Well, Clarabelle has begun missing on #5 Cylinder. It has developed over the last few weeks. I located the miss by pulling each plug wire off, at idle, and observed the RPM drop significantly. #5 had no effect with the plug wire pulled off. Next, I swapped the plug and wire from #2 Cylinder to #5. Started up and checked in the same manner. #5 still not "carrying load" (missing). Here's where I contacted my Friend, Bill Hanlon! He came over with his compression tester, and an abundance of knowledge! We went to work, troubleshooting. Ran compression check and found all 6 cylinders to have good compression, ranging from 125# to 150#, with #5 having 135#. Couldn't come up with an explanation for #5 missing... It has spark, compression, and since #6 is firing properly, assume it's receiving fuel/air mix. Went through the valve adjusting procedure for good measure, (for solid lifters) and had no change. We checked the travel of the rocker arms on several cylinders, including #5 and found #5 to be comparable to others, (suspecting a cam lobe problem). Somewhat stumped for an explanation, We pulled the pushrod cover and removed the pushrod and lifter on 3 different valves. (Side note, with question later. The lifters are HYDRAULIC type). I used my "laproscope" attached to my laptop to view through the lifter opening and observe the camshaft lobes. All of the lobes we checked, including the ones for #5 cylinder, appeared to be Normal.... We have re-assembled the truck and started up, with the miss still intact. Adjusted the HYDRAULIC LIFTERS per the proper technique with the engine running, (which made it much quieter, so the miss is more obvious). I'm scratching my head trying to figure what is wrong. Between the other Bill, and I, we thought sure we'd come up with a solution to the problem, but alas, we have not. I need help from some of you contributors in diagnosing this, please! Additionally, as referenced earlier, We discovered hydraulic lifters. So, do solid lifters require use of a different cam from hydraulic lifters. My gut feeling is that it shouldn't matter to the cam, but would like input from this forum as well. As usual, thanks for the help. Bill B. PS. Bill H, if I left out any pertinent info chime in and help.
If compression is good, the problem is not likely related to cam/lifters/valves. The problem is likely spark related. If you switched the plug AND wire between #2 and #5, and the miss was still at #5 then the spark problem is likely in the cap. I believe you have a bad distributor cap. The #5 post in the cap is probably bad or there is a small crack somewhere. Replace cap and rotor and see what happens. Anbdy
Well the good part is, as Andy said, you likely have a spark issue. Much better than a cam issue! And finding out you have hydraulic lifters isn't a bad thing at all.
We did hold #5 plug wire near ground while running and were rewarded with a fat blue spark. That said, replacing the cap is on the list of things to try.
BTW, Thanks Bill Hanlon for the help, and Kens 50 for "phone in" help and online research while we worked!
Another bit of troubleshooting we did not do is take a vacuum gauge reading. If you have a gauge, please do so and post results Bill. If not, I have one and a replacement distributor cap that you are welcome to. I've got a bunch of work that needs doing at home today, so either come by and get them or wait for delivery.
Guys try this first, pull any other plug wire off and leave it off and then pull #5 off; see if the rpm changes. I don't know why but it seems that an engine just doesn't miss one cylinder as much as some others. The more cylinders the more this happens. V12's can drop a cylinder and if it's one of these "orphans" one can tell no change at all.
Another thought or two. Vacuum gauge and also squirt a little starting fluid or anything combustible at the seam where the intake runner bolts to the head. Since #5 has it's own runner lack of a good seal could affect it and not the others. Gauge should be steady and in the neighborhood of 18" of vacuum. Repair manuals have a chart for different gauge readings and actions. Italics are unintentional; damn computer. Check distributor cap with a magnifying glass around the #5 terminal. A fine line is called "tracking" and a no-no.
5 & 6 share an intake runner Evan, but it wouldn't hurt to try. Only problem is the exhaust port that 4 & 5 share is leaking at the head to manifold junction. Those that still have hair (like Bilbo) might not want to be standing too close when shooting ether in the area. Bilbo ordered a distributor cap from FLAPS that is supposed to be available this afternoon. I have a vacuum gauge, but forgot to take it to his house yesterday. Reading one is somewhat of a lost art, especially when more than one thing is wrong at the same time. Now that we think we have the valves adjusted properly, maybe the gauge will help.
OK Group... Replaced the distributor cap and rotor, (close examination of each showed no signs of carbon tracking or dendrite growth ). No change in problem. The other Bill called and told me about Evan's suggestions, and the one about spraying a flammable liquid/gas in the area of the intake juncture and an exhaust leak sounded like a GOOD IDEA! So that's what I did Now that I've got everyone's attention, I let the engine cool down for a couple of hours before this step. Thanks Evan for the tip! The engine sped up with the spraying of Ether, and lost the "miss." I now have a plan of action. Gonna pull the intake and exhaust manifolds and get some surfacing done, and replace when all is smooth. Thanks for all the help from the forum! Residual question... Any issues with the hydraulic lifters that anyone knows of? Man is that engine quieter now! (except for the annoying exhaust leak by #4 and 5 cylinders. Fixing that will be included in the manifold work!
A little off topic, but... Bilbo, did you ever get the time to repair the paint damage from gasoline? Maybe you told us, and I missed it. Steve.
Well, I've been on restricted duty for so long I've only been "putting out fires". Now able to do most of what I want so the cab Paint repair is back on the radar, but down the list a bit. Gotta get Clarabelle fit to go to Ft. Worth at end of month for Pate Swap Meet.
I'll let Bilbo go over the details, but let it be said that we rotated Clarabell's muffler bearings, aligned the IF section of her radio and lifted her hydraulics and she is now feeling much better.
Ok, Bill. In addition to the things that Bill covered, here's what went on. Upon removing the manifold assembly the problem was clearly evident. The last person to assemble said manifold failed to install intake manifold alignment rings,(which I purchased from our host). Since it takes either a spider monkey, or three hands to install properly, I assume neither was available on previous install. The exhaust manifold has alignment pins at each end, so it was close to right, but they allowed the rear of the intake to drop down to the point where it only engaged about 1/16" of the gasket. My use of the truck and repeated heat/cool cycles eventually produced the leak at #5-6 intake, and also some leakage at #3-4. I cleaned up each of the surfaces, including mating of intake to exhaust, and found all surfaces to be true, and in good condition. To reassemble properly here's what you do. Assemble intake to exhaust, with new gasket, but barely snug the bolts. Insert intake alignment rings into cylinder head. Affix new manifold gaskets to head with high temperature RTV and allow a few minutes to establish hold. After having previously chased threads in head, and cleaned bolts up, (and in my case painted everything), apply antisieze to bolt threads, and sparingly to face of gaskets. (This allows the required "creeping" of the manifolds with heat cycles). I use nickel antisieze as its more compatible with the metals than Copper Kate. Both work. Now is when you need a spider monkey, or three hands. I had the very capable hands of Bill Hanlon to help me. I set the manifold assembly against the head, being sure to wiggle the exhaust onto it's 2 pins and intake onto its 3 alignment rings,(this is why you only tighten the intake to exhaust bolts hand tight). Then with your third hand, because both the other ones now hold the assembly against the head, you start a couple of the bolts with their lugs. There are no studs to help, which made it easier to clean up the head surface. Now go through and torque your bolts up. Start at the center of manifolds and work toward the endS. Give them each about half the required torque on first pass, then full torque on second pass. In my case, this was 20 lb/ft each. Important: Over torqueing can cause the exhaust manifold to break later with heat cycling! It needs to be able to "creep" with thermal expansion. Now go back and torque up the intake to exhaust juncture. Reassemble the other stuff you took apart and be on your way! I always use a steel donut gasket on the header to manifold joint, too, because this joint does a lot of creeping too, and that's what causes those fibrous donut gaskets to break down. I'll bet I left out a few key points, so feel free to add as needed, Bill H. or anyone else. Clarabelle is back to roadworthy. I do have a couple of hydraulic lifters that won't pump up, but parts are on the way.
Glad you got it figured out, Bill, and Bill. Spider monkey... That's what I've been missing in my toolbox for all these years. Wonder if Sears would have one on sale, Craftsman Club days? Just have to get past their biting, and throwing poop at you... Steve.
The only thing I'll add is that I was surprised to find bolts holding the manifolds to the head on Bill's 235. My GMC 228 uses studs and nuts and I thought (but not very well lately) that the Chevy sixes used studs and nuts too.
I have a couple of "Monkey Wrenches" in my tool box, though... Now and then one gets thrown into the works, (perhaps by a spider monkey?)
You guys in Texas have it made. Here in New England (as Nate will no doubt attest), we have to make-do with muffler bushings. You guys get muffler bearings. Must have something to do with the judicious road-salt applications we suffer through.
