Roller lifter life expectancy

[bevans6]

I participate on a board for 6.0 Powerstroke Diesels, and one issue that is starting to creep in as the engines get up over 300K is roller lifter failure.  Needle bearings get out, engine is trashed, needs full rebuild.  So I thought that one of the very first engines to use roller lifters (cam followers, I don't know what the correct DD name is) is of course our Detroit two stroke.  What is the word on failures of roller lifters on our engine?  Do they get lifed and changed out after so many hours/miles?  I honestly don't think I've every heard someone mention a roller lifter failure.

Brian

[c-coop]

the rollers in dd2 strokes do not use needle bearings they have a bronze bushing. very seldom do you see a failure

[bevans6]

Isn't that interesting!  To me at least, I need to get a life.  Bronze bushings would live well since the valve spring and injector spring loads are pretty low since the RPM is fairly low even if the cam is spun at engine speed, and the diameter of the cam lobe and the roller itself should be pretty big compared to a small engine with less room in the block, so the rotational speeds would be lower.  The end result when a roller lifter with needle bearings liberates itself is not very pretty.

Thank you for your response.  Do you happen to know if the lifters would routinely be replace at a major overhaul?

Brian

[Boomer]

That is correct, very seldom do you see one fail.  That said, I have owned and driven 2 strokes for over 40 years and I did have a cam follower fail once in a 12V71N back in the 80's.  Was not a happy outcome financially.

[Zeroclearance]

The S60 use a bushing with a ceramic roller on injector.  Steel on intake and exhaust.  The rocker shafts are coated with a moly graphite.   I replaced mine last season.