Compresion test= bad engine

Hudsonrules
Hudsonrules Senior Contributor
edited November -1 in HUDSON
:(:mad::(:(Drove my /49 Super 6 the other day, has always ran a little rough, missed badly climbing a hill. Brought the car home and found my compresion tester. :eek:Readings from front to back: 60pounds, 74pounds49pounds,74pounds, 0pounds,74pounds Surprising the engine starts easily but little power. We did a valve job last year and the car has very little use. Question due to finances, should I overhaul this engine or is there a used one out there that someone needs to get rid of.I have a lot of money tied up in this car already and do not want to part it out, or is someone willing to take on another project? I have a '49 Hudson Commodore that I have had for nearly forty years and would rather put my money in it. I bought the Super to drive while redoing the Commodore, but the Super needed so mich that I have not touched the Commodore. Thoughts and andvice are appreciated, Thanks in Advance. Arnie

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  • [Deleted User]
    [Deleted User]
    When you did the valve job did you run a compression test after? what were the readings then? did you use new valve springs? have you adjusted the valves since? Is the head gasket good?



    Just some things to check. I know it can sometimes be frustrating but keep at it and you will get it done.



    I am restoring a 54 Hornet sedan.Last year I could not get the trunk lid to line up no matter what I did. Today my daughter and I got it lined up in 10 mins. Just one of those old car things.
  • [Deleted User]
    [Deleted User]
    Hudsonrules wrote:
    :(:mad::(:(Drove my /49 Super 6 the other day, has always ran a little rough, missed badly climbing a hill. Brought the car home and found my compresion tester. :eek:Readings from front to back: 60pounds, 74pounds49pounds,74pounds, 0pounds,74pounds Surprising the engine starts easily but little power. We did a valve job last year and the car has very little use. Question due to finances, should I overhaul this engine or is there a used one out there that someone needs to get rid of.I have a lot of money tied up in this car already and do not want to part it out, or is someone willing to take on another project? I have a '49 Hudson Commodore that I have had for nearly forty years and would rather put my money in it. I bought the Super to drive while redoing the Commodore, but the Super needed so mich that I have not touched the Commodore. Thoughts and andvice are appreciated, Thanks in Advance. Arnie
    Do a valve job, set valves cold at intake, 0.014 and exhaust at 0.017. You should be able to drive the car. You are better off to work on this engine for if you buy another used one it may need the same thing. Walt.
  • Ol racer
    Ol racer Senior Contributor
    FYI



    What was the compression that prompted the earlier valve job, and did it run alright after the valve job, or did the problem surface after setting awhile......



    If your readings were all low but within 10-15 lbs you would lose some power but still run pretty smooth. The 0 reading is the first place to begin looking for the miss. Remove the head, there has to be some obvious reason for no Compression in that cyl.



    Just guessing, A valve may be stuck open or burnt, (If so, Lash may have been set too tight), rings stuck inside the piston, or a hole in the piston....



    If the block isnt worn badly, motors can be freshened in - chassis by honing the cyls, install new rings, and regrind or hand lap the valves. It wont be a full rebuild but it would get you transportation.



    (Yrs ago when every Service Station had a mechanic, people did a lot of in-chassis motor repair even for one bad cyl...

    Good Luck
  • Unknown
    Unknown
    There was a post on here at one time about using compressed air down each cylinder and listening in various places for where the air leaks out which narrows down the problem...possibly someone else is familiar with this test and can refreshen our minds on it....I should have made a copy of that as I found it to be good advice.
  • Clutchguy
    Clutchguy Senior Contributor
    Try resetting the valves?,and take note of the clearences and those in correspondence with the cylinders-good luck.
  • RL Chilton
    RL Chilton Administrator, Member
    Arnie-

    Ol Racer mentioned doing the work "in chassis". I think this is a grand idea that fits within your parameters of not sinking a lot of money in the Super right now. Find some Old World mechanics to help with this. Get the Super running right, put a little money into it now, before it requires a lot of money later. Once she's at least running properly, then start on the Commodore. You'll still have the Super to use in the meantime, which was the original purpose anyway.

    My advice is stick to your original plan as much as possible, it was a good plan. Sometimes the journey just requires an extra stop or two along the way. As soon as the Super is buttoned back up, don't hesitate and start the Commodore immediately. You can't finish unless you get started, and once you start, don't stop. Slow and steady is just as good (if not better) than a sprint to the finish.

    As far as specifics, the advice all ready given is the right ones. As usual, you have to isolate the problems one at a time and then develop your plan of attack. Keep it simple for now. Later when the Commodore is completed, you might want to go back and either do the Super or decide to turn it, but either way, a running, driving car is worth more to you and more to a potential future owner than a space-taker is worth.
  • junkcarfann
    junkcarfann Expert Adviser
    Jimalberta wrote:
    There was a post on here at one time about using compressed air down each cylinder and listening in various places for where the air leaks out which narrows down the problem...possibly someone else is familiar with this test and can refreshen our minds on it....I should have made a copy of that as I found it to be good advice.



    Its called a "leak down test". Here is a Wiki article about it:



    http://en.wikipedia.org/wiki/Leak-down_tester
  • Aaron D. IL
    Aaron D. IL Senior Contributor
    My understanding (and other experts feel free to correct) is that if you have 50 psi in the cylinders it should be able to run fine if perhaps only with more viscous oil. like straight 40 weight. I have an engine that is right there and I reset the valves with Walt's instructions put in 40 W and I did get it to run but at close to 50 psi who knows how long that's gonna last....it's finicky and I don't think I can reliably drive it. plus it needs a new oil pump/ oil pump gear.
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