Why can't I adapt my OEM air cleaner to my TBI/EFI?

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I've just completed a very successful installation of the aftermarket Howell EFI kit on my 71 F engine and I can't believe how well this engine runs, idles and accelerates. My biggest apprehensions about going EFI was trashing the OEM air cleaner and cobbling a functional and reliable throttle linkage. Although I still don't know if my improvised OEM Air cleaner adapter is feeding the necessary 650 CFM of air the throttle body requires, I sure can't tell when fully accelerating or running down the highway at 70mph. If you look at the picture you will see that I basically knocked off STEVE H's (a fellow MUD member and forum contributor) design he use on a 2 F engine. All it required was taking a 2-3/4" section of 5" ID truck exhaust pipe that surrounds the throttle body and clears the top of the inject harnesses. As Steve H illustrated so well, I welded a thin sheet metal plate over the 5x2-3/4" stub and installed it on the throttle body. I will point out that it was necessary to pry the air filter housing bracket (bolted to cyl. head) up approximately an inch so the collar on the filter inlet was level with the plate on the adapter. Once the air cleaner was placed in the exact position to mate with the adapter, I traced the circle where the hole needed to be cut into the blank blank plate and cut it out using a 3" hole saw in my drill press. As much as the air cleaner collar looked centered on the adapter when tracing the hole pattern, it was not and is eccentric as the finished product shows. To complete the connection I welded a 3/4" long section of 3" ID steel exhaust pipe to the hole, finish ground it, painted and installed it. If you know something I don't regarding the function of this please don't hesitate to let me know. Otherwise, many thanks to Steve H and the help he gave in doing this. My next post will show a simple way to use the stock throttle cable to adapt the Rochester throttle body without modifying or changing any original parts on your Cruiser.

f engine air cleaner to tbi adapter.jpg
 
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Jun 10, 2017
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Washington
I've just completed a very successful installation of the aftermarket Howell EFI kit on my 71 F engine and I can't believe how well this engine runs, idles and accelerates. My biggest apprehensions about going EFI was trashing the OEM air cleaner and cobbling a functional and reliable throttle linkage. Although I still don't know if my improvised OEM Air cleaner adapter is feeding the necessary 650 CFM of air the throttle body requires, I sure can't tell when fully accelerating or running down the highway at 70mph. If you look at the picture you will see that I basically knocked off STEVE H's (a fellow MUD member and forum contributor) design he use on a 2 F engine. All it required was taking a 2-3/4" section of 5" ID truck exhaust pipe that surrounds the throttle body and clears the top of the inject harnesses. As Steve H illustrated so well, I welded a thin sheet metal plate over the 5x2-3/4" stub and installed it on the throttle body. I will point out that it was necessary to pry the air filter housing bracket (bolted to cyl. head) up approximately an inch so the collar on the filter inlet was level with the plate on the adapter. Once the air cleaner was placed in the exact position to mate with the adapter, I traced the circle where the hole needed to be cut into the blank blank plate and cut it out using a 3" hole saw in my drill press. As much as the air cleaner collar looked centered on the adapter when tracing the hole pattern, it was not and is eccentric as the finished product shows. To complete the connection I welded a 3/4" long section of 3" ID steel exhaust pipe to the hole, finish ground it, painted and installed it. If you know something I don't regarding the function of this please don't hesitate to let me know. Otherwise, many thanks to Steve H and the help he gave in doing this. My next post will show a simple way to use the stock throttle cable to adapt the Rochester throttle body without modifying or changing any original parts on your Cruiser.

View attachment 2741026
Pretty awesome….was it hard to tune or pretty much bolt in and run?

did you use a in tank pump or an external tank/pump assembly?
 
Joined
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Messages
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Tampa, FL
Pretty awesome….was it hard to tune or pretty much bolt in and run?

did you use a in tank pump or an external tank/pump assembly?
Mark:
I'm using the inline for now to see how it holds up and if it clogs up. I removed and flushed the tank thoroughly, but without mesh filter bag in the tank, it's a good question how long it will flow without clogging. I looked at taking the entire pump mounting assembly with flange from a late model tank and adapting it to the existing tank. May do it eventually. Anyway, you won't believe how well these old motors run until you add EFI.
 
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Steve; thanks for the info. We finished the restoration of our 68 3 years ago and rebuilt the engine using the Rochester B carb that I inherited from the previous owner. I rejeted to run a bit richer on modern fuel with ethanol, It runs great, but I think it would it would run better with EFI. The biggest issue with any carb now, in hot weather, I get into vapor lock issues….again, ethanol laced gas.

I’m looking hard at EFI using Like a Jegs or Summit mini tank, drops the return line back to the main tanks…which is a pain with dual tanks.

My biggest hold up was how to adapt the original air cleaner….and you noodled that out…its awesome. Never even thought about exhaust tubing.

Next question is what are you using for ignition, a stock or some sort of HEI

Anyway, keep posting updates. Great job!
 
Joined
Aug 29, 2018
Messages
129
Location
Tampa, FL
Steve; thanks for the info. We finished the restoration of our 68 3 years ago and rebuilt the engine using the Rochester B carb that I inherited from the previous owner. I rejeted to run a bit richer on modern fuel with ethanol, It runs great, but I think it would it would run better with EFI. The biggest issue with any carb now, in hot weather, I get into vapor lock issues….again, ethanol laced gas.

I’m looking hard at EFI using Like a Jegs or Summit mini tank, drops the return line back to the main tanks…which is a pain with dual tanks.

My biggest hold up was how to adapt the original air cleaner….and you noodled that out…its awesome. Never even thought about exhaust tubing.

Next question is what are you using for ignition, a stock or some sort of HEI

Anyway, keep posting updates. Great job!
Using the OEM distributor but upgraded to pertronix electronic w/ 3ohm coil (Pertronix Flame thrower). Have had this since just after doing engine overhaul last spring. Runs really well w/ EFI. Howell said it would work fine with stock set up. If you're running a header, like I am, you need a heated o2 sensor due to distance from cylinder head. To save yanking the header to weld in the o2 bung, I used one of those stainless steel saddle clamps that easy to put on. The manufacturer is Glowshift and I got it off Amazon for around $35.00.
Years ago, like the 70's, Manafree Toyota in California used to sell bolt on engine upgrade that had a header, Rochester Carb and a distributor that would buy you another 50hp. I was trying figure out what carb that actually was when I gave up on the original Aisin.
Good luck. let me know if you want an idea to adapt the throttle linkage using the stock cable and 2 simple fabs.
 
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Do you have pictures of the throttle cable/ linkage please post. Thanks again.
painting this black and installing it in the shadows of everything makes for crappy pictures. I'll borrow the old lady's new I-phone 69 and see if those 3 lenses can do a better job of showing it than my ancient #5.
 
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Messages
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Do you have pictures of the throttle cable/ linkage please post. Thanks again.
Okay my brother, here's how s***ty my craftsman s*** looks on the Iphone 69.
I used 1-11/2" steel angle because I didn't have any bar stock. As illustrated, you're making a 90 deg. bracket that will bolt up to the predrilled 6mmx1 in the TBody. You'll drill a 1/2" hole to run the throttle cable and adjuster through. Appox. 1-1/2" down from the bottom of the drilled angle you'll mount the free wheeling axel that allows the cable travel underneath when cable is pulled by accelerator pedal. Use a 1/4" x1-1/2" long plated bolt with w/ 1/2" shank. You'll need a 1/4" bronze sleeve (in Doorman parts cabinet @ Lowes or HD). Chop the sleeve down to 1/2" or slightly less and shoulder both sides with 1/4" washers, Turn a 1/4" nylon inserted aircraft nut until close to the inside washer, but load it so the washers and sleeve spin freely. You will bolt the axle through a hole in the bracket that you will determine based the amount of cable you've got to work with so throttle can fully open and close on the stop. Make the linkage adapter by taking a plated 1-1/2" fender washer and drilling to 7/16" to snuggly fit on throttle stud. Grind a flat spot about 1/4" back on the side of the washer clamp the 2 drilled nuts, leaving as much of the hole between the 2 nuts to act as a channel to secure the locking barrel at the end of the cable. Make sure the slotted nut is placed nearest the Tbody side of the washer. Tack welding 2 1/4" nuts that you've reamed the threads out of with (I think) a 5/16" drill bit and cut a slot completely through one side of only 1 of the nuts. Once tacked, very carefully chase the hole between the nuts and test fit the cable barrel into it. You can widen with file of pinch tighter with pliers, but you want the barrel to be able to move. Connect the cable to the washer adapter, using whatever washers you need to fill the space between the adapter allowing a 7/16" snap ring to hold solidly in place. Draw the throttle body adapter towards the bracket to see what adjustments need to be made when all is connected. I think a man of your experience can probably go by the pictures to understand regardless of these possibly confusing words. You'll come up with a way to do it better, so let me know when you do.

TBI bracket .jpeg


TBI bracket with cable axle.jpeg


TBI throttle linkage complete.jpeg


TBI throttle stud adapter with removable cable slot.jpeg


LINKAGE ADAPTER.jpg
 
Joined
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Messages
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Location
Tampa, FL
Pm sent. Following
Orange wire at top right to Positive battery terminal
Red wire w/ water-tight connector goes to bare red wire Fuel pump (should have corresponding connector splice onto it from Howell) You'll supply and run a 14ga black wire from bare wire at pump connector to ground source
the black box w/ metal mounting tab is the fuel pump relay (mounts to firewall(
the (2) plastic pouch-like gizmos are fuse holders (mount to firewall)
Red wire w/ tape splice that's chopped off goes to SWITCHED 12-volt power source at truck's main fuse block by gas pedal

572772C0-CC69-46EC-890E-F54473D5E34F.jpeg
 

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