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Compression/etc Question (problem solved)

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  • Compression/etc Question (problem solved)

    I took the car to my shop as I just couldn't get it to smooth out. All new plug wires, dist points, condenser, etc. Did a compression check. Here are the readings
    1 85 2 97
    3 100 4 97
    5 97 6 97
    7 97 8 100

    What does this indicate? Rings/Valves or both?
    There is no visible oil smoke but there is a very strong burnt oil smell.
    Thanks,
    Bob

    Dare to be different... Drive your Studebaker!!

  • #2
    I am sticking my neck out here but it looks like stuck rings or worn rings and No.1 has a bad valve too.

    Comment


    • #3
      Looks like you're cranking it over with the carb closed or stopping right after the first bump on the gauge, or it isn't warmed up. But those readings aren't right for that motor. I've seen mechanics only take one plug out at a time and crank the engine over with a low battery on top of that. If a motor is running rough, it's usually one or two cylinders, certainly not all of them. For rough running to be caused by compression, you'd have to have at least one extremely low one in there. If a motor makes good power, don't go jumping to the conclusion that it's lacking compression. The most important guideline is that all cylinders should be within 15% of each other, and you have that. When an engine burns oil, you're not going to smell it unless it is really rolling out the smoke. You probably have oil on the exhaust. On top of all that, I checked the compression on that motor myself before and after replacing a valve, so I know for a fact every cylinder should be over 125. You're looking for the problem in the wrong place.

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      • #4
        I just talked with the technician that did the compression check. He is a Master Technician with 35 yrs experience and his work is always flawless. I asked him how he did the test. All 8 plugs were out, wide open throttle and battery charger attached to make sure it was getting full cranking. Mike, I'm not asking for any money back as you told me it was a running engine and didn't smoke. Which it is that. I just need my car to run and run properly which is why I asked the question.

        Dare to be different... Drive your Studebaker!!

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        • #5
          The only way those numbers could make any sense is if it jumped time, and that is very doubtful. Possible, but extremely unlikely. I'm not sure how long ago the engine was rebuilt, but I saw crosshatch still in the cylinders, and the timing components should have been replaced at the same time. I guess you could do a leakdown test to verify that the cylinders are holding pressure. I'm not sure how to check cam timing, tho. I would just hate to see that motor completely tore down when I drove it and felt the power myself. Is there a date on the rebuild tag? And you know, if the rings were bad, you'd have oil on the plugs, especially in a points system.

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          • #6
            I don't think its burning oil. The oil smell is most likely from oil on the manifold. It does still have a very rich fuel smell about it. How long did the engine sit out of the car? with the breather caps off perhaps some moisture or something got into it. It does have very good power, but has a very lumpy idle. I'm sure there are still some carb issues as well. The compression numbers really bother me a lot as my understanding was anything under 120 requires a rebuild of some kind top or bottom.

            Dare to be different... Drive your Studebaker!!

            Comment


            • #7
              I don't like those numbers either. Maybe he only let the gauge hit one time. But if the engine makes good power and doesn't smoke, you need to redo your tuneup procedures, no matter how sick and disgusted and frustrated you are with carbs and dizzys.

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              • #8
                All eight Intake ports leaking about the same amount? Seems unlikely but possible. [:0]

                I know a very prominent Orange Empire Chapter(Calif.) SDC member who once sold a nice restored '53 Commander Starliner Hardtop cheap after HE "finished" the rebuild, because it's "NEW" engine ran terrible, which later turned out to be miss-located intake gaskets! [:0]

                StudeRich
                StudeRich
                Second Generation Stude Driver,
                Proud '54 Starliner Owner

                Comment


                • #9
                  You hit the nail on the head Mike.. I was extremely sick and disgusted yesterday. But then I drove it home last night and it made it. It was the first time I actually drove the car any distance. It ran kinda weird. With light throttle the car took off slowly and . If I dipped my foot in it, it kinda bogged down. The first thing that came to mind was pcv... I put the pcv hose on it from the 259 engine. Did the engine have a road tube on it? I'm wondering if putting the pcv on it is part of the problem. The other option is to put the 4bbl back on it. I'm tempted to try that as the engine doesn't seem to be happy with this one as its running rather rich. The other thing that the mechanic brought up is that the radiator is pressurizing quickly when its cold. He indicated that that normally means a leaking head gasket. I hate to admit this, but I sure liked working on my little sixes better. This is my second 8 cylinder Studebaker. My first one was a 62 Cruiser and it was problematic like this one. The rest have all been Sixes.

                  Dare to be different... Drive your Studebaker!!

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                  • #10
                    As noted in an earlier post, a simple Leak down test will pretty much tell you where your problems are.

                    If the guys got 35 years in automotive experience...he should have and know how to use a leak down tester.

                    Mike

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                    • #11
                      Have someone run a leak down test to be sure where the loss of compression is occuring. A V8 Stude normally has compression numbers somewhere in the high 130's to 140's if the engine is in good shape. If the compression is 100lbs or below, there should be smoke blowing out of the breathers with the engine running, indicating a compression loss due to worn rings and tapered cylinder walls. I would suspect that you have some leaky valves too. Bud

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                      • #12
                        I think what I may do is just nurse this engine along and rebuild the one that came with the car over the next few months. Hopefully it will all hold together while going through the process. I don't drive too far. About 4 miles each way to work. Is there a reliable person in socal that knows these engines? I know there are some peculiarities that a normal mechanic won't pick up on.

                        Dare to be different... Drive your Studebaker!!

                        Comment


                        • #13
                          As an added note, has the valve clearance been checked in recent history? I've had problems with exhaust valve recession in several V8's due to the use of unleaded gas. If the valve clearance has decreased, the engine will run rough and the compression will be low. You can readjust the valves, but the heads will have to be reconditioned in the near future if that's the problem as the valve seats are failing and will have to be refaced or replaced. Bud

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                          • #14
                            Where around So. Cal. are you 63Larkcustom?

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                            • #15
                              When I did my first carburetor, I ended up taking it to a shop myself. It cost me so much I bought another car and from then on, I always had a spare car around so I had something to drive while I figured out what was wrong with the first one. You have to do three basic tests like pulling plug wires from the cap to isolate the weak cylinders. After it's warmed up, place your hand over the carb to choke it off and see if it speeds up, indicating a lean condition. Then spraying WD40 around the gaskets to the weak cylinders, and at the base of the carb. Without testing, you're going to end up doing a lot of stuff and spending a lot of extra money and inadvertantly bypassing the actual problem.

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