[T3] lifters
Jim Adney
jadney at vwtype3.org
Wed Jul 23 04:57:37 PDT 2014
On 21 Jul 2014 at 21:02, Fiesta Cranberry wrote:
> We bought a scope to look up the pushrod tubes. What we found was that the
> affected lifters (1&3) were completely dry, while the unaffected lifters
> had plenty of oil on and around them. Tim @ Berg thinks the lifters may
> have collapsed.
Do you understand that the pushrods are hollow, and they feed oil
from the lifters to the rockers and rocker shafts? Once this oil
lubes the valve train, all 8 pushrod tubes serve equally as drains
for oil as it drains back down from the heads. If some of those
passages are dry, it may just reflect the slope that the car was
parked on.
I've tried to find a lifter here to look at and verify, but I haven't
found one yet. Once you get your engine apart, you'll see that each
lifter has 2 relieved grooves around it, and one of them has a hole
that leads into the inside, where it connects to the hole that leads
to the center that feeds the pushrod tubes. The groove with the hole
matches up with the oil feed hole in the side of the lifter bore in
the case, but I can't remember which groove that hole is in.
Berg can machine a slot between the 2 grooves, which allows oil to
feed from either groove. I believe this allows better oiling with
high lift cams, but it might explain why these lifters are dry, now
that the lifters have shifted position in the case.
You should also know that there is a gap in the lifter/pushrod bore,
in the case, where the draining oil can return to the sump. With the
engine running, I would expect some engine splash to get in there and
keep all 8 passages somewhat wet.
So, while I find your observation interesting, I'm not sure what it
means, and it's not clear that it's actually a symptom of your larger
problem. Once you get in there, you're going to find either lifters
with the faces worn away or cam lobes with worn high spots, or both.
The lifters can't really "collapse" (even though that may be the term
that is used) and the pushrods themselves don't ever wear shorter.
No matter what you find, we all understand your disapointment with
being caught up in this. Keith's almost certainly right that this is
a break-in lubrication failure, so this is a lesson for all of us.
--
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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