Pull the plugs and inspect them. Got them laid out in order so I can reference each to a cylinder. Looks recent, the gap looks consistent, but what's up with #7? Might be gas fouled, and there's others with minor discoloration as well. Maybe I was on the right track. The question is, was the discoloration caused by the misfire, or causing it? Inspected each plug, no cracks on the insulators I could find. Inspected each new plug, no cracks either. Gapped them to .060, and chucked them in.
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Originally posted by SuperBuickGuy View Postnever change the post-cat O2 sensors sure you'll have a dash light; however, they are not needed for engine running.
before you get too far into this, run a can of Seafoam through - the randomness of the issues, carbon could be a big issue. Also, while you're running it, do a WD40 test, Vortecs are notorious for intake leaks. When you pull the plugs, take a picture of them in the order they came out....
Edit: I should also add those are damn good suggestions. Two reasons I wasn't looking for a vacuum leak at that point:
1. When it was misfiring bad it would pop and backfire every once in awhile.
2. Metal in the oil was telling me something mechanical was going on.Last edited by tedly; February 3, 2020, 01:03 AM.I'm probably wrong
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Started inspecting the wires, looking for signs of arcing out. They were crossing each other and touching metal in a few places, so it's possible. Found a couple of small white marks on them. Might be from rubbing something, might be from arcing. Might as well change them out.
Got everything put back together, took it out for a drive.
Whoa! This thing woke up! It's running strong and smooth as hell I think I got it licked! Must have been the plugs after...
And the misfire is back. Just as bad, but less frequent. What in the actual... Was I really friggin bad in a former life? Like Genghis Khan or something?!
It does run amazing in between the misfire though!
Last edited by tedly; February 3, 2020, 09:48 AM.I'm probably wrong
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rust on the electrode and threads makes me wonder if you have a head gasket issue. Those motors used the Red anti-freeze. If you didn't change it on schedule, it builds up mud in the corners of the motor then overheats (and cracks the block - don't ask me how I know this). You also have some oil issues on number 2 - well, most of them, but 2 is worrisome and 8 has the same issue. Add to that the erosion on the tip from burning lean.
with the water that got into 3, 4, and 5 - you can avoid SeaFoam.... water cleans carbon nicely too - though number 8 probably has a good buildup.... (it's how you can have 1 cylinder that's burning lean because it increases the compression.
Doing it all wrong since 1966
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Originally posted by SuperBuickGuy View Postrust on the electrode and threads makes me wonder if you have a head gasket issue. Those motors used the Red anti-freeze. If you didn't change it on schedule, it builds up mud in the corners of the motor then overheats (and cracks the block - don't ask me how I know this). You also have some oil issues on number 2 - well, most of them, but 2 is worrisome and 8 has the same issue. Add to that the erosion on the tip from burning lean.
with the water that got into 3, 4, and 5 - you can avoid SeaFoam.... water cleans carbon nicely too - though number 8 probably has a good buildup.... (it's how you can have 1 cylinder that's burning lean because it increases the compression.
Thanks for the input! Reading plugs is an art I have never mastered. It gives me a better idea of what's happening.I'm probably wrong
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I think I should shed some light on why I have been so intent on getting a 4x4. This is a Google maps screenshot of our home, which Keni and I have nicknamed Narnia. It's a duplex on 6 acres way out in the boonies, has a mile or two of woods behind it, and can be stunningly beautiful. The downside? The driveway is friggin nightmare. That's it in red, and the duplex where we live is there at the end.
It's a quarter mile long, has a 60 foot drop followed by a 60 foot rise with a hard 90 degree turn at the top. It's single lane with fully mature pine trees lining both sides. The rise is facing north, during winter it barely gets direct sunlight so ice is very slow to melt. I got stuck one night coming home from work. It took 4 hours, 140lbs of sand, 2 gallons of gas, a tow truck, a plow truck, and $200 to get unstuck. When I snapped my hand off my arm, it was because I took one step too far on the driveway and was on the start of the hill. We love this place, it is truly amazing and magical, but I needed a 4x4. I have to be able to get in and out so I can get to work. Here's a pic from near my garage. The horizon is the road. That's a 2 story house by the road, and the trees at the bottom of the hill are about 25-30 feet tall.
I'm probably wrong
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I live on the end of a 1/8th mile private road. There are 8 houses on our road and my house has 100% of the 4x4s. I also have a tractor - I like most of my neighbors (and I like getting the mail when it snows) so I plow our road.... that said, it would need to be a pretty rough situation if I couldn't get out.
I'm at the point in my existence where, if the plugs are missing, I won't buy the motor. A bit of coolant isn't really a big deal but flushing the rearmost cylinders could really keep it going for a lot longer. Really that motor isn't in terrible shape, but the days of garden-variety gas in it is over. I also would consider running several injector cleaner bottles through it. Around here, a 6 pack of Chevron injector cleaner is 12 bux at Costco - I'd run them all through, maybe even doubling up after the first bottle/tank. Don't double the first one, if there's big stuff in the system, it will mess things up.... by the second tank, the big stuff is gone and what's left needs soaking to get loose.
Perfect plugs - should be a light tan color.
And to help you read what you have, consider:
Tan is perfect
Grey means light oil getting into the motor (including from a bad PCV)
Grey speckled means knocking (all of this is on the white part) - and this is, literally, aluminum being blown off the piston...
black means soot - running rich
shiney black means you're laying down a smoke screen
Red/Rust means water is getting into the cylinder
missing tip means lean
white means excess antifreeze/water (also white built up like a calcium deposit)
there's a lot more but those are the majors - you can tell how a motor is running by how the color changes from the tip to the base of the insulator. A proper running Vortec will have tan on one side and white on the other.... because it burns the mixture so well that the flame path doesn't make it all the back around the cylinder... pretty cool, huh?
Doing it all wrong since 1966
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Tatanka is a big girl, and maneuvering in and out of the garage is a chore. She barely fits. Since I had no idea how long this was going to take or what was going to be necessary, I needed as much room as possible at the front.
Yeah... Time to take out the hitch and back it up as far as I can.
Hitch is stuck in place. Wonderful. Luckily I have a sledge hammer.
Much better.
Last edited by tedly; February 3, 2020, 11:18 AM.I'm probably wrong
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After researching the hell out of this and talking to a bunch of people, I found out that the distributor can be a problem on these engines and that the cam sensor is in the distributor, not the block. OK, if the dizzy is off it would read as a cam/crank relation issue. If the bearings are out it would wobble, but that wouldn't explain the metal in the oil. The distributor drive gear though... If it's worn to hell, that would explain the metal, and it would throw off the timing. It would also get progressively worse as the gear disintegrates. Seems to fit. The Dizzy is $170, but the gear is $46. I'll grab the gear and cross my fingers.
Also, the crank position sensor could play a role as well so might as well pull it and check it. I'll grab it too, but wait to swap it until after the distributor. If it runs good without the new crank sensor, I'll just return it. $77 for the sensor, so with the gear that puts the total at $1873.
After talking with a lot of my friends that are pretty damn good mechanics, I was getting everything from "just replace the cap and rotor every time it starts acting up" to "sounds like the crank sensor, just replace that and it should take care of it". I was really doubting myself, but I planned on inspecting everything I pulled off anyway.
First thing, pull the intake. Since I've got it off, might as well inspect and clean the MAF. All looks fine, but cleaned it anyway. This problem needs solved right now so I'm skipping nothing.
I'm probably wrong
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Next pull the cap and wires. Wires are brand new and I looked them over before installing them, so I didn't inspect them. Cap had a little wear, but it was a month or two old at this point so that's to be expected. cleaned it as best I could. I found out later that part of the problem with these is there is a vent hole in the distributor base that can get clogged, leading to moisture building up under the cap, which causes corrosion. I'll have to go back and clean it out later. Also took the opportunity to label the wires to make reinstallation easy. Label maker, one of the best things I bought for my shop.
Last edited by tedly; February 3, 2020, 12:16 PM.I'm probably wrong
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while you're at it, pull the distributor and physically check for play - they're super cheap to replace, my rule of thumb, if something is super cheap to replace - it means it's been a problem. those plastic housings are not resilient. Also, you can have oil pressure issues if the housing is starting to go.Doing it all wrong since 1966
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Pulled the plugs and set #1 at TDC by spinning the engine at the crank. As I'm turning it over I see there is a dead zone where I can move the crank back and forth some but the rotor doesn't turn. It's not a lot, but there should be no lag or dead zone. Looking more and more like the cam gear. Or the timing chain. Please don't be the timing chain... Got it at TDC, marked the rotor on the distributor body and pulled the distributor.
Bingo.
Drive gear is chewed all to hell and the edges are paper thin, razor sharp, and missing small pieces. This can explain everything.
Here's the new one for reference.
Check bearing play in the shaft, there's a little up and down (which is nothing to be concerned about) and absolutely no side to side. Spins freely, no binding or rough spots. Bearings are good.
Use a punch and a mallet to drive out the old roll pin, swap the gears, and use a vice to push the new roll pin in. Voila.I'm probably wrong
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A quick side note here. I have kept that gear and have it on my home office desk. It's a reminder that following the evidence and thorough research can pinpoint a problem. A lot of people I trust - who are damn good mechanics - told me not to bother with the distributor, the problem was probably elsewhere. They weren't here though. They didn't have the whole picture in front of them, and I'm not slamming them at all. I'm keeping that gear in an easily visible place to remind me that sometimes I do know what I'm doing, and to go with my gut. Even when no one else is with me.I'm probably wrong
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