Date: Sun, 15 Dec 2002 15:12:15 -0600
Reply-To: John Rodgers <j_rodgers@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <j_rodgers@CHARTER.NET>
Subject: Re: Top Overhauls
Content-Type: text/plain; charset=us-ascii; format=flowed
Bob, thanks for the input.
Question. Can the 2.1 rods with their inherent bottom end weakness
(elongation) be replaced with a different rod? If so, what?
TIA,
John Rodgers
Robert Donalds wrote:
> John and Fellow vanagon types
>
>
>
> the aircraft guide lines are always an inspiration and are intended for
> a zero failure rate. To compare that to a van engine's use and intent is
> great concept and one that I try to employ. I also do my best to have
> a zero failure rate because it is always cost effective to do it
> correctly the first time.
>
> In the aircraft you don't have the option of pulling over and
> calling the tow truck on the other hand in a van as long as your AAA
> membership is paid up you only have to wait until they show up and then
> figure how to get yourself and the grocery's home. The other things that
> comes to mind when comparing aircraft engines to vanagon engine is the
> ability to monitor the engine vitals signs, load and the difference
> in the sustained RPM. The fact is that the vanagon engine lives most of
> it's life at twice the RPM as the average aircraft piston engine. The
> load can also be well in excess of the intended limit and the driver can
> remain clueless until the engine fails. these things tend to make this
> somewhat of an apples and oranges comparison .
>
>
>
> The question I think John as getting to is what is an effective
> repair balanced against cost and the possible consequences. Vanagon's
> have two types of lower end the 1.9 engine has a type one bug style
> bearings. The 1.9 one piece bearings are a molded and machined aluminum
> coated with a protective flash coating. All of the larger 2.1 (# 1
> threw $3) main bearings are a rolled trimetal composition bearing and
> they tend not to work lose in the case. The 2.1 and the 1.9 are
> completely different in durability of the lower ends because of the type
> of main bearings used. The 1.9 engine needs lower end work the 1.9
> always needs align boring and fresh bearings due to main bearing working
> itself loose in the case and losing its press fit (crush) as the case
> and the bearing wear out over time. The 2.1 engine rarely has any main
> bearing issues to speak of other than the main bearing bore distorting
> due to excessive loads (towing large boats and the like for long
> distances). The other difference between the two lower ends is the rod
> bolts specifically the distortion of the large end of the 2.1 con rod
> over time that leads to increased bearing clearance, low oil
> pressure and that extra vent hole in the
> case. http://www.bostonengine.com/articles/low-oil-pressure.htm
>
> The top end replacement does add some stress to the lower end not
> always due to increased power as you might expect but to increased heat
> (oil temp) due to the ring drag and restored compression.
>
> To sum it up these are not the only problems I have seen with WBX lower
> ends but they are the most common. High mileage 1.9s engines (as most
> are at this point) need lower end work and case machining to be brought
> back to correct specs clearances and bearing crush.
>
> 2.1 engines need at a minimum to have the rods replaced with properly
> rebuilt units when you do a top end.
>
> The things that separates the reassemblers from the successful
> rebuilders is the ability to properly measure and correct the crush and
> clearances plus the experience to know what works with a willingness to
> have quality without compromise every time.
>
>
>
> going faster miles an hour
>
> and standing by
>
> I remain
>
>
>
> Bob Donalds
>
> http://www.bostonengine.com
>
> as always
>
> all rights reserved
>
>
>
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