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1967 - Big Blue (Stephs Dart) - work in progress!
https://slantsix.org/forum/viewtopic.php?t=59003		 Page 2 of 3
Author:  Reed [ Fri Jan 29, 2016 11:53 am ]
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Consistent low pressures acrss all cylinders suggest (to me) a bad gauge or valves adjusted too tight. A blown head gasket or cracked vlave would have low compression in one or two cylinders, but OK compression in others. Either that or that motor is long overdue for a rebuild.
Author:  sandy in BC [ Fri Jan 29, 2016 12:23 pm ]
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I wonder if the timing chain has jumped a tooth.

How loose is the chain?
Author:  Reed [ Fri Jan 29, 2016 2:17 pm ]
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Quote:
I wonder if the timing chain has jumped a tooth.

How loose is the chain?
:!:
Author:  dookdart [ Fri Jan 29, 2016 2:22 pm ]
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I guess I could move the crank and see how much slop before the cam moves. Can't see it unless I pull the cover.
Author:  sandy in BC [ Fri Jan 29, 2016 3:31 pm ]
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I move the crank back and forth and look at the dist rotor....
Author:  dookdart [ Fri Jan 29, 2016 4:22 pm ]
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Quote:
I move the crank back and forth and look at the dist rotor....
good way as well.

symptom wise, it seems as if it jumped timing. BUT; when I moved the crank 120 deg. per a degree wheel to set tappets.....the valves all appeared to be in the correct position. If anything, they were very loose and needed to be brought down.

I thought about fuel, but it didn't even fire on starting fluid! just a few puffs back through the carb.....signaling timing. electrically, everything seems fine.

I think I'm going to have to pull the timing cover...... I didn't want to get into this right now. I hope it was a quick fix, its turning out otherwise!
Author:  Reed [ Fri Jan 29, 2016 4:38 pm ]
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Is the distributor rotor 180 degrees off? I.E. firing on the exhaust stroke?
Author:  ProCycle [ Fri Jan 29, 2016 4:45 pm ]
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Can you get your hands on a leakdown tester? That would tell you a lot more about the condition of the engine than a compression test.
Author:  dookdart [ Fri Jan 29, 2016 4:58 pm ]
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Quote:
Is the distributor rotor 180 degrees off? I.E. firing on the exhaust stroke?
lol. I knew I had it right...but swapped it 180 just for giggles. no change at all.

agreed. leakdown is best. I'm ready to push it out into the snow until Sept!
Author:  ski [ Fri Jan 29, 2016 5:54 pm ]
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I'd get a good compression check before I went any further.
Author:  Reed [ Fri Jan 29, 2016 6:36 pm ]
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dook- I dug around under my workbench and came up with three Holley 1945 carbs. Two are lean-burn carbs and one is a frankenstein carb I pieced together from various leftover carb parts. The frankenstein carb is missing the idle mixture screw, and I have no idea if it will work when put on an engine.

So those are all I have right now. If you want one, it is yours, but I honestly wouldn't trust any of them to work well.
Author:  dookdart [ Fri Jan 29, 2016 6:45 pm ]
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Reed: I'm OK...I'm not ready for a carb yet. I'll pull one off our 65 D100 for testing the 67.

Ski: yes, I'm with you on the LD test.

I'll go back to TDC and check all tappets.........again.
Then put some pressure to the cyl. , and see where the pressure goes.
If good.........prob as jumped tooth.

I'm starting to lean towards a jumped tooth in timing. cam positions would still be close NEAR TDC......even off by a tooth. If I set the ignition as it should be.....it would explain the no start for sure.
Author:  ProCycle [ Fri Jan 29, 2016 10:02 pm ]
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Thinking out loud here... maybe the valve stems are carboned up enough to keep them from fully closing...you said they were all way loose when you checked them.

If that's what happened resetting the clearances tighter would guarantee that they can't close and would explain the no compression readings.

Anyway, lacking a leakdown test I'd revisit the valve clearances. Maybe even tap the valve end of all the rockers with a rubber mallet just to see if they are sticky.
Author:  dookdart [ Sun Jan 31, 2016 4:14 pm ]
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I'm going with the Polish leak down. Go to TDC, pressurize the cylinder and listen/look for the leaks: bubbles in rad, OR air back out carb, OR air out exhaust, OR air into crankcase.

I'm thinking that if I skipped a tooth, I can just back adjusters off until both valves are closed and look for the air leak.

But listening back at the way the engine was spinning.....it didn't sound quite right....not enough compression in several cylinders.

From one of Steph's posts: The great bearded sage commented: "I'm watching your vids with the sound turned up. It sounds very much like you've got compression on only one-and-a-half cylinders. Are all six spark plugs installed? If so, you've got mechanical problems of one kind or another"


I really starting to think skipped tooth on timing set. Im with you Dan...good call....as usual.....

I'm going to try to set the piston come up to TDC with an inspection camera. THEN look to the timing mark. and see if they line up. I don't know of any other way to look for a single tooth being skipped.
Author:  dookdart [ Tue Feb 02, 2016 11:47 am ]
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I'm pretty certain.......they engine....she is......dead.....

We took off the timing cover, removed and the plugs, backed off all the valve adjusters.....and went to turn the crank.

It was nearly impossible to turn the crank over by hand. PLUS, there was a loud audible squeek, at each movement of the crank. We managed to get it rotated to the timing marks, which were OK. The chain is the original, sloppy....but it didn't jump timing.

I'm pretty certain it has mechanical damage, such as a spun main bearing.

How did this contribute to the no-start? I'm not sure. But I think it was a combination of alot of different issues. Either way, this engine has to come apart.

:cry: [/b]
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