funny thing happened on the way home from cruise night

[Vanderstel]

I had just finished a low and slow drive down Grand in Escondido CA. Opening of Crusin Grand. Anyway, the temp went up a little nothing to worry about.

On the way home I decided to open it up a little, so when it was safe, I stepped into it.

As the revs built, it sounded like it was popping through the carb? I've not had this happen before.

I've got a Edelbrock 650 on top of a Performer intake on my rebuilt 1967 318 with full length headers.

I haven't touched carburation or timing in over a year, I did just replace my fuel pump and filter.

Any suggestions?

 

[Bird 426]

Bad new fuel pump? Happened to me on my van, new chinisium fuel pump.

 

[ackpht]

Bad new fuel pump? Happened to me on my van, new chinisium fuel pump.

Agree- that's the first thing I would check. New does not always equal good.

 

[1 Wild R/T]

Lean is certainly a possibility.. But not the only possibility... What happens if you rap the throttle sharply in neutral?

 

[Kern Dog]

Popping up through the carburetor...?
This will suck if I'm right.
That could be a failing cam or lifters. When an exhaust lobe is failing, the exhaust has less of a clear path out so it finds a way somewhere. I've had this happen. When cruising, cylinder pressure is lower so the lower lift on a failing exhaust lobe still allows enough of a path for the exhaust to escape. When you're harder on the throttle, there is more pressure. Exhaust then exits both the exhaust valve and the intake during overlap.
I hope for your sake that I am wrong.
Are you hearing any increase in valvetrain clatter? Loose pushrods when you're on the lobes base circle would indicate a problem.

 

[1 Wild R/T]

Popping up through the carburetor...?
This will suck if I'm right.
That could be a failing cam or lifters. When an exhaust lobe is failing, the exhaust has less of a clear path out so it finds a way somewhere. I've had this happen. When cruising, cylinder pressure is lower so the lower lift on a failing exhaust lobe still allows enough of a path for the exhaust to escape. When you're harder on the throttle, there is more pressure. Exhaust then exits both the exhaust valve and the intake during overlap.
I hope for your sake that I am wrong.
Are you hearing any increase in valvetrain clatter? Loose pushrods when you're on the lobes base circle would indicate a problem.

Hence my question, what happens if you rap the throttle in neutral..

 

[kiwigtx]

Can be as simple as fouled plug or plugs....I've had that. Sounds like you're shooting ducks as you drive along.

 

[Vanderstel]

No clatter or engine noise of any kind, I'll check plugs first.

 

[kiwigtx]

Start with the easy stuff first.

No point tearing down the carburettor when it might be as simple as a loose plug wire - or bad plug.

 

[Vanderstel]

When I replaced my fuel pump I also replace my fuel filter. I realized the filter was 1/4" not 3/16". I now have 3/16" filter and I replaced all spark plugs. To make sure I didn't have any internal mechanical problems I did a compression check and I'm pretty much running 150 lbs all the way around.

Runs fine now. I wonder if I was getting fuel starvation with the 1/4" filter?

 

[1967coronet]

When I replaced my fuel pump I also replace my fuel filter. I realized the filter was 1/4" not 3/16". I now have 3/16" filter and I replaced all spark plugs. To make sure I didn't have any internal mechanical problems I did a compression check and I'm pretty much running 150 lbs all the way around.

Runs fine now. I wonder if I was getting fuel starvation with the 1/4" filter?

If the plugs you replaced were fouled ck. the lbs of pressure your new fuel pump is putting out. Edelbrock advises to keep it at 6 lbs or under a little.
If your problem showed up after the pump change you may foul another set of plugs.

 

[Kern Dog]

When I replaced my fuel pump I also replace my fuel filter. I realized the filter was 1/4" not 3/16". I now have 3/16" filter and I replaced all spark plugs. To make sure I didn't have any internal mechanical problems I did a compression check and I'm pretty much running 150 lbs all the way around.

Runs fine now. I wonder if I was getting fuel starvation with the 1/4" filter?

3/16" is smaller than 1/4".
Did you mean 5/16" ?

 

[Budnicks]

What kind of ignition does it have ?
if it still is points
the condenser, is my 1st suspect
the coil taking a dump & or burnt points also could be in play
where you parked with the ignition on for a period of time ?
might have nothing to do with the carb
or the ignition

valve, plugs, bad gas/water, sucking air/vacuum leak,
vacuum hose or cap somewhere, orange crud in the dist. cap/cracked cap
(bad rotor or cap) etc.

 

[Vanderstel]

3/16" is smaller than 1/4".
Did you mean 5/16" ?

opps 5/16