[T3] Max rpm

[Jim Adney]

On 5 Apr 2014 at 8:08, Dennis Stiefel wrote:

> The first 1641 (stock bottom end) I had in her took it up to 60 MPH in 2nd
> gear. Of course that engine didn't last but a year and a half. Death by 18
> year old.  I still to this day wonder what the RPMs were.

It's rather easy to tell an engine that's been over-revved when you 
take it apart. 

The first thing you find are little brite wear rings on all the 
pushrods. That seems puzzling at first, because there's nothing that 
they could touch, but then you realize that if they started to flex, 
as in bow out under compression, there are several places where they 
can touch. Touching like that on a regular basis will leave a shiny 
ring where the usual oil darkening has been worn away.

When you split the case halves, you'll find the #2 main bearing worn 
excessively. Once I clean up all the parts, I like to put the 2 bare 
case halves back together and check to see if the 2 halves of the 
center web, the ones that support the #2 main bearing, still come 
back together without a gap between them. It should not be possible 
to get any size feeler gauge in there.

I've seen cases where there was more than 1 mm of gap, even with 
those 2 center main studs fully tightened. Any chance you might have 
of reasonable oil pressure gets lost when the oil can spill out like 
that.

A counterweighted crank will keep that from happening at almost any 
rpm.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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