Well dang it…

[57taskforce]

Don’t you just love when you kill a stamped rocker arm. #4 exhaust. I was just cruising along in my ‘72 tonight running around 55 and it just let go. Luckily I was only a couple miles from home when it let loose. Thought for a minute or two that it was blowing up, oil psi and temp were both good but it had a constant back fire thru the carb and wouldn’t run any more than about 1/4 throttle in second without sounding really really bad. I knew it wasn’t a knock but man it sounded bad. I guess I’ll round up the stuff to do all 16 with new push rods. I’m sure this motor has a butt load of miles on it, it’s tired but still runs pretty good. The valve is still free and the pushrod is still straight. It’ll live to see another day I believe.

[palallin]

Had a similar problem once: the rocker cracked at the base. Replaced, and drove one for many more miles.

[special-K]

Do you think the pushrod got plugged up? I've never been that lucky. I've run a timing chain off the gears once. Had new double roller parts under the seat waiting to go in. Bent pushrods. Too many miles to do new top end, so I rebuilt it

[BAD1916]

I noticed on my suburban that it had a ticking noise that was getting louder. When I took the valve covers off I found that the nut no longer tightened down and the rocker arm was just floating there. Luckily it was intake so didn’t get any backfire issues and the pushrod was good. Gotta love the easy fixes.

[va72longhorn]

I had the exact thing happen to me years ago in my first Chevrolet… 72 blazer factory 2wd. I was 18, taking the GF to the movies on a Saturday night. 20, miles from home, with tool box in the back, I pulled over on the shoulder of the road. Pulled the valve cover off, removed the bad and the corresponding rocker to “kill” the cylinder, threw the valve cover back on and continued on to town. Drove about 60 miles that night on 7 cylinders but at least didn’t have the carb backfiring.
What I’d give to have that blazer back (sigh)

[57taskforce]

I don’t think it was plugged, the top of the pushrod really doesn’t show any signs of big wear or damage. But as we all know anything is possible. The valve wasn’t stuck at all. I could move it with a little persuasion from a dead blow. The motor suffix points to it being originally from a 73 C20. I had the heads off a few years ago and I’m pretty sure it would take .060 to clean up the ridge on top the cylinder walls. It’s tired for sure. I’ll probably just throw a set of rockers at it and see how much longer it’ll run. I’ve got a 90% done 350 with aluminum heads that I’ve been building a little at a time. I might speed finishing that one up sooner than later.

[67C10Step]

Had the same thing happen to my 70 model with a 350 back in college. Roommate and I jumped in the truck to go grab a pizza. Pop, pop, pop through the carb. Looked at my buddy and said, "We better take yours. I think I just dropped a rocker arm." Turns out I was correct. Got him to run me to the parts store and fixed it up later that day. Drove that truck another 3 years at least.

[72SB]

I would put a new set of rockers on and really confirm PR are not partially plugged. If one rocker wore like that, possible others are not far behind

[hugger6933]

I had that happen to a big block I had in my old bracket car. It was before the move to rollers. I sure makes you think the motor is eating itself. Jim

[57taskforce]

Jim, you are right it sure does!
Update. I replaced the rocker with another I had on hand, and re used the pushrod. It’s Running great again.

[57taskforce]

Update #2
The whole reason I was driving the truck in the first place yesterday, was so that my wife and I could get to a safe place for me to teach her how to drive a 4 speed. She’s only driven autos her whole life. After I put it back together earlier we went and ran it around in the hills behind my house for an hour or so. It didn’t have any troubles at all. I like teaching people how to drive manual transmissions in 4 low to start with. Lots easier to get the basics down with out stalling and it’s much more forgiving if you miss a shift. Not to mention no traffic and a much much slower speed to get thru the gears. Momma did great, and so did the truck!!! She’s a natural.

['68OrangeSunshine]

I was 19 years old when my Dad taught me how to use a clutch. We had a '61 Mercedes 190 [~2L i-4, w/ a 4-on-the-column shifter. I called it a 'Mauser Bolt Action.' Same H-pattern as an SM465 but off the floor. Like the 465's Granny Gear, the MBz had a low 1st. On flat streets you could take off in 2nd.]
We used out of the way shopping malls with big, empty parking lots.
I had never heard my Dad cuss before! I burned up the clutch before I got the hang of it.
The Mercedes guys laughed when he brought it in for a new clutch disc, and gave him a deal.

I have broken about 3 or 4 exhaust valve springs on my 292. Never the same one. I replaced them all after the 2nd, and it's happened again. Now I'm cannibalizing springs off a '63 292 core. None of those have broken. We have it down to a pit stop. Cycle cam to that cylinder's valves closed, pump compressed air into cylinder via a compression tester plug fitting, compress spring with tool, R&R spring, put half clips back on, release spring. Usually it's right back in tune and runs great without an extensive valve adjust session.
My machinist thinks my cam lobes are going, due to not knowing about ZDDP being taken out of motor oils. Now I use Valvoline Racing SAE30 exclusively. It has the right ZDDP levels.

[BAD1916]

Glad to hear it was an easy fix and that you got to take it out and teach the wife how to drive it!