Half of block not firing

-
CLAY72dart

CLAY72dart

Well-Known Member
Joined
Aug 13, 2022
Messages
232
Reaction score
98
Location
Summerville South Carolina
I replaced the intake due to a vacuum leak at a 2 barrel to 4 barrel adapter plate and so I bought a 4 barrel intake put it on. Ended up finding out half the block is running at idle, and half the block is not the side of the block with the steering wheel the muffler on that side only heats up when I give it throttle. Its not just one pipe still cold it’s all four any help? I looked up the distributor diagram and unplug and replugged in the wires to be sure, but It did nothing for me.
 
This does not make much sense because most manifolds are 180*, meaning, something like a leak normally will affect every other cylinder, not an entire bank.

What I'd try: You need to SHORT plug wires, not pull them, "if that is what you did." This is because of spark crossfire on a disconnected wire position. What I used to do, is to loosen the dist. boots and wires so you can easily pull them, with an insulated pair of fuse pullers, etc, and then in the other hand, hold a grounded probe, and as you extract a wire, insert the grounded probe into the dist. tower. You should be able to see what ones are firing or not

Did you cross tighten the manifold bolts?

And is this in fact a 180 design, as opposed to something like a Torker/ or 360 design?
 
I'd think if it would actually run with only 4 cylinders on one side firing it would be shaking so hard that the car would walk sideways..
 
If you have the PCV valve plugged into your intake manifold, there's your problem.
 
mbaird said:
Elaborate please ?
Click to expand...
The port on the intake manifold is for the power brakes. If the pcv is plugged in there instead, it basically acts like a manifold vacuum leak because it disrupts those cylinders in that runner.
 
RustyRatRod said:
The port on the intake manifold is for the power brakes. If the pcv is plugged in there instead, it basically acts like a manifold vacuum leak because it disrupts those cylinders in that runner.
Click to expand...
Yes but that wouldnt explain why 2,4 and 6 arent firing.
 
I think Del hit on the head when he asked about the intake torque sequence. If OP torqued one side all the way then the other he may have leaks on that whole bank .
 
CLAY72dart said:
I replaced the intake due to a vacuum leak at a 2 barrel to 4 barrel adapter plate and so I bought a 4 barrel intake put it on. Ended up finding out half the block is running at idle, and half the block is not the side of the block with the steering wheel the muffler on that side only heats up when I give it throttle. Its not just one pipe still cold it’s all four any help? I looked up the distributor diagram and unplug and replugged in the wires to be sure, but It did nothing for me.
Click to expand...
What intake? Single or dual plane?
 
Here's my 2cents;
Just put a timing light on it and watch; if she's missing on four cylinders you will plainly see it in the strobing. If it is steady, then;
Retard the timing to about 8*, which will require you to increase the throttle opening, and this will bring in fuel from the transfer slots. If you now have all eight, then clean out your Idle circuits.
 
You have a dual plane 4 bbl intake manifold feeding half the engine with one side and half with the other side.

Now your "Used" 4 bbl carb has the idle circuit plugged on the cold side of the engine. You will notice that the 2 idle enrichment screws on the front of the carb (Edelbrock 1406), one screw does nothing because it is plugged.

About the only way to fix it is to take the carb apart and run it through an Ultrasonic Cleaner to break up the debris in the internal carb passages. Or buy a new carb.

Screenshot_20220426-104100_Gallery.jpg


Screenshot_20210416-214121_Gallery.jpg



Edelbrock 1406 carb, works good on the small blocks right out of the box.

Screenshot_20200807-121328_Gallery.jpg
 
FIRST thing you need to do....and I'm repeating..........is find out what cylinders are missing. If this is truly one SIDE, it is likely a physical vacuum leak at the head. If it is (dual plane) missing every other cylinder in rotation, then it is likely a carb problem, or a leak into "that side" of the intake.

This is WHY both OldManMopar and myself asked you what kind of intake. "The problems are different"
 
If half of the block isn't working, you should fire it...
 
CLAY72dart said:
318 stock
Click to expand...

OK
For starters then I would say you have too much carb for your stock 318 setup.

Get ahold of an Edelbrock 1406, they are proven to run well on the stock 318s with their stock camshafts.

Beg, borrow, or steal a good known working 1406 carb and get it on there.

I see you are 19 years old.
What year is your 318 engine?

What year and model is your car?

Resized_20200712_194110_8421.jpeg

318 with ^^^ 1406 Edelbrock running nice, idles nice, performs nice.
 
George Jets said:
OK
For starters then I would say you have too much carb for your stock 318 setup.

Get ahold of an Edelbrock 1406, they are proven to run well on the stock 318s with their stock camshafts.

Beg, borrow, or steal a good known working 1406 carb and get it on there.

I see you are 19 years old.
What year is your 318 engine?

What year and model is your car?

View attachment 1716012974
318 with ^^^ 1406 Edelbrock running nice, idles nice, performs nice.
Click to expand...
Engine is from 72
 
You must log in or register to reply here.
-

Back
Top