I am running an original hilborn mechanical fuel injection on my racecar. I am trying to use E85 fuel. I have 20x nozzles, a 110 pill in the main jet, a secondary bypass off the barrel valve and a surge tank with a Holley float bowl. I leaked down the barrel valve to 13% with about 3.5 clearance in the butterfly's to the injector wall. I have been in contact with mike from alkydigger and hilborn. When I rev the car it does not snap back, it stays a little revved and slowly comes down.. Hilborn says I need to keep twisting the barrel valve closed until it leans out enough to rev clean. I adjusted the butterfly's according to hilborn a instruction as well.. I have not been able to find too much info on E85 injection, so it's hard to find a baseline, can anyone help? Thank you for your help! Mike
Mike, are you sure the butterflies are closing when you let off? Have you tried pushing the throttle arm shut to see if it spools down faster? I had a similar problem with my 3" Crower injector. Turns out all the butterflies weren't closing the same (twisted shaft in my case). Normally (with Methanol anyway), we run it a little burbly (rich) at idle. As you close the fuel valve it will clean out and rev UP slightly. Can't see E85 being THAT different...
I will try pushing the shaft down tomorrow, I did change the throttle spring to pull it closed more effectively and thought it was snapping closed, but I will double check what you are asking tomorrow. Thank you for the suggestion. Any idea what spark plug gap to run with an msd? Msd wants 45-50 on gasoline, hillborn wants about 25-30 on a standard distributor, so I am guessing somewhere around 35 should be a happy medium?
I would consider splitting the shafts in the middle (KINSLER has the parts) so you are working 4 2-barrels instead of 2 inline 4-barrels, this will eliminate twist & heat expantion issues within the shafts and blades.
the spark plug gap shouldn't matter what fuel you run. it is dependent on the ignition system and the compression. It's been ten years since I ran an MSD ignition in a midget engine on methanol but I went by MSD's book. In my experience on VW engines, if you don't get the butterflies timed right you have more of a vibration than anything. those VW's were nightmares to time the separate bellcranks! one thing I used to do that helped a lot was to check the timing of the butterflies at half throttle. I would make two blocks. put one in and make sure the others match up.
There may be a problem with a shaft binding, etc. but it can do that if just a little fat on idle, like Hilborn said.
From what I have been learning, it is better and actually preferred to be fat on idle so at high speed your not lean, is there just a happy medium between the two I need to find?
One other thing, have you "tapped in" the butterflies? Back the idle stop(s) off and loosen ALL the screws holding the butterflies to the shafts. Take a small screwdriver handle and tap lightly on the high side of each throttle plate to center it in the bore. Tighten the screws as you go, then when you have done all 8, re-set your idle clearance and try it.
I have no idea of your problem, but as I remember you would have a no.7 or 8 nozzle for gasoline about a no.10 for E85 and the no.20 is over kill for straight alky.
I don't know what brand the nozzles are.. 20 for hilborn, might not mean .20 to kinsler or Ron's etc.. I was told they are around 7s? But I'm not Sure
Those are Hilborn no,s I quoated. Hilbornes are stanpted with the no. on the nozzle and if they are no 7 they are not big enough for E85. Kinsler,s catalog is on line with cross references to other mfg,s nozzles. E85 requires about 20 percent more than gas.
I adjusted all the butterfly's as described and set them all at .003. The number 7 cylinder header started to get glowing red hot and I could feel slight air blowing up through the number 7 injector, I assume it's exhaust, what would cause this? An intake valve not sealing?
I can get it to idle at around 1000 with the butterfly's almost closed. I think I might have a small leak off the back seal of the intake to the block, I will put some rtv there to see if I can get that sealed. I haven't done a leakdown of the cylinder yet, I just got a new leakdown tool, so I will do that as well, thank you for the suggestions, it looks cool but its a pain! I have never had anything mechanical I can't get a hold of but this Injector is frustrating me! I just want to find a good baseline where I can start tuning from
Did you center the butterfly's after you installed and tightened all the bolts? If not, here's how: back off the screws that set the butterfly clearance so they close completely. Back off the butterfly screws so that they move in the bores. Tap the ends of the throttle shafts to center the butterfly's in the bore. While holding the butterfly's completely closed, re tighten the butterfly screws. Now reset the butterfly clearance. Now all are the same. Also how much preasure before your secondary bypass blows? Good Luck, hope this helps
Mike, I wonder if maybe .003 idle slot is just a little too much for that size engine? (don't recall you saying what cubes...) Doesn't really explain the slow snap back, but that combined with a little off on the barrel might do it.
Yep! Still on, I am thinking of being ready to leave my house at 545 since it takes about two hours to get there
Mike;not a total waste of a day[and your money],you learned some things,they reaffirmed all your tests,hopefully the Falcon will be "Right" when you put it back together!!!You can always stick a manifold and carb back on it!!!! ROY.
I checked the mail website and it looks like hilborn will get my stuff on Friday, hopefully get it figured out and back to me by next week... We will see!