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1956 Oldsmobile engine problem


Guest 400mag

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Guest 400mag

I just got my rebuilt engine and tranny in my 1956 Oldsmobile and fired it up yesterday for the first time. For the first couple minutes the motor sounded great, but after warming up and running for awhile, I could hear a squeak-like noise. It is a factory a/c car so I thought maybe it was the a/c compressor making noise so I bought a shorter belt to by-pass the compressor. It still made a squeaking noise. I took all the belts off to see if they were slipping or making noise; but that wasn't the problem either. I had the machinist that machined my engine come listen to the noise and he could tell it was coming from the front of the motor. I pulled the oil filler cap off and the noise became louder. (the oil filler cap is on the front of the motor) If you put your hand over the oil filler tube it would get quieter; so I know it is coming internally from the motor. The machinist couldn't peg what could have been making this noise. This was my first car and have been waiting a long time to get it back on the road; I am hoping to have it on the road this summer. Does anyone have any idea what could be causing this noise? Or have any suggestions on how to figure it out?

Thanks,

Eric.

Edited by 400mag (see edit history)
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Guest 400mag

Thanks for responding. I pulled valve covers off and started it up, and oil was getting to the top of the engine. So tight bearing then?

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Maybe but since you have the valve cover off, have you tried running it to see if the noise is louder? The other thing is to use an engine stethoscope or if you don't have one, a long wooden dowel would work too. You can then listen around various areas of the engine to see if you can narrow down the location.

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Guest 400mag

It did not seem any louder with valve covers off. I am really in a pickle and have a lot of money invested into the motor rebuild... Thank you for responding.

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  • 4 weeks later...

When you say that the engine was rebuilt, what specifically was done to the engine? Did the engine run before the rebuild? How many miles was on the original engine before rebuild? What type and weight oil is in the vehicle now? You live in a rally cold area of the country. What was the temperature outside when you tested this engine? Was it tested outside or inside a building? If inside, is the building heated?

Did your mechanic suggest any break in procedure when you first fired up the engine?

If possible, take a video and post it on YouTube and provide a link here. This would be helpful to understand what is going on.

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  • 2 weeks later...
Guest 400mag

The motor was bored and machined and honed, new rebuild kit(rings, lifters, cam, bearings, seals, pistons, etc) full rebuild. The engine did run before the rebuild but was tired and burned oil. there was 93,000 miles on the engine. I used 10-30 weight diesel motor oil for better lubrication(suggested by my machinist). We ran the car in a 70 degree heated shop. My machinist/mechanic suggested to run the engine at about 2,000 RPM when motor fires for about 10 minutes; I did this. The motor sounded good for the first minute or so, then it started making the squeak noise. I will try to upload a youtube video.

Thanks for all the help,

Eric

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It doesn't sound right to run a new engine at 2000 RPMs for 10 minutes straight. It seems to go against accepted break in routines of varying engine speeds and avoiding excessive RPM's. Maybe 2000 isn't too much but I wouldn't feel comfortable running a fresh engine that high until it was fully warmed up at operating temperature. And even then I would gradually run it up to 2000 and then vary the RPMs slowly up and down.

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Guest Old Codger

Well...My 2 cents says your cam went south. What cam? From what vendor? Where was the cam mfg'd...China? Mexico? Just because it might have a U.S. Brand name on it, does not necessarly mean it was made in the USA.

Your mech put diesel 10-30 wt?????? Why? For better lubrication????..I don't buy that. Diesel oil is not going to lubricate any better than a straight oil will. I'm guessing he put diesel in because he heard about using diesel oil having better Zink properties. Ask your mech, if he thinks you should run diesel fuel in it too, since the diesel stuff is so good for a car, and see what he says....

If you started it right up and went to 2000 rpms and ran it that way for ten minutes, IMO it's time to go back to your trusty mech and ask him to do it all again, (on his nickle since you broke it in like HE said to do) This time, run a mineral, straight weight oil for break in, not some detergent oil.

I won't go in to procedures that have been tried and true for generations on how to break in a engine. But I would highly suggest of getting a second, third and forth opinion on how to best break in a over hauled engine. Bleach, hit upon on how best to break in a engine that has just been overhauled.

Old Codger

Edited by Old Codger (see edit history)
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I know what you said about the oil filler cap but I am not convinced that the noise is really internal. Could the "squeak" that you are hearing be more of a whistle? I am starting to think that it is possible that you have a vacuum leak. I have heard some strange pitches and sounds from vacuum leaks before. The range or pitch is dependent on the size of the leak. Check to see if you have any vacuum hoses off or any vacuum ports open. Check your carburetor nuts and intake manifold bolts for proper torque. If that does not work and you suspect a vacuum leak, there may be a problem with the intake or carb gaskets.

I am a little reluctant to suggest a vacuum leak since your mechanic did not suggest this but sometimes the obvious is just not noticed.

I guess we will know more once we here a video.

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I would remove the fuel pump, and not plug the hole in the front cover. pour about one ounce of fuel down the carburetor and start the engine. If the squeak is gone, you've narrowed down the source of the problem, somewhat. With the fuel pump on the bench, actuate the arm and listen for the squeak. if you hear it from the full pump, that could be the problem, but I doubt it. Hopefully, when you ran the engine with the fuel pump removed, you got a big mess of oil coming out of the access hole. If you got little or no oil squirting out, I suspect that you are not getting oil to the front of the engine and that the eccentric that drives the pump is dry and squeaking, (along with your new timing chain and gear.) To help verify this, apply a dollop of grease to the tip of the pump lever where it contacts the eccentric and re-assemble. Start the engine, and if the squeak is gone, you've narrowed down the problem further. It's not fixed; the squeak will return. You'll have to dis-assemble the front of the engine to determine why. Perhaps the cam shaft retainer plate was improperly installed. Study your Shop Manual!

As far as break in, it is imperative that you load the engine in order to seat the rings. By that I mean drive the car to get the transmission into top gear and then accelerate just hard enough so that the transmission doesn't drop down into a lower gear, up to about forty five or fifty miles an hour and then back-off. Repeat this about a dozen times. Also, you may want to check the break-in procedure in your Owners Manual. Make sure that you're using a motor oil with a HIGH ZINC CONTENT. Closely monitor oil pressure and temperature to make sure they remain within specifications, and shut the motor off immediately if they don't. Don't break-in this motor on a hot day!

As far as a vacuum leak, how does it idle? Is it slow and even? Short out the sparks plugs one at a time, while at idle. The one that has the least effect could be an indicator. Remove all eight spark plugs and compare their appearance. The off color one could be a clue. Acquire a vacuum gage, and learn how to use it. Also, do a compression test. The lowest cylinder could point to a problem.

I've given you enough to ponder for now, let me know what you find. Good Luck!

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  • 2 weeks later...
Guest 400mag

http://youtu.be/TQp1nOJn0bU Here is a link to the video on youtube of the car running. Like I said, when I put my hand over the oil filler pipe, it gets quitter; and when I take it off, it gets louder. So it seems like its internally in the motor.

Thanks for all the help,

Eric.

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That is exactly the way that you described it. I do not think that it is a rod or crank bearing. It obviously is not a vacuum leak as I first suggested. It is not a whistle and is a squeak as you described.

If it is not the bearings, then could it be something that is mounted on the engine. I am searching here, but could it be the water pump? I have heard similar noises from water pumps. How about the fuel pump or oil pump? Were these replaced or rebuilt?

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Guest 400mag
That is exactly the way that you described it. I do not think that it is a rod or crank bearing. It obviously is not a vacuum leak as I first suggested. It is not a whistle and is a squeak as you described.

If it is not the bearings, then could it be something that is mounted on the engine. I am searching here, but could it be the water pump? I have heard similar noises from water pumps. How about the fuel pump or oil pump? Were these replaced or rebuilt?

The water pump, fuel pump, and oil pump were all rebuilt. We took the fuel pump off and ran it, and still made the noise. I took all the belts off and it still made the noise. So that eliminates the water pump and fuel pump. Maybe oil pump then?

Thanks for the help,

Eric

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Guest 400mag
That is exactly the way that you described it. I do not think that it is a rod or crank bearing. It obviously is not a vacuum leak as I first suggested. It is not a whistle and is a squeak as you described.

If it is not the bearings, then could it be something that is mounted on the engine. I am searching here, but could it be the water pump? I have heard similar noises from water pumps. How about the fuel pump or oil pump? Were these replaced or rebuilt?

The water pump, fuel pump, and oil pump were all rebuilt. We took the fuel pump off and ran it, and still made the noise. I took all the belts off and it still made the noise. So that eliminates the water pump and fuel pump. Maybe oil pump then? Or maybe something in the timing chain area? Or rocker?

Thanks for the help,

Eric

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I had a friend of mine look at your video. We both agree that all you can do is rule out what it is not and that is what you are doing. He actually said that he thought it could be the timing chain. I do not see how that can be but I thought that I would mention it. If I think of anything else, I will post it. Please keep us informed of any progress. Good luck.

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Eric,

I watched your video. I am not sure what it is but maybe try pouring some oil and/or Marvel Mystery oil (not a ton but a cupful) down the oil filler tube while the engine is running to see if that quiets down the noise.

It is hard to pinpoint exactly where the noise is originating from but it sure sounds like the front of the engine.

Have you spoken to the guy who rebuilt the motor about fixing it? I mean he should at the very least guarantee that it will run right without any issues.

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Do you have adequate oil pressure? If so, that would eliminate a problem with the oil pump. You've already had the valve covers off and saw nothing wrong there. I agree that the problem is in the front area, possibly with the timing chain. I would remove the front engine cover,(support the front of the engine with a floor jack and a block off wood) and maybe the timing chain and sprocket, and look closely for abnormal signs of wear. Then I would remove the distributor, and with the use of a speed wrench I would drive the oil pump in the proper direction of rotation and observe the amount of oil flowing to this area. If there is little or no oil supplied, then you'll have to determine why.

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  • 4 weeks later...
Guest 400mag

My machinest told me to pull the radiator out to pull the timing chain cover off because he thought there is an oil slinger underneath the cover that could be causing the problem. Does that sound like it could be the problem?

Thanks for the time and help,

Eric

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Guest 400mag

i also tried pooring some marvel mystery oil down the oil filler pipe while it was running, the sqeak would go away for about 2 seconds after pooring, and then come back. the engine gets very good oil pressure, about 50-55 lbs.

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Guest Old Codger

Bleach said it 4 weeks ago, The builder is trying to duck you. INSIST, that since he did the work, then it's up to him to stand behind his work, not you. It's not for you to look for his mistakes.

It'll be too easy for him to come back on you, and say that it was fine until you got your hands in it...It's your fault that it's not right. I say B/S. The more time that goes by, and the car is your hands, the less of a chance you're going to have for him to make it right...

Old Codger

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My machinest told me to pull the radiator out to pull the timing chain cover off because he thought there is an oil slinger underneath the cover that could be causing the problem. Does that sound like it could be the problem?

Thanks for the time and help,

Eric

That's exactly what I was thinking. I can't remember now, but I think that oil slinger only installs one correct way. Defiantly worth checking into. Consult your shop manual, and let us know what you find. PS, a good machinist doesn't necessarily qualify as a good mechanic!

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Question:Did the machinist assemble the engine or did you?

If he did then, as stated before, I wouldn't touch anything he did and I would demand that he take the car/engine back and make it right. It seems to me that he doesn't want to be bothered anymore wasting his time with your problem. Too bad.

If you are not comfortable with him touching your car again - well that would be your call - which means you or someone else are going to have to resolve the issue.

I see you mentioned that the squeak went away for a little bit when you poured oil into the filler tube. So the oil is not getting to that squeak.

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Although I agree that the person who assembled the engine is responsible for the repair, putting myself in your shoes, I wouldn't feel comfortable turning my engine back over to someone who now probably has a chip on his shoulder. If I didn't have the expertise to resolve the problem myself, I'd find someone who does, and after the problem is gone I would pursue damages, in the form of labor paid thus far and additional expenses incurred, in small claims court. Good luck! Looking forward to watching you on Court TV!

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Although I agree that the person who assembled the engine is responsible for the repair, putting myself in your shoes, I wouldn't feel comfortable turning my engine back over to someone who now probably has a chip on his shoulder. If I didn't have the expertise to resolve the problem myself, I'd find someone who does, and after the problem is gone I would pursue damages, in the form of labor paid thus far and additional expenses incurred, in small claims court. Good luck! Looking forward to watching you on Court TV!

judge-joe-brown-030210.jpg

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Guest 400mag

Okay, I pulled the timing cover off and timing chain and gear, there was no abnormal wear marks; everything looked fine, except the cam eccentric that the fuel pump rod rides on has a crack in it. I cant think of what could have cause that to crack? But either way, that shouldn't cause the squeak noise right? The timing gear had no abnormal wear on it, neither did the timing chain, like I said everything looks fine... not sure what it could be.

Thanks,

Eric

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Now that you have the front cover off, I would check to see if you have adequate lubrication coming to the front of the engine, by removing the distributor and rotating the oil pump drive shaft in the proper direction. But before you do that, I would look more closely at the front cover. Is one of the water pump bolts too long or in the wrong location that it's rubbing on the timing chain or gear? How about the bolts that fasten the front motor mount support plate to the front cover, is one of those too long and rubbing? What about the timing pointer pin? Did it get bent and now rubs on the harmonic balancer? Last but not least, is the oil slinger installed correctly? Scrutinize very closely anything that isn't perfect and let us know what you find.

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If you still haven't found anything amiss, you still have two issues here that apparently didn't exist before the engine was torn down. Those being the squeak and the cracked fuel pump eccentric. That being the case, I think we may safely assume that the two conditions are related, possibly having the same cause. At this point, I have to ask, was the fuel pump already installed on the front cover, when the front cover was installed on the engine, after the rebuild? If it was, the fuel pump arm landed on top of the eccentric, causing it to crack, instead of riding on the outside of it. I'm telling from experience here, as I made this mistake long ago on a '65 Buick and cracked the aluminum front cover. Once you cranked the engine for the first time, the arm snapped back into place, but the damage had already been done. Again, look closely at the inner side of the fuel pump arm, and the outside of the chain and gear for witness marks telling that what I have stated has occurred. I suspect that one of the links on the timing chain is bent inward and is riding tight on the gear. This would account for the squeak and the fact that it momentarily silences when you pour oil on it from the filler tube. Hold the gear up, with the chain hanging on it, and slowly rotate it to see if the chain easily lands on each tooth without binding. Let us know what you find. Good Luck!

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  • 1 month later...
Guest pete324rock

I thought it was a lifter noise when I listened to your video. The noise goes away when you pour oil down the tube because it is blocked by the oil. Just for fun, see if the noise is in synch with any of the rockers....

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Guest cmjplayboy

Have not seen this mentioned, but it could be a tight piston. I had it happen to me the ring lands were not properly machined and as soon as it started to warm up and expand the squeak would start. Drove me nuts trying to figure it out and found it when pulled the head off. This was a new set of std pistons and on one they forgot the last machine step it looked like Machine shop did not catch it when they assembled the engine. The skirts were fine, was just the ring land area that was oversized.

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  • 10 months later...
Guest NAJMAN

The oil filler tube was inserted too far into the intake manifold and may be rubbing on the top of the timing chain! I've seen this happen many times! Also, the cam has to be 'run in' for 15-20 mins. @2000 rpm!!! Make sure this has been done!!!! This 'normalizes' and surface hardens the matching surfaces of cam to the lifter! Good luck!

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Guest NAJMAN

You can grab the oil filler tube with large channel locks and twist it upwards a bit to see if the noise goes away.

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