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'35 Commander engine surprise. --- oil in cylinders.

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  • altair
    replied
    You might want to consider first over rings probably .010 over and file the gaps to fit. Some early engines had .002 - 005 over rings and pistons for slightly worn engines that did not need to be bored.

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  • tomlewis
    replied
    Click image for larger version

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ID:	1711151I went ahead and pulled the pistons. The shop manual says the ring end gap specs should be between .013 and .021. HA! All of the compression rings that I checked were at least .105. Oil rings were similar. No wonder there was oil on top of a couple of pistons and obvious blow-by.


    I bought new rings from one of our Studebaker vendors. They are standard rings and I fitted them today. I knew the cylinder bores were tapered a bit so I am not at all upset that all of the ring gaps were right at .016 at the bottom of the bore and most were .025 at the top. It's not in spec, but it's still eighty thousandths better than it was.

    Tom
    Attached Files

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  • TWChamp
    replied
    An oil burning engine with bad rings usually has the outside diameter of the top of the piston washed clean by the oil getting past the rings.

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  • tomlewis
    replied
    Thanks for the responses. I had high hopes for the road tube being plugged up, causing positive pressure in the valve chamber, but when I pulled the tube, it was clear.. Isn't pressure in the crankcase relieved by the oil fill tube? It's all open except for the cap on top of the tube.

    The last 250 cubic inch straight eight engine from the late thirties that I had rebuilt cost right at $10,000. I have no intention of doing that again, especially for a car that otherwise will not be restored (HPOF class in AACA). My goal for this car is to make it a reliable driver.

    The markings on the block and on the pistons indicate that the pistons are original and the engine has not been bored. I'll start checking tomorrow to try to source valves, valve guides and springs. I think I'll do valve work first and then, if I have to, I'll move on to worrying about bore size and pistons and rings. If I have to remove the pistons, then I am forced to check bearings and the bottom end. I have a real sense of "mission creep" heading my way.

    I have had the replacement head and manifold set resurfaced already.

    One other thing that I should note is that months ago I dropped the oil pan to see how much sludge was in the pan. I expected that there would be quite a bit, as it was obvious from the grime build-up that the pan hadn't been off in many years and miles. There was no sludge. I was astonished at how clean the pan was. I don't know how that condition translates to finding liquid oil on the tops of pistons when the head came off.

    There is also a very neglidgeible carbon ring build-up at he top of the cylinders.

    Thanks again. Tom

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  • altair
    replied
    My take FWIW, there appears to several issues, the first thing I noticed is that appears to excessive crankcase pressure caused by a clogged breather that will force oil up past the valve guides and create the excessive carbon deposits. Additionally there may be leaking rings that will contribute to the high crankcase pressure and the issue becomes perpetual. The excessive carbon generated can cause valves not to seat and #7 appears to be just that. There also may have been some coolant leaking in to the cylinders. There does not appear to be a quick fix. Depending on how far you want to go with it, but I feel new valves with oversize stems will be required and you may get away with honing the cylinders with new rings if it is within or close to spec. My list would be, resurfaced head and new gasket, new valves with oversize stems, seats resurfaced (some seats are cut on 3 different angles the top of the seat is at 15 degrees, the center is at 45 degrees and the bottom is relieved at 60 degrees. The valves would be ground at 45 degrees and there should be a very narrow line of contact between the valves and seats. Confirm this with your machinist. You can spend $10,000 or $1000 depending on what you will be using it for, best of luck David

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  • TWChamp
    replied
    I try to pickle my engines if they are going to set idle more than 6 months. Could the oil just be from someone putting it in there for storage?

    Check the bore diameter and tops of the pistons for an oversize marking, such as .020 or .030, etc. Are you going to remove the engine and tear it all down?

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  • '35 Commander engine surprise. --- oil in cylinders.

    I have been planning for some time to replace the head and manifolds on my '35 commander. The head was cracked and the exhaust manifold had multiple cracks and welds. Before starting the project I used a vacuum gauge to check engine condition. The engine was pulling right at 19 to 20 inches of vacuum with a very fast vibration between those two numbers. I thought that looked pretty good. I didn't do a compression test because my tester bleeds down so fast that it is hard for me to read.
    Click image for larger version

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ID:	1752016 When I got the head off I was surprised to find pools of oil on the tops of numbers 7 and 8 Pistons. Number 2 cylinder seemed wet, but no liquid oil on top of the piston. Number 7 was the worst, and that intake valve looks different from all the others too. (All of them have carbon build-up, but that valve is noticeably different).

    I have not yet checked the bores of the cylinders for wear. After I found the oil I was a bit discouraged and just closed up the garage and went to the house.

    Any suggestions on what I should check first? Rings? Valve guides?

    Thanks. Tom
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