[T3] Max rpm

[Keith Park]

Ive seen those wear rings, but due to the push rod tubes
Not being straight.

That's an important thing you mention about checking the case, if things
don't close up properly you need to align bore, if its not too far gone, you
also need to use a bore gauge and check for roundness.

When you get the new bearings they also need to be fit them to the case
without the crank in there, bearing quality has gone way down and everything
needs to be checked these days, as Jim has mentioned this usually shows up
first on the #2 main first, the bad bearings can actually hold the case from
closing properly.   This cost me 10PSI oil pressure on the last T4 build and
that case had *supposedly* been checked by Raby.

Keith

Top Notch Restorations
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-----Original Message-----
From: type3-vwtype3.org-bounces at lists.vwtype3.org
[mailto:type3-vwtype3.org-bounces at lists.vwtype3.org] On Behalf Of Jim Adney
Sent: Saturday, April 05, 2014 9:35 AM
To: type3 at vwtype3.org
Subject: Re: [T3] Max rpm

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.

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

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