Engine Diagnosis

[FINOCJ]

The two cylinders that were slightly low compression are on the left bank...clack seems to be from the right.
Two overhead valves per cylinder but not OHC.

[Jim]

I'll volunteer a hand, Saturday, to help find out where the clack is coming from...

[flashboiler]

Reading thru this thread I'm thinking you flatted a cam lobe or two...

[Jim]

My thought as well. Since the camshaft might not be readily visible, measuring pushrod travel might be in line.

My OHC Honda v4 motorcycle motor toasted one cam lobe 850 miles from home. It made a LOUD RACKET - and operated otherwise flawlessly - all 850 miles home. Heads always turned when it started at the gas station.

www.JimWilliamson.net/motorcycle/2006-09-25-cam-issue/

[FINOCJ]

flashboiler previously posted:

[Hypoid]

FINOCJ previously posted:

[FINOCJ]

Hypoid previously posted:

[Spieg]

I could be wrong (often am), but in my experience a worn cam wont make noise like your engine does. It just fails to open the valves completely.

[FINOCJ]

Spieg previously posted:

[Patrolman]

Would it help to just have the engine turn over with the starter with the valve covers off? Shouldn't hurt anything without any oil in it. Just make sure to unhook the ignition system.

[Jim]

This motor has hydraulic lifters?

I could see measuring pushrod travel distance for each one (an assistant to wrench crank the no-spark-plug motor through one rotation of each cam lobe while you measure travel) - and then pulling out the lifters if they easily pull out - to inspect the bottom of each lifter.

[Hypoid]

Push down on the end of the rocker that has the push rod. You just might find a spongy lifter.

[dieseldoc]

More likely a collapsed lifter.
A cam will wear but not offten leaving a sharp lobe.
Generaly they get shorter in duration and lift.
Offten 1 or 2 cylinders will have an issue.
Cam is not to bad a thing to do. The bearings is the hard part of the job as they have to push in a good distance.
If you need go as far as a cam you may as well have the thing rebuilt completely and get the compression up and even.

[FINOCJ]

Update - oil pan and other stuff removed to view the crank. The oil pick-up screen wasn't filled with pieces of metal, but rather quite a lot of a silver shiny gunk. Actually, the bottom of the oil pan as well as what settled to the bottom of the plastic pan I drained the oil into has sort of light gray/silver sludge. There is also a bit of a unique smell - not quite oily but more like burnt metal (kind of like a welding smell). Its sort of like a graphite or lead in the sense that it smears on your finger and hand when you try to wipe it away. Maybe it was a lead additive some PO put in or maybe it was some sort of engine break in (zinc?) additive from after a rebuild? Or the microscopic metal shavings from something like a lifter? I've changed the oil quite consistently over the last few years myself and never noticed it before in the drain pan but its most prominent in the bottom of the oil pan and I've never taken that off before.

Looking at the crank etc - all seems fine to the initial untrained eye. No obvious missing bolts etc. I tried pulling and moving stuff by hand, can't get anything to move up or down. I assume there is some sort of bearing at the bottom of the connecting rod - these I can move forward and aft along the crankshaft a mm or so. None of the piston skirts look to have any damage, nor any part of the connecting rods that I can see. I do need to try and turn the crank by and watch some new things come in view - can then get better view into #3 and 5.

Here some pics just for reference:
crank blocks view into 3 and 5


#3 below


#6 below


#1 (right) and 2(Left):

[Spieg]

Is the sludge stuff magnetic? If not, it's probably just built up crud that I wouldn't worry about too much.

On a side note; I like to run a diesel oil for about 1,000 miles every couple of years. The extra detergent does a great job to flush out the carbon deposits and other junk.

[FINOCJ]

Spieg previously posted:

[Jim]

Small tip: If you're using a magnet to test for metal bits to be magnetic - place the magnet into a plastic baggie with metal bits outside of the baggie. If the bits are magnetic you won't have to pull them off of the magnet / you'll have a clean magnet.

[FINOCJ]

True - I am always cleaning the magnetic base for my mechanics light that seems to find every piece of metal fillings in my garage!

[dieseldoc]

Hmm I didn't want to say it but connecting rod may have spun a bearing.
Crank is less likely the culprit.
If you are even slightly thinking of taking it to someone, now is the time.
You are not to far into it so not to much is disturbed by trying to find the issue.

The stuff in the pan is it still in said drain pan?
I can have it tested to give some idea of what is in your oil.
This will take a few days but if you really want to know we can figure out getting a sample.

[Hypoid]

FINOCJ previously posted: