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Welcome to the 8-71 EFI Page.

8-71 EFI Project.
This is the 8-71 EFI blower project which will eventually reside on my Nordic Jet Boat. I am trying to complete this on a budget so I will be machining and fabricating as many parts as possible. Follow along for the creation of the 8-71 EFI project.



77 Nordic Jet Boat
-This is the boat the blower will be going on with EFI.

Parts Is Parts.
Here are the main parts. New Dyers 8-71 blower, BDS Bug Catcher prepped for EFI with only the center blade functioning as the throttle body. The outer blades are blocked off. Later the air bypass valve will be hidden in one of the blocked off sides. Included are intake manifold and snout/drive kit.



Ok getting started. Here the plate is a solid chunk of 6061 T-6 aluminum. I mapped out the holes on the Bpt. machine with a drawing I had for the bolt spacing. Drawing courtesy of Kinsler's Web site.
This plate will house the EFI fuel injectors and the fuel rail.

Here is the EFI plate done. I did not machine it on my manual Bpt. machine. I had a good friend write a program and machine it on his Haas CNC machine.


Next up, machining the injector pocket holes. I wanted to make sure when I put the plate in my machine vice it was as square as possible to the spindle. Here the indicator only reads 3 tenths of a thou out.
That is .0003"
Here is the plate clamped in the vice. I am
using an injector pocket tool from Ross Machine. This cutting tool cuts the hole, counterbores and creates a smooth chamfer for the O-ring on the injector.



After some simple math for the injector spacing I
set the digital readout for this. I also will record
these values for later when the fuel rails are
This is after cutting the first hole in the plate.
Just 7 more holes to go.



Here the Rochester style injectors are checked for proper depth. These a 96 LB/HR low impedence injectors. They have a shorter pintle area so I have to make sure the pintle protrudes on the other side of the plate. I set the Z-stop and machined the others the same depth.

Here are the 4 holes cut for this side. Flip it over and cut the other 4 holes. Phew, no mistakes.




Mock up of the blower, blower EFI plate
and the fuel injectors.
Just another shot and checking clearence for the
large -10AN fuel rails.



This is the fuel rail material from Ross
Machine. It is the largest they have
available. Size -10AN.


Once again the digital read-out was used from the
recorded values calculated from the injector plate.
The same Ross Machine injector pocket tool was used.



Here are the fuel rails done. They came out pretty good.
Mocked up and checking the length of
fuel rails. They will be trimmed later on before
O-ring boss threading of the ends.



Ok more mock up. The Bug Catcher on checking for interference of other parts.
Found interference with the TP sensor and made marks on the rails in which they will be trimmed before threading.



Ok fuel rail threads are cut and machined for -10AN O-ring fittings. I machined these fuel rail stands and counter bored them for the hold down bolts.
Here are the fuel rail stands mocked up and getting the proper injector seal is critical so the height of the stands is very important when machining.



Locating the stand holes in the fuel rail. Using the milling vice also makes sure the O-rings on the injectors and seated top and bottom.
Here is the machined plate assembly with the fuel rails, injectors and O-ringed fittings.



Set the assembly on the Dyers 8-71 Blower. This is the start of many little problems after another. These are just some of the hurdles when building custom parts, which is just more customization.

This is one of the problems is that the BDS Throttle position sensor hits the fuel rail fittings. That's O.K. I will just make a new small TP sensor bearing housing.




The stock TPS BDS bearing housing in the center of the pic. Some round stock on the left machined down to the same diameter. Some extra bearings ordered from McMaster. The TP sensor and TP sensor shaft in pic as well.
A little while on the lathe and all done. The new smaller housing on the left. This supports one bearing so I made another bearing housing to mount on the outside of the mount.



Ahh now I have room.
Here is the outer bearing housing which holds the second bearing for better support and smooter action of the throttle shaft.


Yet another dilema. The valve covers hit the lower blower manifold. Off to the Bridgeport Milling machine.
Intake set up in the mill to machine for clearance. This has no effect on strength or performance.



All mocked up and everything clears. Finally.
Just another shot of the EFI blower set up on the Big Block Chevy. This is going to look bad in my Jet Boat. Also kept the picture full size.



Ok. The engine was torn down all the way to get the crankshaft out. I wanted to put a second keyway on the crank for the Romac Blower balancer I am going to be using. I made a JIG. This allows me to locate the factory keyway and the other one will be exactly 180 degrees from the factory one, which is a requirement for the Romac Balancer.
Here is the second 1/4" keyway already cut with the keystock set in place for mockup. Now time to clean the heads, block and many other parts to get ready for re-assembly.



Fast forward. I fabricated an upper engine cradle and home made spreader bar. This allows me to lift the engine with the blower and everything all assembled into the boat. I located both holes in the heads and used thick angle plate. I then drilled 3 inch flat stock that all bolts together.
Upper cradle part close up with the tabs welded on.




D-rings and home made spreader bar. It works great.
Picture of the home made spreader bar and I also made 3 holes in the bar so I could angle the engine when needed. The cradle is holding just fine.



I fabricated a lower engine cradle for storage. I used heavy wall tubing and plate. This will be used when I store the engine in the off season.
Test fitting the engine on the lower cradle. Fits perfect. Ok now onto the EFI wiring and DFI.



Cutting up a brand new Accel Thruster DFI wire harness to get it to fit right. I really did not cut it, I just cut the loom and such.
I also made a box for the DFI computer that will be mounted on the back of the seat of the boat.



Engine mounted on my run-in stand I made a few years ago. It takes about 20 minutes to get it mounted hanging from the cradle on the hoist.
Dressing up the engine and getting the EFI wiring together.




Had a lincoln radiator and used and washing machine water pump to pump the water through the block. A Corvette cooling fan keeps it cool.
All wired up and ready to run.



Cool everything works.
All wired up and ready to go. Made a custom bracket for the throttle return and wire harness holder.


I built my own MAP with the Accel Thruster. Got this beast running. The buzzing noise you hear is the washing machine water pump. I sitll have some major tuning to do.

Running Video
Turn Up the Volume


Next Page
Installing the Engine In The Boat

Site Navigation
Mustang Tech
Chevy Truck
Turkey Rotisserie
Puke Tank Fabrication Big Block Chevy Build Up 8-71 Blower Build Up Page Jet Boat Tech Cheyene Jet Boat Contact  
  Diamond Plow Conversion 99-01 Cobra Intake Fix Headache Rack Build Chevy Frame Crack Fix