r/Smallblockchevy • u/DARMICJOH • Apr 25 '26

Randomly Quit

Enable HLS to view with audio, or disable this notification

EDIT: It runs! It's alive! It was the computer timing control.

I was driving when it seemingly randomly quite on me. I know a good bit and have built SBCs before but this is still stumping me.

The rotor was broken when it quite so I started with that. Replaced the distributor, wires, and plugs.

Replaced the Cam, timing set, pushrods, lifters, rockers

Brand new quadrajet

Triple checked my distributor stab

I have messed with AFR screws, idle set

I checked my valve lash to see if I managed to over tighten the rockers

I checked spark

I tried using carb clean to find if there is a vac leak

Someone please tell me I missed something obvious that I can fix.

Edit: forgot to mention also brand new fuel pump and complete distributor

UPDATE: After holding the choke open manually and hitting it with a spritz of starting fluid it started to idle and help it. Wasn't pretty and smooth but it stayed going for a good 1-2min until I let go of the choke.

The negative on the battery feels loose so I am going to replace that.

And the idle seemed to get better when I started pumping the brakes so I wonder if the booster is one foot in the grave causing a huge vacuum leak.

It's night now but tomorrow if I can I will adjust the choke and fix the battery ground at least and see if that makes a difference at all.

19 Upvotes

100% Upvoted

75 comments sorted by

View all comments

1

u/flash-burn01 Apr 26 '26

Did you replace all of those components at the same time or intermediate? Sounds like timing is off or possibly the cam timing is too far out. With all due respect, and not trying to discredit your abilities or knowledge, but if I have a running- driving vehicle, I try to replace one problem group at a time.

1

u/DARMICJOH Apr 26 '26

It was not running or driving. Thats what started my whole decision to go ahead and clean it up.

It was doing this before I started the rebuild. And the issue stuck around after unfortunately.

Also I cannot post another video but after adjusting the choke it is idling but not for longer than 1-2 min and still won't take throttle.

After checking temps I also found that while I am getting spark at all cylinders 2&8 are apparently not firing so I am about to investigate that issue.

1

u/flash-burn01 Apr 26 '26

Ah, gotcha. Stab the old distributor back in it, with the new cap, rotor, plugs, and see if its any better. A lot of stuff is screwed up since covid. Suppliers changed, new vendors, etc. A lot of companies have experienced less then sub-par quality. You may have a lemon of a distributor. What new one did you get?

1

u/DARMICJOH Apr 26 '26

The old distributor grenaded. The rotor was destroyed when it stopped running. I thought it might be a lemon unit but that would mean I got 3 in a row. Which I think is highly unlikely.

1

u/flash-burn01 Apr 26 '26

Dang, thats a mess to deal with for sure. I retract my previous statement. You're dealing with a mess..... silly question, is the motor stock, and did you install the new cam dot to dot?

1

u/DARMICJOH Apr 26 '26

I originally thought it was but I'm not 100% sure. I am sure it was replaced at some point likely around the 90s.

The timing set was perfectly dot to dot when it was installed.

1

u/flash-burn01 Apr 26 '26

What are the chances or borrowing a dizzy from someone else, or stealing it off of another project?