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Knocking nosie comin from the flywheel/starter area

well wasted wages,
That did it! I replaced the PCV valve and installed a breather in the valve cover. The engine idles much smoother and I have no more leaking pressure sounds.

I will plan on replacing the intake gaskets next month when I replace the carb with an edelbrock 650.

Thanks a bunch guys, this one is resolved!
 
The breather cap he posted will work fine, and ran on engines for decades.
But, it only has a screen and maybe some steel wool for a filter.

Several years ago they came out with a better way. Check the junkyards. The best way is a hose that hooks to the fitting on the cover and goes either to a small separate filter in the air cleaner, or to a port inside the main filter so that it only sees well filtered air.

If you only do highway driving, a little oil sprayed on the screen of a breather cap will do pretty good.
But, it it sees offroad dusty conditions, you need to have a better filter so that you are not sucking dust and grit into your engine.
 
Ok this is drivin me crazy, I pulled the starter checked it, all looked good, made sure all the bolts were tight, and re checked everything. It still knocks. I dont get it, Sounds like something in the torque converter came loose. As soon as you rev the engine it goes away. Any thoughts? Here is a quick video

 
I have the same knocking and I have ruled out everything discussed in this thread and we narrowed it down to Bearings or thrust bearing to be exact.
If I rev it a bit the noise goes away, it also almost goes away when the engine warms up.
While driving I do not hear it till I stop and idle or I am coasting in neutral.
I am driving it as is for now since I don't care about the engine and as long as I am not more than 100 miles away, I can get a tow with AAA:dunno:
Budrun said:
Ok this is drivin me crazy, I pulled the starter checked it, all looked good, made sure all the bolts were tight, and re checked everything. It still knocks. I dont get it, Sounds like something in the torque converter came loose. As soon as you rev the engine it goes away. Any thoughts? Here is a quick video

Click to expand...
 
imiceman44 said:
I have the same knocking and I have ruled out everything discussed in this thread and we narrowed it down to Bearings or thrust bearing to be exact.
If I rev it a bit the noise goes away, it also almost goes away when the engine warms up.
While driving I do not hear it till I stop and idle or I am coasting in neutral.
I am driving it as is for now since I don't care about the engine and as long as I am not more than 100 miles away, I can get a tow with AAA:dunno:
Click to expand...


Well when the truck is cold there is no noise, once it get to temp then it starts knocking like that. Sounds like its in the converter.
 
Flexplate noob question...not hijacking...since I have the engine out should I just go ahead and replace the old flexplate with a new one? Just had the trans rebuilt and new torque converter....:dunno:
 
Imiceman,
Are you sure the tranny is bolted up good to the block? That sounds like the exact issue I was having.

Also have you checked your tranny fluid level and made sure your filter isn't clogged?
 
Chief,
Please replace the Flexplate while you have everything out. I wish I knew that mine was brand new and in good shape. For 50 bucks you can get a good one too. Trust me... When it comes to narrowing things down, it is good to know where you have trustworthy components.
 
cameronsaddress said:
Imiceman,
Are you sure the tranny is bolted up good to the block? That sounds like the exact issue I was having.

Also have you checked your tranny fluid level and made sure your filter isn't clogged?
Click to expand...
I would check the bolts again, but the tranny is a fresh rebuild and it started a few weeks after the rebuild I was told.
I bought the truck as is with the knock and I had assumed it would be a flexplate or bolts issue, not so unfortunately.
I did check the crank and it does move back and forth more than it should so I am pretty sure it is the thrust bearing.
 
Chief Brody said:
Flexplate noob question...not hijacking...since I have the engine out should I just go ahead and replace the old flexplate with a new one? Just had the trans rebuilt and new torque converter....:dunno:
Click to expand...

I would give it a good inspection, looking at the bolt holes and look at the teeth. If they are rounded off, replace it.
 
I don't know if you can see this in the pictures or not but mine is badly warped:


HOOD01DSC_0005.JPG

HOOD02DSC_0006.JPG

HOOD03DSC_0007.JPG

HOOD04DSC_0008.JPG
 
How do I know which one to get...there isn't a single number stamped on this one...:dunno:
 
On Summit or jeggs you can do a model year specific search. lmc truck has them too. Have you checked your local auto parts store?
 
cameronsaddress said:
On Summit or jeggs you can do a model year specific search. lmc truck has them too. Have you checked your local auto parts store?
Click to expand...

yeah...standard models about $19.99 and heavy duty is at least $82.00
 
You've probably already checked it,
but I know of a guy that had a similar sound,
and it was the trans cooler lines vibrating against the oil pan of the engine, at certain rpms.
 
Geez! 77 posts later and all these posts count for nothing?

Take it to a mechanic and let him listen to it. Or take a video and post it here. It can be hard to diagnose a motor without a video or actual in-person status. Most of us here gave you suggestions and ideas from our opinions. Didn't you check them out?
 
Ok this may sound weird but i had the same problem for a few months just after i fitted a re-built th350,it was nothing to do with the flex plate or tranny,it was the dam distibuter cap! When the tranny was removed it being a big block the engine sits very close to the bulk head especially the dizzy cap!when the tranny was removed the engine was tilted back and the cap at the back poped up a bit, i had no idea what this sound was for months even took it a pro to check my valve clearences!
Any way long story short check the dizzy cap.
Cheers Simon.
 
It sounds alot like rod or wrist pin knocking in your video...

You say it goes away as soon as you rev it and only when warmed up? Hows the oil pressure?


Try this: warm up the engine till it starts knocking, rev it to see if the knocking goes away as usual. Shut engine off, Then unplug the Number 8 spark plug, start engine again and rev it to see if the knocking still goes away like before. Repeat proceedure with Number 7 spark plug.

If unplugging any of these spark plugs changes the way the knocking sound behaves...you have a bad rod bearing or wrist pin/piston.


EDIT: after closely looking at the video, I realized that the knocking sound happens every OTHER revolution which can still be a wrist-pin (knocks during the power stroke) or stuck/collapsed lifter. I still recommend trying the method above.


Badrun's video http://s30.photobucket.com/albums/c335/Budrun/Blazer/?action=view&current=IMG_0534.mp4
compared to:




.
 
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