My scenario is this. Just recently got the truck on the road after 15 years of tinkering. Have a 1955 inline 235 that was fully rebuilt. Cam is still stock grind. Installed fenton split headers, dual Edebrock intake, dual 32 DFT carbs from Tom Langton, Pertronix ignition. The truck runs, it idles smooth in my opinion and runs only fair when driving around. It seems like something is lacking after hearing so may praise and talk about how good these 6's can be. I have fully and properly set up the engine to my knowledge prior to getting it on the road about 2 weeks ago. - Found TDC on #1 (yes I mm sure its not 180 out) Confirmed rotor position and valve positions. - Set the octane selector to 0 - Started engine and set timing to stock setting using the ball bearing in flywheel. - Got to running temps. - Used vac gauge on intake manifold and found the needle jumping around so I rechecked my valves and found that some were set wrong. Corrected valve rocker gaps and vac needle was steady like a rock. - Adjusted timing via the distributor to get best vac reading on gauge with the vac advance unhooked and blocked off at carb. 19 was the best it would do. It took a bit of timing advance to get the vac reading it to that number. Backed off the timing just slightly to get 18 vac reading after by using the octane selector so I can make easy adjustments later. -Played ever so slightly with the idle mixture screws on the carbs but they were set perfect and the adjustments in either direction only made it run rougher. - Set the RPM to 500 ish Been driving it now for 450 miles and i have filled the tank 3 times. This cant be right. Accelerating moderately or aggressively it just slowly climbs, gets a bit more torque around the 2000rpm area and keeps moderately climbing after that. If I carefully let off the pedal as I am accelerating it actually for a brief a second accelerates with power. As if the second it leans out by me not applying and acceleration it stars to accelerate correctly. The smell of gas is so strong after accelerating almost every time I try to get up and go. Every time i also let off the gas and decelerate with it in gear the exhaust sputters and i get slight backfiring and pops. Well I tested out the truck today with one carb at a time. All I did was disconnect the linkage arm but left it connected to the fuel line. The first try with carb "A" felt the same. Acceleration was slow and there was still a slight popping / backfire sound when letting off the throttle and letting it decelerate in gear. Truck still ran and never starved its self on the single carb like i thought it would. Switched to carb "B" and the truck ran even smoother than what I thought was set up correctly before. You can't feel the engine running now but you can just hear it it's that smooth. It has sooooo much torque now compared to running both carbs together or just carb "A". When accelerating and getting to the point with the pedal travel that actually opens the secondaries you can feel it take off even more it and it starts to pull even harder!. The way it performs now is more what I was expecting form this inline in the first place. The strange thing is with just one carb attached and working it should be too undersized in cfm to run the engine by itself but it runs it like it was meant to be. Something still bothers me about both of these carbs even though one works better than the other. It still seems like jetting is off or possibly its something else. I have yet to call Tom and ask him what he thinks. Thoughts?
Sounds like the power valve in carb "A" is not working right, too much fuel and the engine cannot rev. Vacuum actuated power valve. I borrowed this pic....
If I carefully let off the pedal as I am accelerating it actually for a brief a second accelerates with power. As if the second it leans out by me not applying and acceleration it stars to accelerate correctly. The smell of gas is so strong after accelerating almost every time I try to get up and go. Every time i also let off the gas and decelerate with it in gear the exhaust sputters and i get slight backfiring and pops. this is running too rich. Based on the rest of your explanation carb A is the culprit. Your thinking on CFM is not entirely accurate. Only once the maximum velocity and volume of air thru the throat of the carb is reached will it limit rpm. If you were to make the adapter, you could run your engine on a small brigss and Stratton carb.
Hi, with the Pertronics installed, did you have to go to a hotter or extended tip plug? I did for the Mini HEI from Langdon. Never a problem with a pair of older Carters on my 54 235. Maybe you need more spark and fire? Dom
Im having such bad luck with this carb setup I'm ready to sell the truck for a dollar. So I removed the carb tops to punch the holes in the gasket because the holes were already done in the top cab half already. Inspection it closely i noticed the gasket holes are probably unnecessary. The gasket is actually open around the float pivot pine any ways to allow for the pressure to be the same on both sides of the gasket. I also noticed there is also a stock pin hole vent port that goes from the top cap into the top of the venturi. Not sure why tom says the holes are mandatory possibly the stock one is just too small? So i went out with the truck for a test drive with both cabs reconnected. Drove like it did before. All groggy, smelling like gas again, no acceleration. All of a sudden she just went all boggy. Like no fuel was being pumped in or delivered. then all of a sudden it working again and then not working. Opened the hood to see that one of the accelerator pump arms is actually stuck in the open position. Could not push it back in but had to take the cover off and reinstall it on the side of the road. Truck fired fine after that and i managed to turn the truck around and start driving back home. Then like sure as **** when i started to press the pedal the truck would just die 100% and stall. Opened the hood. pump arm was ok...................disconnected the carbs so they were independent of each other to see if one was causing an issue and guess what! the other carb that was running the truck by fine by itself (carb "B") about a week ago would kill the engine every time you you try to open the throttle slightest bit. If you just push on the carb throttle 1/16" the motor would die. Re attached the other carb that was not working correct as diagnosed last week (carb A) and managed to just roll her home in 1st gear. Yesterday i gave up and ordered 2 more carbs from tom. I have no idea what it can be or what i have done. I bought the carbs last year, i installed them via the 4 bolts on the bottom i hooked up a fuel line after flushing it and installing a filter and im having this issue. Thinking a V8 is in order as much as im not wanting to go that route.
Im having such bad luck with this carb setup I'm ready to sell the truck for a dollar. I know I'm taking a chance, but ill give you $100.00 for it. Just think, that's 100 times more money and you'll not spend another second worrying about this. Good riddance Id say.
Carbs can be confusing but they are not smarter than you are Be patient My O/T vehicle is having nearly identical issues. It sits in a barn far from my house so I can only work on it now and then I got nice carburetor parts from Daytona Carburetor - daytonaparts.com. The more you pull these carbs apart, you might want fresh floats andone of their specialty needle/seat ***ys they offer for certain vintage carbs Posted using the Full Custom H.A.M.B. App!
I got the new carbs yesterday and installed them last night. Relocated all fuel line further away from the block to keep it cooler. My existing runs were just above the intake and exhaust ports. It is now about 5" above that at carb level and runs across the engine bay near the rear. Installed a 1-4psi fuel regulator as i have got lots of recommendations to do from here and other forums. Will try setting it at 2.5-3 psi for the first try. Should have it running later today. I will post up what happens. Think that the ignition system not working correct in terms of not enough voltage or not sparking right can cause this? Weak spark possibly? I also did get a HEI system. I will try the new carbs first without the new HEI installed. I need to take a closer look at it anyways because the inner reluctor teeth are hitting the outside pick up ring. No quality control here boys!
I have always thought, in my mind ....... how does Tom Langdon sell these Weber carbs all over the United States, with no regard to elevation. I don't know if you are at sea level or 8,000 feet. Reading ongoing posts from carb rebuilders, the general consensus is that carbs should be calibrated, based on elevation. You will see by my Avatar, that I have dual Rochesters on a 235, WITH A PATRICKS 3/4 CAM, Fenton intake and exhaust with a Petronix ignition. FYI, ignition timing is set at 6* advanced, without regard to vacuum reading. It runs well, will NOT burn rubber in 3rd gear, but runs well.
Yesterday was a good day. I installed the carbs as I noted t posts ago and got the truck back up and running. I forgot to mention that i also split the carbs for a clean out prior to installing them. I found a little debris in on of them and found that both of them had a metal build up around the idle mixture screw right at the tip. Looked like some sort of pigtail drilling debris around the tapered tip of the screw. The tips were fine and were not damaged. I also re-plumbed the lines and kept them further way from the block this time so they don't get so hot. After getting it running and warmed up i rechecked the timing to see where i left off. Currently set at 12deg and vacuum is 17in. Everything seemed fine with the distributor and was advancing during revving. Checked all the new fuel line connections and set the regulator pressure to 3psi. Went back and forth setting the idle mixture and rpm and timing till everything was ok. Final readings were, 500 rpm, timing still 12 and vac 17.5 ish. With my AMA card in hand and the tow truck number read on speed dial i got in a took her out for a boot. First thing i noticed doing neighborhood speeds is the engine was smoother than before. Got to the back paved country roads and tested out my new lead shoes. Its a completely different truck ! It pulls hard compared to before. Way more torque. When in third (final) and cruising at 1500rpm you mash it and she just gets up and goes. Still nothing to brag about but 100 times better than before. The harsh smell of gas during acceleration is little to none compared to before, and when costing in gear it almost never spits and backfires now. At higher rpms the engine is smoother and does not want to jump out of the ch***is and onto my lap. It still has a slightest feeling that it wants to go harder when you just let off the throttle when accelerating hard. I will play with the timing using the octane selector now for easy adjustments and see what else i can squeeze from it. Parking in the garage the only smell i got from it was from the header wrap burning from playing so hard and a bit from the top valve cover breather, the smell of gas to me was not present in my garage anymore. I should probably install the HEI setup i got sooner than later before i go taking all the time to play with timing and then change out the system and have to do it again.
Your air cleaners look cool as heck but I'm thinking they offer some restriction to the cfm capabilities of those 2 Webers. That might cause them to run a little fat in stock configuration. You're a couple thousand feet up also so leaning it a touch and adding some more timing may improve the inline's performance. Clean engine BTW. Nicely done.
As much as i want to lean the jetting it is guaranteed to mess up the threads in these bodies. I already have two of the same carbs i just shelved because trying to find my previous issues i took them apart and the jet threads got damaged. I think its safe to say the other 2 carbs were bad. I found nothing in them for debris and i never touched or adjusted a thing prior to installing them before. The air cleaners do only have a 3/8" gap around the bottom of them. I might have to look into something else that would fit that round shape.
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