Latest winter project....
 

Last year I posted my winter project of restoring the teak dash and gauges and installation of headers. Well I thought I'd share the results of my latest winter project. By the end of last season the motor was starting to get a little difficult to start and running a little rough - not terrible, but enough of a reason to do some work. After looking into the distributor and seeing it needed to be rebuilt along with the carb AND having just read the "EFI for everyone" thread I started thinking.....maybe I ought to fuel inject this thing. After doing a lot of research and talking with Alex Haxby (OP of efi for everyone), I decided to take the plunge. Now not any EFI would do. It had to fit under the hatch and still look cool so I chose the path less traveled and opted for an 8 stack. Well this decision turned out to be quite a project! The following posts will show what I went through....as a reminder, here is the "before" shot of the motor:

finding the right intake
 

My main criteria was that the intake had to fit under the hatch so the search began. Talking with several people and getting measurements from the block valley china wall to the underside of the hatch less than 12"were quickly ruled out Crower and Kinsler stacks. This left Hilborn, Enderle and Inglese that would fit with the right velocity stacks. The next criteria I quickly found myself wanting is to retain the Merc thermostat housing and water connections. This eliminated the Hilborn because it just had -12 water ports that I would have had to come up with a custom thermostat housing mount. Between the Inglese and Enderle, I opted for the Enderle since it was what I considered a true 8 stack (not that the Inglese was bad, I just didn't want 4 two barrel throttle bodies). I found the Enderle had a casting setup for EFI (the throttle bores are smaller for better flow modulation) and it had pads cast to allow for injector mounting along with an integral water passage and thermostat mount. Here's a picture of the setup I decided to buy. Still needed a lot of work to get it to work.....

intake modifications begin
 

For EFI, the speed density system needed a manifold vacuum reference for the MAP sensor to determine engine load. Since the 8 stack does not have a common plenum, a vacuum log had to be fabricated tying all the cylinders together to create the vacuum signal needed. This also will serve as the idle air control circuit for the IAC motor. Since I wanted a really clean installation, this was mounted under the intake. A 1 x 2 aluminum extrusion with welded ends was mounted and tied to each port with a hardline. Two reference ports were passed through the intake; one for the MAP sensor, one for the IAC.

intake modifications...
 

The throttle position sensor was next. I mounted this toward the back on the odd port side of the intake - again to be for the most part to be out of sight.

intake modifications....
 

Next was the throttle cable attachment. Since the push/pull action of our cables typically run along the length of the intake and the common 8 stack is across the width, this had to be converted with the use of a bell crank. I wanted this mounted low to clear the fuel rails and be in the same general location as the cable mount for a carb. Another important aspect I discovered is to limit the sensitivity of the throttle plates opening I had to attach the long arm of the bell crank to the throttle cable and use the short arm to actuate the throttle plates (I needed large cable movement to result in relatively small throttle plate movement to aide drivability).

more intake modifications - injectors and rails.
 

I ran across a really clean fuel rail system for a BBC intake from FAST. I really liked the simple and clean stainless mounting studs. Note how the throttle bell crank is low to clear the injectors.

cross-over
 

Since my motor is not making crazy horsepower, I decided to use a cross-over to connect the fuel rails. I'll run the fuel into one rail, cross-over to the other and then out to a pressure regulator and then return to the tank. I probably made three of these before I got the bends right to clear the distributor!

vanity.....
 

Before mounting the intake, I decided I didn't like the look of all the anodized red and blue fittings and fuel rails. I broke out the EZ-off oven cleaner and became a polishing fool. I also did an initial setup of the linkage to get it close on the bench (in hindsight I should have done more) and made sure there were no leaks with the vacuum log (it is not going to be accessible with the intake mounted - the trouble with vanity!). Also mounted the injectors and the wire harness to minimize the visibility of all the wires running to each of the injectors. They tucked up real nice under the fuel rails.

mount the intake...
 

With the intake mounted, I was able to determine the stack height I needed to clear the underside of the hatch. This resulted in a staggered setup because I had to make them fairly short and the bell mouths would interfere with adjacent stacks. I think the staggered look turned out nice. While I was at it, I broke out the buffer again and polished the outside of the stacks and used scotch bright on the insides to give a nice contrast and be somewhat consistent with the cast look of the intake.

engine wiring, paint
 

Along the way, I completely remade the engine wiring harness (from the Merc plug to all the sensors, alternator, etc.). Also mounted the MSD box in a different location on the back of the head. While I was at it I blasted and painted all the brackets and even painted the motor too.

EFI plumbing
 

Now time to get all the ancillary items in that are required for fuel injection.....fuel filters (pre and post), fuel pump, fuel lines, pressure regulator. This required design and fabrication of some mounting brackets. Luckily, the oil cooler was mounted on the bulkhead and the shelf that holds it made for a great mounting location for the fuel pump and post filter. The pre-filter stayed in the same location as the fuel/water separator when I was running the carb, except I upgraded to a 1/2 NPT head so I could run -8 supply lines to the pump and -6 from the pump to the rails and return line. Also needed to make a bracket to mount the MAP sensor, IAC motor, and MAT sensor. A convenient location was at the back of the motor. Here you see how the MAP and IAC are connected to the bulkhead connections running to the vacuum log.

wiring
 

I went with the Holley HP EFI computer system (thanks Alex!!). This was ordered with the universal wiring harness. After deciding to mount the ECU on the bulkhead under the rear bench I ran the harness back to the motor. Since I didn't want a mess of wires I ended up redoing most of the harness to get the connectors to come out in the right location to keep every thing as clean and as neat as possible. This took the better part of a day to redo; any splices I used heat shrink marine grade connections. Also, you can see in the last picture I opted to go with a MSD small cap HEI distributor so I could control the timing with the ECU (really slick). In the first picture you can see I was lucky in that my tank had two fittings (one was just plugged when the carb was used so I just opened it up and used it for my return line). A nice thing about the Holley is that the ECU is fully potted and USCG approved.

hoses....
 

Here you can see I routed the fuel lines (I used the USCG approved low permeation fuel lines) and also installed the thermostat housing that I ground the casting numbers off of and painted cast aluminum so it looked nice sitting on the intake. Also mounted all the water hoses and dressed up the ends a bit with chrome. In the last two pictures you can see the fuel pressure regulator mounted with the fuel pressure sensor mounted to it. Getting close to starting it! One last thing was to make the flame arrestors for the stacks. I modeled these after a standard carb flame arrestor using the same screen schedule (multiple layers of various size mesh). I designed the shape to ensure no loss of air flow since the various screens do cut down on the area quite a bit. The last pictures you can see one in progress (my Dad came up with a clever way to form and make these). Screen cuts really well with industrial scissors. Finally the motor was complete.....but will it run? Stay tuned - I'll post the rest when I get more time.

Wow - very cool...........

looks rear good ....still working on my project I feel your pain

very cool

WOW!
You and that Haxby guy did a great job. I am excited to see how it runs.

Thanks guys. Alex has been a tremendous help! He answered my rookie EFI questions, walked me through setting up the base map, and helped me troubleshoot some things when I started it for the first time (probably the second time, maybe even the third time, an even when I had it on the prop dyno! Yes - I had a number of questions!). Most of the issues I had were between the seat and the keyboard so to speak since this was the first time I ever set one of these up. I must say now that I am a little more familiar with it, the Holley software is really good. Now if I can figure out how to insert a video link I'll let you hear it run on the hose and then with me in the back seat on the laptop while my Dad is driving....

on the hose....
 

Here it is on the hose after learning in just in the idle area of the fuel map (set the AFR, O2 sensor is providing feedback and the computer is automatically making pulse width corrections to maintain the target AFR). I was trying to dial-in the idle before launching it for the first time. What I learned with the 8 stack is that they flow like crazy and the smallest of butterfly opening (thousands of an inch) will feed air and it will idle high (this is where I wish I had spent a little more time on the bench adjusting the butterflies and linkage). I had it set fairly good here with it idling around 850-900. I did buy a synchometer to check the airflow for each cylinder and I had two that were flowing just a tad more than the rest. When this occurs, you get a lean idle pop in those cylinders from time-to-time. I was able to add a touch more fuel to bring that down here, but ultimately I adjusted those butterflies to so they are flowing the same as the rest and it goes away. Unfortunately right after this video was taken I burned up the O2 sensor. The first picture shows where NOT to locate an O2 in the tailpipe. When I had the tail pipes made last year I had them put in an O2 sensor not knowing how important the location was. Dumb! Anyway, I learned it should be mounted between 10 and 2 to prevent condensation from collecting on the sensor and shorting it out. BTW - this causes the O2 sensor to report a full lean condition and the computer compensates by trying to richen the motor, black smoke then starts to come out the exhaust, and then the engine dies. The second photo shows a brand new O2 in a better location (at least it hasn't shorted since).

Some observations:
1. The 8 stack really smoothed out the idle - it's not as lumpy as it was with the carb. I don't know if that is a result of the EFI or as I'm told because there is not a large common plenum the cylinders aren't cross-referencing each other. Regardless, it is different.
2. Throttle response is insane!


http://www.youtube.com/watch?v=aLItJChhvlA

another video....
 

After getting it running again with a new O2, I decided before dropping it in the water it would be better to build out the MAP (learn) on a prop dyno and make sure I don't burn up another sensor. The dyno session went real well with me making several pulls under various loads and rpms to facilitate the computer learning. This culminated in a few WOT pulls and needless to say I was quite surprised by the power this thing made (keep in mind this is just a 468 that started life as a Merc 420 - nothing crazy). After the dyno my son and I pulled it a couple of hours and dropped it in the lake. Here I'm in the back seat on the laptop monitoring the motor and watching it continue the learn process while my Dad is driving. We have not held it WOT much at all yet but I can say it is wickedly responsive through the mid-range. To say I am happy so far with how it turned out is an understatement.

http://www.youtube.com/watch?v=wwoobucp6PQ

what is an engine without lights??
 

I couldn't help myself.....I bought some red LED lights and put those in right after I installed the new O2.

Very , very nice. Looks Great

Wow, really cool project and it looks and sounds amazing!!!

Good luck with her and enjoy!

Thanks all! It certainly has been a fun project and if anyone wants to venture down the EFI path I'm sure I can answer a few question since I've learned a few things in the process.

Wow, this is too cool! Amazing job.

Thank you!

Very cool. What are the engine specs and power?

very slick !!! we have had the same issues with killing 02's...with my lightning/silent choice setup cannot get them to live at all...and no room to move it...kinda stuck....fine tuning now without...Rob

korvet: Motor is a pump gas 468 that started life as a merc 420. Prop dyno'd north of 500.

ez: sorry to hear about your o2 issues. I've gone over 30hrs now w/o issue. Last thing I did was use the Innovative motorsport o2 heat sink. Nice but pricy piece. Really shields the sensor and I noticed no difference in reading. I also setup the ecu so closed loop is now off up to 1500 rpm just in case I short another one I can limp home. If another one goes at this point I think I'll just eliminate the o2 altogether as I am really happy with the tune.

Wow! Excellent Job, looks and sounds Great!!

Rvander68, I'm late to the party, but just have to say this is truly impressive work! Your forethought and attention to detail show through on this project. I am thoroughly impressed with the intake work (not to mention all the other details you covered) and really appreciate the write-up! Incredible job keeping a classic engine looking classic even though you have the advantages of EFI. Well done!

Tibbstoy2 - thank you for the kind words. She's still running strong and I've not changed much of anything since this write-up.....until probably this year when I look to upgrade to a crank triggered ignition (thank you for the information on that!) and go to V4 of the Holley software to take advantage of some of the new features they have added.

This is an outstanding project, your workmanship shows everywhere and the written detail of your project again is outstanding.

Thank you! The project was a blast to do and I'm happy to pass along the path I took and what I learned so hopefully someone else doing similar has a good starting point.