Date: Tue, 22 Aug 2000 08:17:09 -0700
Reply-To: Stuart MacMillan <macmillan@home.com>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <macmillan@home.com>
Subject: How an oil gauge can save your engine-was how to throw a rod
Content-Type: text/plain; charset=us-ascii
Mark,
No, the nuts cannot be re-tightend, they are "torque to stretch," and
once torqued they are stretched and set. If they were torqued again,
they would break in short order, because they would be stretched beyond
their limits.
You are a perfect candidate for an oil pressure gauge. Here is how you
use it: Figure the minimum pressure you should have on an engine with
good bearings is 10 psi per 1000 rpm, which means approximately 9 psi at
idle and 30 psi at cruising speed. Pay particular attention that
pressure at idle stays around 8 to 10 psi, especially when the engine is
hot from a long run on the freeway. Worn bearings will typically lower
the idle pressure more than the cruising pressure.
So, when your cruising pressure starts to drop below 25 psi and your
idle pressure below 8 psi, start the savings plan, this indicates
excessive bearing wear. If the idle goes below 4 psi, and the cruising
below 12 psi, stop driving (preferably WELL before this point, my
mistake was that I kept driving)!!! Also note: If the pressure drops
significantly from it's normal levels and into the danger zone while
climbing a long grade, that is also a good indicator that your bearings
are starting to wear beyond normal tolerances.
The comfort and security you will gain from understanding what the gauge
is telling you is worth far more than the cost of the gauge! It is not
just the cost of the core, it will be the difficulty of finding and
shipping a new engine, the oil covered mess your van will be that you or
your mechanic will have to clean up (at $60/hr), and the risk of
breakdown in a dangerous situation that you will also avoid.
I'll be installing my sender on the new engine tomorrow and will send
Tom some pix he offered to post, so that might help you some.
Mark Dorm wrote:
>
> Hey my PO did the head gaskets - any chance these nuts were tightened then -
> I have 108K miles on a 2.1 and bought it with less than 90K. Also: if I have
> an oil pressure gauge - exactly how is that going to help me? Is it just
> going to save the cost of the core ($500) or will it do more???
>
> >From: Stuart MacMillan <macmillan@home.com>
> >
> >Well, I disassembled the poor 2.1 engine I destroyed a week ago, and it
> >turns out the rod failure was indeed caused by a rod bolt, but it did
> >not break, the nut came off! This could only happen from "bolt stretch"
> >that allowed the nut to loosen and eventually come off.
> >
> >I'm with Bob Donalds on these bolts causing the vast majority of 2.1
> >catastrophic failures. The "torque to stretch" rod bolts used in the
> >2.1 are USELESS, and even worse, a time bomb sitting in every stock 2.1
> >engine just waiting to go off and cause total destruction. I don't know
> >if they offer any assembly efficiencies for the manufacturer or are just
> >a "planned obsolescence" device.
> >
> >When one of the #1 rod nuts came off the bolt did too of course, and it
> >was thrust up through the top of the case by the crank counterweights
> >where it was embedded, hence I was able to recover the bolt and nut and
> >know it did not break. After that #4 got hit by some shrapnel from the
> >rod and the cylinder fractured, taking out half the cam along with it as
> >well as knocking two more holes in the top of the case. The resulting
> >oil/coolant emulsion was then sprayed all over the engine compartment.
> >I took me all day Sunday just to clean things up in preparation for a
> >new engine.
> >
> >So, I cannot stress this enough: For those of you that have a factory
> >2.1 with more than 100,000 miles on it (the consensus is these engines
> >are good for between 125,000 and 150,000 miles) I strongly recommend
> >that you do two things:
> >
> >1: Install an oil pressure gauge!!! This will tell you more than
> >anything else about the condition of the bearings in your engine, and
> >can help you avoid catastrophic failure. 2: Start a savings plan for
> >that rebuild BEFORE 150,000 miles, and make sure that the "stretch to
> >torque" rod bolts are not used in the rebuild, substitute the
> >conventional 1.9 engine rod bolts.
> >
> >Rebuildable 2.1 cores are getting scarce for this reason. If you
> >destroy yours it not only will be difficult to find another engine, but
> >it will cost you the core charge as well, at least another $500.
> >
> >I have some interesting pictures of the remains of this engine, I'll
> >send them to anyone who would like post them on their web site if there
> >is any interest.
> >
> >--
> >Stuart MacMillan
> >Seattle
> >
> >'84 Vanagon Westfalia
> >'65 MGB (Driven since 1969)
> >'74 MGB GT (Restoring)
> >
> >Assisting on Restoration:
> >'72 MGB GT (Daughter's)
> >'64 MGB (Son's)
> >
> >Parts cars:
> >'68 & '73 MGB, '67 MGB GT
>
> ________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
Good luck!
--
Stuart MacMillan
Seattle
'84 Vanagon Westfalia
'65 MGB (Driven since 1969)
'74 MGB GT (Restoring)
Assisting on Restoration:
'72 MGB GT (Daughter's)
'64 MGB (Son's)
Parts cars:
'68 & '73 MGB, '67 MGB GT
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