I've been working on a 63 bel air that I picked up for my girlfriend. It is clean and in decent shape with the 283 2 barrel and 3 ott. I've got it running but I'm having some problems with it popping through the carb when I try to drive it. Here's what Ive done lifted from the bel thread: After rebuilding the carb and changing the plugs out the Bel starts. We ran a bunch of seafoam though it and it helped a lot. It idles super smooth. Now it's popping through the carb under load though. I tightened the exhaust and intake manifolds and double checked the carb. It all seems to be good. I know I still need to put a timing light on it and check that, but it idles too smooth to be too far off. I put new cap, rotor, points, condensor, and coil. I ordered new plug wires which will be in tommorrow, as well as intake gaskets, exhaust gaskets and doughnuts. I know I need to pull the valve covers and adjust the rockers. Any suggestions on what else to check? <!-- / message -->
Sounds like you are on the right path of elimination. When you check your timing you will get a better idea. Could be the timing is off or worse the timing chain is stretched.
Check your valve lash like you mentioned. Then start it without the valve covers on and see if the rockers are all moving the same. It sounds like a bad exhaust lobe on the cam to me.
Could be. Nowhere near as prevalent on the '60s sbcs as on '80s 305s, but I've still torn down a few 283/327s over the years and saw a lobe or two that was only half there.
I changed the water pump and was going to do the timing cover just to check the chain, but I got lazy. Im thinking it might be a valve as well. I'm just hoping it's not a cam lobe because I don't want to get that far into the motor unless Im going through the whole thing. Shitty part is my daily just took a dump and I need this up and running soon!!
Like PORKNBEANER says... start simple. I'd look for timing advance issues first if it starts and idles but coughs under load.
I agree with a bad cam. If it's popping pretty badly on acceleration, it's almost for sure a bad cam-lobe...or very likely more than one. Pull the valve-covers, and I bet you'll see that one or more of the rockers aren't moving nearly as much as the others. It's not so hard to change a cam and lifters. If you do determine it's a wiped cam, get as much of the metal shavings out of the engine as you can. Good luck.
Gonna try that this weekend! Nope, pulled off the line and plugged it with same results No vac leaks, but I printed out 8 pages of carb service and adjustments I'm also going through this weekend. I was hoping not as many bad cam responces would come up as did, cause thats what Im thinking worst case is. I guess if Im gonna have to change the cam its gonna be something with a little more thump, and I'll have to throw the double humps on there, and the 4 barrel intake and 650 demon, and..............see why I'm hoping its simple!!!
chunk of shit in your high speed jet? or the accel pump squirter? i see you said you rebuilt the carb..but did you clean out all the jets and passages? if so..than I'll shut up
I've only rounded off 2 cams in 25 plus years of driving,and both happened right after most of the zinc was taken from most motor oil. I've heard people try to say this doesn't normally occur except during break-in,which I feel is untrue. Both of these cams were fully broken in before the zinc fiasco. I'm gonna run roller cams from now on.
I hope I got it clean, I spent 4 hours cleaning and 15 minutes putting it back together! It went together so fast and easy I took it apart and did it again just to make sure I did'nt miss anything!
well than.. must be somethin else My 235 with a single BBl carb would do exactly this when it sucked some shit out of the tank..I could clean it out where ever I was and go on from there til it happened again..than i cleaned the tank. probably an intake valve not seating, or burned..is it random? or steady? (the popping)
It will idle smooth after warm up, you can rev it up with no problems. Its only when its in gear under load that it pops and then its steady poppin. Thats why Im thinkin its just valve sticking. Just not gonna know till I get done testin everything and go through it all. It has been sitting since 1980 and the original owner was prolly a depresion kid because it had the original plugs and 5 original wires with the production date printed on em! My grandparents were like that, only replace what really needs replacing!
Also on the list for this weekend. My brother is coming over to help and he has a compression guage and a vac guage. I've got the timing light and old sun tach-dwell meter.
After I change the oil again Im putting the ?zzpp? whatever its called crap in that replaces all the zinc they took out.
Thanks guys, I just wanted to make sure Im in the ball park. I'm a metal guy, not a mechanic! I'll find out this weekend.
If it is a very steady rapid popping it is probably intake valve related, if you are lucky it could be rocker arm, pushrod, or a pulled rocker stud, unlucky a cam lobe.
I second Russco. The exact same thing happened to me last week. The rocker came off the pushrod because I have a bad cam lobe.
I had a issue like this years ago, the wire from points to coil had worn thru insulation and idled great but under load the vaccuum plate would move and short out points, let up on gas and all OK, easy enough to check as sometimes the small crap eats you an ass.
maybe something you've already done and i missed reading through the posts but did you change out the points, if it even still has point haha. When ever my car ran like shit the first thing i always did was change the points. up until i wised up and got rid of them
Look for a broken valve spring. Have you put a vac gauge on it? is it steady, or bouncing all over the place?
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