The truck accelerates from zero to whatever speed fine. It idles fine. I talked to another poster on another blog and he says he has the same engine transmission differential setup and it works great. He believes the issue is the power valve.
Told you there would be more pieces, Read thru your posts here and see if you can find the contradictions.
I also spotted another mistake. After doing some research I found out that he differential ratio is actually a 2:73. We counted the teeth to get the other number of 2:56. The problem is Camaro only had two differentials that year. The 2:73 and the 3:08 which was an option. I care little about contradictions. All I care about is finding an answer to the problem. The fact is it idles fine. It accelerates up to a cruising speed fine (say 45-50 mph). After staying at this cruising speed it will stumble but this too goes away upon acceleration. I am now convinced that it is a carb or power valve problem. I know very little about Holley carbs so I am going to take it to a guy who is a Holley expert to ghet his opinion. I am also convinced that it is not a torque converter issue. I also had a guy on another message board tell me he has a car with the same drive train as my truck and it performs great. That the Camaro 2:73 differential is not the problem. It will not win any drag races, but it runs great at cruising speeds with very little engine strain and great gas mileage.
OK, now I'm confused. I thought the problem was loading up at low speed. I will throw one more thing out there about power valves. It may have been good when you got it but 1 backfire can kill a power valve.
Your confusion is of little concern stock racer. Gag1025 said " I care little about contradictions. All I care about is finding an answer to the problem." Its hopeless .
I did use the term low speeds and I can see where this is a confusing term especially in this case. I guess the term mid speed should have been used. Like I said it actually occurs once the truck has shifted through the gears and is now in 3rd gear and cruising along at a steady speed (45-50 mph) but as soon as it stumbles I accelerate and everything is good. Again once I hit a level speed (55- 60 mph) it will do it again. It only happens when I hit a steady speed. It never happens during the acceleration process. I agree with you on the power valve. I have completely dismissed the torque converter. It has to be either a carb jet issue or a power valve issue. Thanks.
Nothing in life is hopeless. Playing games in an effort to find a solution makes things seem hopeless. When I have a problem I want concrete possible solutions. I do not want to be led through a maze. Confusions have nothing to do with contradictions. People choose to either be a part of the solution or a part of the problem.
Like I said hopeless, and more pieces yet to come. The drivability problem is yours, your descriptions and thought process are irrational, contradicting, and misleading. Yet you seem to think the solution is attainable by providing garbage information. Somehow this also isn't your problem either. Now where's that ignore*****on?
Vicky, thanks for all the information you provided. I am sorry that you are taking all of this personally. Although you choose to take out your frustrations on me by using derogatory terms directed toward me as well as creating sentences with the same negative connotations I still appreciate the information provided. I hope the rest of your day is a happy one. I actually do not have an ignore*****on anywhere on my computer because I actually strive to learn something from every response. I will reiterate the fact that I know very little about Holley carbs but plan on learning more as time goes on. Again thanks to all the people on here who have provided possible solutions. I will definitely let you know what we find out once we get to this part of the rebuild. We are hoping to send it to the upholstery guy this wek and as soon as we get it back we will install a new rear suspension system and the bed wood. A photo will be provided as well.
I'm with Vick on this one, of course it's not the converter now that you completely changed what the issue is!!! Have to remember that people on here are attempting to help and only have the posted description to go on. There has been a major change in what the problem is. Hope you get it sorted out, but done take it out on the helper when their given faulty data. Keep us posted on you progress, I for one am interested in what turns out to be the issue here.
I never said it was the torque converter. What I said was someone told me that it might be the torque converter. What I also said was I think it is a carburetor problem. I also said that it idles fine. It accelerates from standing start fine but once you get to cruise speed (45 or 50) and let it stay at that speed it stumbles (loads up). When you accelerate it does so without any hesitation. Stay at that speed for a while and it will again hesitate. I don't know what else I could have done to describe the issue. I never changed what the issue is. When people asked me a question I answered the question. I am on two other message boards and posted the same information. The responses on both of them was totally different. What I got there was it is not a differential problem or a torque converter problem. That it is more than likely a jet problem, vacuum problem, or a power valve problem. I got the same information on here in a few posts (which I appreciate) but some were downright arrogant.
If you counted the teeth to get 2:56 then its 2:56 not 2:73 dont care what its supposed to be, the math doesnt lie
Gag, You DID****le this thing Torque Converter. That's the reason I tuned in. Now that it's about Holleys...can't help you..That's why I suggested a Qjet. I think you're one of the few here who is NOT a Holley expert..but if you like*****in' around with carburetors all the time , you will be one too. Carry on...
ottoman, my guess is that I was one tooth off. I say this because I looked up the year of the Camaro differential and the only two offered that year was a 2:73 or a 3:08. That is why I think I was wrong about the 2:56 ratio. You are correct in that the math does not lie, but my counting skills may be a part of the problem.
You are correct and that probably was not a good****le. I guess a better****le would have been My Truck Stumbles While Driving At A Steady Speed. But I did say that someone suggested that my problem might be caused by the TC. I also said that my thinking was that it was a carb problem. You are also correct on the Holley. I know more today than I did yesterday. Had I built this engine I would not have used the carb that's on there now. But, since I bought the truck from a guy in CA and he had already had the engine rebuilt as well as replaced the stock carb with the Holley the thought of replacing it never crossed my mind. The Q Jet is a good carb and I agree with you. Thanks for the information. I will post the results as soon as we get to the bottom of the problem. I am taking it to the upholstery shop sat. and after he finishes all that is left is the new rear suspension system, bed wood and tail pipes. Then we will tackle the hesitation/stumbling/loading up problem. Answers and pictures hopefully in a couple of months.
I'd be looking at that Holley, too. I run one on my SBC-powered Buick with street gears and it works fine...when it works. If yours is "loading up" it's probably the power valve leaking which has been an ongoing problem for me. And for others, too, it would seem. Every auto parts store on the planet stocks Holley power valves and accelerator pump diaphrams three-deep in bubble packs. It's easy to replace. And, while you've got the carburetor front bowl off, you might as well change the accelerator pump diaphragm at the same time. It seems that the alcohol in "Obamafuel" deteriorates them both - especially if the car sits for any length of time. Power valve leaks internally, accelerator pump leaks externally. Annual replacement has become a part of my maintenance program. Good luck!
"My 1953 Chevy truck has a 350 engine with a mild cam (I bought the truck with the engine installed so I have no information on the cam) The rear differential is a1976 Camaro 10 Bolt with a 2:56 ratio. At low speed the carburetor (Holley 4150 670ccfm) loads up. Once you accelerate it is OK. I was told that I need to replace the torque converter to correct the problem. My question is how do I determine which torque converter to replace it with. I am running a Chevy turbo 350 transmission. All ideas will be greatly appreciated." Maybe you should read your own post!!! One last comment and I give up. It's your truck so you can do what you want, but if you think a carburetor is going to fix this with that ratio of rear end gear I think you are in for a surprise. But, I wish you the best of luck with your project.
Actually I did go back and re-read everything I posted. I stated early on that someone told me that it was the Torque Converter. That is why I mentioned this. I guess it was a mistake using this as the****le of the post. I have had many people on this message board as well as two other message boards tell me that it had to do with the carbs so that is why I added this into the conversation. The only other things I found wrong with what I posted was the fact that I probably got the ratio wrong. I don't think it has a 2:56. I think it has a 2:73. I can only verify that if I take the cover off and find the numbers on the ring gear. Plus the use of the term low speed when in fact I meant cruising speeds. My question is why would the differential come into play when the truck is cruising along at 60 mph? I could understand that it would have an impact if it happened at low cruising speeds only, but not at a high speed. I know I am not the smartest person in the world when it comes to solving these types of problems but that part of the problem makes no sense to me. The problem occurs at every steady speed whether it is 45, 55, 65, 75, etc. That's what puzzles me. A lot of people on the other message boards have posted that the problem has to do with the jetting or the power valve, but that is their opinion just like you have yours. If it does not fix the problem I will be the first to admit that it did not and I will change the differential. Thanks for your reply. I do respect your opinion. I appreciate all of your comments and advice. I will do whatever it takes to correct the problem.BTW I looked at your 5 window coupe and that is one nice looking car. Congratulations on a job well done.
You must have skipped over this post [QUOTE="gag1025, post: 10839333, member: 142297" Thanks guys. I have a lot of great information to process and will definitely let you know what we find out. keep the solutions coming because I enjoy reading through what you post. I keep everything in a folder because you never know when you will need it down the road. One other thing is I had another differential with a higher gear raatio (3:??) in it before I swapped it out for the Camaro differential and it worked fine so I never thought that the carb was the problem. Actually the Holley Street Avenger 80570 is a new carb and like I said it worked fine with the other differential. We determined that the original differential came from a 1955 -1957 Chevy. We do not know because like I said originally I bought the truck like it sat.
And just for future reference, 3:?? would be a lower ratio, not a higher ratio rear end. Larger number ratio rear end gears are referred to as low gears and lower number ratios are referred to as higher gears. Your 2:whatever is a high gear, a 3:73, 4:11 etc. would be a low gear.
I do remember posting that. The thing is also that the truck went for over 3 years without being started up while we were working on it. That too could enter into the equation. After looking up the numbers on the original differential last night I found out that it actually is a 1957 - 1961 differential with a 3:36 ratio. We swapped it out for the Camaro (which was free) because it is a wider rear end and it pushed the wheels out and looked better. Since I am not that familiar with Holley carbs I was referred to an older guy here close by who I am told is the Holley man to see if you have Holley problems. before I change out the differential I want to talk to him to get his opinion. Like I said, I will post the results. It makes no difference to me who is right or wrong or which solution solves the problem. All I want to do is get the truck running smooth.
Okay, lets forget about the torque converter. You need to do some very basic testing to determine if you indeed have a carburetor problem or something else. This shouldn't take long or cost much. You need to check vacuum, both at idle and while cruising, fuel pressure, too. I would also like to know if the centrifugal and vacuum advance are working correctly. Borrow, rent or buy vacuum gage, fuel pressure gauge, tachometer, and a timing light. Based on your input, the proper order is: vacuum at idle Vacuum under load (brake torque) Vacuum at cruising speed particularly when it 'loads up' Squirt carb cleaner at the base of the carb and along the intake manifold to cylinder head joint Does the engine speed up or slow down? Check base timing Check timing at higher engine speed (3000) Snap throttle & check timing (if the timing retards below base timing you may have a timing chain problem) Fuel pressure at idle Fuel pressure under load Fuel pressure at cruise (note RPM where 'loading up' occurs) My guess (and this is strictly a guess) based solely on what I gather from your posts is that you don't have a carb problem. I think what you are seeing is the beginning of a fuel pump failure. What you call 'loading up' could actually be a lean condition. At cruise, the pump is not keeping up with the demand because the rpm is too low. When you accelerate, the accelerator pump covers up the lean condition and the fuel pump picks up volume due to the increase in rpm. Of course if you are running an electric pump, that shoots my theory all to hell. Next best guess if it is truly going rich, is power valve. The problem I see with your posts and the thread in general is that the premise that the torque converter is a likely cause for your problem is misleading. That is because you say someone told me that it could be a TC and we don't have a clue as to why he would have guessed that. I taught Autoshop for may years. The number one problem for students diagnosing their car problems was, "My buddy says.............................." Logical testing, is the ONLY way to find the problem. everything else is an opinion. I have never seen an opinion fix a car. Come back with some test results and I'll bet that these guys can help you.
Thanks for pointing that out to me. I know better but did not catch myself doing this. I stand corrected. Please continue to post because I like to learn all I can. I will probably not be able to respond until later on this afternoon. My Stihl chain saw is in the shop and I promised my wife that those four huge Oak trees in the back yard would come down today so I need to go sharpen my trusty old axe so I can chop them down the old fashion way.
Thanks for the information. I will run these checks and get some information based on what I observe. It does have a Holley electric fuel pump. I have had a lot of people tell me in their opinion it is the power valve.
Jseery, While I agree with you that this is far from the best rear gear if indeed the camshaft is even a little bit radical. I'm not sure that it is. How many times have you heard, "got a cam in it"? I have a 5000# crew cab with a 2.42 rear gear. It pulls real well from a light and at cruising speed it just motors along. (Milage went from 9 to 13 with the change from 4.10) Now, it doesn't have a cam in it (well it does, but just the stocker). I wouldn't change it, but I would suspect that if I did the take off would be where I would notice the difference. Not arguing, just saying, "Consider the source."
Agree 100%, did you notice that he claims this problem didn't exist until he put the higher rear end in it. Anyway, I'm a performance guy and like lower rear gears, run 3:73s in several mustangs and a 4:11 in my 33 coupe (quick-change by the way). I am going to sit back and see how it comes out.
those cars ran really short 14" tires....if your running 29" tall tires it is making the gears even worse
After months of finishing up this truck we went back to square one and determined that the problem probably had something to do with the the carburetor. That it was probably the power valve. It turned out to be a faulty vacuum advance and after putting a new one on the problem was solved. We are also going to swap out the Victor Jr. intake for a Weiand Street Warrior Dual Plane 8120 which we feel like will be more compatible with the Holley 4150 carburetor. My friend had a Camaro 3.08 differential and I traded him for the one that I had in the truck which was a 2.73 Camaro differential. The truck runs fine and will probably run even better when we install the Weiand intake. Thanks to everyone who posted helpful information trying to help me solve this problem. I learned a lesson that sometimes the problem is created by something simple. In the beginning I listened to people who were advising me that there was something major wrong (like the Torque Converter) and this turned out not to be the case. After rethinking everything my thought is that when I stated that the problem did not exist until we swapped out the differential the first time that this is when the Vacuum Advance went bad so I figured that the differential had to be the problem. A situation in which two things happened at the same time. I guess this is possible. I admit that I don't know it all.
Well, I just deleted what I had wrote as it looks like you've got it sorted out. But, with 3.55-373 gears and a 22-2500 RPM stall converter, the truck would be an entirely different animal. But, as long as you're happy with it......................................I am Butch/56sedandelivery.
The Jalopy Journal
