Technical Hilborn Mechanical Fuel Injection

Ok, before i waste any time, how hard is it to get an early hilborn setup to run well for street use? I know hilborn doesnt recommend it but a lot of people do it anyway. Im not concerned with fuel efficiency, i just want it to function properly if i decide to take it out for a cruise. If its just notworth it ill pull itoff and run something else but itd be nice to use what i have. I understand how the system works but dont have any experience with it. Thanks

 

Just do a search. We have covered many times here going back over 20 years. A LOT of info in the archives

 

Fuel injection huh? It’s alright, in fact it’s a gas. He he.

 

I have a set of 2 1/16 that I want to run on the street ,but am looking for some larger ones,2 3/16 or 2 7/16 to put on my street rod rodeck 427 sb.It now has a holley carb with a victor jr,My buddy and I made a surge tank and I plan to run a vacuum advance dist.

 

The only ones I've heard of that worked were converted Hilborns to EFI setups. And a couple guys I know who did those both said it took a fair amount of money, and effort to make them work. And they never got even reasonable gas mileage with them.

 

The issue that causes the problems is the lack of an Off-Idle accelerator pump to get you going for drivability when running gasoline. Fuels like alcohol , you can run rich without effecting drivability

 

An injected caddy!
Damn straight, that's killer, Any pic's of the rig You can share...

 

I looked into that pretty heavily for quite some time. Did a lot of research, talked to a few people and unfortunately s****ped the idea. Finding one that’s decent for a decent price is tough. When you do find one add about 1500-2000 in pump, check valves, lines and brackets. As for drivability, I think it’s doable if you carefully leak the barrel valve. Probably have to compensate idle and or top end to get the mid range. I wanted to run alcohol. Good luck if you go that direction. Keep us posted.

 

On the street most of the time is spent at part throttle with various loads from idle to hill climbing. Mechanical race injection (Hilborn etc) was never intended for this and had no provisions for dealing with the varying load/speed demands needed to be even slightly street friendly. An EFI conversion can work beautifully, but you can tweak your mechanical Hilborn for the rest of your life and never be able to drive it through a city with a population of more than 10.

 

TCTND is partially correct. It's the idle and part throttle that causes issues. However, you can use an idle control valve that controls idle pressure. There are also individual idle valves to use on each injector line. The idle really needs to be pretty fat since there are no accelerator circuit. There needs to be a reserve of fuel in the intake to cover the "hole" when the throttles are cracked.
Smaller nozzles help without impacting high speed operation much. In fact it's preferable to use smaller nozzles along with higher line pressure to atomize the spray better.
It'll take some finagling, for certain. You will have to accept that perfection is unattainable, but it can be made driveable.
Another thing is certain....fuel mileage will not be anywhere near good! In fact it will ****! But you will be a cruise night hero!

 

Doing this exact thing on my hemi model a now.

 

Many were done with with a “float” tank with Holley end fuel bowls. The stock or an electric pump kept the small tank with the floats full. The tank also has a vent and cap if you want.
With the tank set high enough the Hilborn pump always had fuel ready to send to the barrel valve. There is no need with this design to squirt fuel in the tubes when cold. It’s best to have a push ****on starter that is separate from the ignition. (This is why it was so easy with a mag) Crank the engine over with the throttle pedal down opening the barrel valve acts like an accelerator pump. A cable operated fuel shut was right in front of the barrel valve..
Guys I’ve talked to at Donut Derelicts on Saturday mornings say the smaller the throttle bores the better it runs on the street..

 

Here you go.

 

Thanks for the replies, i really appreciate it. I have a blower manifold for it so i may just go that route if it becomes a h***le after some tinkering. lol

 

No electronics for me,mech only,I have a dial a jet,a belt driven hilborn 150 and a surge tanks,a electric fuel pump with a holley float bowel on the surge tank.

 

It won't be to good in city driving I don't think. I ran it for 20 yrs on the drag strip on alky.

 

Like dreracecar says, there is no acc pump . They were never designed for the street, so if you are looking for mileage and driveability go with the EFI setup. On gas it will have to be pretty rich at idle to cover up the transition between Idle and mid or wide open throttle. They were designed for wide open throttle. You need to get the system flowed with the pump and that will still not help you with street driveability. But If you feel you must run it on the street on gasoline, good luck and tell us how it works out for you. On gas It will be temperamental as hell. But you can put a small electric pump from the tank line to the barrelvalve for priming to start it. I wish you success. I can tell you your MFI knowledge will be a lot greater after you mess with it. LOL. JMO Lippy

 

I ran this roadster for decades with a set of Enderles. In fact, it was my only car for a few years. Sometimes too rich, sometimes too lean -- it's easy to tell. Temperatures in SoCal vary all over the map, so just set it up "medium". You'll be easy to tell. Would have been great with a "Dial-A-Jet". A front tank in conjunction with a feeding rear one is helpful in keeping away from running away with the fuel. I think the Dial-A-Jet would have made it so much easier.

 

Get a 30-gallon steel barrel.

Fill it with $20's.

Pour in a cup of gasoline.

Toss in a match.

That will cost about the same as trying this, and will at least keep you warm for a little while.

 

For a beginner I would run a bug on a tunnelram. Lippy

 

I've built a couple blower motors with carburetion with much success, But my third Will be Blown/ injected, An street'd!
I'm really dig'n your truck!
At whatever cost, It'll be worth it !

 

It can be done, it take alot of trial & error & a understanding of working's,
Not just a bolt on & go
There are afew individual and Company working on development of a Electric controlled barrel Vale that uses a O2 & still a Mecanical F injection

 

I'd say the comments are well covered and I agree. On the EFI side I've been working hard designing EFI Conversions for Hilborn Injectors. The problem with your Early Caddy along with many of the earlier injectors is its very challenging to keep things clean looking and hidden where you can so it doesn't take away from the "look." EFI requires a bunch of sensors and sometimes you have to fabricate plates for p***ages to make things work properly. Some of the castings just lack real estate to get it all put in without it looking bad. The other thing I try to consider is not modifying the castings very much or at all just so the value can be retained. Really have to think outside the box! The blown setups for example I make a 1" thick plate with everything incorporated into it so a two hole, four hole, or hat can sit on top. This way the casting doesn't get affected to make it functional. Dig the ride man!

 

Over 20 years ago a fellow named Fran ( I don't remember his last name ) from the Boston area had a injected early hemi powered "T" bucket that was street driven. IIRC it had long stacks. He drove it to the NSRA Nationals. He told me that he got 19 MPG with it.

 

I have 2 words to add for which direction to look. ROAD RACING. I can't believe those early efforts were only WOT-off actions. Surely a lot of flat out but some part throttle, no? To that end fuel management and the required pieces had to have been sorted some time ago. They worked. Just sayin...

 

Jimmy
Did you have occasion to see the Nova that Augie Delgado drove on the street in SoCal?

 

I can handle a carbd blower setup. This mfi just seems like some kind of crude witchcraft in comparison. lol

Heres my scott blown buick engine.

 

5... 4... 3... 2...

 

I don't agree with the mid range cruise problems. When I ran sprint cars you had to be able to come off a corner smoothly on a slick track. That meant getting into the throttle gently so as not to spin your tires. My Hilborn operated quite well at part throttle. However, I was running alcohol.

I always wanted to put one of my engines complete with injection into a street car like a Camero or Chevelle. Wanted to but never did.