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1931 Buick Model 60 Engine Noises- any ideas?


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Video album link:  https://photos.app.goo.gl/NRnkuW83CiLx9n3M8

 

My model 60, which was recently started after sitting dormant for about 26 years is making a couple noises I don’t like and I can’t seem to ID.   There is a light “rapping” or “knocking” noise near the front of the engine.   The strange thing is the noise is not present on a cold start up.  (See first video which demonstrates this- the knocking noise starts at about 22 secs into the video)  It takes about 30 to start appearing.   This would make me think it is NOT a function of low oil pressure as the oil pressure would be lowest at startup and there is no noise then.  There is also a noise in the front that is very hard to make out and hard to describe but it is not a constant noise and almost sounds like something “slipping”.  (not a belt, brand new fan belt). I used a stethoscope and the noise does not appear to be coming from inside the block.   You can hear it most on the front lower cover and bracket that goes over and serves as the front left mount bracket.  You can also hear them very clearly thru the radiator if you stand in front. (you can hear the “slipping” noise in the 4th video from in front of the radiator if you listen carefully)   I’m also getting an irregular exhaust note with a notable “burp” or “chuff” every few seconds that does not seem right.  Sometimes there is a brief white-ish or gray-ish puff when these chuffs occur. (see exhaust pipe video)   If you click on this link it will take you to a google photo album with a few videos of the car running.   You can also hear a slight exhaust leak and some upper valvetrain noise (I assume this valvetrain noise is typical).  Please try to disregard those noises.  Any input much appreciated thanks!  I am a nervous to drive it much with these noises, but I’ve driven about 150 miles and no issues.  Oil pressure is 25 lbs at low idle and 30 lbs at anything above a low idle but never reads higher on the dash gauge. 

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It's hard to say anything about a noise without actually hearing it, but early Buick straight-8s do have a distinctive sound that many people mistake for a knock. It's not, but it's that same kind of sound. Every one I've had and every one I've been close to has made that faint knock sound at idle. I suspect it's a little bit of piston rocking from the long stroke and later engines had redesigned pistons to cut down on it. It usually disappears at anything over idle and things smooth out. 


Again, hard to identify what you're hearing, but it's not unusual for Buicks of that vintage to have a sound similar to what you're describing. Maybe that helps?

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Thank you Matt.  I wish i could report that is went away as RPM's increase but it does not.  It just gets faster along with engine RPM.    I've watched a few Videos on '31-32 Buicks running on youtube and to be honest most of them sound noisier than mine, though I could not hear any of them making this specific noise.    I thought straight 8's were supposed to be quiet and refined?  Maybe not Buicks?!

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My 37 seems to be quiet when cold and then a bit of lifter noise when warming up a bit. I heed to redo the rocker shaft.

Have you adjusted the valves when engine hot?  If a valve is hanging up that would account for your "chuff". A misfiring or cross firing plug wire can telegraph noises thru the system also. Also a "Chuff". Your last video going to the front of the car sounds a bit like water pump bearing?

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My 31 66s does not make that knocking sound but many of the other sounds are familiar. My oil pressure is a little higher on the gauge, 30 at idle and about 40 going down the road. Are you running the original fan bearing with the oil and pump inside?

 

Dave

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You could first remove the fan belt, run it for a bit to rule out your water pump bearing.

Then, as Larry stated, take the rocker cover off and check your valve clearance while hot.

 

At least you can check a couple external things off the list.

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It's difficult to make a definitive conclusion, but several things that I've seen on the early 8's:  People for whatever reason removed the springs that keep the pushrods in contact with the lifters.  this will give your a distinct noise.  The other issue is that on early 31 engines, the cam bearings were bronze.  There were significant issues with these bearings and somewhere in mid year they changed to babbit bearings.  Wear on the fiber cam gear can cause strange noises.

 

Bob  Engle

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Does the 1931 Buick engine have bolt on crankshaft counterweights? My 1929 engine does. Has anyone ever seen the bolts loosen in this location? I may would drop the pan to inspect rod and main bearings. Especially in the front half of the engine. Good oil pressure is a good sign of not having excessive clearances there. Your engine's under hood sounds are very similar to mine. Mine always has a slight valvetrain sound . My piston slap goes away at fast idle.

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Once the oil is drained the oil pan is just an inspection cover. I would open it up, sound out the rod bearings and drop a main cap to check, not a big deal.

 

When a car gets laid up for a few decades the owner rarely says "Oh, this is going to sit for a long time. I better put fresh oil in it." They usually sit with oil that contains some amount of contaminates and a bit of sulfuric acid from combustion. Over the years that acid may slightly etch the babbit material surface, maybe to .0005", but that could be a limit on a used engine. The first couple of rotations of the crank will wipe that off when the car is started. Maybe just enough to knock or rattle.

 

It's 10AM here. I could have that pan dropped and everything inspected by suppertime. Might take a day to get a big enough piece of cork to make a new pan gasket.

 

There's also and opportunity to look for rust pits in the bottom of the pan just in case it wasn't in climate controlled storage for all those decades. Wouldn't want it mixing a pint or two of condensation with the oil. That condensation can collect in the transmission and differential, too.

 

Brake lining tends to lose flexibility over years and not grip drums well. That's another check for long term storage.

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Further notes:  I have removed the fan belt and spun the fan by hand and no noise.  Will try it again and start it up.  I’m quite certain that is not the issue.   I have already dropped the oil pan (no sign of rust) and cleaned out any sludge I could get to.  Have also removed rocker shaft, completely disassembled it and cleaned everything on it, blew out all lines feeding to it and from it.  I’m leaning towards it being the timing gear or the generator gear/bearing, though I did put my scope on the generator directly and it did not seem to be coming from there.  As pointed out, the water pump is not driven by the fan belt and it is quite far back on the right side of the engine so is nowhere near the area the noise is emanating from.   The thing that puzzles me the most is that the knock is not there immediately at startup, it only seems to show up once oil pressure has risen.   Has anyone pulled a front cover to look at the timing gear?  Can it be done with the radiator still on the car?  Can the engine be run with the cover off?  thanks!

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No, you will need to remove the radiator.   And you cannot run the engine with the timing cover removed without lots of oil loss. 

After removing the radiator, you may need to lift the front of the engine off the motor mount to remove the timing cover & inspect the timing gears.

 

 

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By all means drop the Pan, Olson makes the gaskets. My 32 engine make a clicking noise and I thought it was coming from the trans until I lost oil pressure. A cotter key did the damage on the oil feed line, broke a verticle and almost wore through the main line. Have you used a stethoscope around the engine?

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