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Going to check the vacuum lines. I am not sure if I am reading the timing tab correctly, please see attached image. Which marker represents 12 degrees before top dead center. I do not know how to read the increments and there are no numbers on the tab.
deepest v is 0.
at this point doesn't matter, timing may be way off from 12 but
that won't usually cause misfires and rough running.
idle, yes. timing off will affect idle.
a vacuum leak. unless extreme won't make it rough running in a no load situation.
good luck, i know how frustrating this can be.
Need some guidance I have a 1979 L48, I cleaned up my engine put a new timing chain on, new oil pump, new water pump, changed spark plug wires, rebuilt the carb. It will start but stalls as soon as I take my foot off the gas pedal. When it is running it will run a bit rough, any guidance will be greatly appreciated. I did verify on the distributor the rotor is pointing to #1 spark plug at top dead center. Thanks in advance for the guidance.
Absolutely the first thing you must do before you chase any other issues is set the base timing. Your method only gets it close enough to start, now you need to use a timing gun and set it correctly. Disconnect the vacuum advance, have a buddy help you keep it running and see where the timing mark is at around 800 RPM. Adjust to what the emission tag under the hood recommends and then it should run pretty well if all is correct with the rest of the car. Start trouble shooting issues after that is done.
thats close to 12 , timing being off at the distributor is not going to make it skip or run ruff at all rpms , the reason I mentioned run it with the vacuum gauge to see if its steady is to see an indication of a bad cylinder , if a valve is hanging open the needle will bounce a bit. Since you changed the chain and gears is it at all possible there were three dots on the crank gear ? and you used the wrong one? I have seen that gear before were they put three marks on it in case you want to advance or retard the timing, there might be a triangle for 0 on it. Any time I have ever had a bad running engine I always did a compression test I know its a pain but sometimes it can save a lot of unnecessary work if you have a bad cylinder.
thats close to 12 , timing being off at the distributor is not going to make it skip or run ruff at all rpms , the reason I mentioned run it with the vacuum gauge to see if its steady is to see an indication of a bad cylinder , if a valve is hanging open the needle will bounce a bit. Since you changed the chain and gears is it at all possible there were three dots on the crank gear ? and you used the wrong one? I have seen that gear before were they put three marks on it in case you want to advance or retard the timing, there might be a triangle for 0 on it. Any time I have ever had a bad running engine I always did a compression test I know its a pain but sometimes it can save a lot of unnecessary work if you have a bad cylinder.
Thanks I had taken a picture of the timing chain after I installed it, I went back and found the images I took of the timing chain , fortunately I found a good one that I took and it looks to be installed correctly. see image
Nice Klein multimeter. A clamp that does DC current is usually really expensive. I didn't know that even existed.
I'd suggest this timing light: https://amzn.to/2IRWzpR
INNOVA 5568, if you don't already have one that does advance. This will do up to 90 degrees of advance. So, for example, when you are running at 3000 RPM, you can confirm that your mechanical advance is "all in" at whatever you want it to be (perhaps 36 degrees, depending on your engine setup).
My "fix" for dodgy timing (due to a worn distributor), was to get a new HEI distributor (a take-off from a ZZ4 crate motor) and a set of shims to close the endplay gap. It came with all new parts, including a coil.
Here's a quick video to get you started (please excuse me if you already know this stuff, I'm just learning as I go, too).
Hopefully this is helpful in some way.
Last edited by Bikespace; 04-13-2018 at 08:16 PM.
Reason: Added Freiburger with a Mullet!
Nice Klein multimeter. A clamp that does DC current is usually really expensive. I didn't know that even existed.
I'd suggest this timing light: https://amzn.to/2IRWzpR
INNOVA 5568, if you don't already have one that does advance. This will do up to 90 degrees of advance. So, for example, when you are running at 3000 RPM, you can confirm that your mechanical advance is "all in" at whatever you want it to be (perhaps 36 degrees, depending on your engine setup).
My "fix" for dodgy timing (due to a worn distributor), was to get a new HEI distributor (a take-off from a ZZ4 crate motor) and a set of shims to close the endplay gap. It came with all new parts, including a coil.
Here's a quick video to get you started (please excuse me if you already know this stuff, I'm just learning as I go, too).
Hopefully this is helpful in some way.
Thank you I will check out the video, I bought a new coil and the HEI module I had in there came with a lifetime warranty so I replaced that also. Will see how it turns out.
av81 post is correct about the manufactures marks on the crank gear sprocket. But, just because your dots line up, does not mean you chose the correct slot or keyway. One is called straight-up, one is usually 4* retarded and one keyway is 4* advanced.
If your instructions were like mine it was tough to read. My timing chain set came from a top of the line company but the instructions looked like somebody dipped them in a bucket of bleach. I knew I wanted straight-up which was the "O" mark on the sprocket.
Also, that photo of your dots matching I believe is for number 6 cyl, not #1.
av81 post is correct about the manufactures marks on the crank gear sprocket. But, just because your dots line up, does not mean you chose the correct slot or keyway. One is called straight-up, one is usually 4* retarded and one keyway is 4* advanced.
If your instructions were like mine it was tough to read. My timing chain set came from a top of the line company but the instructions looked like somebody dipped them in a bucket of bleach. I knew I wanted straight-up which was the "O" mark on the sprocket.
Also, that photo of your dots matching I believe is for number 6 cyl, not #1.
Thank you, I went back and found the instructions see image below, I installed the stock way (second method in diagram) exactly how I installed it. The keway I used was the same on that you used on your engine. Thanks for reminding me to check it out.
OK guys I thought I would post my latest, it has a hard time starting but when starts it can rev up. However will stall out if I take my foot off the gas. Thinking maybe I screwed up the carb rebuild, might take it and have it professionally gone through. see video https://cl.ly/qtVF
Choke hooked up? Did you set the float(s)? Set the air/idle screws? Have you tried turning the curb idle up to keep it running long enough to try some adjustments?
Carbs are tricky things.
Good luck!
Sorry guys been busy with other family stuff now back on the car. OK so I had the carb professionally rebuilt by Rod's Carburetor in Phoenix. They tested it on an engine they have in their shop. I put the carb and this time I capped off the vacuum lines that go from the carb to charcoal canister and the direct vacuum outlet at rear of intake manifold that I believe goes to operate the lights and other stuff. I started the car and it ran a little rough then I loosened the distributor and advanced it to about 30 degrees and the car ran pretty good. So now I am a bit baffled how it idles rough at 12 degrees TDC but good at 30 degrees TDC. I guess at this point I should just be happy it is running decent.
I took my distributor to the carb shop they also do distributors, they put in on the dial cleaned it and checked it out all out. I also brought them the carburetor they rebuilt for me, they have a SBC 350 on engine running stand and they attached my carb which fired right up on their engine. The owner came over and checked it also, he was nice enough to look it over and told me stock set up was a bit lean so he richen the jets free of charge, put it back on the shop's motor and it fired right up again. I put the carb back on my car started it up and it will still only run with high advance, the carb shop owner told me that what he was doing would not address the high timing issue.
So I went to bed last night with a major frustration head ache, then I got to remembering that I installed new valve stem seals when I had the engine out last year. I went by all of the published write ups to set the valve lash. I got up early this morning popped off the valve covers and moved the engine to TDC #1 adjusted rocker bolts back for valves that shop manual state should be set at TDC #1, basically gave the push rods just enough play so I could just twist them. Then turned motor over to TDC #6 and did the same procedure for the valves shop manual recommends in that range. I turned the motor over to 12 degrees before TDC #1, made sure I had the rotor pointed to the #1 distributor tower.
And to my absolute delight, the engine fired right up, my wife heard me yelling with joy in the garage. Thank you all for your help and encouragement. Will need to post this to other discussions I jumped on. Thanks again.
04-09-2018, 11:59 PM
, extreme retarded timing
