47-55.1 What's going wrong inside my 350?

[NeoJuice]

Originally Posted by mongocanfly

Haha...I was just thinking of making a list of all the suggestions he's got so far....hopefully your issue will be a simple fix....

Me to. I mean I'm a fairly mechanically inclined guy but when it comes to internal motor stuff I have no clue and I appreciate everyone stepping up and giving me a hand. Now I just wish someone was a neighbor or close by to give me a hand lol.

[dsraven]

if you pull the filter and find bad news it would be in your best interest to pull the engine out and completely disassemble the engine and see what you have. I have seen some guy's idea of a rebuilt. some are a car wash and some engine paint. some are dissassemble, ball hone,, rering and bearing and assemble without even checking ring end gap or bearing clearances. some are a complete, properly checked, cleaned, spec'd rebuilt like you would expect when told it is redone. I installed an engine for a fiend who had a reputable engine builder do his 350 into a 383. it arrived all nice and fresh looking. when I poured coolant in there was a leak right away at the rear somewhere. turned out the frost plugs weren't even replaced let alone the block hot tanked. there was a whole load of problems with the engine including stripped bolt holes, leaky seals etc. best to take it apart and see for yourself if it comes to that. hopefully it is something simple and you can carry on.
I have found it is best to see the bills for the work or else make the deal as if the engine were an old clunker. unless the guy has bills for new parts and actual specs for clearances, work done etc, you just can't tell. some guys honestly believe what they have done constitutes a "rebuilt" engine. one easy way to tell if it has at least had some work is with a boroscope through a spark plug hole and through the oil filler to see what that part looks like.
anyway, hopefully it is an easy fix and it doesn't keep you up at night.
keep us posted

[1project2many]

After getting the motor and pulling off the intake manifold the insides and the water jackets were gummed up with crud. So was it rebuilt?

No. That kind of crud takes years to accumulate.

Could the build up in the engine because it sat for such a long time with dexcool in it instead of antifreeze?

No. Dexcool is antifreeze. It has a different additive package but it still resists corrosion. That type of buildup requires many heat cycles to develop.

[NeoJuice]

Here are some old pictures I took back on 4-1-2017 when I ripped the manifold off.

[1project2many]

Thanks for posting.

Here's what a clean coolant passage looks like:


Look at rightmost port on rear head to see "normal accumulation of deposits":


This is what "gummed up with crud" looks like.

[DransportGarage]

Originally Posted by NeoJuice

Here are some old pictures I took back on 4-1-2017 when I ripped the manifold off.

The pictures don't really show any crud, through it might be there. That's promising for you, because that engine may have been rebuilt a few hunderd miles ago.

I bought a Cutlass about 5 years ago. It came with two engines. The original was out and a "newly rebuilt" one was in it. I sold the "newly rebuilt" one on Craigslist. When the guy came to buy it, he asked if we could take a valve cover off. I said sure. Was I embarrassed! We could hardly see the rockers. I cut the price in half and he took it anyway. Unbelievably, we're good friends today.

[NeoJuice]

Originally Posted by 1project2many

Thanks for posting.

Here's what a clean coolant passage looks like:


Look at rightmost port on rear head to see "normal accumulation of deposits":


This is what "gummed up with crud" looks like.

My ports did definitely not look like the crud pictures you posted. Thanks for the clarification.

Wow I guess you did luck out on that 'newly rebuilt' one in the Cutless. Under my valve covers was pretty clean and no build up at all with all clean passages.

I hope to have some answers tomorrow and more pictures. I was hoping to get out to the garage tonight but the wife had other chores for me to do.

[GreasyLikeaBurger]

That coolant looks like inter mixing of two different types of coolant. I have seen it on some VAG coolant when it is mixed with store bought green stuff.

[GreasyLikeaBurger]

ps. By VAG i mean the pink stuff VW, Audi, Porsche and every other manufacturer under the VW umbrella uses.

[1project2many]

Originally Posted by GreasyLikeaBurger

That coolant looks like inter mixing of two different types of coolant. I have seen it on some VAG coolant when it is mixed with store bought green stuff.

Good eye! That's exactly what happened. The picture was taken from a thread on an antique car forum. The vehicle owner was sold Dex-cool by a parts chain zombie and found after a year or two that the two additive packages do not play well together.

ps. By VAG i mean the pink stuff VW, Audi, Porsche and every other manufacturer under the VW umbrella uses.

LOL. A young man in this state worked hard to convinced the state censors to allow a vanity plate for his highly modified Audi that reads "LV-VAG." He even wore a T-shirt to the hearing that read something like I heart VAG.

[NeoJuice]

Ok update time folks. I hired a local Mobile mechanic here where I live. He charged me $90/hour to come look at the truck. I didn't want to spend the money but I needed professional opinion.

We spent an hour going over the truck. He checked the starter bendix and it is disengaging when the motor is running. He checked the flex pate and torque converter and the bolts on the flex plate. Everything appeared to be working as it should and no rubbing marks or anything was found.

He then started to do some investigation further using his stethoscope and start pointing it all over the motor top and bottom. He said the noise is coming from behind the timing cover. So now I know that something is f*cked up with the timing chains/gears.

I mentioned to him that when the truck came back from the exhaust shop that the motor did make a couple loud ping noises and I wasn't sure what it was. I told him I thought it might have been the starter skipping a tooth on the flex plate or something like that and that's when the noise started.

So now I think I have a place to start. I'll have to pull the rad out. Drain all the fluids. Pull the water pump off and harmonic balancer and see what is going on behind the timing cover. I'll also have to rent or buy a puller to get that balancer off.

What I'm going to find behind the timing cover? I don't know and what parts will need replaced. Ill also see maybe if it needs a new harmonic balancer as well depending on the shape its in. The mechanic said probably not, but he's only seen maybe a handful needing replaced on 350s over the 20+ years he's been a mechanic.

He said it could have broken a tooth off. One of the bolts could have come loose or something like that and parts could be flying around on the inside of the cover causing all the noise. Now this could be a possibility because the previous owner said he put a mild cam in the engine, so at some point the engine must have been apart. Also because of the chrome timing chain cover.

So if you have any idea what I might find broken behind the cover please pass me on your thoughts.

[mongocanfly]

hmmmmmm....I do believe if it were mine the engine would come out and id go thru it completely...a SB is the cheapest engine to rebuild anyway...

[DransportGarage]

Originally Posted by NeoJuice

<snip>

So if you have any idea what I might find broken behind the cover please pass me on your thoughts.

I really hate to be the bearer of bad news, but...

My guess is, the same brain surgeon that forgot the converter bolts didn't tighten the three timing sprocket bolts...and you can assume he's the same guy that did the rest of the engine. It's time for a full engine disassembly and inspection. At a minimum you'll be finding circular score marks on the inside of the timing chain cover, or something similar. To make yourself feel better about all of the work, check the torque specs on the bolts. They're probably all over the place. Leave the heads together, don't take the pistons off of the rods and leave the freeze plugs in unless you find something screwy or you decide to have the castings hot-tanked.

There's plenty of YouTube on the assembly (e.g., https://www.youtube.com/watch?v=UmIslf3ANTs), but if you're not comfortable with this level of work, do the disassembly yourself. Keep track of the location of EVERY push rod, lifter, piston, etc. Clean everything, then buy some steaks and invite a knowledgeable friend over for a Saturday of fun. Keep the beer in the fridge until your done. (Man, I wish I lived closer. I like mine medium-rare...)

Don't rent the tools until you find out what your friend will bring. Then go to AutoZone and they will lend you most of what you need for free.

[Driver_WT]

Originally Posted by DransportGarage

I really hate to be the bearer of bad news, but...

My guess is, the same brain surgeon that forgot the converter bolts didn't tighten the three timing sprocket bolts...and you can assume he's the same guy that did the rest of the engine. It's time for a full engine disassembly and inspection. At a minimum you'll be finding circular score marks on the inside of the timing chain cover, or something similar. To make yourself feel better about all of the work, check the torque specs on the bolts. They're probably all over the place. Leave the heads together, don't take the pistons off of the rods and leave the freeze plugs in unless you find something screwy or you decide to have the castings hot-tanked.

There's plenty of YouTube on the assembly (e.g., https://www.youtube.com/watch?v=UmIslf3ANTs), but if you're not comfortable with this level of work, do the disassembly yourself. Keep track of the location of EVERY push rod, lifter, piston, etc. Clean everything, then buy some steaks and invite a knowledgeable friend over for a Saturday of fun. Keep the beer in the fridge until your done. (Man, I wish I lived closer. I like mine medium-rare...)

Don't rent the tools until you find out what your friend will bring. Then go to AutoZone and they will lend you most of what you need for free.

Great advice. If you find two things that were not done right, there are bound to be many more. And if for nothing else, it will provide peace of mind and confidence that you know what you have after the engine has been gone through.

[Black_Sheep]

Originally Posted by whitedog76

The high pitch squeal on the you-tube video is concerning, sounds like a spun bearing, or some sort of metal on metal.

The flex-plate video, I didnt' hear the squeal, but sounded like the starter hanging up.

1) I know there were some alignment issues with GM starters.

2) I've seen the center broken out or flex-plates. Everything appeared normal until dis-assembled.

3) Did the torque convertor get seated properly? May be an issue with your front pump.

It sounds like metal to metal to me too. Pull the plugs and rotate the crank by hand, without the engine running it should be easier to hear where the sound is coming from.

[joedoh]

hi, sorry if this has been asked or answered, you said the torque converter wasnt bolted to the flex plate, but what if it was? loosely, I mean. did you find any bolts in there, like something that came loose and fell out?

to me, the video sounds like metal on metal squealing, like a bolt got stuck behind the flex plate.

[NeoJuice]

Originally Posted by DransportGarage

I really hate to be the bearer of bad news, but...

My guess is, the same brain surgeon that forgot the converter bolts didn't tighten the three timing sprocket bolts...and you can assume he's the same guy that did the rest of the engine. It's time for a full engine disassembly and inspection. At a minimum you'll be finding circular score marks on the inside of the timing chain cover, or something similar. To make yourself feel better about all of the work, check the torque specs on the bolts. They're probably all over the place. Leave the heads together, don't take the pistons off of the rods and leave the freeze plugs in unless you find something screwy or you decide to have the castings hot-tanked.

There's plenty of YouTube on the assembly (e.g., https://www.youtube.com/watch?v=UmIslf3ANTs), but if you're not comfortable with this level of work, do the disassembly yourself. Keep track of the location of EVERY push rod, lifter, piston, etc. Clean everything, then buy some steaks and invite a knowledgeable friend over for a Saturday of fun. Keep the beer in the fridge until your done. (Man, I wish I lived closer. I like mine medium-rare...)

Don't rent the tools until you find out what your friend will bring. Then go to AutoZone and they will lend you most of what you need for free.

Thanks for the video link. I'll be doing my research before I start to rip things apart. I'm still contemplating on what to do with the engine. I still have the guys phone number I bought the truck from. I was thinking of giving him a call to discuss the situation. But its not like he would be honest with me this time right since he already got his money. But it might be a little beneficial to hopefully get some more information out of him if he would be entirely honest this time. If I have to junk the block then it's junk. If it was truly rebuilt then there should be no problem right?

Hell if all it takes is some cold beer and steaks your a mighty good neighbor. I'm firing up the bbq now lol.

[NeoJuice]

Originally Posted by Driver_WT

Great advice. If you find two things that were not done right, there are bound to be many more. And if for nothing else, it will provide peace of mind and confidence that you know what you have after the engine has been gone through.

It might need an entire tear down I dont know yet. I have good oil pressure, I will do a compression test and check the plugs and go from there.

One thing that I did notice a long time ago when I went to turn the motor over before dropping the distributor in was the crank bolt was missing. It was also stripped out because I tried to put the proper bolt in and it would thread in then spin. So I bought a helicoil kit and drilled it out, tapped it and put in the proper crank bolt.

So there is a small indicator right there. He might have put in a new cam but in the process stripped out the crank and left it and removed the bolt.

As far as I'm aware in order to fix that issue you need to pull the crank and take it to a machine shop and have them re-drill it to a larger size and make sure it's straight. Hence tearing the motor down.

When we fired up the motor trying to figure out what the noise was we were looking at the belts the bottom pulley was shaking a little bit. So apparently I didnt drill it straight enough for the helicoil so i pulled the bolt out for now.

Thinking back on it the other dozen times we started the truck there was no issue before that I would have noticed. But could the crooked re-tap cause the crank to get all out of wack? Could it have damaged the balancer? now I have this noise?

Something to think about. Also I can put the bolt back in and out no problem because the hellicoil is holding but I dont think the bolt can stay in there permanently. Can you run the 350 without a bolt holding the balancer on? I mean it's pressed on so it should hold? Then the pulley bolts to the
balancer.

[NeoJuice]

Originally Posted by Black_Sheep

It sounds like metal to metal to me too. Pull the plugs and rotate the crank by hand, without the engine running it should be easier to hear where the sound is coming from.

I will give this a try to see if I can hear what might be going on inside the motor. If it makes it easier to turn over by hand I'll defiantly give it a shot.

[NeoJuice]

Originally Posted by joedoh

hi, sorry if this has been asked or answered, you said the torque converter wasnt bolted to the flex plate, but what if it was? loosely, I mean. did you find any bolts in there, like something that came loose and fell out?

to me, the video sounds like metal on metal squealing, like a bolt got stuck behind the flex plate.

There were no bolts in the torque converter at all. I had to go buy three new ones. I'm going to crawl under the truck tonight and do one more inspection but the mechanic said everything looked to be in order.

[dsraven]

a gasket set is fairly cheap, get a felpro or another good quality set. pull the engine and strip it down, check everything, get it all to spec and reassemble. torquing everything as you go. then you will have the satisfaction of knowing what you have plus YOU did it. that feels good all by itself. you can do it and you will learn something as well. lots of help on this forum if you just ask.
when you take stuff apart just remember to keep parts that wear in together, like lifters on cam lobes and pushrods on rockers etc, together. and then assemble them in the same position. if all looks good you can likely just reuse the rings and bearings so it will be take apart, check, reassemble with new gaskets.

[dsraven]

on the crank pulley deal, that vibration damper part is "pressed on" and needs to be "pulled off" but some guys will not put anything against the crank snout when they pull it off so the threaded end of the puller center bolt will extend deep into the snout's threaded hole and can rub against the inner threads of the crank and damage or strip out the snout of the crank. it may be that the threads were repairable before the bolt was attempted to be screwed back in. who knows. the other thing that can happen is the vibration damper is supposed to be "pulled on" the crankshaft snout. there is a puller stud/bolt that screws into the crank snout, the damper is slid on the snout of the crank and then a thick flat washer or thrust bearing is used against the front of the damper with a nut on the threaded stud/bolt is tightened to pull the damper onto the crank. without the proper tool some will hammer the damper onto the crank. this can damage the thrust bearing, the damper or the crank's snout, the threads on the damper's pulley retainer holes or can bend the damper a little so it doesn't run true. when you take it apart ensure to use the right tools and then use a dial indicator on the crank snout so you know if it is bent before the crank is removed or if sending the crank to a shop for checking make sure to tell them about the possible issue. if the helicoil was not installed straight it should have no effect on the damper running true, it would just mean that the bolt would not be flat against the flat washer holding the damper on. I suggest to use the bolt rather than run without it.

damper removal
https://www.youtube.com/watch?v=QORm5fnCvYA

installation
https://www.youtube.com/watch?v=R7BuijqjcUk

[dsraven]

also,pull at least one frost plug so you know if they were replaced as part of the rebuild. if not then replace them when the engine is out. trust me, it sucks to have to pull the engine or trans because a frost plug behind the flywheel has a pin hole.

[weim55]

Good for you to pay the $$ and get an experienced set of eyes and ears on the problem. I've spent most of my working years as a mobile construction mechanic. It's always baffled me people will spend $$ like crazy throwing parts at a problem but refuse spend $$ toward experienced labor to diagnose a problem first.

You mention you thought the sound might have started after you worked on the crankshaft to balancer bolt issue. Plus the mechanic found the noise to be in that area. From the information above here's what I would do: remove water pump to have good visual and next the crank drive bolts and pulley. Water pump could be hitting the timing cover or crank pulley bolts too long. Fire the engine, if the noise still exists, remove the crank to balancer bolt and grab the balancer with both hands and see if it is loose on the crank. I know this sounds silly to some but if the crank snout-balancer is damaged you've chased the problem to here. Perfectly OK to run the engine for testing without the bolt if the balancer is tight. Fire the engine again, if the noise still exists shut down the engine and look very carefully with a good light 360 degrees on backside of the balancer for good clearance between the balancer and timing cover. Any witness marks of the backside of the balancer rubbing something. This is very tight even when everything is perfect. A junk China timing cover has me suspect as would a used or junk China balancer. When you installed the balancer bolt and snugged it up the balancer it might have fully seated to the crank and caused the noise to appear you are trying to chase. Likely you'll find the problem in the above paragraph. If not post and we can dig a little deeper.

Second, ask the previous owner if the engine was purchased as a crate long block. If so I wouldn't be so concerned with removing the engine for a teardown- inspect.

Steve weim55 Colorado

[NeoJuice]

Originally Posted by dsraven

a gasket set is fairly cheap, get a felpro or another good quality set. pull the engine and strip it down, check everything, get it all to spec and reassemble. torquing everything as you go. then you will have the satisfaction of knowing what you have plus YOU did it. that feels good all by itself. you can do it and you will learn something as well. lots of help on this forum if you just ask.
when you take stuff apart just remember to keep parts that wear in together, like lifters on cam lobes and pushrods on rockers etc, together. and then assemble them in the same position. if all looks good you can likely just reuse the rings and bearings so it will be take apart, check, reassemble with new gaskets.

Noted. Thank you again DsRaven.