1969 472 rebuild?
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500, 472, 425, 368 Discussion, 1969 472 rebuild? in Cadillac Engine Technical Discussion; Hello My engine has some old engines problems like worn piston rings, oil leaks, oil burning, running bad etc. I'm ...
  1. #1
    3dfx is offline Cadillac Owners Member
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    1969 472 rebuild?

    Hello

    My engine has some old engines problems like worn piston rings, oil leaks, oil burning, running bad etc.

    I'm starting to think some kind of engine rebuild. I'm rebuilding my engine myself.

    I have never done any rebuild to american V8. I have only rebuilded old european engines.

    Are there any weak points in this engine which should be specially inspected?

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    deVille33 is offline Cadillac Owners Connoisseur
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    Re: 1969 472 rebuild?

    The 472 is a very formidable engine, as are the 500's and 425's. A decidedly weak point is hard to determine. How do you know the rings are worn? Have you done a compression test / cylinder leak-down test? Have you pressurized the cylinders to determine where the cylinder sealing problems are? Pulled plugs and evaluated the condition? Burning oil can come from the valves before the rings go bad. Cadillac engines do not wear cylinder walls like other GM engines do, unless they have been run at elevated rpm's and even then there is little wear. The valves do not have a propensity for stem wear because of the low lift of the cam, but will wear in the case of a high mileage engine, around 300 K. Do some tests and come back with the results and we will consult with you on how to approach the problem.

  4. #3
    3dfx is offline Cadillac Owners Member
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    Re: 1969 472 rebuild?

    I have made compression test and pass leak test:

    Pass-leak results:
    Cyl. 1 24%
    Cyl. 2 20%
    Cyl. 3 28%
    Cyl. 4 40%
    Cyl. 5 36%
    Cyl. 6 30%
    Cyl. 7 26%
    Cyl. 8 30%

    Compression test results:
    Cyl. 1 13 Bar
    Cyl. 2 13 Bar
    Cyl. 3 14.5 Bar
    Cyl. 4 11 Bar
    Cyl. 5 12.5 Bar
    Cyl. 6 11.5 Bar
    Cyl. 8 11 Bar

    These test was made in summer when my engine was operating correctly. Now my engine has some problems and car cannot be driven. First my car started to idle bad and now it doesn't work right at any rpms. I opened a thread when my problems started: Cadillac 1969 quadrajet bad idle First I thought my mixtures only need adjusting but problems got worse..

    The engine was cold when we did these tests. Our plan was to make these tests first with cold engine and then with hot engine but we didn't have enough time....

    Majority of pass-leaks leaked from piston rings, there was very small amout of leak in valves too. We poured oil into cylinder and checked the readings again. I don't remember those readings but those were the piston rings which were leaking. That much I remember. Also my car used to burn oil 1 liter for every 1000 miles, but now it burn something like 1 liter for 500-800 miles.

  5. #4
    deVille33 is offline Cadillac Owners Connoisseur
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    Re: 1969 472 rebuild?

    At this point it is advisable to do a complete engine teardown and evaluation as to the extent of this engines wear. You could have a scoured cylinder wall in #4, which will pump a lot of oil through that cylinder. Pull the head on the #4 side and look for a scratch or gouge in the wall. If the other cylinders are clean you could repair that one cylinder without any consequence. Some shops have means to make repairs like this with the block in the car, but it is rare to find shops with this technology. You could pull the pan and check for debris which would cause this problem. You can also check the condition of the timing chain and the bottom end to see if the crank and rod journals are within specs.

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    3dfx is offline Cadillac Owners Member
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    Re: 1969 472 rebuild?

    You could have a scoured cylinder wall in #4, which will pump a lot of oil through that cylinder.
    Or my piston ring is cut. I had this kind of problem with one Saab, it idled bad but worked good when near 2500rpm.

    Should I pull my engine up and clean everything, replace my timing chain, measure if my block, crankshaft etc. needs machining?

  7. #6
    deVille33 is offline Cadillac Owners Connoisseur
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    Re: 1969 472 rebuild?

    Quote Originally Posted by 3dfx View Post
    Or my piston ring is cut. I had this kind of problem with one Saab, it idled bad but worked good when near2500rpm.
    Or you could have a piston that has burned through and down the ring lands from detonation.
    Should I pull my engine up and clean everything, replace my timing chain, measure if my block, crankshaft etc. needs machining?
    Yes, if it is easier for you to work on it that way. I suggested checking it out in the car, so that you might know what you were dealing with before you opened it up completely. I would do this with customers cars so that I could make educated descriptions and offer alternatives depending on the customers financial situation. Some people want to keep the original engine, others are willing to swap the engine out or do a conversion.

  8. #7
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    70eldo is offline Cadillac Owners Connoisseur
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    Re: 1969 472 rebuild?

    cad500parts will have all the parts you need for your rebuild

  9. #8
    3dfx is offline Cadillac Owners Member
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    Re: 1969 472 rebuild?

    I suggested checking it out in the car, so that you might know what you were dealing with before you opened it up completely
    If this engine is over 50 years old, and no one know how much it is driven, I think it's just easier to lift the engine out of the car and then inspect damages and wear.

    For newer engine with less miles driven, lifting the engine up wouldn't be the first thing to do. I would try anything else before I would lift the engine up. But with 50 year old engine with serious pass-leaks and running problems, I think it's wiser to pull the whole engine out from the car. Of course I could open my oil pan and inspect my engine wear from there but I don't have a car lifter and thats why I avoid working under the car.

    I think I keep the original engine. It's high compression, so It's fast and it has decent mileage against the late low compression engines with all emission equipment. Those Cadillac engines are expensive here in Finland, from 500 to 1000 euros from running engine. It would be wiser to put all those money into rebuild (I can get pretty much parts with 1000 euros..) than buy another old engine with it's old engine problems. Of course here in Finland, machining work is the most expensive part of rebuild. I don't have tools to bore or hone my cylinders or balance my crankshaft etc. I need a reliable engine and I think rebuild is the cheapest and the best way to achieve it.

    But, I'll post some photos when I start working on my car. I have one small project to finish first..

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