I added Sta-Bil and the engine started knocking. Uh Oh...

[Schurkey]

Sta-bill cleaned the crud off a valve (exhaust port valve, piston 7) and it was causing the rocker arm to rattle. Followed procedure to tighten, no more issue.

Unlikely.

If the rocker arm was loose, it is more likely a failing cam lobe/lifter.

 

[Hipster]

Unlikely.

If the rocker arm was loose, it is more likely a failing cam lobe/lifter.

agree

 

[JimFixes]

It's running like a dream now with zero issues.

 

[Schurkey]

It's running like a dream now with zero issues.

Excellent. Keep us posted if that changes in 5000--10000 miles.

Lifter preload should be good for the life of the engine. When it isn't, it's usually because the cam/lifters have failed. Other causes include rocker arm or pushrod wear. I suppose a potential cause could be that it wasn't set properly to begin with.

 

[PlayingWithTBI]

When it isn't, it's usually because the cam/lifters have failed.

^^^This. As an example, I had a lifter collapse and beat itself to death last year. I replaced it, set preload, and haven't had an issue since. Yes, I checked the cam lobe too, visually and with a dial indicator.

Here's what I found, left to right - the lifter from the cylinder next to the bad one, a new lifter, and the worn out one (note how it's dished too).

You must be registered for see images attach

 

[JimFixes]

^^^This. As an example, I had a lifter collapse and beat itself to death last year. I replaced it, set preload, and haven't had an issue since. Yes, I checked the cam lobe too, visually and with a dial indicator.

Here's what I found, left to right - the lifter from the cylinder next to the bad one, a new lifter, and the worn out one (note how it's dished too).

You must be registered for see images attach

Good thing I intend to rebuild soon!

current plans are a full tear down and rebuild outside the vehicle as part of a homeschool project showing the kids the operation and engineering of an ICE and how all of the many small parts work in tandem to move us down the road.

 

[Erik the Awful]

...just needs a longer pushrod.