Did I kill my cam....lobe.....

[bandit67]

Guys, kinda of a bittersweet moment. Had this 73 basket case for years and finally got serious with making it roadworthy again. Reworked my first 440 backup to somewhat stock set points. Used a Howards cam and lifters at a bit over a stock cam, TQ and cast intake. At first fire up for cam break the pass side exhaust manifold seemed to get hotter than the driver side. I had timing off for a bit but got it set after a 25 minute run at 2300 rpm. Got some fine tuning done and it idled great, put about 25-30 miles on it, running good. I changed oil and filter and failed to put any zddp add on in the oil. I know better now. Still concerned about a lean condition I pulled the TQ carb and reverified it was a from a 73 440 automatic and had the correct listed jet rods and nothing unusual was found.
On my next ten mile drive it was running terrible when I got home, like a dead cylinder. Pulled the plugs, all looked the same. With my compression checker I was able to check only six cylinders, all running spot on at 158 pounds. Initial timing was set at 16 degrees with vacuum near 18 inches earlier and now vacuum gage was swinging wildly between 8 and 15 inches.
I just pulled and examined all the lifters and they all looked perfect. If I had had a lobe failure would not there be visible lifter face damage? Just turning over the engine and seeing what I can see from the lifter gallery, all looks good. Now Im starting to think I just had the cast iron intake manifold with a bad vacuum leak that got worse. What am I missing....thanks all.

 

[Don Frelier]

Is your heat riser valve stuck shut maybe?

 

[WileERobby]

Before going to my MEF method, check plug cable connections. Remove & plug ALL vacuum sources off the manifold, including the booster. Run engine to see if any change.

 

[Don Frelier]

You can also do the old pull a plugwire at a time while it's running test.
See if you can get an adapter or whatever you need to check the other 2 cylinders. It will be worth it.
And yes get some high zinc oil in there.

 

[PRHeads]

I just pulled and examined all the lifters and they all looked perfect. If I had had a lobe failure would not there be visible lifter face damage?

If the lobe were worn bad enough to cause a running problem, there should be evidence of a problem on the lifter face.

 

[HawkRod]

As stated by PRHeads, if it was running poorly due to a wiped cam lobe, you should be able to see evidence. I'd also suggest turning over the engine with the valve covers off and look at the valve train - see if you notice limited movement of any rockers.

You said you pulled and looked at the lifters. So I assume you then were also able to check the pushrods and assure that none were bent or out of place?

 

[bandit67]

Yes, I pulled both rocker tubes, pushrods to get at the lifters to pull and inspect them. All looked fine, NOTHING unusual. Something happened. The first 25 or so miles she ran smooth, peppy, happy. During the last run, at a stop sign, I had it in third thinking it was in first gear, and it rolled back and choked down. It started right up but when I pulled out and heard some valves rattle, for the first time. A few miles later when I slowed for a turn I could tell it was on seven or less cylinders. Just noticed pass. side valve cover paint got very discolored on exhaust manifold side. I just assumed it was from running it with the timing way off during first twenty five minute cam break in time. I am with you guys that if a lobe was damaged so much to cause a skip, there would have to be a noticeable lifter face damage. So, thinking now to put it all back with new gaskets and a sharp eye on ensuring intake sealing. The Felpro vally pan came with a small tube of RTV, I used it on both the ends and for intake sealing. Is there something better I should use around the intake. I remember placing the intake on the bare heads and found no large gaps as in if the heads were over surfaced. Looked good to me.
Seeing no evidence of any problems with the cam or valve train parts I feel its ok to go back with all that. Don asks if the heat riser valve is stuck shut. Not sure what that is. Is that the valve on the driver side just under the carb return springs? I thought that was the EGR valve and yes, it is not hooked up and stays closed. thanks guys......

 

[furious70]

Guys with more experience than me here but the one time I wiped one it smoked out of that bank and oil fouled the plug on the bad hole. Then when apart you could easily see the lobe was messed up

 

[threewood]

Heat riser valve is located in the stock passenger side exhaust manifold. It is there to help warm the intake air. When it warms up, it should be open, allowing exhaust games to flow free. It acts like a carb choke.

 

[70bigblockdodge]

Wire the choke so it stays almost closed, maybe ~1/3 open and see if that makes a difference. If it does it's a fuel problem, proceed from there.

 

[wagonman]

Vacuum gauge swinging between 18 and 8 indicates an intake valve issue. Time to do a leak down test on all cyls not just 6.

 

[bandit67]

Yes, the heat riser is open as should be. I will need another type of compression checker in order to check the other two cylinders. Mine needs a fairly straight shot to get at and I have two with only about 4 inches of clearance at the power steering box and column coupling. I am thinking now to put it all back , ensuring best I can no intake leaks and see if that leads to any improvements. If not, I will pull the driver side head. Was able to check compression on all the pass. side cylinders and found no problems with any of those. The engine got all new wiring harness, dizzy, electronics, all ignition parts and fired right up on first crank. Im hoping I just made some errors in assembly.

 

[1967coronet]

Guys, kinda of a bittersweet moment. Had this 73 basket case for years and finally got serious with making it roadworthy again. Reworked my first 440 backup to somewhat stock set points. Used a Howards cam and lifters at a bit over a stock cam, TQ and cast intake. At first fire up for cam break the pass side exhaust manifold seemed to get hotter than the driver side. I had timing off for a bit but got it set after a 25 minute run at 2300 rpm. Got some fine tuning done and it idled great, put about 25-30 miles on it, running good. I changed oil and filter and failed to put any zddp add on in the oil. I know better now. Still concerned about a lean condition I pulled the TQ carb and reverified it was a from a 73 440 automatic and had the correct listed jet rods and nothing unusual was found.
On my next ten mile drive it was running terrible when I got home, like a dead cylinder. Pulled the plugs, all looked the same. With my compression checker I was able to check only six cylinders, all running spot on at 158 pounds. Initial timing was set at 16 degrees with vacuum near 18 inches earlier and now vacuum gage was swinging wildly between 8 and 15 inches.
I just pulled and examined all the lifters and they all looked perfect. If I had had a lobe failure would not there be visible lifter face damage? Just turning over the engine and seeing what I can see from the lifter gallery, all looks good. Now Im starting to think I just had the cast iron intake manifold with a bad vacuum leak that got worse. What am I missing....thanks all.

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Nice Charger ! You mentioned (set points) if you have a dwell meter handy I would recheck,plus swap out the condenser they can cause some strange symptoms.
Like the other guys think it's prob a vacuum leak but just for the heck of it I would check the distributor.

 

[wagonman]

Yes, the heat riser is open as should be. I will need another type of compression checker in order to check the other two cylinders. Mine needs a fairly straight shot to get at and I have two with only about 4 inches of clearance at the power steering box and column coupling. I am thinking now to put it all back , ensuring best I can no intake leaks and see if that leads to any improvements. If not, I will pull the driver side head. Was able to check compression on all the pass. side cylinders and found no problems with any of those. The engine got all new wiring harness, dizzy, electronics, all ignition parts and fired right up on first crank. Im hoping I just made some errors in assembly.

You can rent a tester fro O Reillys.

 

[Fran Blacker]

Knock the porcelain out of an old plug and modify it to work.

 

[bandit67]

Ok, racefans, a quick update. Got her back together and fired up and still have a dead/misfiring cylinder. Still have the vacuum gauge bouncing up and down between 10 and 14 at idle. It was cylinders 3 and 5 that I was not able to get my compression checker on and now suspecting the problem is with one of them. Will see if I can test them before I pull the head to see what, if anything , is going on with that. Heads were reworked with new valves, guides , seats, springs, so just wondering if I could burn a valve in 25-30 miles. Dang, don't we hate reworks....thanks all.....

 

[furious70]

What do those plugs look like in the meantime?

 

[bandit67]

Looked like new plugs with a little gray forming on the porcelain tips. I would think if it was something like a severe lean condition I would see something with a plug. I pulled the plug wire off 5 while it was idling and noticed no change in the motors idle. I suspect that s where the problem lies. That plug is still firing. Plan to see what type comp tester OReillys has for rent....those folks know me well.

 

[WileERobby]

Remove the valve cover on that side and crank the engine with the ign cable pulled from the coil. Observe the valvetrain.

 

[Geoff 2]

Blown head gasket between 3 & 5?