77 Seville Noise update

[MarkV]

Okay so had a guy come out and look at that seville noise. It is for sure not the flex plate or the harmonic balancer. It is coming from the throttle body. They checked the plugs, wires, etc. Also the fuel pressure was perfect. Said it could be that it needs a new throttle body. I looked at the bills from a few years ago and the owner 2x ago was told that the compression in one of the cylinders was 20 percent lower. They advised in 2015 an engine replacement (which is a joke). Anyway the guy told me to take it to a carb/fuel injection shop.  He said it could be likely that something is not right in the top part of the engine if it is not the throttle body. However I just don't think it's likely given the low miles and the fact the car has been regularly serviced for years. Does anyone have an extra throttle body carb looking thing they would like to part with?  The car is sputtering and essentially backfiring with the popping sound and won't go very fast.

[joe_padavano]

41 minutes ago, MarkV said:

Okay so had a guy come out and look at that seville noise. It is for sure not the flex plate or the harmonic balancer. It is coming from the throttle body.

 

There are no parts in the throttle body that can make any kind of a noise. Find "a guy" who has a clue.

[MarkV]

This is a throttle body injection system that looks like a carburetor there when malfunctioning according to my manual it could make a noise like this. Fuel pressure is good, everything else looks fine. But it is getting bogged down and essentially backfiring 

[vermontboy]

Try googling "throttle body noise" - videos. There are dozens on youtube videos of throttle bodies and apparent noises. When you find a match to the sound you are hearing you may have your answer.

[MarkV]

I forgot to mention that it also looks like too much fuel is going in as well. 

[Bloo]

2 hours ago, MarkV said:

The car is sputtering and essentially backfiring with the popping sound and won't go very fast.

 

This is classic valvetrain failure, usually a flat camshaft lobe. In this case, I would take the valve covers off and look for the rocker trouble Joe mentioned in the other thread. You are looking for an exhaust valve that is not opening. If it is a rocker bridge or something it will be an easy fix. If the cam is flat, you will need to do a cam and lifters.

 

To clarify, and to be sure we are really talking about the same thing, the condition I refer to will cause a loud snapping in the intake as you try to rev the engine. Instead of revving up you get a rythmic backfiring in the intake.

 

Remove the valve covers. Crank the engine, better yet have a friend crank it so you can watch the valves (with the plugs out and the ignition disabled or unplugged or something). Find the valve that doesn't open. Figure out why. This is what you will need to fix. Don't replace the throttle body. That wont do anything. Good luck.

 

 

 

 

[intimeold]

59 minutes ago, Bloo said:

 

This is classic valvetrain failure, usually a flat camshaft lobe. In this case, I would take the valve covers off and look for the rocker trouble Joe mentioned in the other thread. You are looking for an exhaust valve that is not opening. If it is a rocker bridge or something it will be an easy fix. If the cam is flat, you will need to do a cam and lifters.

 

To clarify, and to be sure we are really talking about the same thing, the condition I refer to will cause a loud snapping in the intake as you try to rev the engine. Instead of revving up you get a rythmic backfiring in the intake.

 

Remove the valve covers. Crank the engine, better yet have a friend crank it so you can watch the valves (with the plugs out and the ignition disabled or unplugged or something). Find the valve that doesn't open. Figure out why. This is what you will need to fix. Don't replace the throttle body. That wont do anything. Good luck.

 

 

 

 

 

Yes, when this thread started, some of us ; related to the poster that, he should take a look at the cam, lifters, rockers. 

 

It doesn't take very long to pull the valve covers off and  check the valve action , on each cylinder.  Apparently he got sidelined, and started to look in other areas. Yes,  all possible  noise areas too.

 

Has he even taken a compression test? 

 

And also yes, I have put cams and  lifters in Oldsmobile engines, somebody here said they never go bad.  Never, is a word a technician/mechanic seldom uses.  Follow simple diagnostic procedures and the fault will be found, no short-cuts.

But as Bloo just posted; it sure sounds like a valve-train noise. But I am not there, and can't diagnose it over the internet. Somebody stopped running that car; because of the $$$ possible repair bill.  

[Bloo]

 

15 minutes ago, intimeold said:

Yes, when this thread started, some of us ; related to the poster that, he should take a look at the cam, lifters, rockers. 

 

It doesn't take very long to pull the valve covers off and  check the valve action , on each cylinder.  Apparently he got sidelined, and started to look in other areas. Yes,  all possible  noise areas too.

 

Has he even taken a compression test? 

 

And also yes, I have put cams and  lifters in Oldsmobile engines, somebody here said they never go bad.  Never, is a word a technician/mechanic seldom uses.  Follow simple diagnostic procedures and the fault will be found, no short-cuts.

But as Bloo just posted; it sure sounds like a valve-train noise. But I am not there, and can't diagnose it over the internet. Somebody stopped running that car; because of the $$$ possible repair bill.  

 

When you have an exhaust valve that wont open all the way, for any reason, you get a rhythmic snapping/popping/backfiring in the intake. All that exhaust and fire has to go somewhere. MarkV's most recent post sounds like that to me. In fact, his description REALLY sounds like that to me. When it gets bad enough you cant even drive. Could be with or without valvetrain noise, depending on what it is.

 

And yes, a compression test couldn't hurt.

[retiredmechanic74]

I would also suggest to check for a severally plugged exhaust system. 

[intimeold]

47 minutes ago, retiredmechanic74 said:

I would also suggest to check for a severally plugged exhaust system. 

 Yes, I have seen plugged exhaust system, cause the inability to get up to full power.

 

Catalytic converters are the main culprit there; but  also saw dual walled exhaust pipes, collapse inward.  Big V-8 Fords and Mercury  seemed to have this problem.  The header piped was dual walled; and collapsed right where the left and right engine bank merged. Found that by removing header to manifold bolts and dropping the Y-pipe, the engine would achieve full revs.  But you could not see the collapse  until you removed the Y-pipe from the exhaust pipe leading to the muffler.  Saw several like that. 

 

Keep looking you will find it; these tips are only suggestions    

[retiredmechanic74]

1 hour ago, intimeold said:

 Yes, I have seen plugged exhaust system, cause the inability to get up to full power.

 

Catalytic converters are the main culprit there; but  also saw dual walled exhaust pipes, collapse inward.  Big V-8 Fords and Mercury  seemed to have this problem.  The header piped was dual walled; and collapsed right where the left and right engine bank merged. Found that by removing header to manifold bolts and dropping the Y-pipe, the engine would achieve full revs.  But you could not see the collapse  until you removed the Y-pipe from the exhaust pipe leading to the muffler.  Saw several like that. 

 

Keep looking you will find it; these tips are only suggestions    

I once bought a Merc wagon that had been setting for a number of years and when I got it running it acted the same as the description given by the poster. After dropping down the exhaust and found that was the problem I found that mice had made a nest in the exhaust pipe and plugged it up.  

[60FlatTop]

20 hours ago, MarkV said:

They advised in 2015 an engine replacement (which is a joke).

 

Recent Cadillac advertising has Edith Pilaf singing her famous song "No Regrets". Interesting song for the company to pick, isn't it.

Bernie

[cheezestaak2000]

16 hours ago, Bloo said:

 

 

When you have an exhaust valve that wont open all the way, for any reason, you get a rhythmic snapping/popping/backfiring in the intake. All that exhaust and fire has to go somewhere. MarkV's most recent post sounds like that to me. In fact, his description REALLY sounds like that to me. When it gets bad enough you cant even drive. Could be with or without valvetrain noise, depending on what it is.

 

And yes, a compression test couldn't hurt.

 

[cheezestaak2000]

i was the guy that said in 10 plus years as an olds mechanic that i had never replaced a cam, did not say they never go bad, just pointing out that is rare. the earlier post on this car sounded to me like an oil pressure/ oil starvation problem, that's my story and i'm sticking to it  lol. and by all means ,don't wast 20 bucks on a gauge to see what kind of oil pressure you have, roll out the checkbook and buy injectors, radiator caps, ash tray slides or tire valves. why waste time on a diagnosis by a competent mechanic when you can spend money on internet guesses?

 

[C Carl]

Hey Bernie : Look what spellcheck did to poor Edith !  Oh yeah Mark V , that compression check will narrow down and make your valve gear analysis so much easier if you do find just one dead/weak hole. The suspense is killing me !    - Carl 

[60FlatTop]

6 minutes ago, C Carl said:

Look what spellcheck did to poor Edith !

 

Inspired me to Google Bill Gates and look at images. He did better.

 

The compression test is needed, for sure. Probably a leak down test and some running vacuum readings. What Cadillac would replace an engine for can be repaired. They were most likely trying to cover all bases with the replacement.

[TerryB]

My first new car, a 1973 Chevelle SS, was equipped with one of those dual wall exhaust pipes.  A drive though cold standing water after a heavy rain all of a sudden made the car barely drivable.  Lucky a friend with a local service station recognized the problem.  I thought it was ignition related but he knew about the exhaust pipe issue.  His sister with a 1974 Chevelle had gone through the same problem.  A new pipe from the local NAPA store fixed things up just fine.  He said the first one was the hardest to diagnose, after that the rest were easy.  Putting your hand at the output of the pipe and feeling very little exhaust coming out was a clue plus the noise it made.

[retiredmechanic74]

I should like to point out a compression test is a good thing to do but it will not tell you if you have a bad cam. A compression test tells you if something is leaking, burnt valve, rings, burnt piston but if the valves close properly ( which they do with a bad cam, they just don't stay "open" long enough to exhaust or take in fuel) you will get a good reading. It's best to remove the valve covers and run the engine while watching the rocker arm movement.

[joe_padavano]

21 hours ago, MarkV said:

This is a throttle body injection system that looks like a carburetor there when malfunctioning according to my manual it could make a noise like this. Fuel pressure is good, everything else looks fine. But it is getting bogged down and essentially backfiring 

 

NO it is NOT a "throttle body" injection system.  Look at your intake manifold.  There is an injector in each of the eight ports, NOT at the throttle body.  I suggest spending more time reading the service manual. Note the eight black PORT injectors and fuel rail in the photo below. There are no moving parts in the throttle body except the throttle valves that open with the accelerator pedal. NOTHING in the throttle body makes noise.

 

Edited March 11, 2018 by joe_padavano (see edit history)

[Bloo]

3 hours ago, cheezestaak2000 said:

i was the guy that said in 10 plus years as an olds mechanic that i had never replaced a cam, did not say they never go bad, just pointing out that is rare.

 

This.

 

As a driveability tech, I never recall sending one of these to get a new cam either. Olds made about eleventy billion of those big Cutlass Supreme coupes in the 70s, and I recall seeing them all the time (in the 80s) with 150-180k miles on them, and NO engine mechanical issues and NO oil burning.

 

IMHO the Olds 350 was GMs best engine of the 70s, and not by a small margin. That said, ANYTHING can have a flat cam.

[mike6024]

How come no wagers are being made as to what the cause is?

[retiredmechanic74]

Chevy V8 small blocks in the 70's were notorious for the cams going bad, I can't count how many I've replaced and being if the engine in the caddy is a 350 there is a chance it could have gotten one. Can't say for sure but taking off the valve covers and running the engine will confirm if the cam is good or bad. 

[MarkV]

Well I'm going to call the old shop tomorrow where my 41 Dodge was brought back to life and send it to them. Regardless of cost it was still a steal as most of these are goners this one has had several thousand dollars of work put into it over the last several years  and I was looking for this exact color combo and year as my grandpa had one. I will keep you updated. I'm just as curious as you all are never had a problem like this before!

[Laughing Coyote]

Just going to throw this out there. I remember an issue my brother was having with his shop truck. It was a Ford, but it had little power and was back firing and sounded pretty rough.  Come to find out it caused by the cat on the exhaust system. It was plugged up  They replaced it and it worked fine. Just another thing that COULD be a possibility.

[joe_padavano]

8 hours ago, retiredmechanic74 said:

Chevy V8 small blocks in the 70's were notorious for the cams going bad, I can't count how many I've replaced and being if the engine in the caddy is a 350 there is a chance it could have gotten one. Can't say for sure but taking off the valve covers and running the engine will confirm if the cam is good or bad. 

The engine is an Oldsmobile-sourced 350. It is NOT a Chevy motor. Contrary to what some people think, not all GM 350 motors came from Chevy.

[retiredmechanic74]

4 hours ago, joe_padavano said:

The engine is an Oldsmobile-sourced 350. It is NOT a Chevy motor. Contrary to what some people think, not all GM 350 motors came from Chevy.

I didn't say it was a Chevy.....But you would be surprised at how many interchangeable parts there were in the GM line in those years. I don't know if you know this or not but back in, I believe it was 1975, GM purchased a load of steel from Japan and as it was being shipped over sea water got into the cargo hold and the steel was contaminated and GM used it anyway. That's why the 76 through 79 GM cars rusted out so bad and it also effected internal parts as well. 

[retiredmechanic74]

9 hours ago, MarkV said:

Well I'm going to call the old shop tomorrow where my 41 Dodge was brought back to life and send it to them. Regardless of cost it was still a steal as most of these are goners this one has had several thousand dollars of work put into it over the last several years  and I was looking for this exact color combo and year as my grandpa had one. I will keep you updated. I'm just as curious as you all are never had a problem like this before!

That is one good looking car, I found one that has a manual trans but to much money for the condition. Let us know what the shop finds. It well help to put an end to all the chatter.

[joe_padavano]

1 hour ago, retiredmechanic74 said:

I didn't say it was a Chevy.....But you would be surprised at how many interchangeable parts there were in the GM line in those years. I don't know if you know this or not but back in, I believe it was 1975, GM purchased a load of steel from Japan and as it was being shipped over sea water got into the cargo hold and the steel was contaminated and GM used it anyway. That's why the 76 through 79 GM cars rusted out so bad and it also effected internal parts as well. 

 

The only parts that interchange between a Chevy 350 and an Olds 350 are the distributor cap and rotor.  Maybe the thermostat. Your prior post was in reference to the cam.  Not only do they not interchange, but the Olds cams never had a "flat lobe" problem. I have no idea what body panel rust or suspension interchangeability has to do with the engine cam having a flat lobe.  Obviously GM has been using common suspension, brakes, and internal structure since loooong before the 1970s.  The Seville was originally based on the Nova X-car platform.

Edited March 12, 2018 by joe_padavano (see edit history)

[retiredmechanic74]

4 minutes ago, joe_padavano said:

 

The only parts that interchange between a Chevy 350 and an Olds 350 are the distributor cap and rotor.  Maybe the thermostat. Your prior post was in reference to the cam.  Not only do they not interchange, but the Olds cams never had a "flat lobe" problem.

Well I'm not going to argue the point but after 18 years as a mechanic in the dealerships of Oldsmobile, Pontiac, Chevrolet and Cadillac I would beg to differ. 

[Frank DuVal]

18 hours ago, joe_padavano said:

Contrary to what some people think, not all GM 350 motors came from Chevy.

 

That's right, Joe!

 

Chevrolet, Buick, Pontiac and Oldsmobile 350s are all different engines. They might share some internal parts (none that I can think of right now), but the block is not one of those shared parts! Heck, even the bellhousing bolt pattern is different between BOP and Chevy.

 

 

[joe_padavano]

8 hours ago, Frank DuVal said:

 

That's right, Joe!

 

Chevrolet, Buick, Pontiac and Oldsmobile 350s are all different engines. They might share some internal parts (none that I can think of right now), but the block is not one of those shared parts! Heck, even the bellhousing bolt pattern is different between BOP and Chevy.

 

 

 

They do not share any internal parts - even lifters are different, despite what some aftermarket vendors will try to tell you.  As I mentioned, about the only parts in common are the distributor cap/rotor and maybe the thermostat.

[retiredmechanic74]

You know what I find that is very annoying? A person post a question or a problem they are having and "most" of us try to help find a solution by making suggestions as to what could "possibility" be the cause of the problem. Then we have those who come along and instead of trying to help would rather dissect the suggestions and removing the question completely out of the answers. 

[CarlLaFong]

My flagging memory tells me that there was some sort of issue with the rockers or the trunnions on some of the 350 Olds engines. I recall when I rebuilt my 77 Seville, I had to replace a few of them

[joe_padavano]

3 hours ago, CarlLaFong said:

My flagging memory tells me that there was some sort of issue with the rockers or the trunnions on some of the 350 Olds engines. I recall when I rebuilt my 77 Seville, I had to replace a few of them

 

Your memory is fine.  That was suggested as a possible issue in the OP's original thread about this car. It is unfortunately a not uncommon problem with these Olds motors.

Edited March 14, 2018 by joe_padavano (see edit history)

[60FlatTop]

19 hours ago, retiredmechanic74 said:

You know what I find that is very annoying?

 

Maybe I can reread all the posts and aggravate the information.

Bernie

[cheezestaak2000]

14 hours ago, joe_padavano said:

 

Your memory is fine.  That was suggested as a possible issue in the OP's original thread about this car. It is unfortunately a not uncommon problem with these Olds motors.

usually, it required replacing 2 rockers and the piviot on the left bank, closest to the EGR valve

 

[retiredmechanic74]

1 hour ago, 60FlatTop said:

 

Maybe I can reread all the posts and aggravate the information.

Bernie

Don't quite know if that is a positive or negative response????  

[C Carl]

Hi retiredmechanic74 ! Don't take anything personally around here , man. You are very direct , and do get right down to business. But it is just human nature to drift around , or get a bit off topic. Don't let it annoy you. We are all friends here , and you are very highly regarded. It is interesting to see how this whole process works to solve problems , sometimes way more complicated than this Seville. Speaking Seville , and to drift while so speaking , I am sure that I am not the only one who would be quite interested in more info on the one you found with a MANUAL (!) trans. Could you please elaborate on that ?

 

Now , Bernie is cool ! He enjoys words , writing , and humor. I do too , but I have to admit he sometimes gets a fastball past me too ! It's a great treasure to be a part of this wonderful group of guys and gals. I assume the 74 in your handle is your age ? I hope to get there with you in 4 months. If you are like me , you probably have already lost considerably more of your best , oldest friends than still live. I miss them terribly , more so with the passing of time. Be grateful for your friends , yes , REAL friends here in this remarkable format. No need to be annoyed by anything here , my friend !                                                                                           Stick Shift Seville ?   - Cadillac Carl 

 

Edited March 14, 2018 by C Carl
Spacing (see edit history)

[Ben Bruce aka First Born]

6 hours ago, retiredmechanic74 said:

Don't quite know if that is a positive or negative response????  

 Obvious you do not know Bernie.

 

  Ben

[retiredmechanic74]

CCarl.....Thank you for being so open and honest. I don't take these things personally but I do get frustrated. I don't respond, so I can be dissected, I only offer possibilities. If I thought I was being offended I would end my relationship with this forum  which I don't intend to do, but I wish people would stop and think about the problem and NOT the answers it doesn't help the questioner one bit. With that said the manual trans Caddie was listed on Crags List in Greenville South Carolina, you could run a search if interested. In closing I would like people to STAY ON SUBJECT. The last post I read from the guy with the Seville sounded like he wished he didn't ask.