Rough idle and takeoff 250 inline

[68gmcdude]

Originally Posted by '68OrangeSunshine

I asked at Don's Hot Rod Equipment in Tucson, but you should be able to get these anywhere:
Cornet....3/8 - Inverted Flange Plugs...p/n: 106-6....$1.60 [each] x 6 =$9.60

Prices may vary nationally. Other manufacturers may offer similar products with different prices and quality.

Thank you!

[geezer#99]

If you’re setting the valves, make sure to check all the rockers are moving the same amount.

[Rust_never_sleeps]

Maybe check that the points condenser is healthy with a multimeter. I know it's new, but chaotic timing and backfires might be caused by a dying one

[68gmcdude]

Originally Posted by geezer#99

If you’re setting the valves, make sure to check all the rockers are moving the same amount.

Will do. Plan on doing that after work tonight.

[68gmcdude]

Originally Posted by Rust_never_sleeps

Maybe check that the points condenser is healthy with a multimeter. I know it's new, but chaotic timing and backfires might be caused by a dying one

I will check that. I also have another condenser I can try putting on.

[68gmcdude]

Originally Posted by geezer#99

Redo the lifter adjustment.
Only do 1/4 turn from zero lash.

I readjusted the valves and set them a 1/4 turn from zero lash. When I did a 1/2 turn it was still idling a little rough. I did this with the engine running. The idle is smooth now. Before I put the valve cover back on, I'm going to let it sit overnight and start it again tomorrow to see if it's still ok.
So are the 1/4, 1/2 and 3/4 turns on a valve adjustment simply recommendations and each motor is different? I originally did a 3/4 turn on each valve.

['68OrangeSunshine]

Cut-Out Valve Cover. That's a Pro move!

[68gmcdude]

Originally Posted by '68OrangeSunshine

Cut-Out Valve Cover. That's a Pro move!

My buddy had one laying around. Makes a nice splash guard.

['68OrangeSunshine]

Originally Posted by 68gmcdude

My buddy had one laying around. Makes a nice splash guard.

Especially as the little spoon clips they sell for adjusting V8 heads just wobble off L6 rocker arms. I have an old valve cover to use iike that, too.

[Rust_never_sleeps]

Originally Posted by 68gmcdude

I readjusted the valves and set them a 1/4 turn from zero lash. When I did a 1/2 turn it was still idling a little rough. I did this with the engine running. The idle is smooth now. Before I put the valve cover back on, I'm going to let it sit overnight and start it again tomorrow to see if it's still ok.
So are the 1/4, 1/2 and 3/4 turns on a valve adjustment simply recommendations and each motor is different? I originally did a 3/4 turn on each valve.

The book says preload is 1 turn from zero lash for everything from 250-427
For SBC the consensus seems to be 1/2 or 3/4 turn, but for a battleworn six, I'd guess you're going to know better than anyone else where it's happiest

[68gmcdude]

Originally Posted by Rust_never_sleeps

The book says preload is 1 turn from zero lash for everything from 250-427
For SBC the consensus seems to be 1/2 or 3/4 turn, but for a battleworn six, I'd guess you're going to know better than anyone else where it's happiest

When I adjusted them the first time, I tried the one full turn like the shop manual said, but the motor really didn't like, it barely kept running, so I ended up doing 3/4 turn. At the time it seemed ok. When I readjusted last night, it didn't like the 3/4 turn, so I tried a 1/2 turn and it was still idling rough. I backed it off to 1/4 turn and it idled good. Gonna go back out there this evening, start it up, let it run and see how it goes. If all seems good, the valve cover is going on and I'll take a test drive.... We'll see.