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Discussion Topic:
239 c.i.d. missing on 2 cyls.
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Reds34 |
06-06-2010 @ 6:49 PM
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Member
Posts: 16
Joined: Jun 2010
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Well, I got to work on the '34 today. Looks like I'm going to need to get the engine rebuilt. I sprayed carb cleaner in the idle mixture screw and it didn't make a difference. I took the carb off and prepared to take another look at it, but I decided to put my hand over the barrels on the intake. I had my dad turn it over to see if it had any vacuum. The passenger side had noticeable vacuum, but the drivers side didn't. I took the intake off and found the problem. The valve guides broke on cylinders 2 and 5. Sweet. Thank all you guys that have given me advice, I REALLY appreciate it. Red
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TomO |
06-07-2010 @ 7:09 AM
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Senior
Posts: 7244
Joined: Oct 2009
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Red, I m sorry to hear that your problem turned out to be a major one. If the engine was not an oil burner, you may be able to get by with just having a valve job done.
Tom
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supereal |
06-07-2010 @ 11:09 AM
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Senior
Posts: 6819
Joined: Oct 2009
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That is why the recommended compression check would have saved a lot of guesswork. Now, the question is: why did the valve guides break? One would be understandable, but unusual, while two indicate a more serious problem of some kind.
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Reds34 |
06-07-2010 @ 2:25 PM
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Member
Posts: 16
Joined: Jun 2010
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I did a compression check back when this whole thing first started last year, and nothing seemed to be too out of the ordinary. I may do another one just to see, but it's crazy. The keepers are still attached to the valves so I'm not really sure what exactly happened. I may try to get some pictures of the "carnage". Thanks again everyone. Red
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supereal |
06-08-2010 @ 9:28 AM
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Senior
Posts: 6819
Joined: Oct 2009
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That would help, Red. The probable reason for valve guide failure would be loss of the fork that holds the guide in place. Carbon buildup in the valve stem might do it, if it caused the valve to seize in the guide. My problem is understanding why it would involve two valves at the same time. The old style two piece guides almost never break, but a broken or weak valve spring could allow the fork to fail by releasing tension on the assembly. We check for valve problems with dry/wet test. Compression is checked dry, then oil is squirted into he cylinder, and a new test is run. If the compression stays the same, or close to it, the valves are leaky. We will be interested in what you find, such as a missing fork lying in the bottom of the valve chamber.
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Reds34 |
06-18-2010 @ 7:58 PM
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Member
Posts: 16
Joined: Jun 2010
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Well, I got some pictures for you guys.
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Reds34 |
06-18-2010 @ 8:01 PM
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Member
Posts: 16
Joined: Jun 2010
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I can't make this stuff up. This piece was in the number 5 intake runner. I thought it was a piece of the valve guide, but I ended up taking the valve guide out and it was complete. I really have no idea how it got there.
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Reds34 |
06-18-2010 @ 8:03 PM
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Member
Posts: 16
Joined: Jun 2010
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One more of the flywheel. A little machining will take care of this right?
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TomO |
06-19-2010 @ 5:34 PM
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Senior
Posts: 7244
Joined: Oct 2009
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It is hard to tell what that piece is. In the first photo, it looks like a piece of the block is missing in the left hand intake port, but that piece doesn't look like it is the piece.
Tom
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Reds34 |
06-19-2010 @ 7:33 PM
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Member
Posts: 16
Joined: Jun 2010
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In the first photo, the left intake runner (#1 cylinder) is "normal", while the right one (#2 cylinder) the piece that is higher is part of the valve guide. The second picture is the piece that was in the #5 valve port, but didn't come from that valve. I hope to get more photos after I get the engine rebuilt. Red
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