duvall172 Posted September 16, 2019 Share Posted September 16, 2019 I need some big time help. i have a '72 Monte with the stock 350 and 2bbl. No matter what I do or replace, this car runs like crap especially from 0-50. From 0-50, the car will shake the fillings out of your teeth. After that, it skips a little but runs pretty good. I have no idea what the problem is or even where to start. The carb in new and I've been adjusting on it for 2 years with no results. Any help would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
imr Posted September 16, 2019 Share Posted September 16, 2019 Might have a miss. you can pull plug wires while i tr s running to see if the idle drops. if it does not then you have a weak cylinder or spark. be careful you dont become the ignitions ground. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted September 16, 2019 Share Posted September 16, 2019 Hi. Could be a ton of things. Check and see that #5 and #7 spark plug wires are not crossed. Very common. How's the fuel pump? Pick up in the tank? Where is the timing at? Is it the original timing chain? How many miles on it? Could be stretched. Vacuum leaks? How are the advance weights in the distributor? Stuck? Broken spring/s? Quote Link to comment Share on other sites More sharing options...
cbolt Posted September 16, 2019 Share Posted September 16, 2019 Start from scratch. A compression test, a vacuum gauge, a timing light, etc. What have you done besides replacing and adjusting the carb? What else have you replaced? Does it idle okay? At this point you don't really provide enough information to point you in the right direction, but there are lots of folks here willing to help you figure it out. Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 16, 2019 Author Share Posted September 16, 2019 20 hours ago, imr said: Might have a miss. you can pull plug wires while i tr s running to see if the idle drops. if it does not then you have a weak cylinder or spark. be careful you dont become the ignitions ground. Might try that. Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 16, 2019 Author Share Posted September 16, 2019 19 hours ago, MC1of80 said: Hi. Could be a ton of things. Check and see that #5 and #7 spark plug wires are not crossed. Very common. How's the fuel pump? Pick up in the tank? Where is the timing at? Is it the original timing chain? How many miles on it? Could be stretched. Vacuum leaks? How are the advance weights in the distributor? Stuck? Broken spring/s? Checked and plug wires are not crossed. Haven’t checked fuel pump, pickup, timing or the timing chain. Engine was rebuilt right before I got the car in 2011. Since I’ve had it, I’ve driven it less than 1700 miles. Here’s my cycle: I uncover it, take it out of the garage, runs like crap, spend a few hundred dollars trying to fix it, nothing changes, cover it back up, back in the garage, and a few months later, I do it all over again. Insanity. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted September 16, 2019 Share Posted September 16, 2019 Hmmm. It always ran like crap? Could be cam. Not lined up properly or maybe not broken in properly and you may have bad lobes. Check the easy stuff first obviously. Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 16, 2019 Author Share Posted September 16, 2019 12 hours ago, cbolt said: Start from scratch. A compression test, a vacuum gauge, a timing light, etc. What have you done besides replacing and adjusting the carb? What else have you replaced? Does it idle okay? At this point you don't really provide enough information to point you in the right direction, but there are lots of folks here willing to help you figure it out. Haven’t tried a compression test yet, I have a vacuum gauge, but I’m not all that sharp with it. I wish I had a good vacuum hose diagram to see if maybe those are wrong. All the fluids, filters, and plugs have been replaced. Idle is sketchy at best. I’ve adjusted and adjusted and it either does nothing or makes it worse. If I could ever get it running correctly, I’d sell it. Definitely not the car for someone who’s not an old carbureted V8 expert. I thought “a chimp could tune a small block Chevy”. Well, not this one. Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 17, 2019 Author Share Posted September 17, 2019 4 minutes ago, MC1of80 said: Hmmm. It always ran like crap? Could be cam. Not lined up properly or maybe not broken in properly and you may have bad lobes. Check the easy stuff first obviously. See, this is the problem. It could be 40 different things or it could be something simple. All I know is I can’t figure it out. Does anybody know a great SBC mechanic near Atlanta? Quote Link to comment Share on other sites More sharing options...
1970mcss Posted September 17, 2019 Share Posted September 17, 2019 I would check the timing , when I bought mine the timing was off a little. If you don't have a timing light you could try to advance vance the timing to see if the car runs any better. A timing light would be a cheap investment if you don't have one. I thought it was an idle adjustment. I got it close and then had a shop fine tune it. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted September 17, 2019 Share Posted September 17, 2019 Agreed. Could be one of a few issues or one thing. Start with the easy stuff. On the outside of the engine. Wish I was closer to you, would love to help you out. ☹️ P.S.- how are the plugs? Fouled plugs do weird s**t. Quote Link to comment Share on other sites More sharing options...
imr Posted September 17, 2019 Share Posted September 17, 2019 what disteibutor do you have, is it points or has it been changed to hei 1 Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 17, 2019 Author Share Posted September 17, 2019 5 minutes ago, imr said: what disteibutor do you have, is it points or has it been changed to hei Points Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 17, 2019 Author Share Posted September 17, 2019 54 minutes ago, MC1of80 said: Agreed. Could be one of a few issues or one thing. Start with the easy stuff. On the outside of the engine. Wish I was closer to you, would love to help you out. ☹️ P.S.- how are the plugs? Fouled plugs do weird s**t. Wish you were closer too. I changed the plugs last week so they’re fine. Surprisingly, the plugs I pulled out looked normal. I was really hoping they’d tell me something, but nope. Honestly, I don’t think it’s anything internal. I think it’s carb, vacuum, ignition related “outside” stuff. I guess if I replace enough stuff, I’ll get it going eventually. Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 17, 2019 Author Share Posted September 17, 2019 1 hour ago, 1970mcss said: I would check the timing , when I bought mine the timing was off a little. If you don't have a timing light you could try to advance vance the timing to see if the car runs any better. A timing light would be a cheap investment if you don't have one. I thought it was an idle adjustment. I got it close and then had a shop fine tune it. I’ll get a timing light tomorrow. Quote Link to comment Share on other sites More sharing options...
imr Posted September 17, 2019 Share Posted September 17, 2019 at idle does it smell rich or normal. when you say runs like crap what do tou mean. does it lack power and miss. does it pop our of the carburetor. do you have stock exhaust manifold or headers Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted September 17, 2019 Share Posted September 17, 2019 I'm thinking it's timing related. I would look closely at the distributor. Especially with/at the points. I would either convert to a pertronix electronic conversion or the whole pertronix distributor and coil also. A weak coil can make the car run rough also. Quote Link to comment Share on other sites More sharing options...
cbolt Posted September 17, 2019 Share Posted September 17, 2019 Hard to diagnose with the information at hand. Tests will tell you what is going on. Find the vacuum port behind the carb and hook your vacuum gauge up there. (Plug the hose of course) and see what the needle is doing. Most vacuum gauges have a legend included to help diagnose the issue, or a quick google search will show the different vacuum gauge indications and their associated problems. Oh, and in a pinch you can roughly adjust the timing and mixture using the vacuum gauge. (Youtube is your friend) A quick check of the compression (you mentioned having the plugs out) will give you an indication as to what your moving parts are doing and show possible leaks in the cylinder head gaskets, sticking valves, etc. From there you can check your initial timing and get that all set (youtube is a great resource for how to vids) and at least eliminate or pinpoint where you need to look. Oh, and make sure you inspect your points, rotor, and distributor cap while you are at it. A good visual inspection is just as important as testing with gauges. Your described problem could be a lot of things, or a combination of problems, but you have to start somewhere. Heck, I wish I was closer too. I love diagnosing and fixing difficult engine stuff like what you are experiencing. I admit, I looked. You are southeast of Atlanta and about 5-6 hours away. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted September 17, 2019 Share Posted September 17, 2019 I would do a compression test on it. Pay close attention to the plugs as you remove them prior to the compression test. One of the may give you an indication as to the cylindr that is giving you trouble. I hate to bring this to the game, but you might have a wiped out lobe on the cam. Modern oils are not good for break in on flat tappet cams. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted September 17, 2019 Share Posted September 17, 2019 Hey Sean, you need to start from the beginning. You said you changed the spark plugs. Great. What else did you change? Are you certain you didn't mix up the plug wires? Are the wires, ignition cap and rotor old? Is this an original points-style ignition? Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 17, 2019 Author Share Posted September 17, 2019 12 hours ago, Paul Bell said: Hey Sean, you need to start from the beginning. You said you changed the spark plugs. Great. What else did you change? Are you certain you didn't mix up the plug wires? Are the wires, ignition cap and rotor old? Is this an original points-style ignition? I didn’t mix up the plug wires. I’m positive of that. As for the wires, cap, and rotor, those haven’t been changed. Yes, it’s an old points style ignition. Quote Link to comment Share on other sites More sharing options...
duvall172 Posted September 17, 2019 Author Share Posted September 17, 2019 15 hours ago, imr said: at idle does it smell rich or normal. when you say runs like crap what do tou mean. does it lack power and miss. does it pop our of the carburetor. do you have stock exhaust manifold or headers Smells normal. It idles fair. Acceleration from 0-50 is a challenge. Shakes, skips, just terrible. After 50, it will keep accelerating with no shaking but an occasional miss. Stock exhaust manifold. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted September 17, 2019 Share Posted September 17, 2019 12 minutes ago, duvall172 said: As for the wires, cap, and rotor, those haven’t been changed. Yes, it’s an old points style ignition. Alright great. I'd suggest you complete the ignition tune up, cap, rotor, points, check & set dwell and timing and maybe wires if you think they're old and "iffy". If you have a decent spark during cranking, the coil is fine. Consider one of the electronic pickup systems to replace the point system and a more powerful oil filled canister ignition coil. Pertronix makes good stuff. This all adds reliability, smoothness and throttle response. Quote Link to comment Share on other sites More sharing options...
imr Posted September 17, 2019 Share Posted September 17, 2019 it does sound like a spark issue. idles ok then misses on load. Quote Link to comment Share on other sites More sharing options...
Leghome Posted September 17, 2019 Share Posted September 17, 2019 My small block ran like crap when I bought the car in 2011. My son in-law and I played with it for over a year. One weekend we were at his house I got pissed and pulled the carb. It was a Holley dual line and after looking at it closely the base of the carb was warped thus causing it to not want to run at slower speeds and on take off. When you punched it it fell flat on it face and dang neigh died. Went to AutoZone and bought an Elderbrock 1406 stuck it on and it ran like a pickle seeder after we re plumbed the fuel and vacuum lines. From the sounds of your description it very well could be a vacuum leak but like others have said that is not the only possibility. Good luck on your search for a quick and inexpensive fix especially after all the time and money already spent. Quote Link to comment Share on other sites More sharing options...
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