1972 350 Surging Under Load When Stopped and at Operating Temperature

single or duel exhaust?

 

I was betting hard on that metering rod being bent up was the culprit ....have you double checked
for crossed plug wires ? also check short rubber fuel line ....you should have small one that connects
the lines at the frame -drivers side near center of car length .

 

Single exhaust.. and that heating flap is a great idea to check if I have it.

I was really hoping it was that, too. At least I found that, though! I did verify the wires weren’t crossed - I will definitely check that rubber fuel line. Thanks!

 

I’m going back to early on in this thread. Did you ever correctly adjust timing? Whenever I experienced surge on these cars, timing was too far advanced.

 

SE that explains good flow. one side open.

 

Jake,

I would clean it up & give it a slight bend up to be sure.

 

I believe my term “surging” may now be inaccurate. Should I change the thread title? And I did check timing, yep.. 4* BTDC right now. I thought the same as you.

 

Thanks, Tom! Will do.

 

I’m going to check this tomorrow for sure. Thanks so much, Bob. Crossing my fingers I find it soon. The warm weather is getting here.

 

Something else to consider is the fuel tank may be rusted on the inside and rust flake is blocking fuel flow?

This happened to me with my '65 Impala. Would run good for a while until the rust flake would get sucked to the pickup sock and restrict fuel flow. The outside of the tank looked great but the inside not so good so it took a while to figure out!

You say "I believe my term “surging” may now be inaccurate" , how exactly would you explain what the car is doing?

Fuel/air/spark, one of these are more than likely the culprit.

Fuel, the above is one of many possibilities as well as the already mentioned things that can go wrong.

Air, could be a vacuum leak, clogged or restricted air filter, some how air not flowing in the carb.

Spark, weak spark, gap to much, bad plugs among many other things that can go wrong that some have been mentioned already.

Hope you get this solved soon, GL.

 

Guys, problem solved.

As someone stated in the beginning of the thread, it'll be something simple. I popped the distributor cap off to check out the rotor like Tom suggested, did that. Upon reinstalling, I noticed the block on the points (I believe it's called a block? The thing that the cam lobes push) wasn't even touching the cam lobe almost at all even though the cam was on the highest point. The points remained closed as I rotated the motor by hand. If they opened, it wasn't anywhere near where it was supposed to be. Then, the smoking gun: one of the screws that holds the points in was completely loose. I got my feeler gauge in there and reset the gap and tightened it down. I put everything back together, and the car immediately ran smoother through all phases of the choke pulling off. I took it on a half hour drive, and threw some stop and go in there, not a problem to be had. I will be fine-tuning the dwell angle next.

Thank you all SO much for all of your input. Without it, I wouldn't have thought to look at the electronics, and I wouldn't have found that bent metering rod. I also wouldn't have had the confidence to rebuild my first carb, so I'll scratch that one off the list, too.

All this is just in the nick of time - it's 50-something degrees in sunny Aurora, IL today!

Now, off to Larry's power timing thread to get it dialed in to perfection. Can't tell you guys how much I appreciate your time and information throughout this process.

-Jake

 

many of us said ...keep it simple and it was something simple .....

fill her up with some premium and let her rip

 

another week of this mystery and we would of had you pull your motor apart for a cam change



next project I would suggest an easy upgrade to electronic ignition set up


contact Todd Miller / http://www.diecastmusclecars.com/buick_distributor_kit.htm

 

Good work Jake! Sometimes you have to go through all the motions to find the demon. Great feeling, isn't it?

 

Jake,

Replace those points at least. In my experience by adjusting the points with a worn rubbing block it comes back to haunt you in short order. Go to NAPA & get the GOOD points. JUST the points & NOT a Uniset with the condenser. Don't forget to add the lube to the rubbing block. It usually comes in the box with the points. Although they may try to sell you a separate condenser. DON"T go for it. JUST THE POINTS.

Tom T.

 

YES. I even mentioned early on that I had a kit in my cart at Jegs, but I’ll take this recommendation, instead. Thanks for the recommendation!

 

I passed a guy just smiling looking at the car earlier, I had the biggest grin on my face! Great feeling, indeed, sir. Thanks!

Will do, Tom! Thanks again!

 

Time to anger the neighbors.. Woo!

 

All your parts, cap, rotor, points, weights & springs look new.
You dont need to buy anything, just set your dwell & timing. Tighten points so they won't move again.

 

Yep, what I was planning on for the time being. I know there’s a lot of debate of points vs. electronic, but I do think I’ll go electronic eventually.