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Re: [T3] Number four failures...


<x-flowed>Probable causes:
Worn case: line-bored cases don't last like a new one;
Compression too high (<7.5:1) either this time or in this case's earlier life;
90's are risky in anything but a Bug;
What oil wt was in use?
Did you ever monitor the oil temp?




----- Original Message ----- From: "Frank Meek" <ftalker@hotmail.com>
To: <type3@vwtype3.org>
Sent: Thursday, June 01, 2006 10:23 AM
Subject: [T3] Number four failures...



The number four bearing has failed on two of my T-3's engines...one on a factory FI '69 with 120K on it and another on a rebuild, (76X90,5 stroker) at 90K, that took the left side bearing saddles with it. They actually fell out, (cracked at the bases), as I lifted the crank out. The bearing had completely dissolved.
These two very different engines with different setups shared two similarities: first, declining oil pressure, precipitously so in the final 5K of their "lives."
The stock motor had no oil filter and its oil changes were regularly under 3K. The stroker did have an oil filter and external cooler and shared a similar oil change schedule. I did not forget to blow out the passages on the rebuild...and hey, it lasted 90K.
But, oil pressure was an issue and it is my empirical guess that despite having "plasitgaged" the crank on the stroker rebuild that there were other rebuild-related issues either with the case or the crank or the rods, (each of which was machined at a very reliable race shop). I am guessing the rods on the stroker and general wear on the factory motor.
Also, the second similarity that these failures shared was mountains: the factory engine failed (it got so hot the crank broke in two...I have never seen this in any VW), climbing out of Denver heading west in the summer. And, the second failed going up Teton Pass (10% grades), also in the summer.
Another supposition is that on the flats both of these motors would have lived considerably longer.
So, while I can't contribute a "reason" for these curious number 4 failures, I can suggest that these may well be T-3 idiosyncrasies worthy of further investigation. It should be noted that I also have a '63 T-1 and a '65 T-2...never a problem with number 4.


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