like it in the aftermarket. I have begun to map out the high and low pressure zones with a 0-5" water column magnehelic gauge but I haven't finished the front and rear of the radiator yet.
Solution B is actually the basis of another thread I tried to start on why isn't there an engine splash shield for the E-series as there is for most other cars and light trucks. An undertray of hard rubber or plastic running from the bottom of the bumper or air dam to the rearward edge of the front suspension crossmember would stop the hot air recycling loop into the radiator. If the tray ended 1-3 inches below the edge of the crossmember, the air running under the body and frame could form a low pressure duct to extract air from the engine compartment as well as the radiator exiting air. I'm going to fabricate one of these out of 0.25" neoprene with some riveted Aluminum reinforcement and measure the pressures and flows with the magnehelic gauge, but I can't get to it until late spring. I will leave ports to the front wheels to take advantage of the low pressure zone created by their rotation. It will interfere with oil filter changes, but will have to be taken down for such service.
C. As far as ducting is concerned around the radiator proper, several rubber panels going from the edge of the fan shroud to the end of the cab area on either side of the engine would smooth out airflow to generate a self evacuating duct. In the front, sheet heavy rubber strips from the edges of the open grill structure to the edge of the radiator cores would seriously reduce the entry turbulence and possible assist the overall system flow.
Anyway, the the Dorman fans are in the right range of competitive with the OEM mechanical fan/clutch assembly and will solve the overheating problem at idle and super hot days. If I'm wrong (probably for the nth time), I will solve the long pull up the mountain problem with a water spray on the radiator core. Given I'm driving a motorhome with a 36 gallon supply of high purity drinking water, I'll set up a mister in the grill area, feed it from the water tank and hose 'er down!
Thought I would update this thread with the current progress to date, as I have discovered a few things that I didn't anticipate and found surprisingly difficult to find through internet exploration.
To begin, while local snow levels oscillated between 6 inches and 3 feet, I set up to measure the current draw with the existing configuration of my dual battery motorhome, stereo with subwoofer, high energy ignition, primary and auxiliary lights and motorhome loads (fridge, heater, vent fans, pumps, etc.). This was prompted by the difficulty I have been having stopping the fan belt squeal on the v-belt driving my 140 amp rated alternator. I measured a maximum load of 112 amps! Adding to this the approximate 40 amp load of the dual Windstar electric fan system, I have exceeded the rating of the alternator. Perusing a number of posts here on FTE as well as other internet threads, it appears that a single v-belt driven alternator can support about a 100 amp draw before the belt begins to squeal. Further, as I have noted in another thread, the Summit 140 amp alternator I'm using is based on the classic 10Si GM alternator case which is poorly cooled in general. The mounting of the alternator on my 1982 460/7.5L engine places its cooling air inlet directly aligned to the exhaust manifold. Finally, under 100 degree ambient conditions, I have found the output voltage to drop to 12.6V from 13.5V, suggesting alternator overheating.
As a result, I decided to look into higher capacity alternators and better cooling for the unit. This quickly lead to the Ford 3G alternator series with its vastly improved cooling capability with dual internal fans and redesigned case. After considerable study, I decided to go with a 200 amp rated 3G large case straight ear unit. This also demanded either a dual v-belt or serpentine belt drive for the alternator since I realistically expect a 150 amp maximum load. Exhaustive searching showed no dual v-belt drive capable crank pulley for the 460 without custom fabrication, because of the added complication of air conditioning and power steering.
Consequently, I began to look into converting the existing 3 v-belt accessory drive system into the stock (88-94) 460/7.5L engine poly-vee 6-groove serpentine-like system. This stock system uses two serpentine poly-vee belts to drive the alternator, air pump, AC compressor and power steering pump. The necessary bracket system is on all EFI versions of the 460/7.5L engine which was mounted in the F-series, E-series and the F53 chassis. However, the Saginaw "canned ham" power steering pump compatible bracket is only to be found in the E-series engines. A special bracket mounts the alternator and smog air pump on the passenger side of the engine while another massive aluminum bracket mounts the AC compressor, PS pump and a belt tensioner on the driver's side of the engine. I quickly found that both of these brackets are obsolete and can only be obtained from junkyards or eBay. The bracket for the Alt/air pump is common to all EFI 7.5L engines and can be sourced from both the Ford vans and the far more abundant F250/F350's. On eBay this bracket runs about $150-$200. The AC/PS bracket can only be obtained from the Ford vans and is quite rare commanding prices up to $400! As a result a visit to a nearby PicknPull resulted in the Alt/Air pump bracket, alternator tensioner, air pump with 6 groove pulley, thermostat radiator output port, AC/PS bracket, tensioner, power steering pump and pulley, water pump pulley and crank pulley along with all necessary bolts for $112 and about 6 hours of stressful crawling in and about many wacked vehicles. The AC/PS bracket, PS pump, pulley and tensioner came off a '94 E350 and the remaining items came off an F250. The long bracket mounting bolts were all 7/16-14 and 5.5 in long flange head. There are warnings in the appropriate FTE threads that the 88-91 7.5L blocks have two mounting points that are smaller than the 92-94 blocks with 3/8-16 threads. I purchased grade 8 3/8-16 hex cap screws at 5.5" length for those should I encounter them in assembly. No flange head bolts in 3/8-16 are available in 5.5" length.
For the alternator, I bought a Powermaster 47759 with 6.93" pivot to tensioning bolt distance, rated at 200 amp. This poly-vee serpentine conversion also gave the opportunity to upgrade the York AC compressor. When dismantling the bracket from the '94 E350 in the junkyard, I thought the AC compressor had the standard Direct Mount AC compressor body instead of the very common 4-ear mount seen on Sanden and Seltec units. Not so! Serious warning! The stock compressor for the EFI 7.5L engines with this bracket with factory installed air is either the Ford FS6 or the Ford FS10. After studying a number of discussions on Auto AC forii, the FS10 has a very poor reputation, the FS6 is described as an adequate replacement for the older York, but the Sanden/Seltec compressors are far more highly rated for performance and reliability. Studying the Ford parts manuals one finds that the dealer installed AC units for these models used a Sanden compressor model 4628 or 7501. The ringer is that the AC mount is very Ford specific. Facing the mounted compressor, the two mounting holes on the left are spaced 90 mm while those on the right are set at 78 mm. There is only one Sanden compressor with this Ford Direct Mount pattern and that is the 8105. It also goes by two other model designations, 4628 and 7501 (the dealer installed AC units). This is a heavy duty version of the SD7H15 compressor. New OEM Sanden units can be had for $200 and Sanden-Style knock-offs for $120. This unit comes with a JD rear compressor head which uses #8 and #10 male insert o-ring ports. The original ports on the York compressor are tube-O fittings. These correspond to a Sanden CB or CBA rear compressor head. These as well as many other port configuration heads can be separately purchased and swapped onto the rear of the Sanden compressor.
This becomes an issue if one wants to keep the existing AC hoses during the compressor swap. The existing hoses are very stiff and difficult to move from the area of their connection to the York compressor. The suction and discharge ports on the York exit horizontally from the compressor face. In contrast, the Ford AC mounting bracket mounts the compressor on a surface making about 45 degrees above the horizontal and the intake and suction ports of the JD head are bisecting that 45 degree plane and pointing to the passenger side of the engine. There is no Tube-O fitting approach for the Sanden compressor that conserves the fitting location plane of the original York compressor. New AC hoses fabricated locally have been quoted as $50 plus fittings or less each, so I will replace the hoses as well as the receiver/drier and the expansion valve in the course of the upgrade. The Sanden 8105,4628,7501 comes with a 6-groove 119 mm diameter pulley and bolts into the Ford bracket perfectly. The measured diameter of the crank pulley for the 7.5L poly-vee setup is 167 mm, so the drive ratio for the AC compressor is 1.4 times the crank speed.
The next phase is teardown and assembly. all parts are in hand so I hope to start the process within two weeks!
nice writeup, thank you for the great detail and information, I am following this closely!
As I read the second paragraph, I was preparing to reply with a "you might want to find a serpentine setup off an EFI engine with a 6PK drive belt to drive your alternator etc" - but you were already onto that!
I have a 92 E350 van with motorhome conversion, and the 7.5 EFI engine. I removed the engine driven cooling fan,drove it around a little bit, and just the reduction in noise would make the electric fan conversion worthwhile I think. Then reading those figures you published regarding parasitic hp losses associated with driving the fan has me convinced this is a good idea. Like your vehicle, mine has the typically cramped engine compartment, which is prone to heat buildup. No doubt the engine driven fan helps in this regard. So removing it would necessitate some other form of cooling in and around the engine. I am thinking of using a pair of OEM fans, similar to the Winstar ones you used (Australian Ford Falcon, I think they are the same fans as the Winstar) to take care of radiator cooling duties. But for the engine compartment, I am thinking of a couple of 12V bilge blowers, something like this:
They are only rated at 90 cfm, but can be ducted with cold air from under the front bumper, and then maybe one either side pumping air down the side of the engine, perhaps through a diffuser would do the job? I have a K type temperature sensor/meter, so I might take some readings from the doghouse area, to see what sort of heat we are having to deal with.
Conrod, it appears that strange minds think alike! I remain concerned about airflow through the engine compartment. I have been implementing two prospective solutions. The first I discussed briefly in this thread, namely controlling the air circuit but forcing all frontal air through the radiator and then closing off the hot air return circuit from behind the radiator that then moves forward under the radiator and bumper assembly for reentry in the radiator stream. Those comments , of course, were directed at BTU removed by the radiator for cooling. The other aspect of this control, which involves putting a semi-flexible splash shield from the end of the air dam to the end edge of the front crossmember, is to generate a low pressure area to help draw air through and out of the engine compartment. To do this, I have ended the shield with a 2.5" gap between the bottom surface of the crossmember and the edge of the the end of the splash shield. The shield is also fully open to the wheel wells. This essentially closes off the exit air path below the radiator and the front of the engine block forcing air to specific locations. Both of these areas are at significantly lower pressure than the engine compartment area at the outlet of the fans. My preliminary measurements give 0.5 inches of water pressure in the engine compartment at 50 mph, minus 0.3 inches in the wheel wells and minus 0.2 inches at the end of the splash shield or engine tray. I'll have better numbers when I complete this changeover, but the principle is clear, make certain the engine bay is no hotter than the air exiting the radiator by using aerodynamics to move the air.
Going back to your suggestion of the bilge pump approach for moving cool air into the engine compartment. Again, we are on the same page! I had purchased two in line 12V 3" bilge air pumps rated at 130 cfm, along with two '97 BMW 525 OEM Alternator Air Cooling Ventilation Duct Vent Pipes and Dorman 2.5" Defroster hose. The BMW ducts fit perfectly in the front of the wheel wells with the inlet facing the front tire surface. This is the highest pressure area under the van that I have found. The wheel well low pressure area I cited above is on the inside facing the rotating radial axis of the wheel and the area at the rear of the front wheel well. I mounted the 130 cfm bilge air pumps on the back side of the air dam, coupled to the BMW ducts. Then I ran the defroster hose up into the engine compartment and directed it towards the carburetor from the valve cover. A diffuser or duct as you suggest would be a better finish! Finally, I wired them into the same 12V power line feeding the electric choke but through a 160F thermal switch. I originally started with the bilge fans to provide cooling for my current 10SI case alternator. I had a rear alternator air duct from a Porsche 944 to direct the air from the bilge pump into the air inlet of the alternator. But as you can see, the 3G alternator approach negated that. Still need to figure out the air flow direction for the dual fan 3G unit. Sure looks like the air enters the front and back and exits in the middle!
The 3G I put on my 73 is a scream queen, I am considering swapping to a 2 belt setup to dual the V-belts or a serpentine swap, it is extremely annoying.
The 3G I put on my 73 is a scream queen, I am considering swapping to a 2 belt setup to dual the V-belts or a serpentine swap, it is extremely annoying.
There is a limitation to how much a single v belt will drive. Anything alternator over around 80 amps really requires dual belts or a multi rib belt. And if you have less belt wrap around your alternator pulley, the situation becomes much worse. The belt needs to be run very tight, and adjusted constantly to maintain that. As soon as you start getting slippage (squealing) it eats the sides of the belt away, and will render it useless in quite a short time, as well as leave a lot of black powder rubber everywhere! Even my serpentine belt will squeal occasionally, if the van has been sat for a while and the battery is low, and the belt is not tight. Unfortunately, although the 7.5 EFI had a serpentine belt, it did not have the spring loaded automatic adjuster that is almost universal these days. But still miles better than multiple V belts driving everything !
I wish I had a dual pulley, right now I'll have to replace them all, not certain the serpentine is functional for mine, there is no AC, power steering, or air pump, just the water pump and alternator. Yeah, I have gone through several belts so far, the electrical load is minimal, I've not been listening to my stereo system.
The problem with the serpentine belt, as I am sure you know, is that it is designed for the reverse rotation water pump, so the water pump pulley has no grooves in it, meaning it would not work on your van if you are just driving the water pump and alternator. You might have to go to an aftermarket kit like this one maybe?
Yeah, had already looked at a setup on ebay, just not sure it's best as they are designed to have a tensioner, not be pulled tight, dual V-belts is best I think, need to see if my crank pulley is 3 or 4 bolt. https://www.ebay.com/itm/March-Perfo...53.m1438.l9372
Maples01, and Conrod, the poly-vee serpentine system for the 460/7.5L engine uses a two belt 6-groove system with a two belt track water pump pulley with a normal (not reverse) direction water pump. Ford has never made a reverse rotation water pump for the 460. So there are several possible solutions to Maples01's dual belt or serpentine drive problem. I have not measured the distance of the water pump pulley hub to the block for the 302, but I do have several dual serpentine 6-groove belt 460 water pump pulleys in hand. The innermost belt track is closest to the block (on the 460). It could be used with the 460 crank pulley (also dual track) and drive a serpentine pulley on your alternator. Getting the right size belt will require measurement and tensioning by adjusting the alternator. The crank and water pump 460 pulleys are all 4 bolt. but my lack of familiarity with the 302 will stop further comments on the serpentine approach.
However, during my search for a 2 v-belt approach for the 460 to drive the 3G, I found several 3 and 4 groove crank pulleys in which all 3 or 4 pulley sheaves were the same diameter. I couldn't use them because I had to drive the AC and Power steering pump. The 4 groove crank pulley is available at bronco graveyard.com, and the details of the same diameter triple sheave can be found in several posts by Gary Lewis including this thread:
Of course, you will have to find the corresponding dual or triple sheave for the water pump, but there appear to be several custom units out there. Then its just the dual sheave pulley for the alternator.
Frank - you are correct sir, the 460 EFI is a normal rotation water pump, I must have been thinking of the 302/351W engines!....
I do like your idea of adding the undertray to create a low pressure zone, so that air will be drawn through the engine bay. This is much better than adding "devices" such as blower fans to do the job, less is more! The only concern I have is that at low vehicle speeds airflow would be low, which may cause temperature buildup. Although in many cases, low vehicle speeds also equates to low engine speed, (idling at lights, low throttle opening etc) so the engine will be creating less heat in these instances. I think some real world testing might be in order to test if this is an effective solution on its own, or if an auxiliary blower such as we have been discussing is necessary?
This is the setup on my 95 E350 460 with a 2nd A/C compressor and a honking big alternator(not sure what is it is as label is gone).
The smog pump locked up and the ole 460 just smoked the belt last weekend so in a autoparts parking lot I got rid of the smog pump pulley and got a slightly smaller belt. As I have that 2nd A/C compressor on top, the belt I used will not be the same as a standard setup.
This is the alternator I have in my Bus. Not sure but it may be a Leason(SP?) brand probably at least 200A output to drive the rear A/C condenser fans(3 of them) and 2 rear evaporator fans. And it's maxed out so adding a electric fan in place of the mechanical fan is not passable. With all fans and lights running the voltage is down to 12.7V !
Conrod, the undertray approach had been validated by many factory designs and by finite element calculations, but I have never seen any real world measurements of airflow. After thinking about your comment, I'm thinking about measuring the actual CFM flowing out of the wheel well and out of the duct at the end of the undergrad. My anemometer has a hold feature to measure the maximum value obtained but I'd rather get a real time measurement vs. road speed. Time to scan eBay for a remote anemometer! Had a short discussion with one of my aerodynamic engineering friends and he suggested that the flow at the undertray duct for a vehicle with the frontal area of the E350 would be in thousands of CFM!
Eddiec, its just amazing that someone (you?) stuffed that second AC compressor in a EFI 460! I also thought that additional idler was a very important possibility for increasing belt contact area on the alternator pulley. Wonder if it could be used with the regular belt setup just for the alternator?
Frank, yes I agree the undertray is a good idea, many road cars have this, as do many race cars!
I would like to measure air pressure at a few points on my van, it will be different to your vehicle as I understand yours has a coach built body? What gauge or meter are you using to measure air pressure?
