Rod knock on an engine with 4000 miles??????

[highperf4x4]

Originally Posted by americanmusc1e

to thin down 4 quarts of 20w50 (which i run because i have a flat tappet camshaft)

Your oil is only 20w. It's never any thicker than that unless it's extremely cold outside. That 50 only means that when it's "hot" is "equivalent" to straight 50w that's also hot. They use "fillers" to keep the 20w050 from thinning down much as it heats up. You sacrifice some lubrication for it.

I run straight 30w.

Also, thicker oil doesn't help a flat tappet cam. Lubrication and heat reduction does. A multi-grade oil has less lubrication than a straight weight oil. You can use a zinc additive if you're worried about the camshaft.