GM had a better idea and used American and metric nuts and bolts on their engines.
CK5
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Advanced timing ****ed my pistons
- Thread starter Kyle1983
- Start date
Blow-by can be caused by several types of failure, including just having an old, worn-out engine (which yours should not be). So it's easy to prove the opposite, that you can't have loose pistons without blow-by. But having blow-by may mean a chipped piston, cracked ring, a hole in the block, old worn rings, YaddaYaddaYadda.
And, yes, I'm referring to partially-burned EXHAUST gas blowing by the piston, not raw gasoline. Excuse my vagueness. Clean air blowing around is perfectly fine. A little bit of smoke is ok. Big, steady smoke is what you're looking to find (or hopefully not find).
We're all bench racing at this point, but based on what's been said I'd be looking at the top end. Listen for exhaust leaks first and valve train issues second. Third I'd listen to the flex plate. Combine that with the blow-by, and you'll have at least 4 new pieces of information for us. 
wasted wages
1 ton status
His engine runs pretty smooth, which leads me to believe that it has some issue not related to every cylinder firing... but advancing the timing and raising the idle speed can mask a lot of rough idle problems. Being there to watch it crank, start, drop off fast idle, etc. would all give clues to what is happening.
I once had a small block in my K5 that ran great...it started making a strange noise that got progressively louder... sounded like a loose rocker arm. It happened after I had wound the motor up really tight during a weekend of off roading.
After a week of driving, the noise was much louder, and I figured that I better look into it.
The noise was coming from the left side of the engine and the seemed to be a little blowby from that side as well. Upon first look of the rockers etc. everything looked ok, I cranked the motor with the valve cover off and it was immediately easy to see that exhaust was blowing up past a valve guide.
I had bent a rocker stud, and that caused the rocker to push sideways on the valve stem of an exhaust valve and wore the guide and valve stem to the point that everytime the cylinder fired it would "pop" past the valve
seat, up the worn guide and into the valve cover...
point is, it's going to take some detective work to trace down the source of the noise on the OP's engine... with a little time and help from the brotherhood, he should be able to get to the bottom of his problem.
I once had a small block in my K5 that ran great...it started making a strange noise that got progressively louder... sounded like a loose rocker arm. It happened after I had wound the motor up really tight during a weekend of off roading.
After a week of driving, the noise was much louder, and I figured that I better look into it.
The noise was coming from the left side of the engine and the seemed to be a little blowby from that side as well. Upon first look of the rockers etc. everything looked ok, I cranked the motor with the valve cover off and it was immediately easy to see that exhaust was blowing up past a valve guide.
I had bent a rocker stud, and that caused the rocker to push sideways on the valve stem of an exhaust valve and wore the guide and valve stem to the point that everytime the cylinder fired it would "pop" past the valve
seat, up the worn guide and into the valve cover...
point is, it's going to take some detective work to trace down the source of the noise on the OP's engine... with a little time and help from the brotherhood, he should be able to get to the bottom of his problem.
I made a list of things everyone suggested. I will get started on them as soon as I can. Can probably do most of it in a few hours.
Check blow-by
Check and tighten torque converter bolts
Check for cracked flexplate
Remove belts and run motor for a few min.
Remove plug wires one by one after startup
Remove spark plug and do compression tests check condition of spark plugs
use digital flex camera to inspect pistons
Tighten header bolts
Tighten header manifold bolts
Remove valve cover and inspect rocker arms
Anything that I missed?
Check blow-by
Check and tighten torque converter bolts
Check for cracked flexplate
Remove belts and run motor for a few min.
Remove plug wires one by one after startup
Remove spark plug and do compression tests check condition of spark plugs
use digital flex camera to inspect pistons
Tighten header bolts
Tighten header manifold bolts
Remove valve cover and inspect rocker arms
Anything that I missed?
If you aren't getting a lot of blow-by out of the oil filler cap opening with it running,then those tools are likely going to be a waste of money (unless you just want them anyways for future uses)..
..if the pistons were damaged even slightly,one of the first symptoms is lots of blow-by...and you'd see bits of melted aluminum on the spark plugs ,like that chart I posted earlier shows..compression would be lower,you'd notice it feeling like one or more cylinders isn't doing its share of the work,and there would likely be oil getting past the rings onto the plugs and making exhaust blue smoke..
I do not think your engine has piston troubles,something else sounds like its making the noise..the exhaust manifold or header bolts allowing exhaust to leak past them can make noises very similar to a bad lifter,loose engine parts as noted already,and the noise may go away after the engine warmed up and the parts expand and seal up the leaks..
..if the pistons were damaged even slightly,one of the first symptoms is lots of blow-by...and you'd see bits of melted aluminum on the spark plugs ,like that chart I posted earlier shows..compression would be lower,you'd notice it feeling like one or more cylinders isn't doing its share of the work,and there would likely be oil getting past the rings onto the plugs and making exhaust blue smoke..
I do not think your engine has piston troubles,something else sounds like its making the noise..the exhaust manifold or header bolts allowing exhaust to leak past them can make noises very similar to a bad lifter,loose engine parts as noted already,and the noise may go away after the engine warmed up and the parts expand and seal up the leaks..
Ok so if no blow-by, return the compression machine. If I have blow-by, use compression machine to see which pistons are damaged.
There is a exhaust manifold and then the headers. Which bolts should be tightened? Tightened with a cold motor or warm?
It is possible for a piston skirt to collapse and let it slap around without making much blow by,but in most cases if any piston damage happens you'll get at least some blow by..some engines had piston slap from day one,and run for years and thousands of miles with no real issues that way though too,and some GM engines were noted for that..
I'll let others tell you how to tighten the header or manifold bolts,I've only run cast iron stock manifolds and I've had to tighten the bolts back up after driving the truck some distance after a week or so..
I'll let others tell you how to tighten the header or manifold bolts,I've only run cast iron stock manifolds and I've had to tighten the bolts back up after driving the truck some distance after a week or so..
red EOD
1/2 ton status
For a camera (usually called a bore scope) get one of the cheap ones that plug into your phone, no point in spending hundreds of dollars on the big name models since those cheap ones often have a better picture.
All that blowby diagnoses is that there is compression gasses getting out of the cylinders where it shouldn't be. It's usually the first test done because it diagnoses whether there is a minor problem/not engine internals, or if there is a much more significant problem going on inside the engine.
Don't want to send you down the rabbit hole of 'check this/this/this/this.......' Gotta start at the beginning, and work from there. So blowby test, and take a look at the oil on the dipstick are the first 2 steps.
All that blowby diagnoses is that there is compression gasses getting out of the cylinders where it shouldn't be. It's usually the first test done because it diagnoses whether there is a minor problem/not engine internals, or if there is a much more significant problem going on inside the engine.
Don't want to send you down the rabbit hole of 'check this/this/this/this.......' Gotta start at the beginning, and work from there. So blowby test, and take a look at the oil on the dipstick are the first 2 steps.
that compression tool you ordered looks like a cylinder leak down tester. It may do both, but is defiantly a leak down tester. Which is not a bad thing, this tool will tell where your compression is leaking when/if you have a low cylinder.
The bolts that go through your manifolds / headers and into your heads. Make sure you tighten them when they are hot.
Yes that's what I bought. Guess I ****ed up.
So will it test the compression of the pistons because it said 100 PSI max. My pistons have to be around 150 right?
Yes both of those bolts.
Leak down is important as well and possibly more so than compression. Seen many times where a cylinder had good compression but bad leak down. Think of it as a more thorough compression test.
I would check something first, the noise you hear does it go away when it warms up you said or when you get off idle?
I have an engine that does that I thought it was a flexplate or piston slap,turns out it was a thrust bearing.
The flexplate moves in and out 1/4" with the crank
When it's idling it's noticeable then you drive it and can't hear it. Been driving it for 8 years waiting for it to fall apart but I should have fixed it a long time ago.
Easy enough fix
To check put a pry bar on the flexplate and try to move it back and forth.
It will also tell you if it is the flexplate.
But after hearing the video it sounds like my engine
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