1977 Seville Got it running but making a noise

[MarkV]

Okay got the seville running. It idles fine for the most part (once I burn off the old gas I think it will be Much better). I replaced the radiator, battery, hoses, so i am having an issue that I cant find what it is. When I depress the gas pedal hard or once I get to a certain point I hear a click click or knock knock noise and you can feel it in the pedal. I'm wondering what this could possibly be? 

[ragtop4two]

I'm sure it could be a number of things, but years ago I had a similar problem with my 75 Chevy van. I changed the vacuum advance and it fixed the problem for me.

[JACK M]

Could it be a motor mount?

[joe_padavano]

34 minutes ago, MarkV said:

Okay got the seville running. It idles fine for the most part (once I burn off the old gas I think it will be Much better). I replaced the radiator, battery, hoses, so i am having an issue that I cant find what it is. When I depress the gas pedal hard or once I get to a certain point I hear a click click or knock knock noise and you can feel it in the pedal. I'm wondering what this could possibly be? 

 

Tick-tick-tick would likely be a valve noise (worn rocker, broken rocker bridge, sticking lifter).

 

Knock-knock-knock is more likely bearings.

 

How many miles on this motor? Olds used a cam gear with molded nylon teeth.  These last about 80,000 miles before they wear down to nubs and allow the timing chain to jump.  A very loose chain can make noise.

 

Other possible noise sources are fuel pump, loose or cracked flexplate, trans or torque converter, and exhaust leak at the manifolds.

[MarkV]

At idle everything is normal. Motor has 36k on it

[Zimm63]

First thing I would do is put fresh gas into it and change the plugs.  Then see what you have.

 

[Bloo]

1 hour ago, JACK M said:

Could it be a motor mount?

 

I second this. To find out, open the hood and power brake it. Do this far away from anything in case your foot slips off the brake. Open the hood and have a friend watch from the side. Hold the brake pedal down hard, and slowly roll on a little throttle. Try this in both Drive (or low) and reverse. The engine will normally come up a bit under load, but what you are looking for is a sudden jump up as the engine tries to come up and bang the air cleaner on the hood. A sudden jump means a broken mount, and it is time to get the car on a hoist and confirm.

 

54 minutes ago, joe_padavano said:

 

How many miles on this motor? Olds used a cam gear with molded nylon teeth.  These last about 80,000 miles before they wear down to nubs and allow the timing chain to jump.  A very loose chain can make noise.

 

And if it still has one of these it needs to be replaced right now. This is something that never should have happened in the first place. Oldsmobile and Cadillac are not the only guilty parties. Ford and Chrysler did it too. It is supposed to be quieter. As Joe mentioned, they are a guaranteed failure at about 80K miles. You will be walking home, or calling the tow truck.

 

Nylon is fairly soft when new, but by the time it fails it is hard like little rocks. On Ford FE engines, you are playing with fire if one of these nylon sprockets fails, and you do not remove and clean out the oil pan and replace the oil pickup. One of those little nylon "rocks" will get in the oil pump and stop it, twisting off the oil pump drive and causing a catastrophic failure of the engine. I have never yet had to clean up a mess like that on an Olds 350, and I don't know if it is common, but I sure wouldn't risk it. Get that plastic sprocket out of there before it fails.

 

Keep in mind that it has probably been dumping those little pieces of nylon in the oil for a while when the timing finally jumps and it leaves you stranded.

 

 

Edited February 16, 2018 by Bloo (see edit history)

[joe_padavano]

The 1977 Seville uses the Chevy clamshell style mount.  Even if the rubber is completely gone, the engine can't move that much. This is the whole point of the clamshell mounts.

 

At 36000 mi, I'm not particularly worried about the cam gear.  Definitely on the to-do list, but not a urgent fix.

[8E45E]

4 hours ago, Zimm63 said:

First thing I would do is put fresh gas into it and change the plugs.  Then see what you have.

 

And add a can of Seafoam to the tank.

 

Craig

[Harold]

Check the flex-plate bolts for tightness and the plate itself for cracks.

[cheezestaak2000]

sounds like a spark knock, or ping. fresh gas should reduce that.let the engine warm up to normal operating temp, and with the right foot firmly on the brake to keep car from moving, put the car in drive and rev it up to about 3000 rpm (also known as power brakeing) it should make that same noise. thats bad gas or over advanced timing, both easy fixes. if it had a clicking noise at idle, could be lifters or rocker arms. your car has the olds engine, and the first rocker arms to get noisey are almost always on the driver's side bank right by the EGR valve. that seems to break rocker piviots first. still not a big deal. good luck.

[Bleach]

See if you can post a video clip of the sound. That might narrow it down for you.

[EmTee]

Torque converter clutch issue?  Flex plate and/or inspection cover interference?  Is the noise anywhere near the bellhousing?

[John348]

4 hours ago, EmTee said:

Torque converter clutch issue?  Flex plate and/or inspection cover interference?  Is the noise anywhere near the bellhousing?

 

5 hours ago, Harold said:

Check the flex-plate bolts for tightness and the plate itself for cracks.

 

The first thing I thought was a cracked flex plate, If he feels it i the pedal I don't think it is  bad gas or a spark knock.Maybe that is why the car has not run in a long time?

Edited February 17, 2018 by John348 (see edit history)

[joe_padavano]

13 hours ago, EmTee said:

Torque converter clutch issue? 

 

GM didn't use a torque converter clutch in 1977

 

While the flexplate is a POSSIBLE source of the noise (as mentioned back in post #4), it is highly unlikely.  The only time I've ever had a cracked flexplate on an Olds motor was when the trans to block bolts came loose.  The resulting slop between motor and trans caused the flexplate to, er, FLEX, which eventually cracked it.  Certainly this is easy to verify.  Unbolt the three torque converter to flexplate bolts, push the converter all the way back in the bellhousing, and start the motor.  If the sound goes away, you've isolated the source to the flexplate or converter.  If not, you've eliminated one possible cause.

 

Again, we still don't know if this is a tick-tick-tick of a valvetrain problem or a more ominous knock-knock-knock.  The Olds valvetrain is not adjustable and is sensitive to sticking lifters.  After sitting for a period of time it is not uncommon for the lifters to bleed down or stick, causing valvetrain noise. The Olds rocker bridge design is also susceptible to broken bridges (OEM ones were die cast aluminum).  This can wreak all kinds of havoc with the valvetrain. Either of these failures are FAR more likely causes of noise than the flexplate that many seem to be fixated on.

Edited February 17, 2018 by joe_padavano (see edit history)

[MarkV]

The noise

20180217_091049.mp4

[MarkV]

Again with hood up

20180217_091635.mp4

[Bloo]

Wow. That sounds like exactly none of the problems we have been discussing. Ive got nothing.

 

It sounds external from the videos. It is probably time to find somewhere to get it up on a hoist and look around while it is making the noise.

Edited February 17, 2018 by Bloo (see edit history)

[Harold]

Seems to me that the engine starts to shake when the noise happens.  I'd get a mechanic's stethoscope and methodically (and carefully!!) put the pickup on various engine components to localize the source of the noise.

[Bloo]

Could the fan blade be touching something?

 

When a fan clutch fails, often it seizes. When it seizes, often the fan is no longer straight with regards to the water pump shaft. This opens up the possibility that the fan could touch something, like the balancer or another pulley or the shroud, depending on how close things are.

 

Assuming it has a fan clutch, turn the fan and make sure that it will turn without turning the pulley. Also check the water pump for slop by rocking the fan front to rear.

[Larry Schramm]

One way to help diagnose it would be to take all of the fan belts off and see if the noise is still there.  If it is not then add the fan belts back on one at a time.  If you have the noise with all of the fan belts off, then you might be looking at a base engine problem or even a flex plate.

 

To me it sounds a noise coming from the engine lot like a pulley or rotating part like the AIR pump with the noise.  That is why the suggestion above.

 

I have also used a yard stick to track down noises.  Like said above, BE CAREFUL around rotating objects.

[Grimy]

15 minutes ago, Larry Schramm said:

ne way to help diagnose it would be to take all of the fan belts off and see if the noise is still there.  If it is not then add the fan belts back on one at a time.  If you have the noise with all of the fan belts off, then you might be looking at a base engine problem or even a flex plate.

 

To me it sounds a noise coming from the engine lot like a pulley or rotating part like the AIR pump with the noise.  That is why the suggestion above.

 

I have also used a yard stick to track down noises.  Like said above, BE CAREFUL around rotating objects.

I'd remove one belt, then test.  Then the next...  Why take all off?  Actually, I'd replace ALL the belts on general principles.....

[cheezestaak2000]

is it full of good oil? i would start by remov

ing oil pressure sender switch, and put a gauge on there. the valve train shouldn't be that noisey. that klunk  sounds a bit serious. you may have dioscovered why it has sat in a barn for all these years.

 

Edited February 19, 2018 by cheezestaak2000 (see edit history)

[AJFord54]

Sounds like a valve.  I'd take off the valve cover and check before running it much more.  

 

[DAVES89]

I'll bet a lobe is worn off a cam. Idles quiet and as you increase the RPMs the noise comes. Had that happen to me on a '72 El Camino 454.

[Matt Harwood]

36 minutes ago, DAVES89 said:

I'll bet a lobe is worn off a cam. Idles quiet and as you increase the RPMs the noise comes. Had that happen to me on a '72 El Camino 454.

 

I'm leaning this way, too. We had a Corvette in here with a big block and it idled nice, apparently ran fine for many years, but when we filmed the marketing video I heard a slight popping through the side pipes that wasn't audible to the naked ear. Pulled the rocker cover on that side and saw this:

 

20171222_104212.mp4

 

Pulled the cam out and found this:

 

 

Cam lobe wiped. It probably happened over a long period of time, not instantly, because the pan and filter weren't full of metal. If I hadn't heard that little pop-pop-pop on the video, we never would have known. Pull a rocker cover on the side you suspect and see if all the rockers are popping away as they should. It's easy and quick and will at least eliminate a potential cause if nothing is awry in there.

 

[joe_padavano]

The cam may be the problem, but there are plenty of other possible causes that don't involve replacing the cam.  Oldsmobile uses a unique rocker bridge design.  The die cast bridges can break, causing the rocker arms to move out of position.  This is easy to check by pulling the valve covers. Of course, before doing that, (and rather than guessing) I'd try to isolate the exact location of the noise using a broomstick, dowel, metal tube, or stethoscope to better locate the source of the noise. This is troubleshooting 101.

[tripwire]

Take the top of the air cleaner off and listen, and watch.  You might see / hear some backfiring there. That will tell you if it's something internal to the engine.

Edited February 20, 2018 by tripwire (see edit history)

[Bloo]

3 hours ago, Matt Harwood said:

 

I'm leaning this way, too. We had a Corvette in here with a big block and it idled nice, apparently ran fine for many years, but when we filmed the marketing video I heard a slight popping through the side pipes that wasn't audible to the naked ear. Pulled the rocker cover on that side and saw this:

 

20171222_104212.mp4

 

Pulled the cam out and found this:

 

 

Cam lobe wiped. It probably happened over a long period of time, not instantly, because the pan and filter weren't full of metal. If I hadn't heard that little pop-pop-pop on the video, we never would have known. Pull a rocker cover on the side you suspect and see if all the rockers are popping away as they should. It's easy and quick and will at least eliminate a potential cause if nothing is awry in there.

 

 

If that is an exhaust lobe, you were very close to needing a tow truck. I doubt it happened slowly. When the lifter can no longer spin and is just dragging across the top of the lobe, things get bad in a hurry. The symptom of a flat exhaust lobe is a rhythmic snapping in the intake or carb. When it makes the final transition from "barely opening" to "not opening" the effect is pretty sudden and dramatic. It changes from a snapping noise to undriveable within a few feet.

 

70s Chevrolets were prone to flat lobes even before the oil formulations changed. Oldsmobile, not so much.

 

 

[intimeold]

4 hours ago, Matt Harwood said:

 

I'm leaning this way, too. We had a Corvette in here with a big block and it idled nice, apparently ran fine for many years, but when we filmed the marketing video I heard a slight popping through the side pipes that wasn't audible to the naked ear. Pulled the rocker cover on that side and saw this:

 

20171222_104212.mp4

 

Pulled the cam out and found this:

 

 

Cam lobe wiped. It probably happened over a long period of time, not instantly, because the pan and filter weren't full of metal. If I hadn't heard that little pop-pop-pop on the video, we never would have known. Pull a rocker cover on the side you suspect and see if all the rockers are popping away as they should. It's easy and quick and will at least eliminate a potential cause if nothing is awry in there.

 

 

I agree with the above post and the flex-plate check; and also the removing of the fan belts to isolate the noise.

 

But I also have found the Oldsmobile engine to have cam, lifter and rocker arm problems; usually form not changing oil regular. 

 

Not sure if you took the valve covers off yet; but it would be a good thing to do; especially if the car has set for a long while. I had one Olds engine that apparently hadn't see oil changes in it's running lifetime.  Then the car sat for a few years; all the sludge that was just sludge when it was running regularly; but when it sat and the sludge dried out it started to flake off, in chunks.  The new owner, had changed the oil and filter; but the engine had a noise , sort of what Matt Harwood is talking about.   The area under the valve covers was just packed with hard sludge. 

 

If the sludge was that bad there just imagine what the  engine valve train galley probably looked like and the cam area.  Not to mention the oil pan.  

 

That  owner had us put it back together and the car , was sent off to the auction by the owner.   Hope you have better luck there.

 

intimeold

 

 

[Bloo]

Frankly, it didn't sound like any of that to me, the noise didn't sound in sync with the engine. It is so hard to tell from a video. That said, if it IS a valvetrain problem, I am guessing that rocker bridge problem Joe mentioned is a lot more likely than a flat cam in that engine. A lot easier to fix. too..

[sfair]

1. Put in drive.

2. Hold down brake.

3. Step on gas and see if that changes anything.

[padgett]

Thought I heard some ringing in there also particularly with hood shut like something external hitting something.  Is way under engine speed. Could be a collapsed motor mount hitting the retainer arm. Should be visible

[pfloro]

I've waited to respond because I'm not an engine expert by any means.

 

But..., after listening to this noise through a good set of headphones, it just feels external to the engine (as others have suggested).

There is a certain crispness to the sound which I think wouldn't be there if it was coming from, for example, under a valve cover, etc.

It seems as though above a certain speed, the vibrating engine is causing a resonance triggering some external engine part to 

hit another part which is too close. 

 

As suggested, power braking, a stethoscope investigation and belt removal are all in order to isolate this noise.

 

Since the engine doesn't seem to shutter when speed is increased, I don't think a weak cylinder caused by a valve train issue is the cause of the noise.

 

Please keep us posted.  This is an interesting one.

 

Paul

 

[cheezestaak2000]

On 2/20/2018 at 1:52 PM, intimeold said:

 

I agree with the above post and the flex-plate check; and also the removing of the fan belts to isolate the noise.

 

But I also have found the Oldsmobile engine to have cam, lifter and rocker arm problems; usually form not changing oil regular. 

 

Not sure if you took the valve covers off yet; but it would be a good thing to do; especially if the car has set for a long while. I had one Olds engine that apparently hadn't see oil changes in it's running lifetime.  Then the car sat for a few years; all the sludge that was just sludge when it was running regularly; but when it sat and the sludge dried out it started to flake off, in chunks.  The new owner, had changed the oil and filter; but the engine had a noise , sort of what Matt Harwood is talking about.   The area under the valve covers was just packed with hard sludge. 

 

If the sludge was that bad there just imagine what the  engine valve train galley probably looked like and the cam area.  Not to mention the oil pan.  

 

That  owner had us put it back together and the car , was sent off to the auction by the owner.   Hope you have better luck there.

 

intimeold

 

 

worked at an olds dealership for over 10 years back in the 70's and 80's, and NEVER had to replace a camshaft on an olds engine, even those with over 100,000 miles. the ones with the chevy engines were a different story. i'm not dumb enough to say it's not possible, but i think the noise would be more rythmic at about half engine speed.i think it's been oil starved, and gonna need a short block