1971 Coupe Deville 472 engine issues help needed
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, 1971 Coupe Deville 472 engine issues help needed in Past Cadillac Vehicle Discussion; OK, I purchased a 71 CDV several days ago that was parked in a garage since 1979. I put new ...
  1. #1
    imabadczech's Avatar
    imabadczech is offline Cadillac Owners Member
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    1971 Coupe Deville 472 engine issues help needed

    OK, I purchased a 71 CDV several days ago that was parked in a garage since 1979. I put new plugs and points in her, fresh gas in carb and she took off. She was banging a bit and so we only let her run for a few min. Later that night after dinner, we started her back up and she was quiet as a normal engine should be. A couple days later, we put new belts on her so water pump would be turning as normal and it was somewhat quiet but man o man was she smoking like crazy! We did a compression test and the 2 cylinders on passenger side coming from fire wall out were at ZERO compression. We removed valve cover and one pushrod was completely gone (dropped down in engine I guess) and the other was bent real bad and so we removed it. Obviously, that was our compression problem. 1 valve on each of the dead cylinders is stuck. We cannot knock them loose at all. So, my questions to yall in this forum are, how would i get valves unstuck, and if I did, would replacing the pushrods fix the problem or when something like this happens, is there more damage done that I cannot see? I was thinking of having valve job done and having all new valve stem seals and valve guides replaced. I just dont know if pistons are ok or not. When car ran, it was smooth and beautiful for a bit. I am thinking maybe the head gasket is bad between those 2 cylinders and when the water pump started pumping like normal, the water was just blowing right out where the gasket was shot.

    Sorry to babble, just trying to get ideas and suggestions from folks on here. I love this car and it is just beautiful.

    Thanks for your time.

    Craig

    here is link to my you tube video of it starting for the first time in over 30 years!...............

    https://www.youtube.com/watch?v=qyZVkAZyI9c

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  3. #2
    cadillac kevin's Avatar
    cadillac kevin is offline Cadillac Owners Master
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    This is why you fog the cylinders and roll an engine over by hand several revolutions prior to reawakening it. I would recommend rebuilding the engime as you have most likely scarred the cylinder walls and damaged the pistons due to dropping pushrods.

  4. #3
    carnut is offline Cadillac Owners Master
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    Re: 1971 Coupe Deville 472 engine issues help needed

    You cannt free up the valves with the rockers out of the way and hitting the valves and springs with a hammer? Have you tried spraying wd40 into the valve guides? I presume it had oil in it?

  5. #4
    smelvis is offline Cadillac Owners Fanatic
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    I had 4 stuck valves on Daisy when I first got her. Trying to avoid a rebuild I first tried to free em up. It worked but it took 4 days or so.

    You gotta pull the valve covers, intake manifold and remove valley pan to inspect the pushrods and get any that dropped out. Remove rocker arms (note where they go) and spray pb blaster on the stems every chance you get and hit the valve stems with a rubber mallet or dead blow hammer. Be careful not to bend or mangle valve stems or ends. I did have to use a heavy hammer on a couple but it has to be done very precisely. Note with any type of hammer you can knock the springs loose if you don't hit em square.

    After a few days of lubing and banging they moved pretty freely. Put it all back together, ran it for a while and compression and leak down tests were good.

    It's never a bad idea to do a valve job either. I just didn't have the $$$ at the time.

    Good luck
    talismandave and imabadczech like this.

  6. #5
    imabadczech's Avatar
    imabadczech is offline Cadillac Owners Member
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    Re: 1971 Coupe Deville 472 engine issues help needed

    I put oil down each spark plug hole and let it sit for 24 hours before turning the engine over little by little. Yes, the car itself had oil in it as well. I was referred to a guy in his early 70's who owns his own shop with his son. Back in the day, these were the type of cars he worked on. I guess I will have him pull heads and do valve job. I want new valve guides and seals and such. I guess that is all included in valve job anyway. I am hoping no other damage has been done.

  7. #6
    imabadczech's Avatar
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    Re: 1971 Coupe Deville 472 engine issues help needed

    I decided to go for broke and have a total rebuild. They are going to pull engine and do heads in house, and then send block to machine shop. Every part of the engine will be brand new and repainted to factory color. They are also going to take the tranny out and put all new seals in it as well as new filter/fluid. It is going to be a long 3 weeks till i get it back.

  8. #7
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    Re: 1971 Coupe Deville 472 engine issues help needed

    Dunno how many miles the engine has but make sure the cylinders really need an overbore or else leave the bores alone.

    A lot of machine shops think these engines wear out same as cheap stuff. Not so.

    I agree with pulling the engine at this point because it most likely needs new core plugs to be reliable again.

    Consider finding a better camshaft and or changing camshaft timing to what was used in a '72. The new low compression '71 was a dog and Cadillac made changes. '72s ran well. I had several of these cars/engines in the past.

  9. #8
    austingta is offline Cadillac Owners Member
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    Re: 1971 Coupe Deville 472 engine issues help needed

    Three weeks for a total rebuild? Good luck with that...

  10. #9
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    Re: 1971 Coupe Deville 472 engine issues help needed

    what the hell is that supposed to mean? They ordered all the parts last monday when they got the car. Once they come in, they will remove engine and send block to machine shop. If shop is not busy, they will have block back in 4-5 days. Then they will reassemble it. While block is at machine shop, they will do heads at their shop. They have done 2 other total rebuilds for me and have done them in 2 weeks and were perfect when I got them back.

  11. #10
    The Ape Man's Avatar
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    Re: 1971 Coupe Deville 472 engine issues help needed

    Any good machine shop should be able to turn a job over like this within a week.

    Problem is how do they know exactly what parts to order without a teardown?

  12. #11
    imabadczech's Avatar
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    Re: 1971 Coupe Deville 472 engine issues help needed

    i told them i wanted every part of that engine new. so, they have not removed engine yet but when they do, they will have everything there they will need. they are a great bunch of guys that have been doing engines since the 70's.

  13. #12
    deVille33 is offline Cadillac Owners Connoisseur
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    Re: 1971 Coupe Deville 472 engine issues help needed

    Disassembling an engine is like opening a Whitman's Sampler. You never know what to expect. I have seen "mechanics" put new bearings in an engine, start it up and it still had rod knock. Surprise, Surprise! He didn't know how to check clearance. Not saying your guys are cut from this cloth. Under close inspection, disassembly will often expose some unexpected wear that may take extra measures to correct. Waiting for parts sometimes makes a simple rebop into a marathon.

  14. #13
    csbuckn is offline Cadillac Owners Master
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    Three weeks is an excellent time frame for a cadillac specific motor rebuild. What are you doing for the cam and oil pump? MTS has a blueprinted oil pump that would be good for longevity. That will probably be one of my winter upgrades.

  15. #14
    imabadczech's Avatar
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    Re: 1971 Coupe Deville 472 engine issues help needed

    thank you csbuckn. I know 3 weeks is but apparantly others dont know what the hell they are talking about. I have had over 40 cars, mostly old one and have had many engines rebuilt. I would rather someone take their time then rush it back together. machine shop is checking cam and certainly replacing oil pump with a good one. thanks for responding.

  16. #15
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    Re: 1971 Coupe Deville 472 engine issues help needed

    That is a good looking Coupe de Ville! What is the history--did you stumble on it? Good luck with the engine repair--anxious to hear how things work out for you.

    Congrats,
    Mitch

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