Holley 1920 issues

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59dodge

59dodge

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mansfield ohio
I am building a Rat out of a 59 Dodge truck and it sits on a 85 Dodge truck chassis running a 225/6 w/904 a/t. I eliminated the smog carb and distributor and went with electronic ignition and tried to fabricate a two one barrel intake and headers from scratch , I purchase online two Holley 1920 1 bbl carbs and had a friend who has rebuilt carbs for several years and very good with Holleys and had him rebuild them for me.
We mounted the intake and headers tried to start the /6 and we developed a leak at a few welds and one of the carbs poured gas to the point it ran down the block from where it bolted to the head back by the starter.
So since we were trying to get this truck to a Rod Run that I had been busting hump to drive this truck to that was coming up in a week we decided to pitch the header and intake we built and go back to the stock 1bbl intake and exhaust manifold and use the one good Holley we had.
We made up new linkage mounted up everything but ran into other issues like brakes and wiring and needless to say had to drive the civilian car to the run instead.
What I am having problems with now is I have the /6 running and idling really good until I go to mount the air cleaner on and it starts to idle rough and begins to pour black smoke (running rich) and eventually stalls but pull the air cleaner off it clears up and runs fine ?
The air cleaner I am using is what I planned on running on the 2 1bbl intake they are the small 4 or 5 inch diameter air cleaners you can buy at the local parts stores could that be the problem ? Are they to small and not getting enough air to the carb and choking it out or is there another problem that I am over looking ? I have limited space for a air cleaner since we had to recess the fire wall and the carb sits close to it and can not use the stock 85 Dodge truck unit but may have room for the smaller ones like ran on the 60s and early 70s Abodies that ran the /6 ?
I also believe I have a brake booster that may be bad because with the engine not running my brake peddle is perfect , but start it up and the peddle drops about half and won't spring back enough to turn off the brake lights ?
If the brake booster is bad and is leaking could this be giving me my problems I am having with my carb ? I would really like to find a 2 1bbl intake and headers for this rat rod of mine but I would think hens teeth would be easier to find and when I do I would have to give up my first born to pay for it so I think I am just gonna run her stock and put the biggest y pipe I can mount off the exhaust manifold and run straight pipes all the way to the tail gate for now.:burnout:

Any input would be great ..
 
Hard to tell from here, but I would guess that the small air cleaners are not the issue..... unless you forgot to take the plastic wrapper off LOL. The engine should not be pulling huge amount of air at idle. BTW, have you checked the air cleaner base to make sure it is not contacting any rods and perhaps moving the choke rods and closing the choke?

First thing I would do is check the wet float level; it sounds it might be very high. Pull off the small triangular cover on the bowl for the power valve (economizer) and idle the engine. Use a small scale to measure how far the fuel level is below the flat area on the bowl where the triangular cover sets. It should be very close to the spec; that spec can vary per exact 1920 model. I have seen 11/16" and 27/32". It needs to be exact; look it up by the list number on your Holley 1920. The float level sets all other carb operations and is critical.
 
As to the booster, it normal for the pedal to fall at start-up, with your foot resting on the pedal. But it should pop back up when you remove your foot. I suspect the internal valve is bad.
You can isolate the booster by clamping the vacuum line, to see how that might affect the carb.

As to the carb issue,inspect the distance from the bowl vent to the nearest surface inside the air filter house. Sometimes the carb gets sensitive if there is insufficient plenum volume, or clearance to the vent. I would also suggest to mount the filter house with no element inside it, to see if the tightening of it is somehow distorting the carb body, or affecting the linkages beneath the housing, as nm9 mentioned. Good luck
 
As above, the brake booster may be working fine; it is normal for it to pull in the pedal a bit when it starts. Close it off like said, to troubleshoot the carb first.
 
Thank you so much for this information from AJFORMS and nm9stheham I will look the carb over 1st thing to see if the air cleaner is either touching something or blocking something then check the float level I believe I got a gauge with the rebuild kit if I remember correctly as far as the brake booster some thing does not feel rite , I realize the pedal will drop when the engine is started but from previous experience the pedal while running will spring back enough to touch the switch for the lights the same distance as it does when the engine is not running and it is not ?
Plus when it is running and I take it down the drive at a idle it seems like the peddle goes down further then it should and you have to push very hard to get it to come to a good solid complete stop ?
I was told by a old hot rodder that works at a local parts store here to check the rear brake shoe adjustment that they may need to be adjusted snugger to the drums ,that the wheel cylinders may be having to push out to far and causing the lack of peddle and the peddle not springing back enough ?
But thanks gentleman for all the good info at least I have some where to start and maybe I will be able to get the things done to it I want done before the snow hits the ground around here ! My rocker panels are about 4 or 5 inches from the floor and front fenders are not much higher and I live way out in the sticks so I better get busy cause I don't think it will tread snow very good lol.
Thanks Again Allen
 
You pretty much have it on the brakes and on the rear wheel cylinder adjustments. See where that gets you. And, you may just not have a well bled system.

BTW, the gauge you got with the carb may be for dry float setting, which is done when the bowl a float are off. My recommendation is for the wet float setting as described; that scale may or may not work for the wet float setting. It may not cure you issues, but is an important baseline setting for any carb.
 
Hang on there,with the brakes. Yes its true the pedal should come back to park itself. And yes its true that insufficient rear brake shoe adjustment will require more pedal travel to affect a stop. However, an incorrect rear shoe adjustment will not cause a pedal parking issue. This is because the rear shoes are returned with the return springs, sending the fluid back to the master, helping to lift the pedal,and expose the compensating port, where excess fluid will be dumped directly into the reservoir. The only thing that could prevent this is if something in the emergency brake system was hanging up, or if rust build up in the cylinders was preventing the pistons from retracting.This is why in post #3, I recommended to isolate the front from the rear. If you have a hard,non-spongy, pedal, or can get one with multiple stabs of the pedal, then it's highly unlikely that there is air in the system. Multiple stabs usually indicates a problem in the rear adjustments.
Now, getting back to the booster.
If after adjusting the rear shoes, or isolating the fronts, you still have a pedal that is not returning, then likely the pushrod is too short. I'm talking about the rod that goes from the top of the pedal to inside the booster. There is a giant spring inside the booster, who's job it is to return the control valve, and the diaphragm, and the pedal to a parked position. The first two are unaffected by a too-short pushrod length, but the pedal is. This is best done last, after the rear shoes are known to be correctly adjusted, and also after it has been proven that there is no air in the system and the pedal is hard with one pump that does not go to the floor.
It is somewhat easy to make the rod too long. If it's only a little too long, then the compensating port inside the M/C can become in-operative, resulting in an ever falling pedal, as the pads and shoes wear out. If the rod becomes much longer than this, it becomes possible to break the control valve inside the booster, rendering the booster junk. The correct adjustment would have the system not doing the above, and also not slamming on the brakes for you at the slightest touch; but having nice progressive boost assistance with increasing pedal pressure. This makes smooth stops a joy.
The pushrod adjustment has a baseline measurement, but I am unable to find it. Barring the spec, it would be a matter of trial and error. The adjustment is done by sliding the booster back far enough to expose the adjusting system. Remember this should be done last, and easy does it. It may require multiple tries.
 
I blocked off the line to the booster today and noticed no difference and can not find anything that the air cleaner is touching so time to check the wet float level next I'd bet money that's where the problem lies is in the float adjustment.
As far as the brakes the only thing I have not replaced on the whole brake system are the rear brakes and booster so I'm off to the parts store to get new wheel cylinders shoes and a spring kit install them bleed the system then go from there.
Thank you so much NJ & nm9 you have been a very big help !!!!
 
Carburetor operation and repair manuals and links to training movies and carb repair/modification threads (heavy on the 1920) are posted here.
 
Are you perhaps jumping the gun on purchasing brake parts? I tell you what; you haven't isolated the front from the rear yet have you? If you wanna buy parts, buy a rear brake hose cuz after I tell you this next thing, you are probably gonna need one.
Put a clamp, hard, on the rear flex line. Bingo! the rear brakes are defeated. Now, engine off, do you have a hard pedal, at or near the top? If yes, we can move on. If no we will have to figure out why.
EDIT
Be advised the clamping an old hard rear flexhose, can damage it inside, where you cannot see the damage. Then at some future point, the rear system can go down, usually by locking the rear brakes on. I don't normally use this method, except as a last resort. I offer it here, because the rear hose is old(and thus probably due for a change), and because it kinda is the last resort, and also because it will expedite the diagnostic time.
There is/are another way to block-off the rear system. It just takes a sometimes hard to find plug for the end of the rear hard line, or a plug at the M/C end. Which then takes time to un-install.
When I clamp the line, I use a clamp with large rounded anvils; not a visegrip plier, in an effort to minimize internal stress/damage. Remember, the outer sheath you see is just a protective skin for the internal hose. Damage may not show up for hundreds of miles later.
 
Didn't make it to the parts store been busy at work and cutting and splitting fire wood for winter but I will pinch off the rubber hose tomorrow after work , I did forget about that hose they do get soft and collapse , I made it a point to replace the front ones remembering replacing front calipers because the brakes either were sticking or had issues bleeding the brakes only to find out the rubber line was bad and causing all my problems duhh .. I will pinch the hose off like you said so that I can pinpoint a little closer were my problem lies front or back, its supposed to rain tomorrow so won't be able to cut wood so I will play with the truck instead and give you a heads up as to how the peddle feels with the hose pinched off.... Thanks
 
Well I finally have just about all the fire wood cut and split and ready for old man winter I hope , and was able to work on the truck a little and found the problem with the carburetor .
First off I pulled all the spark plugs and cleaned and reset the gaps to .40 and pitched the wires and got a better set , then pulled the float bowl off to adjust the float level and found part of the needle and seat laying in the bottom that came brand new with the rebuild kit so rummaged through my old carb collection found a good one installed it adjusted the float and she runs and idles like a new one !
I also pitched the little air cleaner and bought a air cleaner at a swap meet off of a Dart or Valiant that was small enough to clear my fire wall for $15.00 that needs a little cleaning and paint , it has a decal that says 225 Charger on it and works perfect ! The funny thing was a new filter cost $10.00 and still have half the money in that set up then what I had in the fancy chrome ones from Advance Auto. Like a old hot rod buddy of mine always used to say Chrome Don't Get You Home..
So one more load of wood to cut and split and I will have the shop warm enough to tackle the brakes next !
Thanks again for all the good information .. :)
 
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