School me on Hilborn Fuel Injection

Thinking about running Hilborn fuel injection on my SBC (yeah I know). How does the mechanical fuel injection work, is it streetable, and what do the nozzle designations mean. Mine says 18a on the nozzles. Thanks.

 

You could have em made into EFI and it would be streetable......

 

Yea but EFI ain't got no soul

 

18A nozzles are for methanol.

 

Find out what you need for gas and i will be happy to set up your low speed, and high speed by passes and barell valve

Roy Caruthers
Indy

 

I have an algon setup for mine. They look a bit menacing to set up but I think she will run. I have some articles that were passed on to me by kind HAMBers and I can pass them to you if you would like, just pm me an email and I will send you the scans. Also, setups have been discussed before so you may still find a thread with the search tool.

True

 

I've got mine idling and running real nice. Its a Hilborn 4-pot sitting on top of a 6-71. I am installing a Kinsler Dial-A-Jet so I can dial it in on the fly. Streetable means a whole lot of stuff for a whole lot of people. Just be prepared to mess with it all the time. It really seperates the men from the boys.

 

Almost every Hilborn you see at a swap meet came off a sprint car which ran on alcohol. (There might be some exceptions which were used in drag racing-on gas.) That means your nozzles are big-for alcohol. You need smaller. If you can locate a copy of an article entitled "STACKED" which appeared in the September 1986 H.R.M. you'll find out about everything you need to know about running one on the street. If you can't locate the article, P.M. me and I'll send it to you. Parts are available from Kinsler and directly from Fuel Injection Engineering (Hilborn.)

 

Mechanical fuel injection for the street isn't for beginners. The reason carbs work so well is the engine vacuum tells the carb what to do. With f.i., you have to tell it what to do. Your understanding of the fuel requirements of the engine need to be dead on or you're going to be walking home alot. If you can find a real exp. racer to set it up for you and explain whats going on, you stand a chance. To learn it on your own will be difficult. The pumps aren't real durable. There is alot on expense to keep one going. If the unit you have has slop in the butterfly shafts or the barrel valve isn't the correct one for small pump gasoline setup, you'll end up spending some money instantly.

 

what size motor..that will give you a basic nozzle size..the pills will require a call to kinsler or other qualified shop

 

The 1986 HRM article that Dale mentioned is excellent. He just sent me a copy over a similar question. Thanks, Dale!

Flattop

 

I talked to a friend, who is an old sprint car driver/builder, about this and he said Hilborns on the street would be a real pain in the ass. Seems Hilborns like your foot on the floor all the time and they load up real easy at idle; gotta keep winging the throttle to keep it cleaned out. I'd say that an electronic converson would be the way to go. I know they look so good on a V8 though. Bob

 

Has anyone tried setting one up with a centrifugal pump - seems to make a ton of sense for a street setup....

 

I'm just getting started on a Hilborn unit in a drag car. Got it started last weekend, but it isn't right yet. Is the metering valve the same for alcohol and gas? I have alcohol nozzels in it now but gas nozzels were in it when I bought it.

 

edit.....

 

Thanks.

When you say "open up the barrel valve", you mean leaking it down at the correct precentage for alcohol vs. gas?

The motor is leaned out by returning more fuel to the tank through the main bypass. So a bigger hole means a leaner mixture. But the bigger hole has a lower number? I thought it was the opposite. We haven't messed with different pills yet.

We leaked it at 18%, have an 80 pill in it and 16A nozzels, so that part should be right. There is no spacer in the secondary bypass though, and we think there should be. It returns a bunch of fuel to the tank at idle. We've got a list of questions for the tech guy at Hilborn, and my crew chief Randy is going to have a conversation with them later today.

All this new to us but we hope to have running right by next weekend.

Dave

 

Dave, you'll have to leak down more on the barrel valve to get it to idle. That kinda acts like your accelerator pump. That's what keeps the motor running til the pump catches up on initial throttle.

The size of the pill is proportional to the amount of fuel returned to the tank.

The larger the jet hole,(smaller number) the more fuel that is allowed to return to the tank. Thus, the engine will recieve less. I told you wrong....the jet (pill) is a decimal equivelant of the drill. A 125 pill is a .125 drill or 1/8". Sorry about the confusion.

Your leakdown on alky, unblown should be between 18-22%. From 200-400 CID motors you can run a -0 pump. Nozzle size should be 18a for 360-430".

 

Does any one have pics of their set up?

 

Root,

Thanks. I think we're in the ballpark and should have a tunable combo. The 18% is a starting point based on advice from Hilborn, as is the pump (an -SO). The 16As came with the unit so that's what we're starting with. I'm also running a very tall stack (16") so the power will be down low and the engine won't see a lot of rpm. Not sure what, if any, effect that has on the required nozzels. 18s may be needed.

They did confirm that our secondary by pass should have a .187 shim to tension the spring. We didn't have one and after woffing the motor once it woudn't idle worth a crap. The spring and poppet were dislodged, and all the fuel was going back to the tank. Before that it was running OK.

The timing is locked at full advance and the plan is to run the barrel valve on the rich side. We are using an MSD instead of a mag so there should be plenty of juice to fire the rich mixture at low idle speed. If our thinking is correct it should have a crackley, nasty idle. Nobody will want to pit next to us.

 

To check your bypasses, make an adapter to hook up a leakdown meter. Start out at zero and keep increasing the air untill the checkvalve opens. If you haven't had the pump flowed by somebody REALLY GOOD, do so. More troubles are caused by bad pumps than most people realize. It costs money to have a system flowed but it's usually the best money you spend. Try Dennis Pirano, Celina Tx.

 

He'll wish he didn't have a soul when he's done with all this.....

 

Thanks for the input. It will be leaked down again next weekend. We're going to drill a 1/4" hole in a jet we won't be using to make a .187 shim for the byass. Everything else appears to be working well. The pump is new and flowed by Hilborn before they shipped it. All the other parts are NOS, 35 years old but never been bolted together.

 

Who is this guy? Does he have the equipment to flow a system properly?

 

Hey Dave,The main bypass only needs about 2-2.5 lb spring. 85 sounds like a good jumping off point on the jet.(I assume we're talking small block here).
The barrel valve should work ok but you'll have to up the amount of idle fuel substantially.I used to start at 28-34% leakdown.Now I just eyeball 'em in and make 'em tell me what they want.
Are they goin on the 32 or have ya got something else going on?
I'm thinkin' 18a sounds a little small for alchy nozzles but I'll have to check my reference material.I believe alchy wants more like 28-32.But I can't recall the nozzle codes off the top of my head.I'm gettin' a little tired.
Gimme a buzz tomorrow.(580)252-0864

 

a little tip, when you set the high speed and low speed bypasses put em in a bucket of water, it is easier to see the bubbles when they open than it is to hear the air, it aint rocket science every sprint car, midget, and silver crown car in the country run mechanical fuel injection

 

I got a copy of that article from Dale, it's got some great information in it! I actually thought it would be a lot more complicated to get it to run smooth on the street than it is. But I still have one question. They mention putting the surge tank above the pump but below the barrel valve so it doesn't gravity feed fuel into the engine, but what about going up hills (or even doing wheelies) in which case you can't help but have the tank above the barrel valve?

 

Remember that these units werent designed with low speed circuitry. I tried it on the street 40 years ago and it would just load up on low end. 327 SBC 365 HP with 30/30 cam - 4 speed. It wouldnt idle below 2000. If you blip the throttle constantly it will run but I gave up and ran dual quads on an Edelbrock ram log manifold. That ran as well upstairs and idled. Just didnt have the WOW of Hilborn injection.

 

Have you read the article, 55chevr? Not to offend you, but the article says, "Most people who tell you injectors won't work on the street probably couldn't get them to work well at the track, either." Also, were you using a low speed bypass? The article says that it's necessary to run well on the street. It's a poppet valve and spring that will release pressure at low RPMs to prevent it from running rich at low RPMs, and there's a similar high speed bypass to do the same thing at high RPMs after the engine has basically passed the point where it can't inhale more air. Two vehicles, a Dodge pickup and a Chevy Chevette, are mentioned in the beginning of the article which use hilborn injections and according to the article, "Both of these cars are literally driven daily." and, "Both of these vehicles start, idle, cruise, and stop as well as any carbureted car, and they accelerate like a supercharged one! They work, and they work good." I'd highly recommend the article, it's not too long and it's easy to overlook a lot of the information, but after you've read it and read certain parts a few times you'll really learn a lot about the system. It's really turned me on to the idea of a mechanical fuel injection's use as a street setup. Just my 2 cents.

 

I raced sprint cars for many years. I can't imagine trying to make mechanical fuel injection work on the street with gasoline.