Carbon build-up on inlet valves?

[Ratau]

When I stripped the cylinder heads off my Blazer I found lots off carbon build-up 2-3mm thick on the inlet valves and almost nothing on the exhaust valves. Could this be the oil vapor from the CDR system? Does this mean the CDR is not working properly :confused:

I found Donaldson's SPIRACLE crankcase filtration system that look promising. Check it here: http://www.donaldson.com/en/engine/support/datalibrary/002509.pdf

[BobND]

Most likely, the oil you're seeing is due more to the engine having a lot of blowby than due to a bad CDR.

In normal operation, the CDR is simply open, an open passage for the crankcase vapors from the crankcase to the intake, or in the case of a turbo'ed engine, to the turbo inlet.

Only in the case of a restricted air filter that causes the engine to be sucking HARD on the CDR does it begin to close, to prevent drawing a vacuum on the crankcase.

The CDR is NOT an oil separator, just a protective device for when there's a plugged air filter, so if there's too much oil-laden blowby, it simply passes through, on it's way to the intake.

The 6.5's have a crude oil separator... a wad of steel mesh in the valve cover, ahead of the CDR.

That Donaldson unit you found looks like a GOOD idea. Did you locate a selling distributor, and get a price?

[BobND]

I did some research on the Donaldson Spiracle units, as they look like a good idea, especially for turbo'd and aftercooled engines, to keep oil in the crankcase, and OUT of turbos and aftercoolers.

The truck dealer partsman I spoke with called Donaldson, and was told the smallest of the three units (which is probably the appropriate size for our pickup truck engines) is proprietary to John Deere, and you can only buy them through John Deere Parts. He did not know what Deere product was using them, possibly gensets, and a person would have to figure out where they are used to get a price from a Deere dealer.

The larger two units are available at a cost of over $500.00 each... WOW!... for a little plastic filter housing!

Did you check on any sources for them?