Just a tip on Cat C-15 that might apply to others?

ktmlew · October 21, 2009

Have one on an air-compressor that had mucho blow-by from the "road-draft-tube"...they got it so hot it quit and wouldn't start so we figured it was a good time to do an overhaul. Pulled it down to find a badly cracked head as expected but no apparent reason for the blow-by? Rings were well within spec for end gap, wasn't dusted, pistons looked great...hmmmmm?

So we replaced head, rings, liners (some looked suspiciously like it has had water in the cyls & had rusted), rod bearings & oil pump. Fired it up and when under load, still had mucho blow-by...or was it actually "blow-by"? Shop foreman thought it could be the turbo seal allowing boost to pressurize the crankcase through the turbo drain tube...I wasn't convinced and felt it was more likely worn ring grooves even though I had cleaned & inspected them (upper portion, ring land area of piston, is steel).

Replaced turbo and surprisngly "blow-by" is gone.

Who woulda thunk it? Posted Image

dieseldoc · October 21, 2009

We have seen that in our shop only one time as well. Our store came up with a test kit to bypass the turbo drain line during blow-by tests on the dyno. I dont remember for sure how it works since I havent used it in a while. We had another store in our company with an air compressor that caused a similar issue. If I recall correctly another dealer down south somewhere overhauled the engine for oil consumption. It came in to us with the same concern. 2 gallons of oil was found in the air tanks and the air drier was full of oil as well.

Keith Browning · October 21, 2009

I was going to say wouldn't that also cause oil in the air tanks?

Great post Gail! It's an obscure fault for sure.

LARRY BRUDZYNSKI · October 23, 2009

Had a similar situation not long ago on a 3406E in a class 8. Sold the o/haul parts plus a head and had the similar oil usage, only to find that the air compressor for the brakes was pumping oil into the air system. Really tough to convince the customer that the o/haul was needed until we showed the cracked head and the cavitated liners to him. Needless to say we get the air compressors checked every time one comes in to be rebuilt now.

ktmlew · November 1, 2009

This is an air compressor used for drilling into coal to de-gas the formation. The most common builders are IR & Sullair. This one was built in-house...the drillers call the two "home-grown" compressors No-air & Less-air...

Jeff Adema · November 3, 2009

I've seen that particular failure before a time or two, at least on Detroit Series 60's. When I worked at the DDC/Allison dealer we'd work the snot out of them on a chassis dyno, and monitor crankcase pressure, etc. with a manometer. Sometimes you're lucky and you'll see oil residue in the CAC piping, pointing you towards a failed/failing turbo seal. Sometimes you're unlucky and you catch something in your zipper.....

ktmlew · November 4, 2009

One of the C-15's in the PowerPack threw the flywheel off over the weekend...800 feet from the bottom of the 7000' hole...these engines where installed long before I was hired. First time they were started I mentioned the one being so noisy and that it sounded like the flywheel was loose. Just got dumb stares from the engineers that built it...

Now the lead engineer is trying to figure-out a way to replace the crank in the field...he tried to get a guy to weld the flywheel on...having a Masters degree doesn't make you smart huh? Fortunately for me I quit the day before the thing came apart. Realized I was in the wrong place and got out-of-dodge before the shootin started...