Very interesting, Ford lifters. I would be a little surprised if those were put
there by Rotax in Austria! I will ask someone with Rotax experience and get
back here. I know old american V8's mostly.
The Rotax service manual's & parts catalogue show very conventional lifters
without
those Ford part numbers, actually when I looked that Johnson HT-900 I get
a aftermarket part. Made in USA , they claim to be best in the world.
Looks like that one lifter was not always rotating, on most flat tappet engines
the cam is taper ground, this should be visible in the cam wear pattern. When
the lifter rides the lobe it will rotate if all is well. The taper will wear
off on the nose of the lobe first but it will still rotate unless the whole lobe
is worn down.
Pull the valve covers on a engine and run it, if some push rods are not rotating
or some are rotating slower, you have a problem!
Some engine's offset the lifter from the cam lobe instead of taper grinding the
cam, they still rotate.
If the lifter had corrosion or deposits on the lifter body it would be hard to
remove, and may not rotate.
Was reading about a guy in Australia who sent his 912 cam to Melbourne for
regrind
after 1800 hrs. and re-nitride (surface harden) and bought new lifters. Your
cam should be good with only 100 hrs. though.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511403#511403
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