[Vwdiesel] Ring Break-In and Oil Consumption
val at swamps.roc.ny.us
Mon Feb 28 14:24:49 EST 2005
OK, I'll chime in. I've rebuilt as many diesels as gasser engines. With
one exception the diesels were all VWs. I'd have to sit down and look
at my maintenance records, but I'll guess between 11 and 13 VW diesel
re-ring jobs, either with glaze-breaking, or a re-bore.
First, the surface should be rough, as most stones will leave it.
I'm sure Gavrik did it, but the bore should be THROUGHLY cleaned
prior to assembly. I use a nylon brush, and water soluible cutting
fluid, with some detergent (as a wetting agent). Dawn works fine.
Simple green does also. After cleaning, a coating of motor oil applied
with a rag or paper towel is just fine.
Ring sizeing is important, as in cleaning and checking the dimension
of the ring lands. I'll file rings so that they are on the smaller
end of tolerance...each and every one. I figure that way I can get the
max amount of wear out of the rings. The rings get motor oil on them
when they get compressed. No grease, so Slick 50, no STP.
Regarding oil, over the last 30 years I've had access to tribologists
who are nationally recognized in their field. Countless hours have
been spent discussing (and getting taught) about lubrication and
the phenomena which occur with lubrication. Their advice 30 years
ago, and today remains that normal engine break-ins should be
performed with mineral oil. Detergent is not needed. Multi-vis
is not desirable, EXCEPT where environmental conditions demand it.
Artic or sub-artic breakings might qualify.
Multi vis oil has a large volume of VI, and that percentage goes up
with the spread. Years ago (30) , I took a can of 10W50 STP oil, which I
though was great stuff, with a wide vis spread. They analyzed it and
showed me just how little of the can was oil, Like 64% or some such
number. Performance testing the oil in a test jig showed how
the service characteristics of the oil were measureably different
from even cheap straight weight oil, under the right circumstances.
Avoidance of detergency is not a big issue, but the thought is that with
straight oils, there are less film strength improvers. The VW diesel
does not require EP lubes due to high contact forces, and a NA
diesel is well within the range of mineral oil temps. The VW diesel
is not a very high speed engine, nor is it a high temp engine, as far as
engines go, so there really isn't the need for anything other than
a straight weight mineral oil, with minimal additives.
During breakin, oil should be added in 1/2 qt increments, and the sump
be kept at it's upper limit.
In this instance, I would revert back to a light straight weight oil,
which would probably be a SAE 30. (The truth is, if it were my own
engine, I would use a SAE 20, which ould work just fine in the temps
we have here (below 40F). Run the car hard, without sustained full
power operation, and varying power requirements on the engine. Do
not run high RPMs without load on the engine.
Dispersant oil is OK. Detergent oil is not apporved in aviation engines,
and offers no real advantage in break-in. The oil should NOT have
anti-scuffing additives, or any EP additives.
The most important aspect of break-in is the seating of rings to the
cylinder bore. Failure of that process results in the requirement to
de-glaze (disassembly) or use other despirate measures (Bon-AMI).
In Garvik's situation, he may have glazed cylinders, and light weight oil
without film strength improvers, extreme-pressure and anti-scuffing
additives is indicated.
Run the vehicle hard, without extended full-power and varying the RPM.
Put time on it. If you can't get the oil consumption lower, you can
escalate to disassembly or other measures.
If you have porous chrome plated bores, rules are different. If you have
high pressure cams and lobes, the rules are different. If you're running
nickel composite (Nickel+Carbide) then the rules are different.
Sorry about the repitition (numerous interrupts). I'd run the light weight
oil, and cut open the filter after 500 or 1000 miles, and see if you have
some new debris.
> Gavrik Peterson relax NOTHING drastic is going to happen.
> I am not and Never was a mechanic ---- BUT the number of coffee breaks =
> and beers after work
> with THE MECHANICS ? ----did something rub off ? .
> I found that the flyboys got the ringseating ---pinned right down.
> Loren mentioned long time ago that to get a gasser shop to fit a VW =
> diesel piston
> with small gap was difficult ----to get a flyboy mechanic to fit it is =
> Aircooled Aircraft fitting would be considered limit of wear for a VW =
> diesel mechanic in Germany.
> I just had an old friend die ---- who designed a diesel many years =
> ago so let me get over the
> grief and I shall explain what I found out about ringseating. He =
> was a nabor and became
> a good friend early 1960 es. 1962 ? .
> Summary ? make the crosshatch DEAP ring gap SMALL and pistons =
> TIGHT in bores.
> And stagger ring gaps. ---I am a flyboy type and lots of the ringjobs =
> I did was aircooled
> AC engines. -----so I have a problem getting those pistons tight . BUT =
> remember they are
> spcial pistons. ----not gasser pistons. --------- wait to we get =
> chromed cylinders then the fun starts.
> I have seen Gavriks engine and it is a beauty ----all painted and =
> CLEAN. And it sounds good
> with NO SMOKE here. Pump a tad too advanced. If you Gavrik drove =
> that Rabbit from day
> one like you did here ??? ----fuddy duddy driving is NOT the problem.
> Let me tell you all he drives a lot more agressive than I do.
> More on this ------when I recover.
> PS : May 1945 I got my sticky little finger on my first REAL =
> diesel Jumo 205 I
> think it was.------ is that not 60 years ? --- right now that plane =
> and engines are in
> a museum ---in Denmark. 3 engine flying boat. "Anders And" Donald =
> Duck..(in english).
> Vwdiesel mailing list
> Vwdiesel at vwfans.com
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