#1 Cylinder seems dead.

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VonCramp

VonCramp

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Hi. Been a long time since I've been on. Having a bit of a problem with my 340. #1 Cylinder is staying cold. I used the water on the header trick. Definitely cold. I then checked valve adjustment. It is a Crane solid roller cam 509". The rockers were a little loose by a few thousandths, but not so much that any damage should've happened. They are pro comp heads and rockers. After readjustment on the rockers, I then proceeded to do a compression check. Here's where I am lost. #1 is showing 170 but not doing anything. #2 is only showing close to 160. 158 after sitting a minute or two. However #2 fires just fine. My fuel pressure from the Jegs Holley knock electric pump off keeps climbing no matter how much I adjust the regulator out. I have tried three different regulators to no avail. I cleaned the #1 spark plug and fired it out of the cylinder. Great spark. So I have cylinder pressure and spark but a cold cylinder. Car runs like crap.

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Pull the valve cover & look for pushrod / rocker/ lifter damage or a wiped cam lobe.

No fuel to that cylinder, no heat.
 
Alaskan_TA said:
Pull the valve cover & look for pushrod / rocker/ lifter damage or a wiped cam lobe.

No fuel to that cylinder, no heat.
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I am hoping the no fuel is the issue. Maybe thats why the fuel pressure is climbing? May not be making it out of front bowl? Site glass is showing fuel to the top even though float is adjusted properly. Solid roller would be hard to flatten it woud seem.
 
You have something holding the exhaust valve on #1 closed. That's why it's showing higher on the compression gauge. Look for something damaged on the #1 exhaust valve train. Broken or worn rocker, bent pushrod, wiped cam lobe or "something" up with that lifter.
 
VonCramp said:
I am hoping the no fuel is the issue. Maybe thats why the fuel pressure is climbing? May not be making it out of front bowl? Site glass is showing fuel to the top even though float is adjusted properly. Solid roller would be hard to flatten it woud seem.
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It's not fuel. Something's broken, bent or worn.
 
You got fuel to the top of the sight plug? you got pressure issues or a bad needle seat. I never liked the adjustable regulators. How do you have it plumbed, In the bottom and out the side with a gauge on the other side? IIRC you loosen the adjuster to lower the pressure. Carb is not going to isolate a runner by itself, there has to be a valve train issue...just look at #1 intake rocker while you cycle the crank. Should move equally.
 
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pishta said:
You got fuel to the top of the sight plug? you got pressure issues or a bad needle seat. I never liked the adjustable regulators. How do you have it plumbed, In the bottom and out the side with a gauge on the other side? IIRC you loosen the adjuster to lower the pressure. Car is not going to isolate a runner by itself, there has to be a valve train issue...just look at #1 intake rocker while you cycle the crank. Should move equally.
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Yes. Fuel is to top on Holley carb site glass. Fuel line goes into bottom of regulator. Exits on one side and gauge on other side. I will cycle the crank and watch the rockers tomorrow. Can videos be posted here?
 
VonCramp said:
Yes. Fuel is to top on Holley carb site glass. Fuel line goes into bottom of regulator. Exits on one side and gauge on other side. I will cycle the crank and watch the rockers tomorrow. Can videos be posted here?
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Yes but you have to host them on another site such as youtube and post the link here.
 
You dont want fuel to top of sight glass, that is a sign of the wrong setting. Demons allow you to get to center of glass as its lower, Holleys need to be at bottom (just dribbling out an opened sight plug) when idling or when they are pumped by an electric pump on a stand, much safer. Post to youtube and send link. loosen lock screw and turn big nut to lower float level (seat) ...supposed to be able to do this while its idling but I always end up spraying fuel everywhere. Turn screw to lock.
 
VonCramp said:
Solid roller would be hard to flatten it woud seem.
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I’ve got a flattened solid roller lifter in my drawer from a big block. Needles failed and roller stopped. Damn near ground through to the axle. The other fifteen are fine. It can happen.
 
Swap plugs around.
There has been the rare occasion where they dont fire under pressure. and re-examine plug for a loose center electrode.
had one that caught me, didnt see it until i held it electrode down and thumped it on a block of wood. Closed the gap.
A vacuum gauge should indicate an anomaly if something in valve train is bad.
 
I had two separate 318s do something similar and on both of them I found a pushrod that had punched thru the rocker If I remember correctly one was an intake valve the other was an exhaust. On the first one It was weird I didn't hear a thing i just noticed that i had lost some power I thought it was carb related I had alot of carb issues with that truck so I pulled it off and cleaned it and rebuilt it and nothing changed. So I popped off the valve covers and there she was lol I replaced the rocker and the pushrod because it had bent and drove it another 5 or 6 years lol the 2nd one was about 10 years after that I bought another truck just like the first one I just mentioned for parts but it was in such good shape I drove it. It was a 2wd I drove it for a year before I parted it and when I pulled the engine sure enough it had the same thing I never noticed it. Lol
 
Rotate engine by hand while watching for the valves to open and close.

Your test of spark across the plug in open air is meaningless and has not proved that you spark system to cylinder 1 is good. It takes only 2000-3000 volts to jump that gap in open air but 20,000 volts or more to jump that same gap in a compressed fuel-air mixture.

Recheck your spark plug wire with an ohmmeter and be sure that the resistance is in the 3000-5000 ohm range. Examine the wire for anything obviously wrong. Place the end of the spark wire 3/8" from a metal surface and crank and see if the spark will jump that large gap in open air; that is the only valid open-air test to do.

Swap plugs.
 
,is the miss at idle or all the time also a wiped exhaust lobe will cause a back fire thru carb at high speed also pull wire off and see if engine smooths out
 
First thing you can do is eliminate the idea that it's the carburetor that's utterly ridiculous that it would feed the rest and not one cylinder unless a rat got caught in one of the ports...
And if it is getting fuel and spark and one of the valves is not opening it would seem I thought you would be getting some popping especially if the exhaust valve wasn't opening which leads me to believe the intake...
 
j par said:
First thing you can do is eliminate the idea that it's the carburetor that's utterly ridiculous that it would feed the rest and not one cylinder unless a rat got caught in one of the ports...
And if it is getting fuel and spark and one of the valves is not opening it would seem I thought you would be getting some popping especially if the exhaust valve wasn't opening which leads me to believe the intake...
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So many different things going on at once. Carb float isn't staying set as evidenced by site glass. The fuel regulator is adjusted all the way out but gauge reads 13 psi. The #1 cylinder stays cold even at operating temp of 180*. The cam is a solid roller and the rocker arms are pro comp rollers. The hot cylinder reads 160 and the dead cylinder reads 170. The fuel regulator did show 6 psi for about 5 minutes of run time and then after that it ran up to 13psi. Float bowl filled all the way up. Is it possible that something is causing the fuel pressure to increase causing the needle seat to malfunction in turn flooding the engine and fouling plugs?
 
teringer said:
,is the miss at idle or all the time also a wiped exhaust lobe will cause a back fire thru carb at high speed also pull wire off and see if engine smooths out
Click to expand...
It backfires through exaust. Due to excessive fuel either from dead #1 cylinder or excessive fuel pressure or both?
 
nm9stheham said:
Rotate engine by hand while watching for the valves to open and close.

Your test of spark across the plug in open air is meaningless and has not proved that you spark system to cylinder 1 is good. It takes only 2000-3000 volts to jump that gap in open air but 20,000 volts or more to jump that same gap in a compressed fuel-air mixture.

Recheck your spark plug wire with an ohmmeter and be sure that the resistance is in the 3000-5000 ohm range. Examine the wire for anything obviously wrong. Place the end of the spark wire 3/8" from a metal surface and crank and see if the spark will jump that large gap in open air; that is the only valid open-air test to do.

Swap plugs.
Click to expand...
I completely understand what you're saying. I just wanted to see if it was firing. The plugs and wires are new.
 
pishta said:
You dont want fuel to top of sight glass, that is a sign of the wrong setting. Demons allow you to get to center of glass as its lower, Holleys need to be at bottom (just dribbling out an opened sight plug) when idling or when they are pumped by an electric pump on a stand, much safer. Post to youtube and send link. loosen lock screw and turn big nut to lower float level (seat) ...supposed to be able to do this while its idling but I always end up spraying fuel everywhere. Turn screw to lock.
Click to expand...
Yes. I was relating the excessive fuel to my current problem of the dead cylinder.
 
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