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ZTedster · 07-24-2010, 12:41 AM

Hi folks.

The 7th cylinder on this 440 is dead. It gets fire and has good compression.

Any Mopar Masters out there have any idea what's wrong?

RV Wizard · 07-24-2010, 02:48 AM

Hello ZTedster and

. We are glad to have you join us here and we look forward to reading of your adventures and experiences. I am sure you will enjoy the website and forums. Good luck and keep us posted.
This brings back memories of our first class A (78 Champion) on the Dodge chassis with 440 ci engine. Sorry I am not a motor-head but if you have fire and compression all you would need is fuel. Have you replaced spark plug or swap a plug wire around to verify the spark is getting into the cylinder? Keep us posted on what you find and what the fix will be. Thanks and enjoy!

ZTedster · 07-24-2010, 03:27 AM

RV Wizard,

This is my first MH, so I'm learning everything on the fly as far as RVimg goes. I got this Minnie to drive 4K miles to Alaska from San Diego. I put a lot of work in the house part, and in the chassis part. Ran into a brick wall when I went to smog it. Started digging in to it to find out why and boy oh boy.

Anyway, new plugs, wires, cap, rotor, coil. Did not make a difference. It still runs the way it did with all the old stuff on it. Tried several different plugs, wires, caps, #7 still won't give an RPM drop when you short that cylinder or pull the plug wire.

I was raised on Mopar and had a 69 hemi that went through six different cars. It was the last BB I owned after sliding sideways across a corn field 600 yards and stopping inches away from a 4' oak tree inches from my door on a '70 GTX. Did all the rebuilds myself, but it was so long ago I can barely remember any of it other than the basic rules of thumb.

I tore off the grounding electrode from one plug, sanded a corner of the valve cover to shiny metal, started the engine then slowly lowered the plug to it. At 1 1/4" away from the valve cover it started arcing with a healthy, snapping spark. So I know juice is getting to the cylinder. Tried gapping the plug from .035 on up to .055. No difference. It's back to .035.

Sprayed carb cleaner around the intake manifold where it meets the head, looking for sucking, or change in RPMs...nothing.

The power brake supply connects to the front of the manifold in the center. #7 is on a lower plane in the back.

All the vacuum lines appear to still be soft and flexible, but I will be replacing them all with new lines when I yank the intake and head off to fix that valve.

I was hoping some old salty Mopar mech would jump in and say, "The #7 on the 440?! Oh yeah, that's always caused by the condemunempin over by the muffler bearing. Just twist this or that with a screwdriver and voila! Fixed!"

I reckon that ain't gonna be the case on this one.

ZTedster · 07-24-2010, 04:22 AM

By the way, the valve I was talking about fixing is the exhaust valve on the #5 cylinder, which has only 50 psi. It's this #7 cylinder that has me baffled.

94-Newmar · 07-24-2010, 04:28 AM

How much compression did it have? I assume you used a screw-in type compression tester. Can you get ahold of a leakdown tester? That would help determine if you have a burnt valve, broken seat, or holed piston.

Could also be a wiped camshaft on either intake or exhaust side. Pull the valve cover, disconnect the coil wire and roll the engine over with the starter while watching those two rockers. Make sure they have as much "lift" as the others, if they're even moving at all.

Could also be a bent pushrod OR those stock steel stamped rockers were famous for perforating where the pushrod rides.

NeilV · 07-24-2010, 04:45 AM

Quote:

Originally Posted by ZTedster

Hi folks.

The 7th cylinder on this 440 is dead. It gets fire and has good compression.

Any Mopar Masters out there have any idea what's wrong?

What did the old plug look like when you pulled it and what do the new ones look like? Are they getting wet, oily, fouled, light gray or dark? Did you verify the firing order? They may have had two cylinder crossed.

94-Newmar · 07-24-2010, 04:49 AM

haha yea, good idea neil.. Ztedster, 18436572 (counterclockwise).. a number I'll never ever forget! hehe.

NeilV · 07-24-2010, 05:52 AM

Quote:

Originally Posted by 94-Newmar

haha yea, good idea neil.. Ztedster, 18436572 (counterclockwise).. a number I'll never ever forget! hehe.

You start with the simple things and work your way up. #5 has a burnt valve so they could have been crossed.

I had the 440 in my Imperial Crown Coupe and Power Wagon W200 E20 Camper Special but that was around 40 years ago.

speed racer · 07-24-2010, 06:42 AM

Take the valve cover off and see if the rocker arm is moving. If the cam is flat and the intake isn't opening it won't get any fuel and won't fire.

toolman1 · 07-24-2010, 08:09 AM

130 PSI compression tells me that all the valve train is in good working order. A bent pushrod, broken valve spring, damaged rocker arm would cause a loud clatter, and compression would be down.

Being a career GM Tech, I'm thinking a worn/rusted/broken primary ignition hub inside the distributor, that may not be letting spark jump across the spark plug gap under compression, or maybe a bent distributor shaft,or worn bushings inside the housing, causing a similar condition. You might have a very careful look inside that distributor, or swap out a known good one, and see if there is any difference in the running condition of the engine. Best of luck.

94-Newmar · 07-24-2010, 08:13 AM

Where did he mention 130psi? Am I missing a post?

ZTedster · 07-24-2010, 12:04 PM

94-Newmar,

I have posted this problem in several forums: Mopar, Allpar, etc. Forums are the most logical places for seeking answers. It's like stepping into a congregation of scientists and popping a question. The avalanches of thought streams is enough to amaze anyone. Anyway, hence toolman1 knowing the compression reading.

It's obvious the man has a wealth of GM training and loves to help people. I'm sure he has tons of training. When I went to work for Capitol Cadillac in 75 they immediately started sending me to schools. I remember the first class when we were taught to troubleshoot the fuel injection of the Seville with that big blue plastic briefcase full of red LEDs. We sneared because they stuck that puny 350 in the Seville. But then, how were they to shoehorn a 500 in that little thing?

Memory lane.

To answer other questions:

The plug is wet with black stains. When I took all old plugs out they all had a slight amount of carbon buildup. I saved each one and numbered it to reference each cylinder, but they all looked the same. I would say the engine, when it was parked 9 years ago ran fine and that the carb was running a tad rich.

When run through the smog test the other day, the numbers showed the engine is running so lean that the CO2 numbers are way low and the HC levels are extremely high. When you smell it running you would think it is running way rich. My mech friend said it smells rich because all you are smelling is the HC.

A motor will smell rich when it is running off 6 1/2 cylinders, I imagine. I can post the smog numbers if that will help anyone.

I have the plugs wired correctly for firing order.

I popped off the valve cover and the valves are all operating, but I did not check to see if they all lifted equally, i.e., all intakes equal lift, all exhaust equal lift. I will look for this when I begin tearing this thing down tonight.

Yes, I used two different screw-in compression gauges, one good NAPA grade and a top notch Snap-On grade tester. Both came up with the same readings.

No flutter in vacuum gauge.

Toolman1,

Looking into this distributor is one thing I have not done. I did tear off the grounding electrode of an old plug then lowered it to the valve cover. It started arcing a healthy snapping spark once it was 1 1/4" away from the shiny sanded spot I made on the valve cover.

Here is what concerns me. I had this same problem on a 1967 318 that had points and I never solved it. It was the #7 cylinder. 35 years later I face the same problem. I have put so much time and money in this thing I cannot give up on it. Besides, I am going to drive this thing 4K miles to Anchorage as soon as I get this fixed. The middle class of the construction industry in San Diego has ceased to exist and I am moving to Alaska where there is work and I don't have to compete with people who work at 10/hr and carry every tool they own in a wheelbarrow.

I thank every one of you for your help and advice. God I love this great nation.

toolman1 · 07-24-2010, 01:27 PM

Quote:

Originally Posted by 94-Newmar

Where did he mention 130psi? Am I missing a post?

Gotta check the same thread over on .Net my friend.....

NeilV · 07-24-2010, 02:43 PM

We are talking about an engine that has sat for 9 years? Is the timing chain frozen in spots making the distributor jump out of time for number 7 or possibly the number 7 cam lobe in the distributor has some hardened lube etc on it that is making the points stay open too long making the spark a bit late?

When did Chrysler switch to the Prestolite electronic distributor we are talking points and condenser here right?